Selection Of Tyrosine Kinase Inhibitors Research Articles

Abstract 4922: Unraveling sarcomatoid features in clear cell renal cell carcinoma with RNA-seq

Abstract Introduction: Sarcomatoid сlear cell renal cell carcinoma (ccRCC) represents a challenging and aggressive subset of kidney cancers with poor prognosis and resistance to conventional treatments. Recent studies have shown the benefit of checkpoint inhibitors (CPIs) for patients with sarcomatoid components; therefore, precise and objective evaluation of sarcomatoid differentiation is essential for CPI selection. Here, we developed a predictive model to identify sarcomatoid features in ccRCC. Methods: The machine learning-based transcriptomic sccRCC model was developed on 512 samples from publicly available datasets: TCGA-KIRC and CPTAC-ccRCC. Samples were excluded with the following criteria: inconsistent with ccRCC, less than 10% sarcomatoid component, or <20% tumor neoplastic cellularity. Sarcomatoid features for each case were assessed by 3 pathologists. The meta-cohort was divided into training (n = 348) and validation (n = 164) cohorts.The model was tested on a publicly available cohort of ccRCC patients from Sato et al. (n = 100). Clinical validation was performed using an additional prospective cohort that received BostonGene’s Tumor PortraitTM test (n = 32) with RNA-seq and whole exome sequencing (WES). The JAVELIN Renal 101 cohort was used to uncover differences in progression-free survival (PFS) associated with a predicted sarcomatoid component in advanced or metastatic ccRCCs treated with a combination of CPIs and tyrosine kinase inhibitors (TKIs). Results: H&E analysis of the TCGA, CPTAC, and BostonGene cohorts identified zones with sarcomatoid features in 129 out of 556 (23.2%) samples. The sarcomatoid predictive model demonstrated robust performance, with weighted F1-scores of 0.85 when applied to the test cohort (Sato et al.) and 0.70 for the prospective clinical cohort. The model accurately classified 9 out of 10 total sarcomatoid samples in the prospective clinical cohort, highlighting its potential for real-world clinical applications. When applied to TCGA validation samples, sarcomatoid patients identified by the transcriptomic model exhibited median overall survival (mOS) of 55 months, whereas sarcomatoid patients based on H&E assessment had a mOS of 67 months, indicative of the model’s superior performance when detecting sarcomatoid features for OS prediction. Moreover, the sarcomatoid ccRCCs predicted by transcriptomic model that were treated with a combination of CPIs and TKIs had statistically (p=0.0001) improved PFS compared to the TKI-treated group. Conclusion: The developed transcriptomic model effectively differentiated sarcomatoid from non-sarcomatoid ccRCC samples with robust performance metrics. With additional investigation, the predictive value of the sarcomatoid ccRCC transcriptomic model can be leveraged to guide CPI and TKI selection. Citation Format: Kirill Kryukov, Suren Davitavyan, Danil Stupichev, Anna Sharun, Anna Love, Mikhail Kleimenov, Stepan Kuznetsov, Arina Tkachuk, Vladimir Kushnarev. Unraveling sarcomatoid features in clear cell renal cell carcinoma with RNA-seq [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4922.

Mutations in myeloid transcription factors and activated signaling genes predict chronic myeloid leukemia outcomes

AbstractAdvancements in genomics are transforming the clinical management of chronic myeloid leukemia (CML) toward precision medicine. The impact of somatic mutations on treatment outcomes is still under debate. We studied the association of somatic mutations in epigenetic modifier genes and activated signaling/myeloid transcription factors (AS/MTFs) with disease progression and treatment failure in patients with CML after tyrosine kinase inhibitor (TKI) therapy. A total of 394 CML samples were sequenced, including 254 samples collected at initial diagnosis and 140 samples taken during follow-up. Single-molecule molecular inversion probe (smMIP)–based next-generation sequencing (NGS) was conducted targeting recurrently mutated loci in 40 genes, with a limit of detection of 0.2%. Seventy mutations were detected in 57 diagnostic samples (22.4%), whereas 64 mutations were detected in 39 of the follow-up samples (27.9%). Carrying any mutation at initial diagnosis was associated with worse outcomes after TKI therapy, particularly in AS/MTF genes. Patients having these mutations at initial diagnosis and treated with imatinib showed higher risks of treatment failure (hazard ratio, 2.53; 95% confidence interval, 1.13-5.66; P = .0239). The adverse prognostic impact of the mutations was not clear for patients treated with second-generation TKIs. The multivariate analysis affirmed that mutations in AS/MTF genes independently serve as adverse prognostic factors for molecular response, failure-free survival, and progression risk. Additionally, there was an observable nonsignificant trend indicating a heightened risk of progression to advanced disease and worse overall survival. In conclusion, mutations in the AS/MTF genes using smMIP-based NGS can help identify patients with a potential risk of both treatment failure and progression and may help upfront TKI selection.

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.

Prospective Assessment of Co-Morbidities and Framingham Risk Score in Newly Diagnosed Chronic Myeloid Leukemia (CML) Patients and Its Impact on Clinical Outcomes Following Frontline TKI Therapy: Toronto CML Genomic Alliance in Greater Toronto Area & Ontario (TCGA-GTA)

Introduction Front-line (1L) tyrosine kinase inhibitor (TKI) drug selection is a pearl of clinical practice in CML. It requires consideration of multiple aspects including the goal of therapy, potency of the drug as well as comorbidity of the patient (pt). Contemporary CML practice emphasizes the importance of comorbidity for TKI selection. However, such data is scarce particularly the prevalence of comorbidity and its impact on 1L drug selection. We are developing a shared care model with community hematologists in Greater Toronto Area (TCGA-GTA). Newly diagnosed CML pts in the community will be referred to the study core center for prospective enrolment into the CML registry, informed consenting for genetic testing/future research, and evaluation of baseline comorbidity. Pt will return to referring hematologists for management of CML, including 1L TKI treatment as per standard of care, and is scheduled to visit the study center at 6 and 12 months, then annually for 10 years. It gives us a unique opportunity to evaluate the impact of comorbidity on 1L TKI drug selection. Patients and method Adult pts with newly diagnosed CML of any phase within 2 months of diagnosis are eligible for the study unless they are not able to visit study core center. Comorbidities and Framingham risk score (FRS) were assessed at the time of initial evaluation. Mutation profile testing is done by a bar-coded error-corrected sequencing platform for 40 genes developed at the Ontario Institute for Cancer Research. Cumulative incidence of molecular response with 2 log (MR2), 3 log (MR3), 4 log reduction or deeper (MR4), and treatment failure (TF) were calculated using cumulative incidence method considering competing risk. Event-free survival (EFS) was defined as time from start of TKI until TKI stop/switch, TF or death. Failure-free survival (FFS) was defined as time from start of TKI to TF [primary resistance, loss of complete cytogenetic response, new additional cytogenetic abnormalities (ACAs), and progression to accelerated or blasts phase (AP/BP)] or death. Results From November 2020 until June 31, 2023 (data cutoff), a total of 77 pts were enrolled in the study. The median follow-up time was 12 months. The frequency of 1L TKI selection was as follows: IMATINIB (IM) (n=23, 30%), DASATINIB (n=25, 32%), NILOTINIB (n=22, 29%), BOSUTINIB (n=1, 1%), ASCIMINIB (n=6, 8%). Majority of the pts were male (n=51, 66%). Ninety-three percent of pts were in chronic phase at diagnosis, while 4% and 3% were in AP and BP, respectively. Presence of ACAs was detected in 18 pts (23%), 10 of which were high risk, while 6% (n=5) were not evaluable. The baseline clinical and disease characteristics of pts on 1L IM vs other TKIs (2G-TKI) are summarised in Table 1. Of note, pts on IM were significantly older with higher FRS and comorbidities, including coronary artery disease, diabetes mellitus, and hypertension. The OS of all pts at 1 year was 98.5% (95% confidence interval 90%-99.8%). At 1 year, pts with intermediate to high risk FRS had lower FFS (73.2% vs 86.5%, p=0.037) while history of hyperlipidemia was associated with lower EFS (59.3% vs 81.5%, p=0.023) and 6 times more likely to stop or switch therapy due to intolerance or resistance (HR 5.9, p=0.002). Baseline comorbidities did not demonstrate signifincant impact on MR2 and MR3 at 1 year but pts with low FRS were more likely to achieve MR4 within 1 year (22.3% vs 0%, p=0.023). Age did not affect any of the clinical and molecular endpoints. Compared to 2G-TKI, IM had worse EFS (HR 3.93, p=0.003), FFS (HR 5.66, p=0.011), and MR2 (47.3% vs 84.4%, p=0.003) at 1 year. Further, IM pts experienced higher rate of any side effects compared to those on 2G-TKI (69.6% vs 31.5%, p=0.003). Conclusion The TCGA-GTA study provides valuable insights into the impact of comorbidity on selection of 1L TKI and its outcome in a real-world setting. Pts who are older and with higher FRS and comorbidities tend to receive 1L IM. However, pts on 1L 2G TKIs are more likely to reach treatment goals faster with lower probability of TF. The present study did not reach a clear conclusion whether the worse outcomes in the pts receiving IM are from IM treatment or concurrent risk factors such as age and comorbidities, thus further study with an expanded cohort and longer follow-up is required. Elderly pts or those with comorbidities would need alternative treatment with better efficacy and tolerability, such as Asciminib, that can overcome comorbidity issues in the future.

Longitudinal, prospective cardiovascular and metabolic risk in treatment-naive patients with chronic myeloid leukemia in chronic phase (CML-CP) starting tyrosine kinase inhibitor (TKI) therapy in a real-world setting.

7053 Background: Multiple TKIs used in the treatment (tx) of CML have been associated with the development of cardiovascular/metabolic (CV/Met) comorbidities, yet no study to date has prospectively and systematically assessed CV/Met parameters after TKI initiation. CA180-653 (NCT03045120) is a non-interventional, prospective, real-world study characterizing the effects of TKIs (dasatinib [DAS], imatinib [IM], nilotinib [NIL], and bosutinib [BOS]) on CV/Met risk factors in patients (pts) with CML-CP in routine care. Baseline CV/Met risks were previously reported (Mauro, GCOS 2019). Here, we report data from the final 2-year follow-up. Methods: Adult pts with newly diagnosed CML-CP due to start tx with DAS, IM, NIL, or BOS were enrolled; the BOS cohort was not analyzed independently due to small sample size. Pts were followed for 24 mo. Blood/urine samples, CV/Met assessments, coronary calcium scoring, echocardiography, and cytogenetic/molecular response assessments were collected at routine office visits at predetermined timepoints. The primary endpoint was change in CV/Met risk from baseline. Results: At the end of follow-up, 118 pts were enrolled; 49 received DAS, 47 IM, 16 NIL, and 6 BOS. Of these, 83 (70.3%) pts completed the study and 35 (29.7%) discontinued; the most common reason for discontinuation was withdrawal of consent (n = 19). No pts died from CML. At baseline, median age was 57 (range, 20–97) y; 59.3% of pts were male and 83.9% were White. Sixty-two (52.5%) pts had CV/Met risk factors at baseline, including hypertension (n = 45/62; 72.6%), hyperlipidemia (n = 33/62; 53.2%), diabetes (n = 19/62; 30.6%), and arrhythmia (n = 10/62; 16.1%). Over the study period, 1 (3.4%) patient receiving DAS and 2 (6.9%) receiving IM developed coronary artery calcification; 2 (9.1%) pts receiving IM developed pericardial effusion. Median left ventricular ejection fraction on 2D echocardiogram was normal for all TKIs at baseline (65.4% [range, 27–81]) and end of study (65.4% [range, 40–80]). Systolic and diastolic blood pressure increased from baseline only in pts who received NIL. Blood glucose levels increased from baseline for DAS, IM, and NIL (median: 1.9, 4.9, and 5.8 mg/dL, respectively), and low-density lipoprotein levels decreased from baseline in all 3 cohorts (median: 72.7, 52.1, and 56.3 U/L, respectively); data from the NIL group were limited by the small sample size. There was 1 death from myocardial infarction related to NIL. Conclusions: These findings suggest more than half of pts with CML-CP have CV/Met risk factors at baseline. At end of study, there was indication of CV/Met effects based on TKI selection. This highlights the importance of appropriate TKI selection based on pt comorbidity characteristics, along with close monitoring and management of CV/Met risks throughout tx. Clinical trial information: NCT03045120 .

EGFR exon 19 insertion EGFR-K745_E746insIPVAIK and others with rare XPVAIK amino-acid insertions: Preclinical and clinical characterization of the favorable therapeutic window to all classes of approved EGFR kinase inhibitors

BackgroundThe epidermal growth factor receptor (EGFR)-K745_E746insIPVAIK and others with XPVAIK amino-acid insertions are exon 19 insertion mutations, which, at the structural modeling level, resemble EGFR tyrosine kinase inhibitor (TKI)-sensitizing mutants. An important unmet need is the characterization of therapeutic windows plus clinical outcomes of exon 19 XPVAIK amino-acid insertion mutations to available EGFR TKIs. MethodsWe used preclinical models of EGFR-K745_E746insIPVAIK and more typical EGFR mutations (exon 19 deletion, L858R, L861Q, G719S, A763_Y764insFQEA, other exon 20 insertion mutations) to probe representative 1st (erlotinib), 2nd (afatinib), 3rd generation (osimertinib), and EGFR exon 20 insertion active (mobocertinib) TKIs. We also compiled outcomes of EGFR exon 19 insertion mutated lung cancers—from our institution plus the literature—treated with EGFR TKIs. ResultsExon 19 insertions represented 0.3–0.8% of all EGFR kinase domain mutation in two cohorts (n = 1772). Cells driven by EGFR-K745_E746insIPVAIK had sensitivity to all classes of approved EGFR TKIs when compared to cells driven by EGFR-WT in proliferation assays and at the protein level. However, the therapeutic window of EGFR-K745_E746insIPVAIK driven cells was most akin to those of cells driven by EGFR-L861Q and EGFR-A763_Y764insFQEA than the more sensitive patterns seen with cells driven by an EGFR exon 19 deletion or EGFR-L858R. The majority (69.2%, n = 26) of patients with lung cancers harboring EGFR-K745_E746insIPVAIK and other mutations with rare XPVAIK amino-acid insertions responded to clinically available EGFR TKIs (including icotinib, gefitinib, erlotinib, afatinib and osimertinib), with heterogeneous periods of progression-free survival. Mechanisms of acquired EGFR TKI resistance of this mutant remained underreported. ConclusionsThis is the largest preclinical/clinical report to highlight that EGFR-K745_E746insIPVAIK and other mutations with exon 19 XPVAIK amino-acid insertions are rare but sensitive to clinically available 1st, 2nd, and 3rd generation as well as EGFR exon 20 active TKIs; in a pattern that mostly resembles the outcomes of models with EGFR-L861Q and EGFR-A763_Y764insFQEA mutations. These data may help with the off-label selection of EGFR TKIs and clinical expectations of outcomes when targeted therapy is deployed for these EGFR mutated lung cancers.

Prophylactic or preemptive tyrosine kinase inhibitor therapy after allogeneic hematopoietic cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia.

Prevention of disease relapse after allogeneic hematopoietic cell transplantation (allo-HCT) in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia remains a major concern. Maintenance therapy with tyrosine kinase inhibitors (TKIs) after allo-HCT has been used to reduce the incidence of relapse. Two main strategies are employed for using TKIs after allo-HCT: prophylactic TKI therapy, which is given before measurable residual disease (MRD) detection, and preemptive TKI therapy, which is given after MRD detection. These strategies both have advantages and disadvantages in terms of treatment efficacy, adverse events, adherence, and socioeconomic factors. In addition, many issues remain to be resolved because of the lack of large prospective studies on how to use TKIs after allo-HCT. These include indications for prophylactic and preemptive TKI therapy, timing of initiation, frequency of MRD monitoring, TKI selection, dose, and treatment duration. While the current available evidence is extremely limited, this article will discuss these issues after summarizing some representative and recent studies. It will also share a novel indicator that can be used to visualize the reversible transition between molecular relapse and remission by TKI therapy.

Significance of Physical Status and Liver Function Reserve for Outcome of Patients with Advanced Hepatocellular Carcinoma Receiving Lenvatinib Treatment.

Tyrosine kinase inhibitors (TKIs) remain the primary therapeutic option for patients with advanced-stage hepatocellular carcinoma (HCC). However, the selection of a suitable TKI is an issue in real-world clinical practice. Thus, this study aimed to identify patients most likely to benefit from lenvatinib treatment. A retrospective review of 143 patients with unresectable advanced-stage HCC treated with lenvatinib between January 2020 and December 2021 was performed. Outcomes related to lenvatinib treatment were measured, and the clinical parameters affecting prognosis were analyzed. Overall, the median time of progression-free survival (PFS) and overall survival (OS) were 7.1 months and 17.7 months, respectively. Prognostic analyses found that Child-Pugh score > 5 (hazard ratio [HR] = 2.43, 95% confidence interval [CI] = 1.55-3.80, p = 0.001) was a significant factor affecting the PFS of HCC after lenvatinib treatment. Child-Pugh score > 5 (HR = 2.12, 95% CI = 1.20-3.74, p = 0.009), body weight ≥ 60 kg (HR = 0.54, 95% CI = 0.32-0.90, p = 0.020), and additional trans-arterial chemoembolization (TACE) treatment (HR = 0.38, 95% CI = 0.21-0.70, p = 0.003) were significant prognostic factors for OS. However, early α-fetoprotein reduction was not significantly correlated with patient outcomes. Additionally, patients with pre-treatment neutrophil-lymphocyte ratio > 4.07 showed a significant worse PFS and OS than other patients. The outcome of patients with advanced-stage HCC remains poor. However, the host condition, including good physical status and better functional liver preservation, largely affected the outcome of patients receiving lenvatinib treatment. Moreover, additional locoregional therapy for intrahepatic HCC, other than TKI treatment, can be considered in certain patients to achieve a favorable outcome.

Evidence-Based Minireview: What is the optimal tyrosine kinase inhibitor for adults with newly diagnosed Philadelphia chromosome–positive acute lymphoblastic leukemia?

The incorporation of BCR::ABL1 tyrosine kinase inhibitors (TKIs) to intensive chemotherapy significantly improved the outcomes of patients with Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). This was first shown with the addition of the first-generation TKI imatinib, which allowed more patients to be bridged to an allogeneic stem cell transplant (SCT) and led to superior long-term outcomes compared with chemotherapy alone. The use of second-generation TKIs (eg, dasatinib and nilotinib) has led to further improvement in outcomes of patients with Ph- positive ALL, with a long-term survival of 40% to 60% in several studies. Ponatinib is a third-generation, more potent TKI that results in high rates of molecular response and promising long-term survival even when allogeneic SCT is not routinely performed. While randomized data to support the TKI selection in Ph-positive ALL are lacking, data from single-arm studies suggest deeper molecular responses and superior survival outcomes with each successive generation of TKI. More recently, chemotherapy-free regimens with blinatumomab and TKIs have shown excellent results in the frontline setting and may represent an emerging paradigm shift in the treatment of Ph-positive ALL.

The Role of Bosutinib in Chronic Myeloid Leukemia: An Indian Perspective

AbstractManagement of chronic myeloid leukemia (CML) has been transformed by the use of tyrosine kinase inhibitors (TKIs). Presently in India, five TKIs are approved for the management of CML with distinct safety profiles. The selection of TKIs for chronic phase (CP)-CML patients is based on treatment goals, underlying comorbidities, and specific TKI toxicity profiles. Bosutinib is one of five TKIs indicated for the first-line treatment of CP-CML and patients with intolerance or resistance to prior TKI therapy. It possesses a distinct safety profile among other TKIs, with less cardiovascular adverse events (AEs), albeit the liver-related and gastrointestinal AEs have higher occurrence. The safety and efficacy of bosutinib have been examined in clinical trials; however, there is a paucity of data from Asia. A virtual expert panel meeting was convened to gather expert opinion from India on the selection of bosutinib as a treatment choice for patients with CP-CML. This is a white paper document drafted with the help of an expert panel of 14 oncologists and hematooncologists from India on bosutinib use in CP-CML. The experts concurred that bosutinib has proven efficacy for CP-CML in global randomized clinical trials and is well suited for CP-CML patients with existing cardiovascular comorbidities. However, it was not recommended for patients with gastrointestinal, pancreatic, or renal abnormalities. This review aims to put forth expert opinion and guidance document on key considerations for CP-CML clinical decision-making in India.

Clinical outcomes of second-generation tyrosine kinase inhibitors versus imatinib in older patients with CML.

Age and comorbidities are important factors to be considered in the selection of tyrosine kinase inhibitors (TKIs) for first-line treatment in patients with chronic myeloid leukemia in chronic phase (CML-CP). However, it is yet unclear whether TKI selection, particularly, imatinib versus second-generation TKIs (2GTKIs), impacts treatment outcomes in the clinical practice. To address this, we compared the clinical outcomes of prospectively registered 452 patients with CML-CP treated with imatinib and 2GTKIs, taking into consideration their age and/or comorbidities. A total of 136 patients (30.1%) were classified into an older cohort (≥65 years) and 316 (69.9%) into a younger cohort (18-64 years). The TKI selection did not vary based on age (70.6% received 2GTKIs in the younger cohort and 66.2% in the older cohort). The median follow-up period was 5.4 years. Treatment responses including the cumulative incidence of deep molecular response (BCR-ABL1 international scale ≤0.0032%) at any time were similar between the two age cohorts regardless of the type of TKI. The 5-year overall survival (OS) in the older cohort was lower than that in the younger cohort (95.9% vs 83.8%; p < 0.0001), whereas the 5-year OS in patients treated with 2GTKIs was not influenced by age factors and comorbidities. Therefore, our results suggest that the selection of 2GTKIs as first-line treatment is an effective option for both younger and older CML-CP patients with or without comorbidities. This trial was registered at UMIN-CTR as 00003581.

Somatic Mutations in Myeloid Transcription Factors and in Activated Signaling Pathway, but Not in Epigenetic Modifier Pathway, Predict the Risk of Treatment Failure and Progression to Advanced Phase in Chronic Myeloid Leukemia

Background Next-generation sequencing (NGS) is currently reforming contemporary clinical practice into precision medicine incorporating genomics-based knowledge into the clinic. Recently, multiple studies showed that mutations in epigenetic modifier genes are associated with poor treatment outcomes following tyrosine kinase inhibitor (TKI) therapy in chronic myeloid leukemia (CML), particularly after Imatinib treatment. However, it is uncertain whether they either originated from clonal hematopoiesis or the CML clone. For example, ASXL1 mutation is the most recurrent mutation at CML diagnosis, and its presence is correlated with adverse prognosis in CML. Finding of rapid reduction in ASXL1 allele frequency following TKI therapy (Kim et al, Blood 2017) raises the question of whether it is a real driver of treatment failure in CML or not. In addition, it is of interest whether 2nd generation TKI (2G-TKI) therapies can abrogate the adverse impact of somatic mutations in CML. Accordingly, the present study attempted to evaluate the prognostic impact of mutation profiles on clinical outcomes in CML patients treated either with Imatinib or 2G-TKIs. Patients and Methods Our cohort includes a total of 394 samples including 254 samples collected at initial diagnosis and 140 samples taken during follow-up from 309 CML patients in two CML treating centers. Disease characteristics and treatment outcomes were evaluated and compared according to mutation profiles at initial diagnosis and during follow-up after TKI therapy. Treatment outcomes include any response with respect to major molecular response (MMR), molecular response (MR) with 2-log/deeper (MR2) or 4-log/deeper (MR4) with any lines of TKI therapy, failure-free survival (FFS), progression and overall survival (OS). Instead of conventional NGS, we applied smMIP-based NGS (limit of detection up to 0.2%) using our in-house CML-specific panel targeting 40 genes including epigenetic modifiers, myeloid transcription factors (TFs), tumour suppressors, genes in activated signaling, spliceosome and, cohesin complex. ResultsPatient group and treatment summary Summary of patient characteristics are as follows: median age of 54 years; male:female n=143/111 (56.3:43.7); disease status at presentation includes chronic- (n=233; 91.7%), accelerated- (n=15; 5.9%), blastic phase (n=4; 1.6%), or N/A (n=2; 0.8%); Sokal score, low (n=61, 24.0%), intermediate (n=84, 33.1%), high (n=74, 29.1%), or N/A (n=35, 13.8%). Frontline therapy includes Imatinib (n=190; 74.8%), or 2G-TKI (n=62) including Dasatinib (n=15; 6.0%), Nilotinib (n=37; 14.7%), Bosutinib (n=10; 4.0%), or other (n=2; 0.8%). Mutation profiles and their correlation with clinical outcomes following TKI therapy70 mutations were detected in 57 (22.4%) out of 254 diagnostic samples, while 64 mutations were detected in 39 (27.9%) out of 140 follow-up samples.Any mutation detected at initial diagnosis is associated with worse outcomes following TKI therapy. The adverse impact of somatic mutation was mainly from myeloid TF or activated signaling pathway mutations. Patients having those mutations at initial diagnosis showed higher risks of treatment failure (HR 2.8 95% CI [1.4-5.4], p = 0.003) and progression (HR 3.1 95% CI [1.1-9.1], p = 0.04), mainly when treated with Imatinib. On the other hand, the adverse impact of epigenetic modifiers was not apparent although a trend was observed toward a lower response rate for MR2 and MMR in patients carrying mutations in epigenetic modifiers.The adverse prognostic impact from these mutations seems to be abrogated by the use of 2G-TKI therapy, supporting the use of smMIP-based NGS for upfront TKI selection in newly diagnosed CML patients.In the cross-sectional analysis of follow-up samples, overall mutation frequency was significantly higher in the treatment failure or progression group compared to the optimal responders (p=0.012), suggesting longitudinal tracking of mutation profiles may help identify cases of impending treatment failure or progression early. Conclusion Our study shows that mutation profiling utilizing smMIP-based NGS can help identify patients with a potential adverse prognosis from initial diagnosis and may help upfront TKI selection. Further follow-up analysis is ongoing to evaluate the effect of TKI therapy on longitudinal kinetics of mutations in serially collected samples. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Challenges of Maintenance Tyrosine Kinase Inhibitor Therapy after Allogeneic Hematopoietic Cell Transplantation in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia

Background: Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) relapse after allogeneic hematopoietic cell transplantation (HCT) is difficult to manage. One strategy to prevent this is tyrosine kinase inhibitor (TKI) maintenance post-HCT, but the vast majority of data discusses the use of imatinib in this setting, with few reports on newer generation TKIs (NG-TKI). Here, we present our institutional experience with TKI maintenance post-HCT. Methods: Ph+ ALL patients who underwent HCT and received TKI maintenance anytime post-HCT from 2003-2019 were included through retrospective chart review. The primary endpoint was overall survival (OS), and secondary endpoints were progression-free survival (PFS), and cumulative incidence of non-relapse mortality (NRM), cumulative incidence of relapse (CIR), and graft-vs-host disease (GVHD). OS and PFS were calculated via the Kaplan Meier method, NRM, CIR, and GVHD were calculated through a competing risk analysis, where CIR was used as a competing risk for NRM and GVHD, and NRM for CIR and GVHD. Results: 110 patients were included, and their baseline characteristics are described in Table 1. 45 (40.9%) patients received imatinib initially, and 65 (59.1%) received NG-TKI initially, of whom, 59 (90.8%) received dasatinib, 4 (6.2%) received nilotinib, and 2 (3.1%) received ponatinib. The median age (range) of the initial imatinib and NG-TKI groups were 42 years (19-64) and 47 (21-73), respectively. 25 (55.6%) vs 43 (66.2%) in the initial imatinib vs NG-TKI groups were >40 years, respectively. 18 (40.0%) vs 39 (60.0%) of the patients receiving initial imatinib vs NG-TKI were female (P=0.052). 20 (44.4%) vs 54 (83.1%) patients in the imatinib vs NG-TKI group underwent HCT ≥2010, respectively (P<0.001). 41 (91.1%) vs 57 (87.7%) in the imatinib vs NG-TKI groups underwent HCT in first complete remission (CR1) (P=0.76), and 21 (46.7%) vs 31 (47.7%) had no measurable residual disease (MRD) detected by PCR at the time of HCT, although 10 (22.2%) vs 10 (15.4%) did not have a PCR report at the time of HCT available (P=0.66). 42 patients (38.2%) required a dose reduction due to toxicity, and 67 patients (60.9%) experienced TKI interruption due to toxicity. Initial imatinib vs NG-TKI maintenance was discontinued in 20 (46.5%) vs 29 (44.6%) due to toxicity, respectively. The median cumulative initial TKI exposure in patients initially receiving imatinib and NG-TKI was 354 days (range, 6-4,473) and 301 days (range, 5-2,740), respectively. Reasons for TKI discontinuation are listed in Table 2. There was no difference in 5-year OS and PFS in patients receiving imatinib vs NG-TKI, 84.1% vs 69.8% (P=0.47) and 75.1% vs 62.5% (P=0.48), respectively. Likewise, 5-year NRM, 5-year relapse, and 4-year GVHD were similar between imatinib vs NG-TKI, 9.0% vs 18.3% (P=0.48), 15.9% vs 19.2% (P=0.92), and 40.7% vs 47.7% (P=0.47), respectively. Univariate analyses showed an improvement in OS and PFS in those who received ≥12 months of TKI maintenance vs those who received <12 months, hazard ratio (HR) 0.26 (95% confidence interval (CI), 0.12-0.55), P<0.001 and HR 0.33 (95% CI, 0.17-0.64), P<0.001. There was no difference in OS and PFS for those who completed ≥12 months of TKI maintenance based on initial TKI of choice, HR 0.85 (95% CI, 0.21-3.51), P=0.8 and HR 0.91 (95% CI, 0.28-2.94), P=0.9. Conclusions: Our findings demonstrate the challenges of delivering post-HCT TKI maintenance. Toxicity leading to TKI interruptions, discontinuation, and dose reduction was common. Post-transplant outcomes were comparable with imatinib and NG-TKI. Therefore, TKI selection for post-HCT maintenance should be based on patient tolerability to maximize TKI maintenance exposure. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

CML-184 A Novel Droplet Digital PCR Strategy for Rapid and Sensitive Detection of BCR::ABL1 Kinase Domain Mutations Conferring Resistance to Second-Generation Tyrosine Kinase Inhibitors

Testing for BCR-ABL1 kinase domain (KD) mutations should always be performed before tyrosine kinase inhibitor (TKI) changes. Next-generation sequencing (NGS) is the best approach to highlight emerging mutations in patients not responding adequately to TKI therapy. However, NGS requires sample centralization and batch analysis and has a non-negligible time to results. In this study, we set up and validated a novel droplet digital PCR (ddPCR)-based multiplex strategy for the detection and quantitation of transcripts harboring mutations impacting TKI selection. In collaboration with Bio-Rad, a 3-tube ddPCR strategy was designed that enables identification and quantitation of 16 nucleotide substitutions encoding the 13 mutations associated with resistance to one or more second-generation TKI (2GTKI). Primers and FAM-or FAM/HEX-labelled probes were grouped on a TKI-specific basis and generated clusters of droplets mapping to spatially distinct areas of the 2D plot based on resistance profiles. Each tube also incorporated primers and HEX-labelled probes for e13a2, e14a2, and e1a2 BCR::ABL1 fusion transcripts to express results as the percentage of mutation-positive over total BCR::ABL1 transcripts. For validation, a total of 101 RNA samples from healthy donors, TKI-sensitive and -resistant patients, and BCR::ABL1-positive and -negative cell lines were used. cDNA (125 ng) obtained with ABL1-specific primers was analyzed in duplicate on a QX200 ddPCR system (Bio-Rad). The limit of blank was determined using 60 blank samples. Accuracy and specificity were confirmed using 48 samples positive for one or more 2GTKI-resistant mutations or mutations at nearby codons (to exclude cross-reactivity). Analysis of serial dilutions of cell line mixtures made using BCR::ABL1-positive mutation-positive cells, BCR::ABL1-positive unmutated cells, and BCR::ABL1-negative cells to mimic different mutation frequencies (70%, 5%, and 0.5%) and different transcript levels (MR0 to MR3) showed that a 0.5% lower detection limit could be consistently achieved irrespective of BCR::ABL1 levels. ddPCR proved highly sensitive and accurate. Total hands-on time was approximately 2 hrs, and time from sample to results was 2 days. Therefore, ddPCR may be integrated into diagnostic algorithms of CML (and Ph+ ALL) patients as a convenient first-level screening tool for mutations impacting TKI selection.

Dose optimization of tyrosine kinase inhibitor therapy in chronic myeloid leukemia.

The therapeutic outcomes of chronic myeloid leukemia (CML) have improved dramatically since tyrosine kinase inhibitors (TKIs) became available in clinical practice. Life expectancy of patients with CML is now close to that of the general population. Patients with CML who achieve sustained deep molecular response may discontinue TKI therapy. However, most patients still require TKI therapy for long periods without sustained deep molecular response. Given the awareness of increased incidence of arterial occlusive events in patients on TKI therapy, the optimal TKI selection should be based on age, comorbidities, risk classification, and goals of treatment. Dose optimization of TKI therapy reduces the incidence of adverse events while maintaining efficacy in CML.

Predicting EGFR mutation, ALK rearrangement, and uncommon EGFR mutation in NSCLC patients by driverless artificial intelligence: a cohort study

BackgroundTimely identification of epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) rearrangement status in patients with non-small cell lung cancer (NSCLC) is essential for tyrosine kinase inhibitors (TKIs) administration. We aimed to use artificial intelligence (AI) models to predict EGFR mutations and ALK rearrangement status using common demographic features, pathology and serum tumor markers (STMs).MethodsIn this single-center study, demographic features, pathology, EGFR mutation status, ALK rearrangement, and levels of STMs were collected from Wuhan Union Hospital. One retrospective set (N = 1089) was used to train diagnostic performance using one deep learning model and five machine learning models, as well as the stacked ensemble model for predicting EGFR mutations, uncommon EGFR mutations, and ALK rearrangement status. A consecutive testing cohort (n = 1464) was used to validate the predictive models.ResultsThe final AI model using the stacked ensemble yielded optimal diagnostic performance with areas under the curve (AUC) of 0.897 and 0.883 for predicting EGFR mutation status and 0.995 and 0.921 for predicting ALK rearrangement in the training and testing cohorts, respectively. Furthermore, an overall accuracy of 0.93 and 0.83 in the training and testing cohorts, respectively, were achieved in distinguishing common and uncommon EGFR mutations, which were key evidence in guiding TKI selection.ConclusionsIn this study, driverless AI based on robust variables could help clinicians identify EGFR mutations and ALK rearrangement status and provide vital guidance in TKI selection for targeted therapy in NSCLC patients.

Choice of Frontline Tyrosine-Kinase Inhibitor in Very Elderly Patients with Chronic Myeloid Leukemia: A “Campus CML” Study

Introduction Treatment of chronic phase (CP) chronic myeloid leukemia (CML) with tyrosine kinase inhibitors (TKIs) proved to be almost equally effective in young and elderly patients. Three TKIs, imatinib (IM), dasatinib (DAS) and nilotinib (NIL), are approved for frontline therapy in Italy. Choice of frontline TKI is based on a combined evaluation of patient's characteristics and expectations, with age usually playing a prominent role. However, to date, few data are available on patterns of TKI selection in very elderly patients.Aim To analyse the use of frontline TKI therapy in a large and unselected cohort of very elderly CP-CML patientsMethods We retrospectively evaluated 332 patients aged ≥75 year diagnosed from 1/2012 to 12/2019 at 36 Hematology Centres participating at the “Campus CML” project.Results Clinical features at diagnosis for the whole cohort and according to frontline TKI are reported in Table 1. As to frontline TKI, 285 patients (85.8%) received IM and 47 (14.2%) a 2G-TKI (DAS n=28, 59.5%; NIL n=19, 40.5%). Of the 285 IM-treated patients, 192 (67.3%) started with standard dose (400 mg/day) and 93 (32.7%) with a reduced dose (300 mg/day n=64, 22.5%; <300 mg/day n=29, 10.2%). Among the 47 patients starting a 2G-TKIs, 35 (74.4%) received standard dose and 12 (25.6%) a reduced dose (NIL <600 mg/day n=3; DAS 80 mg/day n=4 and 50 mg/day n=5). There were no differences between patients treated with imatinib or 2G-TKI (Table 1); only a previous cerebrovascular event was reported in a significantly higher rate of IM-treated patients. It is however evident that the distinct toxicity profiles of NIL and DAS had an impact on TKI choice as, for example, no patient with diabetes or ischemic heart disease received NIL.Following widespread introduction of generic IM in Italy in early 2018, patients were divided in 2 groups: among 238 patients diagnosed from 2012 to 2017, 198 (83.1%) received IM and 40 (16.9%) a 2G-TKI, while patients diagnosed in 2018-2019 were treated with IM in 87/94 (92.5%) cases and with a 2G-TKI in 7 (7.5%) cases only (p=0.028).Conclusions IM remains the frontline drug of choice in very elderly CML patients, and this trend seems to increase after the introduction of the generic formulation. However, 2G-TKI are used in a small but sizeable group of patients, without a clear correlation with baseline CML features, thus probably reflecting a physician's evaluation of patient's fitness and/or expectation. Efficacy and safety of initial reduced TKIs doses in the setting of very elderly patients warrant further analyses. [Display omitted] DisclosuresLatagliata: Novartis: Honoraria; BMS Cellgene: Honoraria; Pfizer: Honoraria. Bonifacio: Novartis: Honoraria; Pfizer: Honoraria; Amgen: Honoraria; Bristol Myers Squibb: Honoraria. Elena: CELGENE: Other: funding for meeting participation; PFIZER: Membership on an entity's Board of Directors or advisory committees; NOVARTIS: Membership on an entity's Board of Directors or advisory committees; GILEAD: Membership on an entity's Board of Directors or advisory committees. Iurlo: Novartis: Speakers Bureau; Incyte: Speakers Bureau; Pfizer: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Sportoletti: AstraZeneca: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Stagno: Pfizer: Consultancy, Honoraria, Other: Support for attending meetings and/or travel; InCyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Support for attending meetings and/or travel, Research Funding. Abruzzese: Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Breccia: Bristol Myers Squibb/Celgene: Honoraria; Incyte: Honoraria; Abbvie: Honoraria; Pfizer: Honoraria; Novartis: Honoraria.

Which Tyrosine Kinase Inhibitors Should Be Selected as the First-Line Treatment for Chronic Myelogenous Leukemia in Chronic Phase?

Simple SummaryThis review discusses the optimal selection of BCR-ABL1 tyrosine kinase inhibitors (TKIs) as the first-line treatment for newly diagnosed chronic myelogenous leukemia in chronic phase (CML-CP). With the advent of TKIs, the treatment goals for CML-CP patients have changed from “simply survival” to “survival with adequate quality of life”, hence the number of CML-CP patients aiming to achieve treatment-free remission has increased, irrespective of age or comorbidities. Therefore, optimal selection of TKIs for maximizing the number of patients to achieve treatment-free remission is an important factor for consideration in future studies. To this end, we must understand the advantages and disadvantages of each TKI in terms of treatment response, disease risk at diagnosis, comorbidities, and medical expenses, and use of effective 2GTKIs based on patient background. This review provides insights into “shared decision-making” in individual cases, including the elderly population.With the use of tyrosine kinase inhibitors (TKIs), chronic myelogenous leukemia in chronic phase (CML-CP) has been transformed into a non-fatal chronic disease. Hence, “treatment-free remission (TFR)” has become a possible treatment goal of patients with CML-CP. Currently, four types of TKIs (imatinib, nilotinib, dasatinib, and bosutinib) are used as the first-line treatment for newly diagnosed CML-CP. However, the second-generation TKI (2GTKI), the treatment response of which is faster and deeper than that of imatinib, is not always recommended as the first-line treatment for CML-CP. Factors involved in TKI selection in the first-line treatment of CML-CP include not only patients’ medical background, but also patients’ choice regarding the desired treatment goal (survival or TFR?). Therefore, it is important that clinicians select an appropriate TKI to successfully achieve the desired treatment goal for each patient, while minimizing the development of adverse events. This review compares the pros and cons of using imatinib and 2GTKI for TKI selection as the first-line treatment for CML-CP, mainly considering treatment outcomes, medical history (i.e., desire for pregnancy, aging factor, and comorbidity), and cost. The optimal use of 2GTKIs is also discussed.

Long-Term Outcome of CML Patients Treated with Second-Generation Tyrosine Kinase Inhibitors in the Second Line: A Single Center Experience

Background: Since the introduction of tyrosine kinase inhibitors (TKI), most patients (pts) with chronic myeloid leukemia (CML) have a favorable outcome with their initial therapy. However, some pts experience resistance or intolerance. Second generation TKI dasatinib, nilotinib and bosutinib are effective (and approved) for pts with failure to one prior TKI. In the absence of specific mutations or patient comorbidities driving the selection of a specific TKI, selecting the next TKI remains at the physician discretion, especially in the lack of randomized data comparing 2nd generation TKI. Methods: We analyzed the outcomes of 621 consecutive patients with CML treated at a single institution with 2nd generation TKI in the 2nd line following failure of frontline TKI. For this analysis we focused on the 572 pts that received dasatinib, nilotinib or bosutinib as 2nd line TKI (not including 49 pts treated with ponatinib, imatinib or investigational TKI). Results: The median age at diagnosis was 47 years (range, 12-86) and 49% were male. 516 pts received TKI as frontline treatment and 105 had other therapies (interferon, chemotherapy) prior to TKI. Pts were switched to a 2nd generation TKI for resistance (n=337; 54%) or intolerance (n= 279; 45%). The median time from diagnosis to start of 2nd line TKI was 32 mo (0 to 206 mo). Dasatinib, nilotinib and bosutinib were used as 2nd line TKI in 338 (54%), 194 (31%), and 40 (6%) pts, respectively. Overall, out of 572 pts who received one of these three TKIs, 401 had cytogenetic evaluation of which 323 (81%) achieved major cytogenetic response (34 (8%) partial (PCyR) and 289 (72%) complete (CCyR)). Out of 428 who had a molecular evaluation, 75% achieved molecular response (94 (18%) MMR, 52 (6%) MR4, 217 (51%) MR4.5). The rates of major cytogenetic response (MCyR) were, with dasatinib 85% (76% CCyR), nilotinib 76% (70% CCyR), and bosutinib 67% (50% CCyR) (p=0.015). Rates of molecular response (MMR or better) were with dasatinib 72% (55% MR4.5), nilotinib 65% (46% MR4.5), and bosutinib 55% (39% MR4.5), (p=0.07). At a median follow-up from diagnosis of 96 mo (range, 4-283), 39 (7%) pts transformed either to accelerated (n=26, 5%) or to blast phase (n=13, 2%) while on 2nd line TKI. Median overall survival (OS) and transformation-free survival (TFS) were not reached and the median event-free survival (EFS) was 121 mo. Seven-year probabilities of OS, TFS and EFS were 66%, 91% and 55%, respectively. Higher OS, TFS, and EFS were found in patients who received frontline TKI (7-yr 70%, 92% and 59%, respectively) vs those who failed another treatment prior to any TKI (49%, 83%, and 38%, respectively) (p Conclusion: This analysis shows that dasatinib, nilotinib and bosutinib remain largely effective in inducing cytogenetic and molecular response when used as a 2nd line TKI with similar OS, TFS and EFS in the overall pts population. A multivariate analysis to identify predictors of long-term outcome, including specific TKI as a variable, is ongoing. Disclosures Kantarjian: Novartis: Research Funding; Bristol-Meyers Squibb: Research Funding; Amgen: Research Funding; ARIAD: Research Funding; Delta-Fly Pharma: Research Funding; Pfizer: Research Funding. DiNardo: Daiichi-Sankyo: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Agios: Honoraria, Research Funding. Daver: Bristol-Myers Squibb Company: Consultancy, Research Funding; Incyte Corporation: Honoraria, Research Funding; Pfizer Inc.: Consultancy, Research Funding; Jazz: Consultancy; Novartis Pharmaceuticals Corporation: Consultancy; Immunogen: Research Funding; Kiromic: Research Funding; Otsuka America Pharmaceutical, Inc.: Consultancy; Daiichi-Sankyo: Research Funding; Sunesis Pharmaceuticals, Inc.: Consultancy, Research Funding; Karyopharm: Consultancy, Research Funding. Pemmaraju: Incyte Corporation: Consultancy, Honoraria; cellectis: Research Funding; novartis: Consultancy, Honoraria, Research Funding; abbvie: Research Funding; roche diagnostics: Consultancy, Honoraria; affymetrix: Research Funding; LFB: Consultancy, Honoraria; stemline: Consultancy, Honoraria, Research Funding. Burger: Novartis: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding; TG Therapeutics: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding; Gilead: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding. Jabbour: Bristol-Myers Squibb: Consultancy. Cortes: Pfizer: Consultancy, Research Funding; BMS: Consultancy, Research Funding; ImmunoGen: Consultancy, Research Funding; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; ARIAD: Consultancy, Research Funding; Sun Pharma: Research Funding; Teva: Research Funding.

Impact of frontline treatment approach on outcomes of myeloid blast phase CML

BackgroundThe natural course of untreated chronic myeloid leukemia (CML) is progression to an aggressive blast phase. Even in the current era of BCR-ABL1 tyrosine kinase inhibitors (TKIs), the outcomes of blast phase CML remain poor with no consensus frontline treatment approach.MethodsWe retrospectively analyzed the response rates and survival outcomes of 104 consecutive patients with myeloid blast phase CML (CML-MBP) treated from 2000 to 2019 based on 4 different frontline treatment approaches: intensive chemotherapy (IC) + TKI (n = 20), hypomethylating agent (HMA) + TKI (n = 20), TKI alone (n = 56), or IC alone (n = 8). We also evaluated the impact of TKI selection and subsequent allogeneic stem cell transplant (ASCT) on patient outcomes.ResultsResponse rates were similar between patients treated with IC + TKI and HMA + TKI. Compared to treatment with TKI alone, treatment with IC/HMA + TKI resulted in a higher rate of complete remission (CR) or CR with incomplete count recovery (CRi) (57.5% vs 33.9%, p < 0.05), a higher complete cytogenetic response rate (45% vs 10.7%, p < 0.001), and more patients proceeding to ASCT (32.5% vs 10.7%, p < 0.01). With a median follow-up of 6.7 years, long-term outcomes were similar between the IC + TKI and HMA + TKI groups. Combination therapy with IC/HMA + TKI was superior to therapy with TKI alone, including when analysis was limited to those treated with a 2nd/3rd-generation TKI. When using a 2nd/3rd-generation TKI, IC/HMA + TKI led to lower 5-year cumulative incidence of relapse (CIR; 44% vs 86%, p < 0.05) and superior 5-year event-free survival (EFS; 28% vs 0%, p < 0.05) and overall survival (OS; 34% vs 8%, p = 0.23) compared to TKI alone. Among patients who received IC/HMA + TKI, EFS and OS was superior for patients who received a 2nd/3rd generation TKI compared to those who received imatinib-based therapy. In a landmark analysis, 5-year OS was higher for patients who proceeded to ASCT (58% vs 22%, p = 0.12).ConclusionsCompared to patients treated with TKI alone for CML-MBP, treatment with IC + TKI or HMA + TKI led to improved response rates, CIR, EFS, and OS, particularly for patients who received a 2nd/3rd-generation TKI. Combination therapy with IC + TKI or HMA + TKI, rather than a TKI alone, should be considered the optimal treatment strategy for patients with CML-MBP.