Major Molecular Response Rates Research Articles

Real-world outcomes of ponatinib treatment in 724 patients with CML and Ph+ ALL: a post-marketing surveillance study with a special interest in arterial occlusive events in Japan.

In September 2016, ponatinib was approved in Japan for the treatment of patients with chronic myeloid leukemia with resistance/intolerance to prior tyrosine kinase inhibitors and patients with relapsed or refractory Philadelphia chromosome-positive acute lymphoblastic leukemia. We conducted a post-marketing all-case surveillance to study the safety and efficacy of ponatinib in clinical practice, focusing on arterial occlusive events. Data from 724 patients were collected for 2years from the initiation of ponatinib. The arterial occlusive events were reported in 6.49% (47/724) with an exposure-adjusted incidence rate of 6.8/100 person-years. The risks associated with arterial occlusive events were age and comorbidities including hypertension and diabetes. At 104weeks, the cumulative major molecular response rate in patients with chronic-phase chronic myeloid leukemia was 67.2% and the complete cytogenetic response in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia was 80.0%. Furthermore, the estimated 1-year overall survival rate was 98.5% for chronic-phase chronic myeloid leukemia and 68.6% for Philadelphia chromosome-positive acute lymphoblastic leukemia. This surveillance demonstrated that ponatinib has a favorable safety and efficacy profile in Japanese patients and also showed the necessity of closely monitoring arterial occlusive events in older adults and patients with predisposing factors for atherosclerosis.

Treatment of chronic-phase chronic myeloid leukemia in patients randomized to dasatinib or imatinib after suboptimal responses to three months of imatinib therapy: final 5-year results from DASCERN.

Early molecular response (EMR) at 3 months is predictive of improved overall survival (OS) and progression-free survival (PFS) in patients with chronic myeloid leukemia in the chronic phase (CML-CP). Although about one-third of patients treated with first-line imatinib do not achieve EMR, long-term OS and PFS are still observed in most patients. DASCERN (NCT01593254) is a prospective, phase IIb, randomized trial evaluating a switch to dasatinib in patients who have not achieved EMR after 3 months of treatment with first-line imatinib. Early analysis demonstrated an improved major molecular response (MMR) rate at 12 months with dasatinib versus imatinib (29% vs. 13%, P=0.005). Here, we report results from the final 5-year follow-up. In total, 174 patients were randomized to dasatinib and 86 to remain on imatinib. Forty-six (53%) patients who remained on imatinib but subsequently experienced failure were allowed to cross over to dasatinib per protocol. At a minimum follow-up of 60 months, the cumulative MMR rate was significantly higher in patients randomized to dasatinib versus imatinib (77% vs. 44%, P.

Efficacy and safety of flumatinib in the treatment of newly diagnosed chronic myeloid leukemia in the chronic phase: A real-world single-center retrospective study, with a focus on premature drug discontinuation

PurposeTo assess the real-world efficacy and safety of flumatinib as first-line and post-line treatments for chronic myeloid leukemia in the chronic phase (CML-CP). ResultsAmong 141 patients receiving flumatinib as first-line and post-line treatment, the 12-month major molecular response (MMR) rates were 69.4% and 67.6%, respectively. The median time to response was 6 and 10.5 months, respectively. In post-line treatment, the early molecular response (EMR) of flumatinib as second-line is significantly superior to that of third-line treatment (3-month EMR rate: 79.2% vs. 39.3%, P<0.001; 3-month MMR rate: 45.8% vs. 21.4%, P=0.033). Contrastively, patients who switched to flumatinib due to intolerance had significantly higher MMR rates at 3, 6, and 12 months compared to patients who switched due to inadequate response (60.6% vs. 24.2%, P=0.003; 66.7% vs. 36.0%, P=0.027; 84.2% vs. 50.0%, P=0.038). Premature drug discontinuation was observed in 28.4% of the patients. Grades 3–4 hematologic adverse events (AEs) were identified as independent risk factors for premature drug discontinuation. Patients who discontinued treatment and those who previously received only imatinib therapy had a poorer molecular response and failure-free survival. ConclusionsFlumatinib demonstrates favorable efficacy and safety. Treatment discontinuation can result in a poorer molecular response and long-term prognosis.

Frontline combination of dasatinib and low-intensity chemotherapy in adults with de novo Philadelphia chromosome-positive acute lymphoblastic leukemia

ABSTRACT Background Studies on dasatinib-based low-intensity induction regimens and post-remission strategies are limited in China. Therefore, we conducted a single-center phase 2 trial in newly diagnosed adult patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) to establish the efficacy and safety of this treatment approach. Research design and methods Patients received one month of dasatinib plus low-intensity chemotherapy and two months of dasatinib monotherapy for induction, followed by a single course of high-dose methotrexate for consolidation. Subsequently, they underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) or tyrosine kinase inhibitor (TKI)-based treatment for maintenance therapy between October 2015 and August 2022. Results Twenty-two patients were enrolled. Median age was 45 years (range, 20–71). The rates of major and complete molecular responses in the third month were 18.2% and 40.9% respectively. With a median follow-up of 15 months (range, 5–89), the estimated 3-year disease-free survival (DFS) and overall survival (OS) were 52.4% and 73.2%, respectively. The TKI-based cohort had a significantly poorer DFS (p = 0.014) and OS (p = 0.008) than the allo-HSCT cohort. Conclusions Our results suggest that dasatinib-based low-intensity chemotherapy is safe and effective as an induction strategy in the Chinese population. Allo-HSCT plays a crucial role in the long-term outcomes of patients with Ph+ ALL. Clinical trial registration The trial was registered at ClinicalTrials.gov as NCT02690922.

Oral arsenic plus imatinib versus imatinib solely for newly diagnosed chronic myeloid leukemia: a randomized phase 3 trial with 5-year outcomes

PurposeThe synergistic effects of combining arsenic compounds with imatinib against chronic myeloid leukemia (CML) have been established using in vitro data. We conducted a clinical trial to compare the efficacy of the arsenic realgar–indigo naturalis formula (RIF) plus imatinib with that of imatinib monotherapy in patients with newly diagnosed chronic phase CML (CP-CML).MethodsIn this multicenter, randomized, double-blind, phase 3 trial, 191 outpatients with newly diagnosed CP-CML were randomly assigned to receive oral RIF plus imatinib (n = 96) or placebo plus imatinib (n = 95). The primary end point was the major molecular response (MMR) at 6 months. Secondary end points include molecular response 4 (MR4), molecular response 4.5 (MR4.5), progression-free survival (PFS), overall survival (OS), and adverse events.ResultsThe median follow-up duration was 51 months. Due to the COVID-19 pandemic, the recruitment to this study had to be terminated early, on May 28, 2020. The rates of MMR had no significant statistical difference between combination and imatinib arms at 6 months and any other time during the trial. MR4 rates were similar in both arms. However, the 12-month cumulative rates of MR4.5 in the combination and imatinib arms were 20.8% and 10.5%, respectively (p = 0.043). In core treatment since the 2-year analysis, the frequency of MR4.5 was 55.6% in the combination arm and 38.6% in the imatinib arm (p = 0.063). PFS and OS were similar at five years. The safety profiles were similar and serious adverse events were uncommon in both groups.ConclusionThe results of imatinib plus RIF as a first-line treatment of CP-CML compared with imatinib might be more effective for achieving a deeper molecular response (Chinadrugtrials number, CTR20170221).

Combination of dasatinib and venetoclax in newly diagnosed chronic phase chronic myeloid leukemia.

The dual inhibition of the BCR::ABL1 tyrosine kinase and BCL-2 could potentially deepen the response rates of chronic myeloid leukemia in chronic phase (CML-CP). This study evaluated the safety and efficacy of the combination of dasatinib and venetoclax. In this phase 2 trial, patients with CML-CP or accelerated phase (clonal evolution) received dasatinib 50 mg/day for three courses; venetoclax was added in course 4 for 3 years. The initial venetoclax dose was 200 mg/day continuously but reduced later to 200 mg/day for 14 days, and to 100 mg/day for 7 days per course once a molecular response (MR)4.5 was achieved. After 3 years of combination, patients were maintained on single-agent dasatinib. The primary end point was the rate of major molecular response (MMR) by 12 months of combination. Sixty-five patients were treated. Their median age was 46 years (range, 23-73). By 12 months of combination, the MMR, MR4, and MR4.5 rates were 86%, 53%, and 45%, respectively. After a median follow-up of 42 months, the 4-year event-free and overall survival rates were 96% and 100%, respectively. Outcomes with the combination were comparable to historical outcomes with single-agent dasatinib (cumulative 12-months MMR rate of 79% with both strategies). The incidence of grade 3-4 neutropenia was 22% with the combination and 11% with single-agent dasatinib (p<.001). Treatment with dasatinib and venetoclax was safe and effective in CML-CP. The cumulative response rates with the combination were similar to those with single-agent dasatinib. Further follow-up is needed to evaluate the rates of durable deep molecular response and treatment-free remission.

Nilotinib with or without cytarabine for Philadelphia-positive acute lymphoblastic leukemia

AbstractWe previously demonstrated that a reduced-intensity chemotherapy schedule can safely replace hyper-CVAD (cyclophosphamide-vincristine-adriamycin-dexamethasone) cycle 1 when combined with imatinib in adults with Philadelphia-positive acute lymphoblastic leukemia. In the present randomized GRAAPH-2014 trial, we used nilotinib and addressed the omission of cytarabine (Ara-C) in consolidation. The primary objective was the major molecular response (MMR) rate measured by BCR::ABL1 quantification after cycle 4 (end of consolidation). All patients were eligible for allogeneic stem cell transplant (SCT), whereas those in MMR could receive autologous SCT, followed by 2-year imatinib maintenance in both cases. After the enrollment of 156 of 265 planed patients, the data and safety monitoring board decided to hold the randomization because of an excess of relapse in the investigational arm. Among the 155 evaluable patients, 77 received Ara-C during consolidation (arm A) and 78 did not (arm B). Overall, 133 patients (85%) underwent SCT, 93 allogeneic and 40 autologous. The noninferiority end point regarding MMR was reached with 71.1% (arm A) and 77.2% (arm B) of patients reaching MMR. However, the 4-year cumulative incidence of relapse was higher in arm B compared with arm A (31.3% [95% confidence interval {CI}, 21.1%-41.9%] vs 13.2% [95% CI, 6.7%-21.9%]; P = .017), which translated to a lower relapse-free survival. With a median follow-up of 3.8 years, 4-year overall survival was 79.0% (95% CI, 70.6%-89.3%) in arm A vs 73.4% (95% CI, 63.9%-84.4%) in arm B (P = .35). Despite a noninferior rate of MMR, more relapses were observed when ARA-C was omitted without impact on survival. ClinicalTrials.gov ID, NCT02611492.

Efficacy and safety of bosutinib in patients treated with prior imatinib and/or dasatinib and/or nilotinib: Subgroup analyses from the phase 4 BYOND study

The BYOND study evaluated the efficacy and safety of bosutinib 500 mg once daily in patients with chronic myeloid leukemia (CML) resistant/intolerant to prior tyrosine kinase inhibitors (TKIs). These post-hoc analyses assessed the efficacy and safety of bosutinib by resistance or intolerance to prior TKIs (imatinib-resistant vs dasatinib/nilotinib-resistant vs TKI-intolerant), and cross-intolerance between bosutinib and prior TKIs (imatinib, dasatinib, nilotinib), in patients with Philadelphia chromosome–positive chronic phase CML. Data are reported after ≥3 years’ follow-up. Of 156 patients with Philadelphia chromosome–positive chronic phase CML, 53 were imatinib-resistant, 29 dasatinib/nilotinib-resistant, and 74 intolerant to all prior TKIs; cumulative complete cytogenetic response rates at any time were 83.7%, 61.5%, and 86.8%, and cumulative major molecular response rates at any time were 72.9%, 40.7%, and 82.4%, respectively. Of 141, 95, and 79 patients who received prior imatinib, dasatinib, and nilotinib, 64 (45.4%), 71 (74.7%), and 60 (75.9%) discontinued the respective TKI due to intolerance; of these, 2 (3.1%), 5 (7.0%), and 0 had cross-intolerance with bosutinib. The response rates observed in TKI-resistant and TKI-intolerant patients, and low cross-intolerance between bosutinib and prior TKIs, further support bosutinib use for patients with Philadelphia chromosome–positive chronic phase CML resistant/intolerant to prior TKIs. Trial registrationClinicalTrials.gov: NCT02228382

Clinical efficacy and safety of flumatinib versus dasatinib combined with multi-drug chemotherapy in adults with Philadelphia-positive acute lymphoblastic leukemia

Introduction: Flumatinib, a highly selective ABL kinase inhibitor, exhibits stronger inhibition of intracellular BCR-ABL tyrosine kinase activity, compared to Imatinib. However, there is limited research comparing the real-world efficacy and safety of flumatinib and dasatinib in patients with Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL). Objective: Investigating the differences in therapeutic efficacy and safety between flumatinib and dasatinib in combination with multi-drug chemotherapy for the treatment of newly diagnosed Ph+ ALL. Method: In this study, we assessed 43 patients with newly diagnosed Ph+ ALL (20 in the flumatinib group, 23 in the dasatinib group). Results: There were no significant differences in gender, age, fusion gene type, initial blood routine, bone marrow blast cell ratio or chromosome karyotype between the two groups. Within 1 month, there were no significant differences in the complete response (CR), major molecular response (MMR) or minimal residual disease (MRD) negativity rate between the flumatinib and dasatinib groups. Similarly, within 3 months, there were no significant differences in CR or MMR rates between the two groups. However, the rates of complete molecular response (CMR) and MRD negativity within 3 months were significantly higher in the flumatinib group, compared to the dasatinib group (P < 0.05). Additionally, the flumatinib group exhibited fewer adverse reactions compared to the dasatinib group. Conclusion: These findings suggest that flumatinib is a safe and effective tyrosine kinase inhibitor (TKI) for achieving CMR and MRD negativity in patients with Ph+ ALL, as supported by this small series of patients.

CFL1 is Implicated in Chronic Myeloid Leukemia Response during Imatinib Therapy.

Cofilin (CFL1) is one critical member of the actin deploy family (ADF). Overexpression of CFL1 is associated with aggressive features and poor prognosis in malignancies. We evaluated the expression of CFL1 in patients with chronic myeloid leukemia in the chronic phase (CML-CP), acute myelocytic leukemia (AML) and healthy controls. The role of CFL1 in imatinib therapy was also investigated using cell line. We found that the expression of CFL1 was lower in CML patients than that in healthy controls, and was significantly upregulated after imatinib therapy (p<0.05). CML patients with lower CFL1 achieved higher Major molecular response (MMR) rate after 6 months of imatinib therapy (p<0.05). Cofilin, P-cofilin and F-actin, especially branched F-actin were all upregulated after imatinib therapy. The lower CFL1 expression before treatment may predicts a better response to imatinib. Imatinib affects F-actin remodeling in CML patients by regulating CFL1 expression and activity.

Sustained Efficacy and Safety with Asciminib (ASC) after Almost 4 Years of Median Follow-up from Ascembl, a Phase 3 Study of ASC Vs Bosutinib (BOS) in Patients (Pts) with Chronic Myeloid Leukemia in Chronic Phase (CML-CP) after ≥2 Prior Tyrosine Kinase Inhibitors (TKIs): An End of Study Treatment (EOS Tx) Update, Including Results from Switch Population

CONCLUSIONS CML requires chronic therapy, emphasizing the need for Txs that are characterized by high, durable efficacy and a low adverse event (AE) burden. ASC, the first BCR::ABL1 inhibitor Specifically Targeting the ABL Myristoyl Pocket (STAMP), demonstrated significantly superior efficacy and better safety/tolerability compared with BOS in pts with CML-CP who received ≥2 prior TKIs in the phase 3 ASCEMBL study. Major molecular response (MMR) rate was 25.5% with ASC vs 13.2% with BOS at wk 24, meeting the primary objective, and 37.6% vs 15.8% at wk 96, meeting the key secondary objective. Despite the longer duration of exposure to ASC, safety/tolerability remained consistently better with ASC vs BOS, with fewer all-grade and grade ≥3 AEs and AEs leading to Tx discontinuation observed. After a median follow-up of 3.7 y, we report EOS Tx results from ASCEMBL (cutoff: March 22, 2023). We also report the first available data from pts who experienced Tx failure on BOS and switched to ASC. Adults (aged ≥18 y) with CML-CP after ≥2 prior TKIs, with intolerance or lack of efficacy per 2013 ELN recommendations were randomized 2:1 to receive either ASC 40 mg twice daily or BOS 500 mg once daily. Pts who met Tx failure criteria per 2013 ELN while on BOS could switch to ASC and were analyzed separately. Pts who discontinued BOS due to intolerance could not switch. EOS will occur 5 y from when the last enrolled pt received first Tx dose. A total of 233 pts were randomized to ASC (n=157) or BOS (n=76). The most common reason for discontinuation was lack of efficacy in 40 (25.5%) pts on ASC and 28 (36.8%) on BOS. At the time of EOS Tx cutoff, Tx with ASC and BOS was ongoing in 77 (49.4%) and 8 (10.5%) pts, respectively; pts deriving benefit from study Tx at EOS TX, per investigator assessment, continued receiving posttrial access. MMR rate at wk 156 continued to be higher with ASC (33.8%) than with BOS (10.5%) (Figure 1). The difference after adjusting for baseline (BL) major cytogenetic response was 23.2%(95% CI, 13.1%-33.2%; 2-sided P&amp;lt;.001). The BCR::ABL1IS ≤1% rate at wk 156 in pts without this level of response at BL also continued to be higher with ASC (43.0%) than with BOS (11.1%). Despite the longer median duration (range) of exposure to ASC (156.0 [0.1-256.3] wk) vs BOS (30.5 [1.0-239.3] wk), safety/tolerability of ASC continued to be better compared with BOS and were consistent with previous analyses. Two new pts had AEs leading to Tx discontinuation since the wk 96 cutoff (1 pt on ASC reported pregnancy; 1 pt on BOS reported diarrhea), and rates remained lower with ASC vs BOS (8.3% vs 27.6%). The most frequent (≥10%) grade ≥3 AEs with ASC vs BOS were thrombocytopenia (22.4% vs 9.2%), neutropenia (18.6% vs 14.5%), diarrhea (0% vs 10.5%), and increased alanine aminotransferase (0.6% vs 14.5%). Most AEs occurred within the first 6 months (Figure 2). Exposure-adjusted incidence rates of arterial occlusive events (AOEs) with ASC decreased since the wk 96 cutoff, from 3.0 to 2.2 per 100 pt-y, and no new AOEs occurred with ASC, indicating that the risk of AOEs did not increase over time. Among pts who discontinued Tx due to lack of efficacy or disease progression, no new mutations occurred since the wk 96 cutoff. Of 28 pts who discontinued BOS for lack of efficacy, 25 switched to ASC. Almost all switch pts (96%) had BL BCR::ABL1IS &amp;gt;10% prior to switch. No switch pts achieved MMR at or by wk 48 post switch. However, at wk 48, 24% achieved BCR::ABL1IS ≤10% and 8% achieved BCR::ABL1IS ≤1%. The safety profile of ASC in switch pts was consistent with that in pts receiving ASC in the randomized period. Most frequent (≥10%) grade ≥3 AEs were neutropenia (32.0%) and thrombocytopenia (24.0%). AEs leading to Tx discontinuation occurred in 8.0% of switch pts. With almost 4 y of follow-up in ASCEMBL, ASC continued to show greater efficacy and better safety/tolerability than BOS in pts with CML-CP after ≥2 prior TKIs. The robust safety profile of ASC was sustained through each analysis in ASCEMBL (wk 24, wk 96, and EOS Tx), confirming that pts receiving ASC can maintain a high level of response and continue Tx without experiencing late-emerging AEs. Results in the switch population support the use of ASC early in the Tx paradigm. ASCEMBL EOS Tx results continue to strongly support ASC as the therapy of choice for pts with suboptimal responses and/or intolerance to ≥2 prior TKIs, allowing more pts to remain on Tx and achieve their Tx goals without needing to switch.

Flumatinib Versus Nilotinib for Newly Diagnosed Chronic Phase Chronic Myeloid Leukemia

Introduction Tyrosine kinase inhibitors (TKIs) have considerably improved the long-term clinical outcomes in patients with chronic phase chronic myeloid leukemia (CML-CP). Most of these patients receive 1 st generation TKI imatinib as first-line therapy; however, an increasing number of patients are now receiving 2 nd generation TKIs as first-line therapy, because of the more potent BCR-ABL1 inhibition with proven efficacy in patients resistant or intolerant to imatinib. Flumatinib is a novel 2 nd generation BCR-ABL1 TKI with promising efficacy and manageable safety in newly diagnosed CML-CP. Compared to imatinib, patients treated with flumatinib have achieved significantly higher rates of 12-month major molecular response (MMR) and complete cytogenetic response were observed in patients with CML-CP and that too within a shorter time duration. Though there have been many studies comparing 2 nd generation TKIs vs imatinib in CML-CP, studies comparing clinical outcomes between different 2 nd generation TKIs are scarce. Here, we report the real-world effectiveness and safety of flumatinib and nilotinib in patients with newly diagnosed CML-CP. Methods In this study, adult patients (≥18 years old) with newly diagnosed Philadelphia chromosome-positive (Ph+) CML-CP who received either 300 mg nilotinib twice daily or 600 mg flumatinib once daily, were included, with a follow-up duration of roughly 3 years (NCT04739826). The primary endpoint was the rate of MMR at 12 months as defined by European LeukemiaNet 2020 recommendations (BCR-ABL1 transcript level ≤0.1% in peripheral blood on RT-PCR assay on International Scale [IS]).The secondary endpoints were the rate of early molecular response (EMR) at 3 months (BCR-ABL1 IS ≤10%), the rate of molecular response at 6 months (BCR-ABL1 IS ≤ 1%) and safety (adverse events [AEs] reports in accordance to Common Terminology Criteria for Adverse Events, version 4.03). Results A total of 446 patients were enrolled in the study between November 2020 and August 2022, of which 150 and 296 patients were enrolled in nilotinib and flumatinib groups, respectively. The baseline characteristics were comparable between the two groups (Table 1). No significant difference in the rate of MMR was observed at 12 months between nilotinib and flumatinib (78% vs 80%; P=0.68) . Similarly, no significant difference was observed in the rate of EMR at 3 months (85% vs 89%; P=0.26) and the rate of optimal molecular response at 6 months (93% vs 92%; P=0.70; BCR-ABL1 is ≤1%) between the two groups. The overall safety profile was similar between the two groups. However, hyperbilirubinemia (47% vs 7%), increased ALT (33% vs 12%), increased AST (24% vs 9%), rash (30% vs 18%) and anemia (19% vs 10%) were more frequent in nilotinib group than flumatinib group, whereas diarrhea was lower in nilotinib than flumatinib (2.7% vs 8.8%). The incidence rate of grade 3-4 AEs were reported to be 13% in nilotinib group and 10% in flumatinib group. The safety of flumatinib was more favorable compared to nilotinib in terms of hepatic toxicities, skin toxicities, etc. (Figure 1). Conclusion The efficacy of flumatinib is comparable to nilotinib in Chinese patients with newly diagnosed Ph+ CML-CP. The overall incidences of grade 3-4 AEs were also accessible for the two drugs, nevertheless, a few AEs inclusively hepatic toxicity, anemia and skin toxicity were remarkably lower with flumatinib intervention.

Update of Olverembatinib (HQP1351) Overcoming Ponatinib and/or Asciminib Resistance in Patients (Pts) with Heavily Pretreated/Refractory Chronic Myeloid Leukemia (CML) and Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph + ALL)

Background Olverembatinib, a novel, potent BCR::ABL1 tyrosine kinase inhibitor (TKI), shows strong antitumor activity in pts with CML and Ph + ALL. Here, we report on the safety, efficacy, and pharmacokinetic (PK) profiles of olverembatinib in pts with CML (all phases) and Ph + ALL outside of China, particularly in pts previously treated with ponatinib and/or asciminib. Methods Olverembatinib was administered orally once every other day (QOD) in continuous 28-day cycles. In the monotherapy cohort, pts were enrolled after treatment failure on at least 2 prior TKIs and randomized to olverembatinib QOD 30, 40, or 50 mg. In the combination cohort, pts with Ph + B-cell precursor (BCP) ALL or lymphoid CML-BP (CML-LBP) resistant to at least 1 TKI were enrolled and received olverembatinib (30 or 40 mg) QOD in combination with blinatumomab. Results As of June 30, 2023, 76 pts were enrolled, including 57 with CML-CP and 19 with advanced Ph + leukemia. The median (range) age was 54.5 (21-80) years, and 56.6% of pts were male. In all, 11 (14.5%), 23 (30.3%), and 39 (51.3%) pts had received 2, 3, and ≥ 4 prior TKIs, respectively. A total of 52.6% of pts were previously treated with ponatinib, of whom 67.5% were resistant and 25.0% intolerant to the drug, and 7.5% experienced treatment failure for other reasons. A total of 27.6% of pts were previously treated with asciminib, of whom 71.4% were resistant and 19.1% intolerant to the agent, and 9.5% experienced treatment failure for other reasons. At baseline, 32% of pts had T315I mutations, 38% hypertension, and 17.1% other cardiovascular comorbidities. Median (range) treatment duration was 24.1 (0-134) weeks, and PK profiles were similar to historical PK data on Chinese pts. Twelve pts with CML-CP and 7 with advanced Ph + leukemia discontinued treatment: 4 because of AEs, 7 disease progression, and 8 other reasons. A total of 54 of 65 (83.1%) pts who received ≥ 1 dose of olverembatinib experienced any-grade TRAEs. Grade ≥ 3 AEs occurring in ≥ 3 pts (≥ 4.6% incidence) included thrombocytopenia (17%); neutropenia (13.8%); elevated blood creatine phosphokinase (13.8%); leukopenia (7.7%); and anemia and elevated lipase (4.6% each). Ten (15.4%) pts experienced olverembatinib treatment-related serious AEs, of which each were experienced by 1 (1.5%) pt. Two (3.1%) pts discontinued the study because of TRAEs. No TRAE-associated deaths were reported. Olverembatinib showed sustained antileukemic activity in pts with CML and Ph + ALL (Table 1). Among 50 efficacy-evaluable pts with CML-CP, the rate of complete cytogenetic response (CCyR) was 57% (25/44) and major molecular response (MMR) 43% (21/49). Efficacy improved over time; the MMR rate in pts with CML-CP treated for 6 months was 66% and 88% in pts treated for 12 months. Among pts whose disease failed ≥ 4 prior TKIs, CCyR and MMR rates were 57% (13/23) and 42% (11/26), respectively. In pts with CML-CP harboring the T315I mutation, rates of CCyR and MMR were 60% (9/15) and 44% (7/16), respectively, and 55% (16/29) and 42% (14/33) in pts without the T315I mutation. Among evaluable ponatinib-failed pts, 8/15 (53%) achieved CCyR and 6/16 (38%) MMR. Among pts who failed asciminib therapy, 3/7 (43%) achieved CCyR and 3/8 (38%) MMR. Of 8 pts with CML-CP who had prior exposure to both ponatinib and asciminib, 2 (25%) achieved MMR. At 24 months, PFS was 75% (95% CI, 56.1-86.7) and OS was 97.6% (95% CI, 90.8-99.4). Thirteen pts with advanced Ph + leukemia were efficacy-evaluable, of whom 3 (23%) achieved MMR; only 1 of 3 pts with the T315I mutation achieved MMR; the other 2 were also resistant to ponatinib treatment. The median (95% CI) PFS of efficacy-evaluable pts with advanced leukemia was 12.7 (4-19.5) months. In the combination cohort, 2 pts with Ph + BCP ALL received olverembatinib 30 mg QOD with blinatumomab; both achieved CCyR and 1 achieved a negative MRD status after 1 treatment cycle. Conclusions Olverembatinib alone or combined with blinatumomab was efficacious and well tolerated in pts with heavily pretreated CML or Ph + ALL . Olverembatinib monotherapy was potent in pts who were either resistant or intolerant to ponatinib and/or asciminib, regardless of T315I mutation status. Olverembatinib may provide an effective new treatment option for pts after failure of 2 or more TKIs. Internal study identifier: HQP1351-CU101. Clinicaltrials.gov identifier: NCT04260022.

Phase 2 Study of Dasatinib with and without Venetoclax in Patients with Early Chronic Phase Chronic Myeloid Leukemia (ECP-CML)

Background Treatment-free remission (TFR) is a therapeutic goal for patients with ECP-CML once patients maintain a deep molecular remission (DMR) on tyrosine kinase inhibitors (TKIs). Only a fraction of patients (pts) achieved sustained (3+ years) molecular remission with 4.0- to 4.5-log reduction (MR4.5). Preclinical studies showed that BCL-2 is a key survival factor for CML stem/progenitor cells. Therefore, the combination of TKIs and venetoclax, targeting BCR::ABL1 and BCL-2, has the potential to significantly improve DMR and subsequently the rates of TFR. The aim of this study is to evaluate the safety and efficacy of the combination. Methods Patients with ECP-CML or accelerated phase (AP; defined by clonal evolution only) were eligible; pts with &amp;lt; 1 month of prior TKI therapy were eligible. Pts received single-agent dasatinib 50 mg/d for the first 3 months. From Month 4 and onwards, venetoclax was administered from Days 1 to 14 each month concomitantly with dasatinib for a total of 3 years. The first 16 patients received venetoclax 200 mg/d, with a rapid ramp-up starting 50 mg on Day 1, then 100 mg on Day 2, then 200 mg daily on Day 3 and onwards. Due to neutropenia observed with continuous dose of venetoclax 200 mg/d, the protocol was ameded: from patient #17 and onwards, venetoclax was administered at 200 mg/d for 14 days per month and upon achievement of MR4.5, venetoclax was reduced to 100 mg/d for 7 days per month. After 3 years of combination, patients received single-agent dasatinib. TFR was offered after ≥ 3 years of DMR. The primary endpoint was the rate of major molecular response (MMR) by 12 months of the combination. The secondary endpoints were the 12-month rate of MR4.5 and the cumulative overall rate of MR4.5; the rates of MR4.5 at 6-, 12-, 18-, 24, and 36-months of the combination; the proportion of patients with sustained MR4.5 of 3 years and more; the TFR rate; overall survival; and the safety of the combination. Cumulative response rates were calculated with treatment failure as a competing event. Failure-free survival (FFS) was calculated from the initiation of therapy to loss of major cytogenetic response (MCyR), transformation to AP or blast phase, discontinuation of therapy for any reason except of TFR, or death. Results Sixty-five pts were enrolled and treated between April 2018 and August 2021. The median age at treatment initation was 46 years (range, 23-73) and 57% of the pts were females. Twenty-one (32%) pts had splenomegaly, 46 (71%) had low Sokal risk disease and 3 (5%) had high Sokal risk disease (Table 1). By 12 months of the combination, 85% of the pts had achieved MMR or deeper response. The median time to MMR, MR4, and MR4.5 were 6.2 months, 13 months, and 23.9 months from the time of TKI start, respectively. After a median follow-up of 25.7 months (range, 8.7-48.1), two pts discontinued therapy due to adverse events (GI intolerance, and pleural effusion); the 2 -year FFS was 96%. One pt switched TKI therapy due to the lack of 18-month complete cytogenetic response (CCyR); no loss of CCyR, transformation, or death was observed. We then compared the outcomes with the combination to the outcomes of 85 pts treated with single-agent dasatinib. From the start of TKI therapy, the 12-month cumulative MMR rates were 78% and 79% in the dasatinib single-agent and dasatinib + venetoclax groups, respectively. The cumulative 24-month rates of CCyR, MMR, MR4, and MR4.5 are summarized in Table 2. In the dasatinib single-agent group, 3 pts switched TKI therapy due to the lack of 12-month MCyR, 18-month CCyR, and the acquisition of ABL1 mutation (1 each); 3 pts switched TKI therapy due to loss of CCyR; 2 pts died during therapy (deaths unrelated to CML). Within one year of therapy, the incidence of grade 1/2 neutropenia (absolute neutrophil count, below lower range of normal to 1,000 x10 9/L) was 21% and 52% in the dasatinib single agent and dasatinib + venetoclax groups, respectively ( P&amp;lt;0.001); the incidence of grade 3/4 neutropenia (absolute neutrophil count, below 1,000 x10 9/L) was 8% and 17%, respectively ( P&amp;lt;0.001). There was no incidence of neutropenic fever in the dasatinib + venetoclax. Conclusion The combination of dasatinib 50 mg/d and venetoclax is safe and effective in pts with ECP-CML. With a median follow-up of 2 years, the cumulative resposne of dasatinib + venetoclax is similar to that of dasatinib single-agent without adding significant toxicities. Further follow-up is needed for the evaluation of TFR.

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 &amp;gt;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.

Evaluating Effectiveness and Safety of Flumatinib for Chronic Phase Chronic Myeloid Leukemia in (CML-CP) without Optimal Response (Warning, Failure) to Imatinib or/and Dasatinib

Introduction Flumatinib is a novel second-generation BCR-ABL1 targeted kinase inhibitors (TKI) with better efficacy and safety than first generation TKIs in first-line treatment of chronic myeloid leukemia in chronic phase (CML-CP). In the previous phase III study, newly diagnosed CML-CP patients receiving flumatinib achieved higher treatment responses and safety than imatinib. When it comes to the patients not achieving the optimal response to TKIs, flumatinib is potentially a better option, nonetheless the robust evidence is unavailable. This study reports the effectiveness and safety of switching to flumatinib in patients who have not achieved the optimal molecular response to imatinib or/and dasatinib. Methods This prospective, multicentre study enrolled Philadelphia Chromosome-Positive (Ph+) CML-CP patients aged ≥18 years and who failed to achieve the optimal response with imatinib or/and dasatinib between March 2021 to October 2022. All patients were treated with flumatinib 600 mg once a day and followed up to 24 months. The primary endpoint of the study was rate of major molecular response (MMR) at 12 months as defined by European LeukemiaNet 2020 recommendations (BCR-ABL1 transcript level ≤0.1% in peripheral blood on RT-PCR assay on International Scale [IS]) and safety was the secondary endpoint assessed with CTCAE 4.03 version. In addition, the optimal molecular response in either the warning or failure patients was evaluated at 3, 6 and 12 months respectively, after switching to flumatinib, and the difference in effectiveness was also analyzed from the available mutation subtypes. Results Overall, 94 patients with Ph+ CML-CP were included in the study. The median (range) age of the patients were 53 (19.0-84.0) years old and 61.7% of the patients were males. A total of 38 (40.4%) patients reported warning response from the previous TKIs whereas 56 (59.6%) of patients reported treatment failure to the previous TKIs. Seventy-seven (81.9%) patients have been treated with one TKI, either imatinib or dasatinib, and 17 (18.1%) have been treated with both prior to the study. Overall, 25 (54%) patients achieved MMR at 12-months follow-up compared to the baseline (Figure 1). The rates of optimal molecular response at 3- and 6-months were also improved compared to the baseline. The optimal molecular response was 76(88%) at 3 months, and 52(73%) at 6 months. Subgroup analysis with previous response to TKIs revealed that flumatinib improved the rates of optimal molecular response in both warning and failure groups. Switching to flumatinib from imatinib or/and dasatinib have been reported with an enhanced optimal molecular response in patients who experienced warning compared with those who had treatment failure after the TKIs with 38 (100%) vs 38 (79%), 29 (91%) vs 23 (59%) and 15 (68%) vs 10 (42%) at 3-, 6- and 12-months respectively (Figure 2). Similarly, the rates of optimal molecular response were improved in patients without mutations compared to those having mutations, 65 (90%) vs 9 (75%) at 3 months, 46 (77%) vs 5 (56%) at 6 months and 23 (59%) vs 1 (20%) at 12 months respectively. The most common adverse events (AEs) were diarrhea in 17 (18%), rash in 11 (12%), bloating in 11 (12%), and thrombocytopenia in 11 (12%) patients. Common hematological AEs of grade 3/4 were thrombocytopenia in 7 (7%), anemia in 3 (3%) and leucopenia in 1 (1%) patients. Conclusion For Ph+ CML-CP patients without the optimal molecular response in previous imatinib or/and dasatinib, flumatinib is a better alternative to the existing treatments. In addition, if the patients were switched to flumatinib earlier, the optimal response was achieved faster. The grade 3/4 AEs were mainly hematologically related, whereas the gastrointestinal events were mostly of grade 1-2.

Efficacy of Frontline Treatment with Initial Low-Dose Tyrosine-Kinase Inhibitors in Elderly Patients with Chronic Myeloid Leukemia: A “Campus CML” Study

Introduction Three TKIs, imatinib (IM), dasatinib (DAS) and nilotinib (NIL), are approved for frontline therapy in Italy. Choice of frontline TKI is based mainly on evaluation of patient's characteristics and clinical expectations. To avoid long term adverse events or potential drug interactions, elderly patients may start CML treatment with a frontline reduced dose of TKI (RD-TKI). Aim To analyse outcome of CP-CML patients aged over 65 years in a large and unselected cohort treated with RD-TKI. Methods We retrospectively evaluated 747 patients from 1/2012 to 12/2019 at 36 Hematology Centres participating at the “Campus CML” project. Results Clinical features for the whole cohort according to frontline TKI initial dose are reported in Table 1. Among all patients, 605 (81%) were treated with standard dose (SD) while the remaining 142 (19%) with reduced dose (RD). As to frontline TKI, 579 patients (77%) received IM and 158 (23%) a 2G-TKI (DAS n=78, 49%; NIL n=80, 51%). Of the 142 RD-TKI, 122 (85.9%) started with IM, 14 (9.9%) with DAS and 6 (4.2%) with NIL. Median RD was 100 mg for IM (range 100-300), 20 mg for DAS (range 20-50) and 250 mg for NIL (range 150-300). RD-TKI was mainly reported in IM treated patients (p=0.018), in elderly (p&amp;lt;0.001) and in patients with comorbidities, in particular diabetes (p=0.005) and ischemic heart disease (p=0.039). Number of concomitant drugs was also significantly associated with RD-TKI (p&amp;lt;0.001) probably to avoid drug interactions and subsequent toxicity. In detail, among RD-TKI, 41.1% of patients was treated with more than five concomitant drugs. Sokal score did not impact on TKI starting dose. No differences emerged between SD-TKI and RD-TKI in terms of haematological or extra-haematological toxicity. TKI frontline dose was not associated with difference in resistance, nor primary neither secondary resistance. Progression to blastic phase was reported in 1.2% of the whole population, none of which in RD-TKI. At 12 months no differences were noted in terms of achievement of major molecular response (MMR), obtained in 22.4% of SD-TKI treated patients and in 19% of RD-TKI treated patients. RD-TKI had inferior probability of deep molecular response (DMR) achievement (p=0.003), reported in 12.6% of patients. No differences were reported in 12-months cumulative rate of permanent discontinuation for any cause and for primary resistance between SD-TKI and RD-TKI as reported in Figure 1. Conclusions RD-TKI was a frontline treatment strategy used mainly in frail elderly patients, with more comorbidities and concomitant therapies. RD-TKI did not impact on primary resistance leading to TKI switch. While no differences were reported in the rate of MMR, the rate of 12-months DMR achievement was inferior in RD-TKI, but this result need to be confirmed with longer follow-up.

ASC4START and ASC4FIRST: Two Ongoing Phase 3 Trials Investigating Asciminib Monotherapy As First-Line Therapy Versus Tyrosine Kinase Inhibitors in Patients with Newly Diagnosed Philadelphia Chromosome-Positive Chronic Myeloid Leukemia in Chronic Phase

Background: The current standard of care (SoC) for newly diagnosed patients (pts) with chronic myeloid leukemia in chronic phase (CML-CP) is treatment with 1 of the 4 tyrosine kinase inhibitors (TKIs) approved for this use (first generation [1G] imatinib [IMA] and second generation [2G] bosutinib [BOS], dasatinib [DAS], and nilotinib [NIL]). Although TKIs have vastly improved treatment outcomes, pts with newly diagnosed CML-CP experience lack of efficacy and intolerance to available treatments. A large number of pts treated with IMA do not achieve major molecular response (MMR) and even fewer pts achieve deep molecular response, a key requirement to attempt treatment-free remission. Treatment with 2G TKIs results in larger proportions of pts achieving deep responses albeit still with a sizeable minority not reaching this goal. Also, many pts are intolerant to 2G TKIs, resulting in therapy switching, frequently multiple times. For pts who remain on treatment, even low-grade adverse events (AEs) may significantly impact quality of life (QoL) given the long-term nature of treatment. Improved treatments with high efficacy and improved tolerability are needed to limit therapy switching, reduce treatment discontinuation, maintain, or improve pt QoL, and allow pts to remain on treatment at an optimal dose for longer duration to achieve deep responses. Asciminib is the first and only approved BCR::ABL1 inhibitor that works by specifically targeting the ABL myristoyl pocket (STAMP). This unique mechanism of action (MoA) has no confirmed overlapping mutation-driven resistance profile with ATP-competitive TKIs. Asciminib shows better selectivity compared to other TKIs, with no known off-target kinase-mediated effects due to its MoA; this translates into improved tolerability. In clinical trials (Hughes et al. N Engl J Med. 2019; Rea et al. Blood 2021), asciminib has demonstrated sustained efficacy and a favorable safety profile over time in pts with Philadelphia chromosome positive (Ph+) CML-CP previously treated with ≥2 TKIs as well as in pts with T315I mutation. Asciminib as monotherapy and in combination with ATP-competitive TKIs is being studied as first-line (1L) treatment in CML. The ongoing ASC4FIRST (NCT04971226) study is investigating the efficacy and safety of asciminib 80 mg once daily (QD) monotherapy vs investigator-selected 1G or 2G TKI in adults with newly diagnosed Ph+ CML-CP ( Table 1). The primary endpoint of ASC4FIRST is MMR rate at 48 weeks. The ongoing ASC4START (NCT05456191) study is focused on pt-centric objectives, assessing the tolerability and efficacy of asciminib vs 2G TKI NIL in adults with newly diagnosed Ph+ CML-CP. The primary endpoint of ASC4START is time to treatment discontinuation due to an AE ( Table 1). Current Status: As of December 20, 2022, the ASC4FIRST study completed recruitment, with 405 pts enrolled worldwide. The end of study (EOS) will occur 5 years from the last pt first treatment in the study. Pts will continue to receive the assigned treatment until the EOS, or until premature discontinuation due to treatment failure, disease progression or intolerance, or due to investigator or participant decision. Between 21 November 2022 and 25 July 2023, 180 pts have been screened for the ASC4START study, with 147 pts randomized to treatment (n=52 France, n=40 Germany, n=9 Bulgaria, n=7 Czechia, n=7 Hungary, n=6 Korea, n=6 Singapore, n=2 Slovakia, n=5 Argentina, n=3 Greece, n=2 each from Slovakia, Malaysia, and Oman, and n=1 each from the USA, Italy, Romania, UK, Jordan, and Canada). Recruitment is ongoing. Patients will be treated until approximately 64 discontinuations of either study treatment due to an AE have been recorded. Conclusions: With demonstrated efficacy and improved tolerability compared to ATP-binding TKIs, asciminib has the potential to become the therapy of choice for CML in 1L, enabling newly diagnosed patients to remain on therapy with improved QoL and overall survival, and reducing the need for therapy switching, ultimately allowing patients to achieve optimal milestone responses and reach treatment goals. Findings from these two trials will provide comprehensive evidenceon the use of asciminib as 1L therapy for newly diagnosed pts with Ph+ CML-CP.

Flumatinib Versus Imatinib As a Frontline Therapy for Patients with Chronic Myeloid Leukemia in Chronic Phase: A Propensity Score Matching Study from Real-World Data

Background: Flumatinib mesylate, as a novel oral BCR-ABL1 tyrosine kinase inhibitor, is approved as a frontline therapy for chronic myeloid leukemia in chronic phase (CML-CP) in China since 2019. Mechanistically, with its structure of trifluoromethyl and pyridine flumatinib blocked BCR-ABL1 kinase autophosphorylation with much more potent activity than did imatinib and even showed higher efficacy than nilotinib against wild-type BCR-ABL1 kinase. Currently, there is still lacking the real-world effectiveness and safety of flumatinib in patients with CML. Methods: We retrospectively analyzed efficacy and safety of CML-CP patients (≥16 years) used flumatinib (600mg daily) or imatinib (400mg daily) as first-line treatment from 2020 to 2023, presenting a real-world comparison study. A propensity score (PS) matching was performed to adjust for Sokal risk score to compare the treatment efficacy, survival outcomes and safety of flumatinib and imatinib in a clinically well matched cohort. Results: PS matching resulted in 20 patients from each cohort being matched for Sokal risk scores. The median follow-up of the flumatinib-treated and imatinib-treated cohorts was 441 days and 487 days, respectively. In the intention-to-treat (ITT) population analysis, there is no differences between flumatinib and imatinib groups in 3-month early molecular response rate (85% vs. 80%, p = 0.677), 6-month major molecular response rate (MMR) (50% vs. 40%, p = 0.525) and 12-month MMR (55% vs. 50%, p = 0.752). In term of deep molecular response, more patients receiving flumatinib achieved molecular remission 4.5 (MR4.5) and molecular remission 4 (MR4.0) at 6 months (35% vs.0%, p = 0.004; and 45% vs. 5.0%, p = 0.003, respectively) and appeared to have higher 12-month MR4.5 and 12-month MR4.0 (45% vs.10%, p = 0.013; and 45% vs. 20%, p = 0.091, respectively; Table). During the follow-up period, treatment discontinuation occurred in 6 and 9 patients in flumatinib-treated and imatinib-treated cohorts respectively, including 2 and 3 patients due to drug resistance and 3 and 4 patients due to toxicity. The 2-year probability of event-free survival was 70% among the patients who received flumatinib and 47% among those who received imatinib ( p = 0.85), and the corresponding 2-year failure-free survival probabilities were 85% and 76%, respectively ( p = 0.77). Adverse events of edema, rash were more frequent in imatinib arm (any grade; 0% vs. 25%, p = 0.017; and 0% vs. 25%, p = 0.035, respectively), whereas alanine transaminase elevation appeared to be more frequent in flumatinib arm (any grade, 15% vs. 0%, p = 0.072). Of note, one patient receiving flumatinib had grade 3 QT prolongation and ventricular premature beat and was discontinued. Conclusions: The real-world data demonstrated that as a first-line treatment setting, flumatinib can bring patients with chronic phase CML higher rates of responses, and faster and deeper responses, indicating that flumatinib could be an alternative effective first-line treatment for CML-CP. The adverse events of flumatinib, such as cardiovascular events, abnormal liver function, and diarrhea, need to be given continuous concern in future studies.

Asciminib (ASC) Once-Daily (QD) Dosing Demonstrates Comparable Tolerability and Efficacy to Twice-Daily (BID) Dosing: Results from the ASC in Monotherapy 4 CML (AIM4CML) Study in Patients (Pts) with Chronic Myeloid Leukemia in Chronic Phase (CML-CP)

CONCLUSIONS ASC is the only approved BCR::ABL1 inhibitor that Specifically Targets the ABL1 Myristoyl Pocket, distinguishing it from other approved treatments that target the ATP binding site. In the phase III ASCEMBL trial (NCT03106779) ASC 40 mg BID was well tolerated and demonstrated superior efficacy vs bosutinib 500 mg QD in pts previously treated with ≥2 TKIs, with major molecular response (MMR; BCR::ABL1IS ≤0.1%) rates of 25.5% vs 13.2% at wk 24 and 37.6% vs 15.8% at wk 96. We present an interim analysis of the primary endpoint of the AIM4CML trial (NCT04666259), which was initiated to assess the safety, efficacy, and QD dosing of ASC in a similar population of pts with CML-CP. This is a multicenter, phase IIIb, open-label study of ASC in pts with CML-CP without the T315I mutation after ≥2 prior TKIs and pts with the T315I mutation after ≥1 prior TKI. Adults aged ≥18 years with CML-CP who had treatment failure with or intolerance of the most recent TKI were eligible. Pts without the T315I mutation were randomized to receive ASC 40 mg BID (cohort A) or 80 mg QD (cohort B). Results for pts with the T315I mutation who received ASC 200 mg BID (cohort C) will not be presented for this analysis. The primary endpoints include adverse events (AEs) and serious AEs by wk 24 in cohorts A and B, with additional safety and efficacy secondary endpoints. This study was not powered to detect statistical differences between cohorts. End of study is when the last pt completes 72 wks of treatment or discontinues prematurely. The numbers of enrolled pts in cohorts A, B, and C were 26, 27, and 3, respectively. This interim analysis included 42 pts randomized to cohort A (n=22) or cohort B (n=20), who reached 24 wks after cycle 1 day 1 of treatment by February 17, 2023. Most baseline characteristics in cohorts A and B were comparable, but median time since initial diagnosis and median baseline BCR::ABL1IS levels were longer and higher, respectively in cohort B (Table). Median duration of exposure was 23.1 (range, 2.7-72.3) wks in cohort A and 24.1 (range, 1.3-71.0) wks in cohort B. Prior to wk 24, treatment was discontinued in 7 and 4 pts in cohorts A and B, respectively. Reasons for discontinuation included physician decision (cohort A, n=4; cohort B, n=2), AEs (cohort A, n=2; cohort B, n=1), or pt decision (cohort A, n=1; cohort B, n=1). At the time of this interim analysis, discontinuation due to treatment failure was reported only in cohort B in 2 pts that discontinued due to physician decision. Cohorts A and B had comparable all-grade, grade 3, and grade 4 AEs. Treatment-emergent all-grade AEs occurring in ≥20% in cohorts A and B were fatigue (32% and 25%), headache (27% and 20%), abdominal pain (27% and 15%), rash (23% and 5%), dyspnea (23% and 10%), nausea (14% and 30%), hypertension (14% and 20%), cough (18% and 20%), and arthralgia (9% and 20%). While many pts had AEs requiring additional therapy, few had serious AEs, and similar numbers of pts in cohorts A and B had AEs leading to dose adjustments/interruptions and treatment discontinuation (Figure). One pt in cohort B had a fatal AE due to sepsis that was not attributed to study treatment. This trial is ongoing; data for the wk 24 primary endpoint for all enrolled pts will be available at the time of presentation. Pts with ≥1 molecular response assessment by wks 4, 12, and 24 were 18, 19, and 20 in cohort A, respectively, and 17, 17, and 18 in cohort B, respectively. The proportions of pts who maintained or achieved BCR::ABL1IS ≤1% by wks 4, 12, and 24 were higher in cohort B with 52.9%, 76.5%, and 88.9%, respectively than in cohort A with 50.0%, 63.2%, and 65.0%, respectively, likely due to higher baseline BCR::ABL1IS levels in cohort B (Table). MMR rates by wks 4, 12, and 24 were 33.3%, 42.1%, and 45.0% in cohort A and 23.5%, 47.1%, and 61.1% in cohort B, respectively. Deep molecular response (MR 4; BCR::ABL1IS ≤0.01%) rates by wks 4, 12, and 24 were 27.8%, 31.6%, and 30.0% in cohort A and 5.9%, 11.8%, and 27.8% in cohort B, respectively. This interim analysis of the AIM4CML trial further demonstrates the tolerability and efficacy of ASC and is among the first clinical reports on QD dosing of ASC in pts with CML-CP. Safety was comparable between the 80-mg QD and 40-mg BID doses, with both demonstrating safety profiles consistent with prior reports. Pts receiving ASC at both doses achieved and maintained molecular responses, which deepened over time. These results support the flexibility of QD dosing with ASC.