Second-generation Tyrosine Kinase Inhibitors Research Articles

Dynamic Changes in ABL1 Kinase Domain Mutations and Comparative Efficacy of Third-Generation Tyrosine Kinase Inhibitors across Different Stages in Acute Lymphoblastic Leukemia and Chronic Myeloid Leukemia Blast Crisis Patients

*Drs.Zixuan Li and Danyue Peng contributed equally. Drs.Mei Hong and Qiuling Wu are co-corresponding authors Background The development of first-generation and second-generation tyrosine kinase inhibitors (TKIs) has played a crucial role in the treatment of Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) and chronic myeloid leukemia (CML). However, the emergence of mutations in the kinase domain (KD) of BCR-ABL1 has increasingly compromised the efficacy of TKIs and become the primary cause of TKI resistance. Testing BCR-ABL1 KD mutations in early phase accurately is of great value in predicting response and guiding therapeutic decisions. Next-generation sequencing (NGS) provided a more comprehensive and elaborate understanding of mutation status. Third-generation (3G) TKI has been designed to overcome resistance problems caused by BCR-ABL1 KD mutations, and it exhibited unique pharmacological profiles and response patterns relative to different mutations and disease characteristics. Therefore, the potential clinical relevance of mutations detected by NGS and the efficacy of 3G TKI are worth exploring. Methods NGS was used to analyze the dynamic changes of both clinically unreported mutations and reported resistant mutations in the ABL1 KD during three stages of the disease course (pretreatment, remission, and relapsed periods) in Ph+ ALL (n = 97) and chronic myeloid leukemia blast crisis (CML-BP) (n = 21) patients. Meanwhile, the comparative efficacy of three generations of TKIs in Ph+ ALL (n = 92) and CML-BP (n = 23) and the relationship between ABL1 KD mutations and different TKI selection were analyzed. Results In Ph+ ALL patients, single ABL1 KD unreported mutations were detected in 30.49% of patients before therapy and 39.73% in remission, which accounted for the highest proportion among other mutation types. Conversely, single ABL1 KD resistant mutations were found to be the most prevalent (54.5%) in relapsed patients ( P < 0.0001). Logistic analysis revealed that the presence of F401V/L in untreated Ph+ ALL patients was associated with a higher risk of relapse ( P < 0.1). Furthermore, through analyzing patients who received TKI treatment, we observed that 3G TKIs like olverembatinib exhibited advantages in prognosis, including achieving deep molecular response, rapid remission reduction, and decreased relapse probability, for both newly diagnosed and relapsed Ph+ ALL patients. Notably, 3G TKIs not only demonstrated strong inhibition against the T315I mutation, as previously reported, but also displayed superior effectiveness against certain ABL1 KD unreported mutations, such as R516L, K262T, and F401V. Similar trends were observed in CML-BP, although statistical significance was not reached likely due to the limited number of patients. Conclusion Overall, our findings indicate the prevalence and impact of ABL1 KD mutations in Ph+ ALL and CML-BP patients, highlighting the necessity for effective therapies targeting these mutations. The promising outcomes observed with 3G TKIs suggest their potential as a treatment option for both newly diagnosed and relapsed Ph+ ALL patients, offering advantages in terms of molecular response depth, rapid remission, and reduced relapse risk. Further investigations are warranted to explore the clinical significance of unreported ABL1 KD mutations and validate the effectiveness of 3G TKIs against them.

Lower-Initiating Dose of Bosutinib for Resistant or Intolerant to Prior Therapy Chronic Myeloid Leukemia Patients (BOGI trial): A Single-Arm, Multicenter, Phase II Trial

Introduction: The introduction of ABL1 tyrosine kinase inhibitors (TKIs) has markedly improved the survival outcomes in patients with chronic phase chronic myeloid leukemia (CML-CP). Second-generation TKIs are highly active for patients with newly diagnosed and resistant/intolerant CML-CP. Although bosutinib is generally safe, drug-related toxicities (DRTs) such as diarrhea or increased transaminase leading to treatment discontinuation, are often observed. The standard initial daily dosage of bosutinib is 400 mg for newly diagnosed or 500 mg for resistant/intolerant patients with CML-CP, whereas some experts suggest lower dose (200-300 mg) initiation is recommended to reduce adverse events (AEs). However, the safety and efficacy of lower dose initiation of bosutinib are unknown. Hence, we conducted a phase 2 study of BOsutinib Gradual Increase as a second/third-line treatment for CML-CP (BOGI trial, UMIN 000032282) to clarify whether a lower initiating dose of bosutinib (200 mg daily) would reduce discontinuation or interruption of treatment due to DRTs. Patients and methods We included CML patients who developed at least one line of treatment failure (resistant or intolerant), aged >18 years with an ECOG performance status of 0-2 and adequate organ function. After enrollment, the patients initiated 200 mg of bosutinib daily; subsequently, dose escalation was performed by 100 mg daily (up to 500 mg daily) every 2 weeks if no grade 3 or higher AEs occurred. BCR::ABL1 mRNA levels were measured by the standardized international scale at a central laboratory at 3, 6, 9, and 12 month since treatment initiation. The primary endpoint was the treatment discontinuation rate due to DRTs at 12 months. Secondary endpoints included the treatment interruption rate, mean bosutinib dosage, dosing days and relative dose intensity until 12 months, achievement of cytogenetic response (CCyR), cumulative rates of major molecular response (MMR) or deep molecular response (DMR). Sample size calculation was performed by research and biostatistics SWOG statistical tools (at null proportion = 0.32, alternative proportion = 0.14, one-sided α error = 5% and β error = 20%, power 80%) with the discontinuation rate of the previous Japanese phase 1/2 study of bosutinib as a reference (Nakaseko C, et al. Int J Hematol. 2015). Considering protocol deviations, sample size was 35 participants. Results Between Feb 4, 2019, and May 24, 2022, 35 patients enrolled from four Japanese hospitals. The median age was 61 years (range, 26 - 81 years); 19 patients were male and 16 were female and 16, 12, and 7 patients had low,intermediate, and high Sokal scores, respectively. Ten patients had hypertension, five had diabetes millitus, three had chronic heart disease, two had solid tumor, and one had cerebrovascular disease, respectively. Numbers of patients with previous TKIs were one for 19 (54%), two for 12 (34%) and three for 4 (11%), respectively and prior TKIs are imatinib (8, 23%), dasatinib (27, 77%), nilotinib (16, 46%) and bosutinib (1, 3%), respectively. In the intention to treat population, the bosutinib discontinuation rate at 12 months was 25.7% (95% CI, 15.6-39.3%) which is significantly lower than that of the previous report (v.s. 43.0%, p=0.019). Similarly, bosutinib discontinuation rate due to DRTs was 11.4% (95% CI, 5.2 - 23.2%), which is also significantly lower (v.s. 32%, p = 0.005). These results suggest lower initiating dose of bosutinib reduced bosutinib discontinuation rate due to DRTs, thus the primary endpoint was met. A total of 22 patients (62.9%) interrupted bosutinib at least once. Median bosutinib dosage, bosutinib dosing days and relative dose intensity until 12 months were 391.7 (204.9-477.3) mg/day, 351.0 (20-365) days and 78% (41-95), respectively. 28 patients (80.0%) achieved cytogenetic response (CCyR) at 6 months; cumulative incidence of MMR and DMR at 12 months were 23 (65.7%; 95%CI, 49.2-79.2%) and 15 (42.9%; 95%CI, 28.0-59.1%), indicating these secondary endpoints were comparable with the previous report. Grade 3 to 4 transaminase elevation was 20% which is comparable with the previous report (v.s. 29%, p=0.427), while a lower rate of diarrhea (3%; v.s. 25%, p=0.009) was notable. Conclusion The lower initiating dose followed by a gradual dose increase of bosutinib reduced the drug discontinuation rate due to severe DRTs, especially diarrhea, while efficacy was assured.

Outcomes of Adolescents and Young Adult Patients with Chronic Myeloid Leukemia in the Era of Second-Generation TKIs and Treatment-Free Remission

Background: While chronic myeloid leukemia (CML) is most often diagnosed in older adults, it is frequently diagnosed in adolescents and young adults (AYA). Defined by the NCI as individuals between the ages of 15-39 years old, AYA CML patients have been understudied by comparison to their older counterparts, with little known about their outcomes in the United States (US) in the era of second-generation tyrosine kinase inhibitors (TKIs) and treatment-free remission (TFR). We sought to determine the clinical outcomes of AYA patients with CML at our institution, a CML specialty center. Methods: We performed a single-center, retrospective cohort study of patients with CML who were diagnosed between the ages of 15-39 years old and seen in our adult hematology clinic between January 2012 and December 2022. Patients were identified by ICD-9 and ICD-10 codes from the electronic medical record and chart review. Descriptive statistics were used to summarize the data. Outcomes evaluating second-generation TKIs (2G-TKIs) started with patients diagnosed in June 2010. Outcomes evaluating molecular response included BCR-ABL1 PCR testing conducted after implementation of the International Scale (IS) in 2012. Molecular treatment milestones were defined per the 2023 NCCN guidelines for CML. Results: Of 396 CML patients evaluated at our institution, 136 (34.3%) were diagnosed as AYA at a median age of 31 years (range 15-39). The majority were male (62.5%; n=85/136) and English speaking (94.1%; n=128/136). The most frequently cited race/ethnicities were Caucasian (40.4%; n=55/136), Asian (20.6%; n=28/136), and Hispanic (19.1%; n=26/136). At time of diagnosis, 91.2% (n=124/136) were in chronic phase (CP), followed by 4.4% (n=6/136) in accelerated phase (AP) and 4.4% (n=6/136) in blast phase (BP). Of those diagnosed in advanced phase, 91.7% (n=11/12) were male and 66.7% (n=8/12) were Asian or Hispanic. Of CP patients evaluated, 75.8% (n=94/124) started treatment in the 2G-TKI era. Most CP patients were first prescribed dasatinib (61.7%; n=58/94), followed by imatinib (28.7%; n=27/94), and nilotinib (8.5%; n=8/94). Of 62 patients in CP with available molecular data after 2012, 64.5% (n=40/62) met a transcript level <10% at 3-months and 80.6% (n=50/62) met a transcript level <1% at 12-months. Major molecular response (MMR) was achieved and maintained in 59.7% (n=37/62) of these patients, with 25.8% (n=16/62) losing MMR and 14.5% (n=9/62) never achieving MMR. Reasons for loss of MMR included TFR attempts (31.3%; n=5/16), non-adherence from side effects (25%; n=4/16), lack of health insurance/inability to afford medication (18.8%; n=3/16), lack of response (18.8%; n=3/16), and pregnancy attempts (6.3%; n=1/16). Fertility was a notable issue for AYA patients, with 16 females (31.4%; n=16/51) and 18 patients overall (13.2%; n=18/136) interrupting or delaying start of TKI because of pregnancy/fertility. For patients who attempted TFR, 48.1% (n=13/27) remained off TKI in MMR at time of last follow-up. Of 130 AYA patients with CP or AP CML at diagnosis, 7.7% (n=10/130) experienced disease transformation, including 3.2% (n=3/94) of CP patients in the 2G-TKI era. Of 14 patients who presented or transformed into BP, 42.8% (n=6/14) underwent allogeneic stem cell transplantation and 64.3% (n=9/14) died. Of the entire cohort, 9.56% (n=13/136) patients died at a median age of 35 years old, including 5.4% who presented in CP (n=7/124) and 50% (n=6/12) of those who presented in AP/BP. Of the 13 who died, 11 (84.6%) died from CML-related complications. Conclusions: This represents the largest analysis of NCI-defined AYA CML patients in the US in the 2G-TKI era. Molecular response, progression and successful TFR rates in AYA CP CML patients appear to approximate those reported in prior large clinical trials that compared 2G-TKIs with imatinib. AYA patients can experience unique challenges that impact their management, including pregnancy/fertility and adherence, which can affect clinical outcomes. Patients may also present with aggressive advanced phase disease leading to mortality despite transplantation. Further study is warranted to better support the needs of this patient population. Evaluation of CML patients ≥ 40 years old at diagnosis at our institution is ongoing. A formal comparison between these groups will be presented.

Chronic Myeloid Leukemia and Myocardial Infarction: A Nationwide Readmission Database Analysis

Introduction Chronic myeloid leukemia (CML) is a hematological malignancy with an excellent outcome. After advancements in CML treatment and the introduction of different Tyrosine kinase inhibitors (TKI), their life expectancy is equivalent to the normal population. As a result of that, coronary artery disease is anticipated to be the leading cause of death among CML patients. It was particularly noted that TKI use is associated with the risk of endothelial dysfunction and it associated risk of cardiovascular events, including myocardial infarction. In this study, we compare the outcome of PCI in patients with CML to their matched non-CML group. Method The National readmission database (NRD) was searched from January 2016 to December 2020 for the study population. Adults above (age ≥ 18 years) with chronic myeloid leukemia hospitalized with a primary diagnosis of myocardial infarction, ST Elevation Myocardial Infarction (STEMI), and Non-ST-elevation myocardial infarction (NSTEMI) were identified using ICD 10 code. The primary outcomes were in-hospital mortality and 30-day readmission, and the secondary outcome was to compare the complications. The weighting of patient-level observations was implemented to obtain national estimates. Multivariate regression analysis models were built by including all confounders significantly associated with the outcome on univariable analysis with a cutoff P-value of 0.2. Variables deemed important determinants of the outcomes based on literature were forced into the models. For readmission comparison, we used the time-to-event Cox regression analysis. Propensity matching was done by the Greedy method. Proportions were compared using the Mantel-Haenszel Chi-square test or Fisher exact test, and continuous variables were compared using the Student t-test. All P values were two-sided, with .05 as the threshold for statistical significance. Results Out of 2727619 patients with myocardial infarction, 2124 CML patients were identified, and 888 CML patients had Percutaneous Coronary Intervention (PCI). Patients' baseline characteristics and major outcomes were compared (table 1). The mean age of CML patients was 68.34 ± 11.14 (P<0.001). The analysis showed no significant difference between CML and non-CML patients after PCI for the primary outcome of death 0.93 (CI 0.49-1.80) P value 0.527 and 30 days readmission rate 1.41 (0.99-2.01) P value 0.056. Also, there was no statistical significance in developing major complications, including cardiac arrest, coronary artery dissection, cardiac tamponade, stroke, thrombosis, major bleeding, AKI, and dialysis. Discussion and Conclusion Patients with hematologic malignancies, including chronic myeloid leukemia, are at increased risk of thrombosis. In CML, thrombosis can be venous or arterial (myocardial infarction, cerebrovascular accidents, and peripheral artery disease). Arterial thrombosis in CML is primarily linked to using different TKIs, and thrombotic events were reported with the second-generation TKIs like nilotinib, dasatinib, and ponatinib more often than with first-generation TKIs. The mechanism of TKI use-associated thrombosis is likely related to TKI-associated endothelial dysfunction and vascular toxicity that lead to accelerated atherosclerosis and subsequent vascular thrombosis. This increased risk might lead to an assumption of an increased risk of complications with vascular intervention like PCI. Some studies showed that PCI for hematological cancer patients with STEMI have no significant difference regarding in-hospital mortality. This analysis of patients with CML with myocardial infarction ( STEMI and NSTEMI ) showed no statistically significant difference in outcome after PCI between the two groups. There were no significant differences in mortality, 30 days readmission rate, and other complications post PCI. Therefore, diagnosis of chronic myeloid leukemia shouldn't prevent patients from receiving routine therapy and intervention because of the theoretical risk of thrombosis. This information aid in patient counseling and achieving the objective of maintaining a normal quality of life for chronic myeloid leukemia patients.

Olverembatinib (HQP1351) Enhances Antitumor Effects of Chemotherapy in Philadelphia Chromosome-Positive (Ph⁺) Acute Lymphoblastic Leukemia (ALL)

Introduction Ph⁺ ALL is the most common subtype of B-cell- (B-) ALL in adults. BCR-ABL1 tyrosine kinase inhibitors (TKIs) are effective against chronic myeloid leukemia (CML) cells. However, treatment with TKIs fails to maintain disease remission in Ph⁺ B-ALL. Although the complete hematologic remission rate is very high, cytogenetic and molecular remission rates are low, so that TKIs are still considered as complements to chemotherapy and bridges to allogeneic stem cell transplantation. Olverembatinib is a novel, third-generation TKI with more potent activity against BCR-ABL1 and overcomes various resistant mutations, including the “gatekeeper” T315I, which confers resistance against all first- and second-generation TKIs. The aim of this study was to assess whether olverembatinib combined with chemotherapeutic agents vincristine or doxorubicin can promote anti-cancer effects in Ph⁺ ALL cells and explore the potential mechanism of action of the combinations. Methods Cell-based antiproliferation assays to evaluate the activities of olverembatinib alone or in combination with vincristine or doxorubicin were conducted using the CellTiter-Glo® Luminescent Cell Viability assay kits. Drug induced cell apoptosis was measured by flow cytometry. Potential mechanism of action analysis was conducted using western blot to evaluate the protein expression involved in BCR-ABL1 and apoptosis signaling pathways. Results Cell-based antiproliferation studies showed synergistic activity of olverembatinib in combination with vincristine or doxorubicin in Ph⁺ ALL SUP-B15 cells compared with single agents after 72 hours of treatment. The percentage of apoptotic cells induced by 24-hour treatment of olverembatinib (100 nM), vincristine (300 nM), and the combination were 27.7%, 27.2%, and 40.7%, respectively, while the percentage of apoptotic cells induced by 24-hour treatment of doxorubicin (100 nM) alone and in combination with olverembatinib (100 nM) were 35.3 and 74.1, respectively (apoptotic cells % in DMSO control group is 6.74). The combination significantly increased cell apoptosis compared with single agents ( p < 0.0001). Mechanistically, the combination of olverembatinib with vincristine showed synergistic effects in inhibiting protein expression and phosphorylation of BCR-ABL1, and downstream signal transducer and activator of transcription 5 (STAT5). The synergistic effects were also seen in decreased phosphorylation of AKT and ERK1/2. In addition, the combination significantly decreased protein levels of antiapoptotic MCL-1, BCL-2, and BCL-xL and increased protein levels of proapoptotic BAX and p53 upregulated modulator of apoptosis (PUMA) in a dose-dependent manner, which led to marked augmentation of cleavage of caspase-3 and poly (ADP-ribose) polymerase 1 (PARP). A similar pattern was also observed when olverembatinib was combined with doxorubicin. Conclusions Olverembatinib, a novel, third-generation TKI, in combination with chemotherapeutic agents vincristine or doxorubicin decreased MCL-1, BCL-2, and BCL-xL and increased BAX and PUMA in a dose-dependent manner, the combinations have demonstrated synergistic antitumor effects by enhancing apoptosis and antiproliferation in Ph⁺ ALL cells, which may provide an alternative approach for treatment of patients with Ph⁺ ALL.

Epic: A Second Interim Analysis of the Non-Interventional, Observational Multi-Centre Cohort Study of Patients with Chronic Lymphocytic Leukaemia Treated with First-Line Acalabrutinib through the UK Early Access Programme

Background: Acalabrutinib, a second-generation Bruton Tyrosine Kinase inhibitor (BTKi), has shown an acceptable safety profile and high response rates in clinical trials of treatment naïve patients with chronic lymphocytic leukaemia (CLL). However, real-world data detailing the safety and effectiveness of first-line acalabrutinib treatment for CLL is limited. Here we present a second interim analysis (IA) of patients with CLL who were initiated on first-line acalabrutinib within the UK Early Access Programme (EAP). Methods: This is an ongoing observational multi-centre cohort study involving retrospective data collection from medical records (ClinicalTrials.gov: NCT05557695). Treatment-naïve patients with CLL from 9 UK clinical centres who initiated acalabrutinib as part of the UK EAP between 1 st April 2020 - 1 st April 2021 were eligible to participate. Patients will be followed for up to 60 months from the date of acalabrutinib initiation (index). Collected data for this IA (data cut-off 31 st May 2023) includes baseline demographics, clinical characteristics, and treatment patterns. Results: 101 patients were included in this IA. Median (interquartile range (IQR)) age at index was 73.8 (66.1-78.4) years; 56% (n=57/101) of patients were male; 89% (n=83/93) of patients were White British, 6% (n=6/93) were White other, 3% (n=3/93) were Asian and 1% (n=1/93) were of Mixed ethnicity (missing data n=8). Median (IQR) duration of follow-up was 32.4 (29.2-35.4) months; 89% (n=90/101) of patients had a follow-up duration of ≥1 year and 84% (n=85/101) ≥2 years. 88% (n=52/59) of patients had an Eastern Cooperative Oncology Group performance status (PS) of 0-1, 10% (n=6/59) had a PS of 2 and 2% (n=1/59) had a PS of 3 (missing n=42). 50% (n=40/80) of patients had a creatinine clearance <60 mL/min at index. 5% (n=5/101) of patients had a confirmed ATM mutation and no patients had a confirmed 17p13.1 deletion. 5% (n=5/101) had a confirmed TP53 mutation and of 10 patients with confirmed IgHV mutational status, 20% (2/10) had mutated IgHV (91 unknown). Median (IQR) time between CLL diagnosis and index was 2.8 (1.2-5.4) years. At index, 100 patients received 100 mg of acalabrutinib twice a day, 1 patient received 100 mg daily. The continuation rate (n=100) at 12 and 24 months was 81.0% (95% confidence interval [CI], 73.7%-89.1%) and 74.0% (95% CI, 65.9%-83.1%), respectively (1 patient not recorded). 68% (n=69/101) of patients remained on treatment at the time of data cut. Of those patients reporting reasons for treatment discontinuation, 48% (n=15/31) were due to adverse events (AEs; of the 14/15 patients reporting type of AEs resulting in discontinuation, 14% (2/14) was reported for each of the following AEs; cardiovascular, haematoma, headache and urinary tract infection), 6% (n=2/31) due to disease progression, 3% (n=1/31) due to patients' decision and 42% (n=13/31) other reasons (1 unknown). Of 39 patients with treatment interruptions, 72% (n=28/39) patients had interruptions due to AEs, 15% (n=6/39) due to a minor operation and/or procedure and 21% (n=8/39) other reasons. Of the 22/28 patients reporting type of AE resulting in treatment interruption, the most common AEs were upper respiratory tract infection (23%, n=5/22) and thrombocytopenia (18%, n=4/22). Of those with relevant medical records, 62% (n=40/65) had a recorded COVID-19 diagnosis; of these, 93% (n=37/40) diagnoses were confirmed via test. Sotrovimab was the most common treatment received for COVID-19 (20% of patients, n=8/40). COVID-19 vaccination and biannual boosters is offered to all patients with CLL as per UK guidelines, available data from 58 patients showed that 72% (n=42/58) of patients had received ≥4 COVID-19 vaccination doses and 28% (n=16/58) had received <4 doses at the time of datacut (missing n=43). Conclusion: This IA reports 12 and 24-month real-world acalabrutinib continuation rates of 81.0% (95% CI, 73.7%-89.1%, n=100) and 74.0% (95% CI, 65.9%-83.1%, n=100), respectively, in treatment naïve patients with CLL in UK. These findings provide clinical decision makers with valuable insights into acalabrutinib use in the real-world as well as highlighting the importance of BTKi AE management in a real-world clinical setting. Further IAs are planned.

Elevate-TN: Impact of First-Year Dose Modifications in Patients with Treatment-Naive Chronic Lymphocytic Leukemia Treated with Acalabrutinib

Background: Acalabrutinib (acala), a second-generation Bruton tyrosine kinase inhibitor (BTKi), with or without obinutuzumab (obin), demonstrated superior progression-free survival (PFS) compared with obin plus chlorambucil in patients with treatment-naive (TN) chronic lymphocytic leukemia (CLL) in the phase 3 ELEVATE-TN (NCT02475681) trial. Despite the long-term benefits observed with acala therapy, data from real-world studies in patients with CLL demonstrate that 22% of patients discontinue acala treatment for any reason in the first year of treatment across therapy lines (Roeker et al. Blood. 2022). To assess the impact on survival outcomes of acala discontinuation and dose modifications occurring in the first year of treatment, we conducted a post hoc analysis in patients treated in the acala-containing arms of ELEVATE-TN. Methods: Patients who received acala 100 mg twice daily with or without obin (fixed duration, up to 6 cycles) with at least 1 year of follow-up were included in this analysis. The impact of dose reductions, treatment breaks, or treatment discontinuations in the first year on overall survival (OS) was assessed. Protocol-specified dose-modification guidelines that included dose reductions, breaks, and discontinuations depending on severity and frequency were applied to patients with apparent treatment-related toxicity. To assess the impact of dose reductions, breaks, or discontinuations, patients were divided into 4 dose-modification subgroups: 1) patients with no dose reductions/breaks >14 days during the first year; 2) patients with dose reductions >14 days, but no breaks >14 days during the first year; 3) patients with breaks >14 days, but who continued treatment in the first year; and 4) patients who discontinued treatment during the first year. Results: With a median follow-up of 60 months, 358 patients (n=179, acala monotherapy; n=179, acala-obin) with ≥1 year of follow-up were included in this analysis. In the first year, 269 (75%) patients had no dose reductions/breaks >14 days, 11 (3%) patients had dose reductions >14 days but no breaks >14 days, 32 (9%) patients had breaks >14 days but continued treatment, and 46 (13%) patients discontinued treatment. Reasons for treatment discontinuation during the first year were adverse events (n=26), disease progression (n=7), physician decision (n=5), consent withdrawn (n=3), death (n=2), loss to follow-up (n=1), and other (n=2). Patients who discontinued treatment within the first year had inferior OS compared with patients who did not require dose reductions or breaks (OS hazard ratio [HR]: 8.39, 95% confidence interval [CI]: 3.96-17.8, P<0.0001; Figure 1). In contrast, patients who had dose reductions or breaks >14 days but did not discontinue treatment had statistically similar OS to patients who did not require dose reductions or breaks. Within the group that had no dose reductions or treatment breaks >14 days, there was no difference in the proportion of patients treated with acala monotherapy (n=133) and acala-obin (n=136). However, OS outcomes in this subgroup of patients with no treatment modifications were superior in patients treated with acala-obin compared with those treated with acala monotherapy (HR: 0.37, 95% CI 0.15-0.87, P=0.0183; Figure 2). Conclusions: This post hoc analysis of acala-treated patients with TN CLL in ELEVATE-TN demonstrated superior OS in patients who did not have dose reductions or breaks compared with patients who discontinued treatment within the first year. OS outcomes in patients who required dose reductions or breaks but did not discontinue treatment in the first year were similar to those in patients who did not require dose modification. Accepting the limitations of retrospective analysis, these data suggest that patients who are unable to tolerate standard-dose acala or who require treatment breaks may benefit from continuing or resuming treatment at a reduced dose rather than stopping treatment altogether. For patients who do not require dose modifications, ongoing follow-up of the ELEVATE-TN trial suggests durable and incrementally improved OS benefit from the addition of obin to acala.

Acrue: A Phase 2, Open-Label Study of Acalabrutinib in Combination with Rituximab in Elderly and/or Frail Patients with Treatment-Naive Diffuse Large B-Cell Lymphoma

Background and Significance: Patients aged ≥80 years with diffuse large B-cell lymphoma (DLBCL) account for approximately 18% of DLBCL cases in the United States (Morrison et al. Future Oncol. 2018). Standard-of-care chemoimmunotherapy (CIT) regimens such as rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP), including reduced doses of CHOP (R-miniCHOP), are not well tolerated in elderly and/or frail patients, leading to high treatment-related mortality rates (Boslooper et al. Leuk Lymphoma. 2014; Freudenberger et al. Ann Hematol. 2021; Peyrade et al. Lancet Oncol. 2011). Therefore, safe, effective, and convenient treatment alternatives to CIT are needed. Acalabrutinib is a highly selective, second-generation Bruton tyrosine kinase inhibitor approved for the treatment of patients with relapsed/refractory mantle cell lymphoma and in patients with chronic lymphocytic leukemia. Acalabrutinib monotherapy has demonstrated encouraging activity in patients with DLBCL in phase 1b (NCT02112526) and phase 2 (NCT04002947) studies (Strati et al. Haematologica. 2021; Roschewski et al. Blood. 2021). However, neither of these studies were conducted specifically in a population of elderly and/or frail patients. Study Design and Methods: ACRUE (NCT05952024) is a phase 2, open-label, single-arm, global, multicenter study of acalabrutinib plus rituximab in elderly and/or frail patients with treatment-naive (TN) DLBCL who are unable to tolerate standard CIT ( Figure). Eligible patients are aged ≥80 years or aged 65-79 years with impairment in ≥1 activity of daily living (ADL) or instrumental ADL (IADL), or with cardiac/renal/liver function impairment or other comorbidities that render them unable to tolerate CIT. Furthermore, patients must have histologically confirmed CD20-positiveDLBCL (not otherwise specified), according to WHO 2016 classification, an Ann Arbor classification of stage II, III, or IV disease, an Eastern Cooperative Oncology Group performance status of 0-2, and ≥1 measurable lesion. Patients with active central nervous system involvement by lymphoma, leptomeningeal disease, or spinal cord compression, or significant cardiovascular disease within 6 months of screening are excluded. Target enrollment is 80 patients. Patients will receive acalabrutinib plus rituximab combination for 8 cycles (acalabrutinib 100 mg orally twice daily beginning on day 1 of cycles 1-8; rituximab 375 mg/m 2 intravenously on C1D15, then 1400 mg subcutaneously, on day 1 of cycles 2-8; cycles 1-8 are 21 days/cycle), followed by acalabrutinib monotherapy until disease progression, unacceptable toxicity, or 24 months (cycles 9-28 are 28 days/cycle). The primary endpoint is the percentage of patients with grade 3-4 treatment-emergent adverse events. The key secondary endpoint is investigator-assessed objective response rate per Lugano 2014 criteria. Other secondary endpoints include progression-free survival, event-free survival, overall survival, duration of response, and Timed Up and Go test. Exploratory biomarker analyses may include genomic characterization of baseline samples to evaluate predictors of survival, and of progression samples to evaluate genomic resistance mechanisms. Descriptive safety and efficacy data will be summarized. If patients discontinue treatment prior to completing 28 cycles of therapy, they will be followed every 12 weeks after their last treatment dose for up to 2 years. Patients who are still on treatment at the end of the study and are deriving clinical benefit may receive continued treatment, with assessments reverting to standard of care. Enrollment is planned to begin Q4 of 2023 in approximately 40 sites from North and South America and Asia. Summary: This study will help determine if acalabrutinib plus rituximab combination therapy is tolerable and effective in elderly and/or frail patients with TN DLBCL who are unable to tolerate CIT.

Toxicity, Progression-Free Survival, and Quality of Life of Patients Treated with Zanubrutinib Versus Ibrutinib: A Q-TWiST Analysis from the ALPINE Study in Relapsed or Refractory Chronic Lymphocytic Leukemia

Introduction: Zanubrutinib is a second-generation Bruton's tyrosine kinase inhibitor (BTKi) with enhanced specificity over the first-generation BTKi ibrutinib. Patients treated with zanubrutinib had a significantly longer progression-free survival (PFS) versus those treated with ibrutinib in the global, phase 3, randomized ALPINE trial in patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) (NCT03734016). Quality-adjusted time without symptoms of disease and toxicity (Q-TWiST) is a clinical tool to assess overall benefits and risks of cancer therapies by integrating progression, survival, treatment toxicity, and patient quality of life (QoL) into a single metric. It provides valuable insights into the quality and duration of improved health states. To gain a comprehensive understanding of the benefits and risks associated with zanubrutinib versus ibrutinib in terms of quality-adjusted survival, a Q-TWiST analysis was performed within the ALPINE trial. Methods: Patients in the ALPINE trial were followed for a median duration of 29.6 months. For the Q-TWiST analysis, overall survival (OS) of each patient was partitioned into 3 mutually exclusive health states: TOX (time before disease progression with toxicity after randomization); TWiST (time from randomization to disease progression without toxicity); and REL (time after disease progression until death or censoring). Survival curves corresponding to TOX, PFS, and OS were estimated by Kaplan-Meier method with a monthly cycle. Restricted mean survival time for each health state was derived from the area under the Kaplan-Meier curve (TWiST = PFS - TOX; REL = OS - PFS). Q-TWiST for each treatment was estimated as the mean time spent in each health state weighted by its respective QoL, denoted by health states' utility value (U; 0 [indicates death] to 1.0 [indicates “perfect” health]). Relative Q-TWiST gain was estimated by dividing the absolute Q-TWiST gain by mean OS with ibrutinib. To ensure the comparability of populations and treatments across published Q-TWiST studies, the base-case analysis focused on a high-risk population (i.e., patients with chromosome 17p deletion, TP53 mutation, or both). In the base case, the TOX health state included adverse events (AEs) of grade 2 or higher. Standard utilities were applied, with a value of 0.5 assigned to both TOX and REL and a value of 1.0 assigned to TWiST. A sensitivity analysis was performed in an intent-to-treat population with same-grade AEs considered for TOX and standard utilities. Results:In the base case, the mean durations of TOX, TWiST, and REL health states for zanubrutinib (N = 73) were 11.54 months, 14.45 months, and 1.70 months, respectively. The corresponding durations for ibrutinib (N = 71) were 11.38 months, 11.09 months, and 3.78 months, respectively. The mean difference (95% CI) for zanubrutinib versus ibrutinib was 0.16 months (−0.18, 0.51) for the TOX state, 3.36 months (2.6, 4.2) for the TWiST state, and −2.08 months (−2.6, −1.6) for the REL state. The mean duration of Q-TWiST was 21.07 months for zanubrutinib versus 18.67 months for ibrutinib. The estimated difference in means (95% CI) for Q-TWiST gain was significantly higher for zanubrutinib versus ibrutinib (2.40 months; 1.9, 2.9; P<0.001), and the relative Q-TWiST gain was 9.14% (Figure). In the sensitivity analysis, using the intent-to-treat population, the mean difference (95% CI) for Q-TWiST gain was 1.30 months (1.0, 1.6; P=0.05) for zanubrutinib versus ibrutinib, and the relative Q-TWiST gain was 4.63%. Conclusions: This Q-TWiST analysis demonstrated a statistically significant gain in quality-adjusted survival with zanubrutinib compared with ibrutinib in patients with high-risk R/R CLL. The slightly longer TOX duration in patients receiving zanubrutinib versus those receiving ibrutinib could be explained in part by better treatment adherence. The results of this Q-TWiST analysis, which integrates both the length and quality of survival in addition to efficacy and toxicity, provide valuable insights that may help to inform clinical decision-making in the treatment of patients with R/R CLL.

A Real-World Study of Zanubrutinib Treatment in Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma

Background: Zanubrutinib, a second-generation non-covalent Bruton's Tyrosine Kinase inhibitor (BTKi), with better BTK specificity, and fewer off-target effects. Zanubrutinib has demonstrated the confirmed effectiveness and safety in clinical trials such as SEQUOIA and ALPINE in chronic lymphocytic leukemia and small lymphocytic lymphoma (CLL/SLL), and earlier studies showed its efficacy and safety profile of zanubrutinib monotherapy in the real world. Meanwhile, more valuable insights hope to be gained on zanubrutinib treatment in Chinese CLL/SLL patients (pts) outside of the clinical trial setting. This report provides some outcomes evaluated in a real-world study. Aims: This study further evaluated the effectiveness and safety of zanubrutinib monotherapy/combination treatment in Chinese CLL/SLL pts in a real-world setting. Methods: CLL/SLL pts who received zanubrutinib monotherapy/combination treatment for at least 3 months from Aug. 2017 to Jul. 2023 were enrolled from Jiangsu Province Hospital. The primary outcome was progression free survival (PFS). Baseline characteristics were also collated. Results: 77 pts were analyzed in all. Zanubrutinib was administered orally at 160 mg, twice daily (BID), mono or combined. Among the monotherapy pts, 20 (35.1%) pts were treatment naïve (TN) and 37 (64.9%) pts were refractory/relapsed (R/R). Among the combination treatment pts, 14 (70.0%) pts were TN and 6 (30.0%) pts were R/R. Baseline characteristics were shown in Table 1. The median follow-up time was 31.8 months, and the median PFS was not reached in the entire cohort. The 12-month PFS rate was 95.8% (95%CI 91.3-100.0%) while the 24-month PFS rate was 90.9% (95%CI 84.2-98.2%) (Figure A). After stratified by line of therapy in monotherapy, the estimated 12-month PFS rates of TN and R/R zanubrutinib monotherapy pts were 100.0% (95%CI 100.0-100.0%) and 91.3% (95%CI 82.3-100.0%) (Figure B). The estimated 24-month PFS rates of TN and R/R zanubrutinib monotherapy pts were 93.8% (95%CI 82.6-100.0%) and 84.9% (95%CI 73.5-98.1%). 4 (5.2%) pts interrupted treatment due to AE. 2 pts were TN and 2 pts were R/R. 2 pts received zanubrutinib monotherapy and 2 pts received combination treatment. The AEs included hemoptysis (1, 1.3%), platelet hemoglobin reduction and atrial fibrillation (1, 1.3%), bleeding points in both lower limbs (1, 1.3%), rash and edema (1, 1.3%). All treatment-interrupted pts still received zanubrutinib after interruption by the latest follow-up. 17 (22.1%) pts experienced treatment discontinuation due to progressive disease (PD) or transformation. No pts discontinued zanubrutinib treatment due to AE. PD was the most common reason for treatment discontinuation. 13 (16.9%) pts experienced PD and 4 (5.2%) pts experienced transformations. S ummary/Conclusion: Zanubrutinib shows good efficacy in Chinese CLL/SLL pts in the real-world study. Incidence of AE was low, and no treatment discontinued due to AE, revealing a good safety of zanubrutinib. PD was the main reason for treatment discontinuation. Therefore, the effectiveness and safety of zanubrutinib have been validated in the real world, consistent with clinical trials.

Retrospective Study to Evaluate Probability of MR4 Maintenance Following Frontline Nilotinib Dose De-Escalation after MR4 Achievement in the Patients with Chronic Myeloid Leukemia in Chronic Phase

Introduction: Nilotinib (NIL) is a potent second-generation tyrosine kinase inhibitor (TKI) approved for the treatment of newly diagnosed chronic myeloid leukemia (CML) patients (pts) in chronic phase, but reported to increase long-term toxicity such as cardiovascular (CV) risks. The ENESTfreedom study (Leukemia 2021) has reported 55% of treatment-free remission (TFR) rate after front line NIL discontinuation with a median 43.5 months of NIL treatment duration. Question still remains how to improve TFR rate after NIL frontline therapy. A potential solution is dose de-escalation (DESC) after MR4 achievement which could reduce the CV risk while extending MR4 duration prior to TFR attempt, thus increasing the chance of successful TFR attempt. DESTINY trial (Lancet Haematology 2019) had attempted TKI dose DESC to half of the standard dose for 12 months before stopping TKI therapy, reporting only 3 pts (2.4%) lost molecular response after TKI dose DESC in 125 pts who achieved molecular response with 4 log or deeper (MR4). However, 85% of this cohort is mainly treated with imatinib, limiting applying this experience in NIL treated pts. Accordingly, the present study attempted to evaluate the efficacy of NIL dose DESC following MR4 achievement based on real-world experience. Patients & Method: We have retrospectively analyzed the outcome of adult pts with CML in chronic phase treated with NIL frontline therapy and achieved sustained MR4 ( BCR::ABL1 transcript ≤0.01%IS). From the pts treated with NIL frontline therapy, we identified the cases attempted NIL de-scalation after achievement of MR4. The molecular response after NIL de-escalation was closely monitored every 3 months using BCR::ABL1 qPCR. Molecular recurrence was defined as an increase in BCR::ABL1 transcript levels above MR4 on at least two consecutive occasions or a single increase in BCR::ABL1 transcript level above MR3 ( BCR::ABL1 transcript ≤0.1%IS). At any time, pts who lost MR3 had returned Nilotinib dose to 300 mg BID. Primary endpoint of the study was event-free survival (EFS) following NIL de-escalation, which was defined from NIL DESC starts to molecular recurrence or death from any cause. Results: We have identified 52 pts who started NIL as first line therapy for CML-CP under clinical practice. With median follow-up duration of 9 years (range:2-12 years), 33 patient (64%) remains on NIL at the last follow-up visit. In 33 pts on NIL treatment, with a median follow up duration of 8 years (range;2-12), 25 (76%) had attempted NIL DESC at median of 6 years (range; 1-10 years) after frontline NIL therapy start, of whom the median time from NIL start to MR4 achievement was 12 months (range: 5-50 months). The median time from first achievement of MR4 to NIL DESC starts was 50 months (range: 3-105 months), while the median time from NIL start to NIL DESC was 77 months (range: 13-121 months). At the latest follow up, only one patient experienced molecular recurrence at 3 months after DESC but regained MR3 in 9 months after re-escalation of NIL to 300mg BID. One patient died of cardiac arrest at 80 months after NIL DESC with other comorbidities of coronary artery disease, hypertension and diabetes. One patient discontinued NIL at 51 months post DESC and has sustained MR4 till last follow up. In the DESC group, the EFS at 3 years, 95% (69.5-99.3%). There is another case developed myocardial infarction while on DESC dose of NIL, who switched the treatment to Asciminib. Conclusion: Achieving early and sustained MR4 with frontline NIL treatment facilitates DESC approach without compromising molecular response and might promote the TFR rate by extending MR4 duration. This DESC strategy can bridge CML pts on NIL frontline therapy prior to NIL discontinuation for TFR attempt.

Novel Insights in TKI Resistance in BCR:: ABL1-Positive B-Cell Acute Lymphoblastic Leukemia Beyond Kinase Domain Mutations

Background and Aim Despite the introduction of tyrosine kinase inhibitors (TKIs), approximately 30% of newly diagnosed pediatric and adult BCR:: ABL1-positive B-cell acute lymphoblastic leukemia (B-ALL) patients experience relapsed or refractory disease (Biondi et al, Lancet Haematology 2018; Bassan et al, Journal of Clinical Oncology 2010). ABL1 kinase domain mutations, hindering TKI binding, explain part of the relapses and are acquired during TKI therapy but are rarely detected in newly diagnosed BCR:: ABL1-positive B-ALL patients (Baer et al, Haematologica 2022). Intrinsic TKI resistance mechanisms in BCR:: ABL1-positive B-ALL present prior to TKI treatment are less well documented. Therefore, we aimed to identify potential biomarkers for TKI sensitivity at diagnosis using primary patient samples and newly generated cell lines made from patient-derived xenografts (PDX cell lines). Patients and Methods Leukemic cells from diagnosis of BCR:: ABL1-positive B-ALL patients without ABL1-kinase domain mutations were used to measure cell survival in an ex vivo co-culture assay after imatinib (1.95-125 μM), dasatinib (1.95-125 nM), or bosutinib (0.016-2 μM) exposure. TKI sensitivity was assessed using the area under the dose-response curve (AUC), with <80 arbitrary units (AU) classified as imatinib-sensitive, 80-120 AU as intermediate, and >120 AU as resistant. Multiplex ligation-dependent probe amplification, whole exome sequencing, and RNA sequencing were performed on diagnostic material if available. ABL1 phosphorylation and expression levels were measured using (phospho)flow cytometry in patient-derived xenografts from diagnostic samples and (PDX) cell lines. Results We determined ex vivo sensitivity to imatinib, dasatinib, and bosutinib in 32 pediatric and 19 adult BCR:: ABL1-positive B-ALL patient samples. We observed a substantial variability in ex vivo imatinib response in pediatric and adult patient samples (median AUC: 98 AU; range: 16 to 281 AU). The sensitivity towards imatinib strongly correlated with the sensitivity towards second-generation TKIs dasatinib and bosutinib (rho = 0.84; p < 0.001 and rho= 0.89; p <0.001). Moreover, imatinib's AUC of samples derived from newly diagnosed patients who relapsed after TKI treatment was higher compared with those derived from patients who did not suffer from a relapse (median AUC 123 vs 84 AU; p = 0.03). We observed that an increase in ex vivo imatinib resistance was correlated with a decreased amount of phosphorylated ABL1 protein (rho=-0.92; p=0.0013) and total ABL1 protein (rho=-0.82; p=0.01) in untreated, newly diagnosed samples. Ex vivo exposure to imatinib reduced the ABL1 phosphorylation levels in both sensitive and resistant samples but resistant cells exhibited lower levels of (p)ABL1 protein, indicating reduced dependence on BCR-ABL1 signaling. The ex vivo imatinib resistance in samples carrying deletions in B-cell development genes IKZF1 and/or PAX5 was higher than in samples without these deletions (median AUC: 122 versus 80 AU; p=0.01). In addition, one imatinib-resistant patient had a p.His1038Arg mutation in ZEB2, which is recurrent in B-ALL and this gene has also been described as B-cell development gene (Studd et al, Blood Cancer Journal 2021). Interestingly, another resistant patient had a mutation in SETD2,a gene previously associated with ex vivo TKI resistance in chronic myeloid leukemia cell lines (Sheng et al, Cell Proliferation 2019). Other secondary lesions included SH2B3 inactivation lesions and CRLF2 rearrangements. These lesions were present in intermediately sensitive and resistant BCR:: ABL1-positive samples and are expected to lead to increased JAK/STAT signaling, potentially serving as a resistance mechanism for TKI. Conclusion Our study revealed that the amount of total and phosphorylated ABL1 protein was correlated with ex vivo TKI sensitivity. Newly diagnosed TKI-resistant BCR:: ABL1 samples were further characterized by somatic lesions in B-cell development genes including IKZF1. These results link the known poor prognostic value of IKZF1 deletions in BCR:: ABL1-positive B-ALL patients (van der Veer et al. Blood 2014; Fedullo et al, Haematologica 2019) with intrinsic mechanisms of TKI resistance other than tyrosine kinase domain mutations.

Antitumor Activity of Axitinib in Lung Carcinoids: A Preclinical Study.

Lung carcinoids (LCs) comprise well-differentiated neuroendocrine tumors classified as typical (TCs) and atypical (ACs) carcinoids. Unfortunately, curative therapies remain elusive for metastatic LCs, which account for 25-30% of cases. This study evaluated the antitumor activity of axitinib (AXI), a second-generation tyrosine kinase inhibitor selectively targeting vascular endothelial growth factor receptors (VEGFR-1, VEGFR-2, VEGFR-3) in human lung TC (NCI-H727, UMC-11, NCI-H835) and AC (NCI-H720) cell lines. In vitro and in vivo (zebrafish) assays were performed following AXI treatment to gather several read-outs about cell viability, cell cycle, the secretion of proangiogenic factors, apoptosis, tumor-induced angiogenesis and migration. AXI demonstrated relevant antitumor activity in human LC cells, with pronounced effects observed in UMC-11 and NCI-H720, characterized by cell cycle perturbation and apoptosis induction. AXI significantly hindered tumor induced-angiogenesis in Tg(fli1a:EGFP)y1 zebrafish embryos implanted with all LC cell lines and also reduced the invasiveness of NCI-H720 cells, as well as the secretion of several proangiogenic factors. In conclusion, our study provides initial evidence supporting the potential anti-tumor activity of AXI in LC, offering a promising basis for future investigations in mammalian animal models and, eventually, progressing to clinical trials.

Flumatinib for Newly Diagnosed Chronic Phase Chronic Myeloid Leukemia: An Open-Label, Multi-Center Study

Background Tyrosine kinase inhibitors (TKIs) ushered in the era of targeted therapy for chronic myeloid leukemia(CML), which greatly improved the prognosis of patients with CML. Flumatinib is a second-generation tyrosine kinase inhibitor (TKI), which is currently approved for patients with Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML) in China. And some current clinical trials revealed that flumatinib has been shown to be a more potent inhibitor of BCR::ABL than imatinib. Methods In this open label, single-arm, multicenter study, 127 patients with newly diagnosed chronic-phase chronic myeloid leukemia (CP-CML) treated with flumatinib were enrolled. The primary endpoint of this study was early molecular response (EMR) rates at 3 months. The secondary were the rates of complete cytogenic response (CCyR), major molecular response (MMR) at 3, 6, 12 months and treatment-related adverse events (AEs). The trial is registered with ClinicalTrials.gov NCT04591197. Results From October 2020 to December 2022, a total of 158 patients with CP-CML were assessed for eligibility, of whom 127 were followed up for more than 3 months. 79(62%) patients were men and 48 (38%) were women. The median age was 47 years (range, 19-82 years), The median time from diagnosis to treatment was 6 days (0-176 days) and the median follow-up was 9.7 months (range 3.1-26.6 months). Of evaluable 127 patients, EMR was achieved by 85% (95% confidence interval [CI], 77.6%-90.7%) of patients at 3 months. After the initiation of flumatinib treatment, the incidence of MMR at 3, 6, and 12 months was 24%, 59%, and 73%, respectively. Patients receiving flumatinib had higher rates of CCyR at 6 months and MMR 12 months than the data from DASISION (dasatinib) and ENESTnd (nilotinib) therapy (85% vs 73% vs 67% and 73% vs 46% vs 44%). Progression-free survival (PFS) rate at 1-year was 97.2%. Diarrhea (34%) were the most commonly reported adverse events. Most treatment-related adverse events were grade 1/2. None of the patients discontinued or died due to AEs. Conclusion Flumatinib as first-line therapy in patients with newly diagnosed CP-CML was not inferior to nilotinib and dasatinib and well tolerated.

Traverse: A Phase 2, Open-Label, Randomized Study of Acalabrutinib in Combination with Venetoclax and Rituximab in Patients with Treatment-Naive Mantle Cell Lymphoma

Background and Significance: Despite advances in treatment for mantle cell lymphoma (MCL), no curative option exists. Currently, the majority of patients with treatment-naive (TN) MCL receive chemoimmunotherapy, which can result in prolonged remissions, but is associated with significant toxicity. Almost all patients inevitably relapse, and therefore, frontline chemotherapy-free options are being increasingly explored. Acalabrutinib is a highly selective, second-generation Bruton tyrosine kinase inhibitor (BTKi) approved for the treatment of adult patients with relapsed/refractory (R/R) MCL. In a phase 1b study in patients with TN MCL, acalabrutinib in combination with venetoclax and rituximab (AVR) demonstrated high rates of clinical and molecular response with an acceptable toxicity profile, supporting its continued development as a chemotherapy-free treatment option (Wang et al. Blood. 2021; Wang et al. Blood. 2022). Furthermore, the occurrence of complete responses (CRs) with clearance of minimal residual disease (MRD) in MCL clinical trials suggests that treatment may be stopped in these patients, as observed in patients with chronic lymphocytic leukemia who received combination therapy with venetoclax and rituximab. Study Design and Methods: TrAVeRse (NCT#05951959) is a phase 2, open-label, randomized, multicenter, international study of AVR in patients with TN MCL. Patients aged ≥18 years with an Eastern Cooperative Oncology Group performance status of 0-2 (3 if due to lymphoma), and Ann Arbor stage II, III, or IV disease are eligible. Key exclusion criteria are active central nervous system involvement by lymphoma or leptomeningeal disease, severe/life-threatening illness or medical condition, clinically significant cardiovascular disease, stroke, or intracranial hemorrhage within 6 months of enrollment, and any active uncontrolled infection. Approximately 125 patients will be screened to achieve a study population of 100 patients. During the induction phase, patients will receive oral acalabrutinib 100 mg twice daily (BID) in 28-day cycles for 13 cycles, starting at cycle 1; oral venetoclax once daily, starting at cycle 2 at a dose of 20 mg daily, with ramp-up to a maximum of 400 mg daily over 5 weeks for a total of 12 cycles; and intravenous rituximab 375 mg/m 2 on day 1 of every cycle for 12 cycles, starting at cycle 1. Patients who complete 13 cycles of AVR induction will be centrally tested for MRD status and continue to receive acalabrutinib 100 mg BID for 1 additional cycle (cycle 14) while awaiting disease response assessment and MRD results. Patients who achieve an MRD-negative CR (in peripheral blood at a threshold of 10 -5) at the end of induction will be randomly assigned in a 1:1 ratio to either continue to receive acalabrutinib 100 mg BID or to observation from cycle 15. Randomization will be stratified according to the simplified MCL International Prognostic Index [sMIPI] score (low [score, 0-3] and intermediate risk [4-5] vs high risk [6-11]), histologic features (blastoid or pleomorphic vs classical histology), and TP53 status (mutated vs unmutated). Those with an MRD-positive CR, partial response (PR), or stable disease (SD) at end of induction will continue to receive acalabrutinib 100 mg BID until disease progression, death, or unacceptable toxicity. Patients who progress during observation may be retreated with acalabrutinib 100 mg BID at relapse. The primary endpoint of this study is the MRD-negative CR rate at the end of AVR induction (ie, end of cycle 13). Secondary endpoints include MRD-negative CR rate at any point during the study, objective response rate and CR rate, duration of response, time to next treatment, progression-free survival, event-free survival, overall survival, safety, and tolerability. The study will also assess the feasibility of response-adapted treatment cessation for those who achieve MRD-negative CR after AVR induction and the efficacy of acalabrutinib retreatment in the subgroup of patients randomized to observation who subsequently relapse. Patients will be followed for 36 months post last patient randomized. Enrollment is planned to begin Q3 of 2023 including sites in North America, Australia, and Europe. Summary: This study will evaluate the efficacy of AVR, a chemotherapy-free triplet combination therapy, in patients with TN MCL.

Effectivness and Safety of Orelabrutinib in Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: A Retrospective, Real-World Study in China

Introduction: Orelabrutinib is a second-generation Bruton tyrosine kinase inhibitor (BTKi) with high kinase selectivity. Clinical studies have demonstrated that orelabrutinib achieved a high complete response rate of 26.3% in relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), showing promising efficacy and acceptable safety profile. However, the real-world data of Orelabrutinib are not available. This study aimed to evaluate the effectiveness and safety of orelabrutinib-containing regimens for the treatment of patients (pts) with CLL/SLL in a real-world setting. Methods: This was a retrospective, multi-center, real-world study conducted. Pts (aged 18 years or older) with CLL/SLL who received at least 3 months of orelabrutinib-containing regimens between December 2020 and March 2023 were analyzed. Efficacy was evaluated by hematologic response rate (HRR), defined as the proportion of pts who met at least 1 of the following hematologic response criteria: hemoglobin response (pts having a recovery of hemoglobin value or ≥50% increase from baseline), platelet response (pts having a recovery of platelet count or ≥50% increase from baseline), or lymphocyte response (pts having a recovery of lymphocyte count or ≥50% reduction from baseline). Safety was assessed by adverse events (AEs) as per NCI-CTCAE 5.0. Results: 24 pts with CLL/SLL (12 males; 22 CLL) were included, with a median age of 62.5 years (range: 38-82). Most pts had an Eastern Cooperative Oncology Group score of 0-1 (17/24, 70.8%) and Rai stage III or IV disease (16/18, 88.9%). 7 pts with hypertension, of which 2 with very high-risk hypertension. 3 pts have previously received other BTKi. A total of 9 pts(37.5%) performed del(17p), TP53, or IGHV testing. Among them, pts received orelabrutinib 100 mg (2/24,) or 150 mg (22/24,) once daily. As of the cut-off date (July 13, 2023), the median follow-up was 10.67 (range, 2.73-25.77) months. 18 pts (16 CLL, 2 SLL) with abnormal hemoglobin value, platelet count, or lymphocyte count at baseline were evaluable for hematologic response. Hematologic response was achieved in 11 (61.1%) of 18 evaluable pts. Pts aged <65 years had a higher HRR versus pts aged ≥65 years (87.5% vs. 40.0%, p=0.040). HRR was 56.3% in CLL versus 100.0% in SLL pts, and 60.0% in pts with hypertension versus 61.5% without hypertension . Four of 11 responders had a hematologic response in at least two criteria (CLL, n=3; SLL, n=1), of which 3 pts had a hemoglobin response (Figure 1). The most commonly reported AEs included hemoglobin decreased (16.7%) and platelet count decreased (16.7%). Grade ≥3 AEs were white blood cell count decreased (4.2%), platelet count decreased (4.2%), and lymphocyte count decreased (4.2%). No pts experienced severe AEs. No cardiovascular AEs were reported during treatment in 7 pts with hypertension at baseline. Conclusions: This real-world study assessed the preliminary characteristics and clinical outcome of patients receiving orelabrutinib-containing regimens under routine clinical practice conditions in China. The orelabrutinib-containing regimens in this study furnished beneficial evidence for the treatment of CLL/SLL and is essential for determining the best treatment option, future data with a larger sample and longer follow-up will be updated.

Real-World Effectiveness and Safety Outcomes of Acalabrutinib Treatment By Line of Therapy in Patients with Chronic Lymphocytic Leukemia and/or Small Lymphocytic Lymphoma

Background: Acalabrutinib is a second-generation Bruton tyrosine kinase inhibitor (BTKi) approved by the Food and Drug Administration for the treatment of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). Data from phase 3, randomized, controlled trials of acalabrutinib, as monotherapy or in combination with obinutuzumab, in patients with treatment-naive (TN) and relapsed/refractory (R/R) CLL with long-term follow-up, including ELEVATE-TN, ELEVATE-RR, and ASCEND, have demonstrated sustained improvement vs comparators in progression-free survival and overall survival (OS) with cardiovascular (CV) and bleeding events consistent with previous reports (Sharman et al. J Clin Oncol. 2021; Byrd et al. J Clin Oncol. 2021; Ghia et al. Blood. 2022). As real-world evidence of the acalabrutinib effectiveness and safety profile is limited in CLL/SLL patients, this study aimed to describe time to next treatment (TTNT), OS, and CV and bleeding events in patients receiving first-line (1L) and later-line (2L+) acalabrutinib for the treatment of CLL/SLL in the real-world setting. Methods: A retrospective, observational analysis was conducted utilizing the Optum Clinformatics © Data Mart claims and electronic medical record database to identify patients aged ≥18 years with TN or R/R CLL/SLL who initiated acalabrutinib in any line of therapy (LoT) on or after November 21, 2019 (FDA approval date for acalabrutinib). Patients with CLL/SLL were required to have ≥6 months of continuous enrollment in the Optum database system prior to acalabrutinib treatment initiation. Patients were followed until the earliest of last day of data availability, death, or end of study period (September 30, 2022). Treatment effectiveness was described as TTNT (time from acalabrutinib initiation to next LoT or death of any cause) and OS (time from acalabrutinib initiation to date of death from any cause or end of study period). The Kaplan-Meier (KM) method was used to estimate TTNT and OS. Patients who continued treatment at the last follow-up were censored. CV and bleeding events were assessed in all patients who initiated acalabrutinib. All outcomes were evaluated in patients who received 1L or 2L+ acalabrutinib therapy. Results: A total of 530 patients were identified and included in the analysis. Of these patients, 63% (n=334) received 1L acalabrutinib and 37% (n=196) received 2L+ acalabrutinib. At acalabrutinib initiation, the mean age was 72.8 years in the 1L cohort and 74.2 years in the 2L+ cohort; 61.7% (121/196) of patients treated with 2L+ acalabrutinib had prior BTKi therapy prior to acalabrutinib initiation (ibrutinib, n=120; zanubrutinib, n=1). Distributions of gender and race were similar between the cohorts. At baseline, 18.1%, 75.3%, and 16.0% of patients had atrial fibrillation/flutter, hypertension, and bleeding episodes, respectively. With a median follow-up of 8.9 months in the 1L cohort and 12.4 months in the 2L+ cohort, the median TTNT and OS were not reached in either cohort. At 18 months, the proportion of patients remaining on treatment was 82% in the 1L cohort and 78% in the 2L+ cohort ( Figure 1). Of the patients that progressed, the median TTNT was 4.0 months in the 1L cohort (n=33) and 4.2 months in the 2L cohort (n=31). The 18-month OS rate was 90% and 85% for the 1L and 2L+ cohorts, respectively ( Figure 2). After initiation of acalabrutinib treatment, the incidence rates of atrial fibrillation/flutter, hypertension, and bleeding events were 2.7%, 8.9%, and 2.7% of patients in the 1L cohort and 7.4%, 2.4%, and 3.3% of patients in the 2L+ cohort, respectively, who had no history of these events prior to treatment with acalabrutinib. Conclusions: This is the first study demonstrating real-world effectiveness (OS and TTNT) and safety data of acalabrutinib treatment in first-line and later-line therapy. While clinical trial and clinical practice settings may differ, overall, the survival findings in this study were similar to those of acalabrutinib trials. The observed incidence rates of CV and bleeding events were not inconsistent with those observed in published acalabrutinib trials.

Gene Panels for Intraocular Lymphoma Can Overcome Diagnostic Difficulties and Enable Precision Medicine

Background: Definitive diagnosis of intraocular lymphoma (IOL) is often challenging, at least partially due to limited accessibility to the lesion and the rarity of tumor cells, with pathologically false-negative results reportedly occurring in approximately 30% of cases. Delayed diagnosis is often an important clinical issue, and the average time to diagnosis is approximately 1.5 years.Because of delayed diagnosis, IOLs are often found only after central nervous system (CNS) invasion has occurred, possibly leading to worse treatment outcomes. In this study, we tried to overcome diagnostic difficulties by using gene panel diagnostics of IOL. Furthermore, genetic analysis of IOLs may be able to predict the risk of recurrence.in Japan, a second-generation Bruton's tyrosine kinase (BTK) inhibitor, tirabrutinib, has been approved for the treatment of relapsed/refractory CNS lympoma. Herein, we present a case of IOL and CNS lesion with MYD88 mutation treated with tirabrutinib as part of precision medicine. Methods: We have developed a digital polymerase chain reaction-based system for multiplex gene panel testing of cell-free DNA (cfDNA) obtained from intraocular liquid biopsies (patent number 7149000, 2022/9/30). Our system can detect specific gene mutations in minute cfDNA by amplifying specific gene loci in bubbles, even from an extremely small number of cells. Using this multiplex gene panel testing, we analyzed genetic mutations in nine regions of four genes, MYD88, CD79B, BTG2, and PIM1, using cfDNA obtained from intraocular liquid biopsies. The diagnostic performance of the novel system was evaluated in 86 samlpes of patients with IOL. We also retrospectively analyzed the prognostic potential of the genetic mutations for IOL. Lastly, in the case of CNS lymphoma and IOL, we presented the MYD88 mutation treated with tirabrutinib. Results: Among the four disease-specific genes, the MYD88 mutation was present in 55 of 86 cases (64%), and frequencies of the CD79B, BTG2, and PIM1 mutations were 47%, 38%, and 29%, respectively. At least one of these mutations was found in 83 of the 86 IOL cases examined (97%), making this assay highly sensitive (Fig. 1). The MYD88 mutation was not associated with recurrence in patients with recurrent and refractory CNS lymphoma and IOL. Conversely,patients with the CD79B mutation had high rates of relapse for CNS lymphoma: the 4-year rate of recurrence-free survival was 35%, compared to 79% in patients without the CD79B mutation (p=0.012). Patients with the BTG2 mutation also had high rates of relapse (Fig. 2). Furthermore, we present a case of CNS lynphoma and IOL. By testing IOL gene panel, only MYD88 mutation was detected in the vitreous sample of IOL patient. We have experienced this case in which the second-generation BTK inhibitor,tirabrutinib, was effective not only for central but also for intraocular lesions. Conclusion: Our panel enables rapid and accurate diagnosis of IOL with only a small sample of intraocular liquid. We believe that this multiplex gene panel testing may aid in the diagnosis of IOL in difficult-to-diagnose patients, including those with chronic uveitis, by preventing CNS invasion due to diagnostic delay. Moreover, genetic profiling panels of IOL can help to stratify clinical outcomes.CD79B and BTG2 mutation is a potent predictive marker for relapse. In the clinical setting, we experienced a case of IOL with MYD88 mutation in which tirabrutinib was effective. Potentially, tirabrutinib also penetrates directly into the eye in intraocular lesions. Oral drug, tirabrutinib as eye dripping drug, might be effective as a therapeutic option for IOL and should be assessed in future clinical trials of precision medicine for IOL.

ASC2ESCALATE: A US Phase 2, Open-Label, Single-Arm, Dose-Escalation Study of Asciminib (ASC) Monotherapy in Patients (Pts) with Chronic Myeloid Leukemia in Chronic Phase (CML-CP) As Second-Line (2L) and First-Line (1L) Treatment

CONCLUSIONS Adenosine triphosphate (ATP)-competitive tyrosine kinase inhibitors (TKIs) have increased survival in CML, although resistance and intolerance remain challenges, which often necessitate switch to another TKI. Many pts discontinue 1L treatment due to resistance/intolerance and switch to 2L therapy, to which resistance is typically higher. A need exists for effective, safe treatment options for pts in 1L and 2L. ASC is thefirst approved BCR::ABL1 inhibitor that Specifically Targets the ABL Myristoyl Pocket (STAMP), with activity against most BCR::ABL1 kinase domain mutations conferring resistance to ATP-competitive TKIs, potentially providing a new early-line treatment option. ASC was first approved in the United States for pts with CML-CP after ≥2 TKIs at 80 mg once daily (QD) or 40 mg twice daily (BID) and for pts with CML-CP with the T315I mutation at 200 mg BID. A large, phase 1, dose-escalation trial (NCT02081378) demonstrated efficacy and tolerability of ASC across a broad range of dosages. Also, with >2 years of follow-up, ASC demonstrated superior efficacy and better safety and tolerability compared with bosutinib in pts with CML-CP without the T315I mutation after ≥2 prior TKIs in the phase 3 ASCEMBL study (NCT03106779). We describe the phase 2 ASC2ESCALATE trial investigating efficacy and safety of ASC with dose escalation in pts with CML-CP receiving ASC as their 2L or 1L therapy. This is a phase 2, open-label, multicenter, single-arm, dose-escalation study with sites in the United States (NCT05384587) (Figure). Pts receiving ASC as their 2L TKI must be adults with non-T315I CML-CP who discontinued their first ATP-competitive TKI for warning response ( BCR::ABL1IS >1%-10% after 6 months or >0.1%-1% after 12 months of 1L treatment), resistance ( BCR::ABL1IS >10% after 6-12 months or >1% or loss of major molecular response [MMR] after >12 months of 1L treatment), or intolerance (with BCR::ABL1IS >0.1% at screening). In addition to pts receiving ASC as their 2L TKI, a separate cohort of newly diagnosed pts will be included, and these pts may receive up to 4 weeks of prior treatment with imatinib or an approved second-generation TKI (Table). All pts will start treatment with ASC 80 mg QD. Pts achieving BCR::ABL1IS ≤1% at 6 months will continue at the same dose; pts not achieving BCR::ABL1IS ≤1% at 6 months will have their dose escalated to 200 mg QD. In pts not achieving MMR at 12 months, dose escalation from 80 to 200 mg QD or from 200 mg QD to 200 mg BID will occur or the pt will be taken off the study. If pts have grade ≥3 or persistent grade 2 toxicity refractory to optimal management, no dose escalation will occur, and pts will remain on ASC at their most current dose. This dose-escalation strategy applies to both the 2L and 1L cohorts. The primary endpoint is MMR rate at 12 months in pts using ASC as their 2L TKI. As all primary and secondary endpoints for the 2L cohort will be measured for the 1L cohort as secondary endpoints, the MMR rate at 12 months in pts receiving ASC as their 1L TKI is a secondary endpoint. Additional secondary endpoints are the same for both 2L and 1L cohorts and include MMR rates at 3, 6, 18, and 24 months; MMR rates by all scheduled time points; MR 2 ( BCR::ABL1IS ≤1%), MR 4 ( BCR::ABL1IS ≤0.01%), and MR 4.5 ( BCR::ABL1IS ≤0.0032%) at and by scheduled time points; time to and duration of MMR; time to treatment failure; progression-free survival; overall survival; and safety/tolerability. Exploratory endpoints include assessment of BCR::ABL1 mutations. ASC2ESCALATE is the first clinical trial designed to assess pts with CML-CP using ASC as their 2L TKI and will provide critical information on efficacy and safety of dose escalation in pts for whom certain response milestones are not met in 2L and 1L. Dose escalation of ASC in 2L and 1L is another treatment strategy and results from ASC2ESCALATE will add to the growing body of evidence for using ASC to treat pts with CML-CP. Recruitment for pts using ASC as their 2L TKI began November 2022, and as of July 10, 2023, 5 pts have been enrolled in this cohort; Up to 92 and 90 pts are estimated to enroll in the 2L and 1L cohorts, respectively, across 90 sites.

Ponatinib Versus Imatinib in Patients with Newly Diagnosed Ph+ ALL: Subgroup Analysis of the Phase 3 Phallcon Study

Background: BCR::ABL1 tyrosine kinase inhibitors (TKIs) in combination with chemotherapy or steroids remain the standard of care in patients with newly diagnosed Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). Most patients treated with first- or second-generation TKIs eventually experience disease progression due to treatment resistance. Ponatinib is the only currently approved pan-BCR::ABL1 inhibitory TKI that potently inhibits wild-type and single resistance mutation variants of BCR::ABL1, including T315I. Multiple studies have shown promising minimal residual disease (MRD) negativity (neg) rates and survival outcomes with ponatinib in combination with chemotherapy or chemotherapy-free regimens. PhALLCON (NCT03589326) is the first randomized study comparing frontline TKIs in adults with Ph+ ALL. The primary endpoint for PhALLCON was met, with a clinically significantly higher MRD-neg complete remission (CR) rate at end of induction (EOI) with ponatinib vs imatinib (34.4% vs 16.7%; risk difference: 0.18 [95% confidence interval (CI): 0.06‒0.29]; P=0.0021) and a manageable safety profile comparable with imatinib. Here we report subgroup efficacy analyses from PhALLCON. Methods: This global, registrational, phase 3, open-label study randomized newly diagnosed adult patients with Ph+ ALL 2:1 to receive ponatinib (30 mg once daily [QD]) or imatinib (600 mg QD) plus reduced-intensity chemotherapy through EOI (Cycles 1-3), consolidation (Cycles 4-9), and post-consolidation (Cycles 10-20). Following post-consolidation, patients continued to receive single-agent ponatinib or imatinib until disease progression or unacceptable toxicity. The composite primary endpoint was MRD-neg ( BCR:: ABL1 ≤0.01% [MR4])CR for 4 weeks at EOI. Event-free survival (EFS; any-cause death, failure to achieve CR by EOI, relapse from CR) was a key secondary endpoint. A post-hoc analysis of progression-free survival (PFS; EFS-defined events, failure to achieve MRD-neg by the end of treatment, and loss of MRD-neg) was conducted. Subgroup analyses were performed relative to baseline demographic and disease characteristics. Results: Of 245 randomized patients, 232 (ponatinib, n=154; imatinib, n=78) had baseline BCR::ABL1 p190/p210 variants verified by central lab (efficacy-evaluable population); median age was 54 years (37.1% ≥60 years). As of Aug 2022, 78 patients (ponatinib/imatinib: 68 [41.5%]/10 [12.3%]) remained on study treatment; the top 3 reasons for discontinuation were hematopoietic stem cell transplantation (HSCT; 30.5%/37.0%), adverse events (12.2%/12.3%), and lack of efficacy (7.3%/25.9%). Median follow-up in the ponatinib and imatinib arms was 20 months and 18 months, respectively. Benefit for ponatinib was observed across all subgroups analyzed ( Table). All age subgroups had higher rates of MRD-neg CR with ponatinib vs imatinib, with the greatest benefit observed in patients ≥60 years (40.0% ponatinib vs 10.3% imatinib; P=0.0005). MRD-neg CR rate was higher for ponatinib vs imatinib among those with the BCR::ABL1 p190 variant (38.6%/17.0%; P=0.0017); it was higher for the p210 variant as well, but not significantly (22.5% vs 16.0%; P=0.51). Median PFS was longer with ponatinib vs imatinib regardless of age, with the greatest difference observed in the subgroup of patients ≥60 years (22.5 months for ponatinib vs 8.3 months for imatinib; hazard ratio: 0.594 [95% CI: 0.332-1.063]). Conclusions: Ponatinib was superior to imatinib in combination with reduced-intensity chemotherapy in the front-line setting for patients with Ph+ ALL, with a clinically significantly higher MRD-neg CR rate at EOI. Benefit was observed across all subgroups, particularly for patients ≥60 years and for those with the BCR::ABL1 p190 variant.