Asciminib monotherapy in patients with CML-CP without BCR::ABL1 T315I mutations treated with at least two prior TKIs: 4-year phase 1 safety and efficacy results

Chronic myeloid leukemia: 2025 update on diagnosis, therapy, and monitoring

DISEASE OVERVIEW

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm with an annual incidence of two cases/100 000. It accounts for approximately 15% of newly diagnosed cases of leukemia in adults.

DIAGNOSIS

CML is characterized by a balanced genetic translocation, t(9;22) (q34;q11.2), involving a fusion of the Abelson murine leukemia (ABL1) gene from chromosome 9q34 with the breakpoint cluster region (BCR) gene on chromosome 22q11.2. This rearrangement is known as the Philadelphia chromosome. The molecular consequence of this translocation is the generation of a BCR::ABL1 fusion oncogene, which in turn translates into a BCR::ABL1 oncoprotein.

FRONTLINE THERAPY

Four tyrosine kinase inhibitors (TKIs), imatinib, dasatinib, bosutinib, and nilotinib, are approved by the United States Food and Drug Administration (FDA) for first-line treatment of newly diagnosed CML in the chronic phase (CML-CP). Clinical trials with second and third-generation TKIs in frontline CML-CP therapy reported significantly deeper and faster responses but had no impact on survival prolongation, likely because of their potent efficacy and the availability of effective TKIs salvage therapies for patients who have a cytogenetic relapse with frontline TKI therapy. All four TKIs are equivalent if the aim of therapy is to improve survival. In younger patients with high-risk disease and in whom the aim of therapy is to induce a treatment-free remission status, second-generation TKIs may be favored.

SALVAGE THERAPY

For CML post-failure on frontline therapy, second-line options include second and third-generation TKIs. Although potent and selective, these TKIs exhibit unique pharmacological profiles and response patterns relative to different patient and disease characteristics, such as patients' comorbidities and financial status, disease stage, and BCR::ABL1 mutational status. Patients who develop the T315I "gatekeeper" mutation display resistance to all currently available TKIs except ponatinib, asciminib, and olverembatinib. Allogeneic stem cell transplantation remains an important therapeutic option for patients with CML-CP and failure (due to resistance) of at least two TKIs and for all patients in advanced-phase disease. Older patients who have a cytogenetic relapse post-failure on all TKIs can maintain long-term survival if they continue a daily most effective/least toxic TKI, with or without the addition of non-TKI anti-CML agents (hydroxyurea, omacetaxine, azacitidine, decitabine, cytarabine, and others).

Dose-escalation of second-line and first-line asciminib in chronic myeloid leukemia in chronic phase: the ASC2ESCALATE Phase II trial

Up to 40% of newly diagnosed patients with chronic myeloid leukemia in chronic phase (CML-CP) discontinue treatment by 5 years, primarily due to resistance or intolerance. Rates of resistance to second-line (2L) treatment are also high. Some patients with resistance respond with dose escalation of tyrosine kinase inhibitors (TKIs). Asciminib demonstrated safety and efficacy across a broad dosage range. ASC2ESCALATE is an ongoing, Phase II, multicenter, single-arm, dose-escalation study of asciminib in 2L and first-line treatment of CML-CP. The primary end point is major molecular response at 12 months in 2L. Secondary end points include molecular responses at and by scheduled time points, survival, and safety. ASC2ESCALATE is the first study investigating asciminib in CML-CP following failure of one prior TKI.Clinical Trial Registration: NCT05384587 (ClinicalTrials.gov).

Impact of BCR::ABL1 single nucleotide variants on asciminib efficacy

Asciminib is a potent and selective inhibitor of BCR::ABL1, with potential to avoid toxicity resulting from off-target kinase inhibition. Forty-nine patients treated with asciminib under a managed access program in the UK were evaluated for toxicity and response. Intolerance, rather than resistance (65% vs. 35%), was the most common reason for cessation of the last-line of treatment but asciminib was well tolerated, with most patients (29, 59%) remaining on treatment at a median of 14 months follow-up, and only 6 (12%) stopping for intolerance. Of 44 patients assessable for response, 29 (66%) achieved a complete cytogenetic response (CCyR) or better, with poorer responses seen in those stopping their last-line of therapy for resistance. Fewer patients with a prior history of a non-T315I-BCR::ABL1 single nucleotide variant (BSNV), or a non-T315I-BSNV detectable at baseline achieved CCyR. Serial tracking of BSNV by next generation sequencing demonstrated clonal expansion of BSNV-harbouring populations, which in some settings was associated with resistance (E459K, F317L, F359I), while in others was seen in the context of ongoing response, often with intensified dosing (T315I, I502F). These data suggest that asciminib exerts selective pressure on some BSNV-harbouring populations in vivo, some of which may respond to intensified dosing.

Asciminib: the next-generation bullet for first-line treatment of chronic myeloid leukemia

The standard of care for chronic myeloid leukemia (CML) involves tyrosine kinase inhibitors (TKIs), which suppress tyrosine kinase activity of BCR::ABL1. Hochhaus et al. reported that asciminib, a BCR::ABL1 inhibitor specifically targeting the ABL myristoyl pocket, showed superior efficacy and favorable safety compared with TKIs in the phase 3 ASC4FIRST trial in patients with newly diagnosed chronic-phase CML.1.

Real-World Disproportionality Analysis of the Food and Drug Administration Adverse Event Reporting System Database for Asciminib

INTRODUCTION

Asciminib is primarily utilized for treating Philadelphia chromosome-positive chronic myeloid leukemia in its chronic phase among patients harboring the T315I mutation or those who have been previously treated with at least two tyrosine kinase inhibitors. The safety profile of asciminib across a broad patient population over an extended timeframe remains unverified. This study uses a real-world pharmacovigilance database to evaluate the adverse events (AEs) linked with asciminib, providing valuable insights for clinical drug safety.

METHODS

Data from the FDA Adverse Event Reporting System (FAERS) database, spanning from October 2021 to December 2023, served as the basis for this analysis. The extent of disproportional events was assessed using sophisticated metrics such as the reporting odds ratio, proportional reporting ratio, information component, and empirical Bayesian geometric mean.

RESULTS

Within the specified period, the FAERS database documented 3,913,574 AE reports, with asciminib being associated with 966 incidents. Reactions to asciminib spanned 27 system organ categories. Utilizing four distinct analytical algorithms, 663 significant preferred terms exhibiting disproportional frequencies were identified. Notably, this investigation uncovered 26 significant AEs linked to off-label asciminib use, encompassing conditions such as gynecomastia, nephrotic syndrome, orchitis, pyelonephritis, hepatotoxicity, and pancreatitis. The median onset time for asciminib-related AEs was 52.5 days, ranging from 17 to 122.75 days.

CONCLUSION

The study sheds light on additional potential AEs associated with asciminib use, warranting further research to confirm these findings.

Therapeutic options for chronic myeloid leukemia following the failure of second-generation tyrosine kinase inhibitor therapy

The management of chronic myeloid leukemia in the chronic phase (CML-CP) has witnessed significant advancements since the identification of a common chromosomal translocation anomaly involving chromosomes 9 and 22, which results in the formation of the Philadelphia chromosome driven by the BCR-ABL1 fusion protein. This discovery paved the way for the development of tyrosine kinase inhibitors (TKIs) that target the adenosine triphosphate (ATP) binding site of ABL1 through the BCR-ABL-1 fusion protein. Following the approval of Imatinib by the Food and Drug Administration (FDA) as the first TKI for CML treatment in 2001, the median overall survival (OS) for chronic phase CML (CML-CP) has significantly improved, approaching that of the general population. However, achieving this milestone crucially depends on reaching certain treatment response milestones. Since the introduction of imatinib, five additional TKIs have been approved for CML-CP treatment. Despite the availability of these treatments, many patients may experience treatment failure and require multiple lines of therapy due to factors such as the emergence of resistance, such as mutations in the ATP binding site of ABL, or intolerance to therapy. This review will primarily focus on exploring treatment options for patients who fail second-generation TKI therapy due to true resistance.

Clinical outcomes of chronic myeloid leukaemia patients taking asciminib through a Managed Access Programme (MAP) in Australia

Asciminib is a novel allosteric STAMP (specifically targets the ABL myristoyl pocket) inhibitor of the BCR::ABL1 oncogene. Real-world clinical outcomes of patients with tyrosine kinase inhibitor (TKI)-resistant/intolerant chronic myeloid leukaemia (CML) in Australia on the Managed Access Programme for asciminib showed higher molecular responses for those with intolerance versus resistance ± intolerance to their last TKI. There remains a clinical need to improve outcomes in patients with CML who have resistance to multiple TKIs, especially in the ponatinib-pretreated cohort.

Asciminib monotherapy in patients with chronic-phase chronic myeloid leukemia with the T315I mutation after ≥1 prior tyrosine kinase inhibitor: 2-year follow-up results

Asciminib targets the BCR::ABL1 myristoyl pocket, maintaining activity against BCR::ABL1T315I, which is resistant to most approved adenosine triphosphate-competitive tyrosine kinase inhibitors. We report updated phase I results (NCT02081378) assessing safety/tolerability and antileukemic activity of asciminib monotherapy 200 mg twice daily in 48 heavily pretreated patients with T315I-mutated chronic-phase chronic myeloid leukemia (CML-CP; data cutoff: January 6, 2021). With 2 years' median exposure, 56.3% of patients continued receiving asciminib. Overall, 62.2% of evaluable patients achieved BCR::ABL1 ≤1% on the International Scale (IS); 47.6% and 81.3% of ponatinib-pretreated and -naive patients, respectively, achieved BCR::ABL1IS ≤1%. Of 45 evaluable patients, 48.9% achieved a major molecular response (MMR, BCR::ABL1IS ≤0.1%), including 34.6% and 68.4% of ponatinib-pretreated and -naive patients, respectively. MMR was maintained until data cutoff in 19 of 22 patients who achieved it. The most common grade ≥3 adverse events (AEs) included increased lipase level (18.8%) and thrombocytopenia (14.6%). Five (10.4%) patients experienced AEs leading to discontinuation, including 2 who discontinued asciminib and died due to COVID-19; these were the only deaths reported. These results show asciminib's effectiveness, including in almost 50% of ponatinib pretreated patients, and confirm its risk-benefit profile, supporting its use as a treatment option for T315I-mutated CML-CP.

Cancer-associated thrombosis in hematologic malignancies

Patients with hematologic malignancies are often complicated not only by severe bleeding due to thrombocytopenia and disseminated intravascular coagulation but also by thromboembolic events, just like in patients with solid cancers, and these events can negatively impact patient outcomes. Nevertheless, the prevention and treatment of cancer-associated thrombosis (CAT) in hematologic malignancies has not been adequately investigated due to the limited size, heterogeneity, and unique pathophysiology of the patient population. This article summarizes the current understanding, risk factors, prediction models, and optimal prevention and treatment strategies of CAT in hematologic malignancies on a disease-by-disease basis, including acute leukemia, lymphoma, myeloma, and myeloproliferative neoplasms. Specific considerations of novel molecular targeted therapeutics introduced in recent years, such as immunomodulatory drugs and tyrosine kinase inhibitors, are also discussed based on the latest clinical trials.

Arterio-occlusive events among patients with chronic myeloid leukemia on tyrosine kinase inhibitors

ABSTRACT

Tyrosine kinase inhibitors (TKIs) are standard therapy for patients with chronic myeloid leukemia. Each of these drugs has a specific profile of tyrosine kinases that they inhibit and, although all are clinically effective, they each have unique toxicity profiles. With the introduction of ponatinib, arterio-occlusive events were first noted and later found to occur with all TKIs to various extents. The recognition of this "class effect" was delayed considering ponatinib was introduced 10 years after the introduction of imatinib. The reasons for the delay in identification of this class effect are likely multifaceted. Importantly, there is an inconsistency in adverse event reporting criteria among the major clinical trials of the various TKIs, likely resulting in mixed reporting of arterio-occlusive events. Reporting events based on a frequency threshold, lack of sufficient follow-up, attempts at causality attribution, and the primary focus on molecular response may all have played an additional role. Considering the increasing rate of arterio-occlusive events over time, the termination of many trials after only 5 years prevents full assessment of the impact of these events. A comprehensive evaluation of TKI adverse effects using uniform Medical Dictionary for Regulatory Activities terms and comprehensive adjudication of these events may be helpful in better assessing the real risk for patients with each TKI. Future clinical trials should use a uniform and comprehensive approach to reporting adverse events without attempting to assign causality to the study drug.

High Efficacy and Safety of Asciminib in a Chronic Myeloid Leukemia Patient with Chronic Kidney Disease Following Renal Transplantation

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm driven by the BCR::ABL1 tyrosine kinase. Tyrosine kinase inhibitors (TKIs) have been established as standard therapies for CML. However, some CML patients experience TKI intolerance. Asciminib was approved for CML patients either intolerant or refractory to TKI therapy. We herein report a 63-year-old CML patient who underwent renal transplantation and exhibited TKI intolerance. He was switched to asciminib, which achieved a deep molecular response without exacerbation of the renal function. Our experience revealed that asciminib is effective and safe for CML patients complicated with chronic kidney disease.

Resistance mutations in CML and how we approach them

Among the variety of resistance mechanisms that may underlie a non-optimal response to tyrosine kinase inhibitor (TKI) therapy in chronic myeloid leukemia patients, secondary point mutations in the BCR::ABL1 kinase domain (KD) represent the only actionable one. Each of the 5 ATP-competitive inhibitors (imatinib, dasatinib, nilotinib, bosutinib, ponatinib) has a well-defined spectrum of resistance mutations. Growing clinical experience will soon allow to also elucidate the full spectrum of mutations conferring resistance to asciminib (that appear not to be confined to the myristate binding pocket). Regular molecular response (MR) monitoring is fundamental for evaluating treatment efficacy, catching early signs of relapse, and intervening promptly in case of confirmed failure. Whenever MR is not deemed satisfactory according to the European LeukemiaNet or the National Comprehensive Cancer Network definitions, BCR::ABL1 KD mutations testing should be performed. When needed, prompt and informed TKI switch can improve response and outcome and prevent the accumulation of mutations, including highly challenging compound mutations. Novel technologies like next-generation sequencing and digital polymerase chain reaction have recently been explored for BCR::ABL1 KD mutation testing; they have both advantages and disadvantages that are discussed in this article. This review also provides suggestions for interpretation and clinical translation of mutation testing results, which may not always be straightforward, particularly in cases of low-level or unknown mutations.

Cardiovascular Adverse Events of Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia: Clinical Relevance, Impact on Outcome, Preventive Measures and Treatment Strategies

OPINION STATEMENT

The introduction of TKIs into the therapeutic armamentarium of CML has changed the disease paradigm, increasing long-term survival from 20% to over 80%, with a life expectancy now approaching that of the general population. Although highly effective, TKIs also have a toxicity profile that is often mild to moderate, but sometimes severe, with multiple kinases involved in the development of adverse events (AEs). Among others, cardiovascular AEs observed in TKI-treated CML patients may represent a significant cause of morbidity and mortality, and their pathogenesis is still only partially understood. In view of the recent introduction into daily clinical practice of new TKIs, namely the STAMP inhibitor asciminib, with a distinct safety profile, hematologists now more than ever have the opportunity to select the most suitable TKI for each patient, an aspect that will be fundamental in terms of personalized preventive and therapeutic strategies. Furthermore, physicians should be aware of the feasibility of TKI dose modifications at all stages of the patients' treatment journey, both at diagnosis for frail or elderly subjects or with multiple comorbidities, and during follow-up for those patients who experience toxicity, as well as to prevent it, with the main objective of reducing side effects while maintaining the response. Consequently, preserving the cardiovascular health of CML patients will likely be a more urgent topic in the near future, with specific measures aimed at controlling cardiovascular risk factors through a multidisciplinary approach involving a panel of healthcare professionals together with the hematologist.

European LeukemiaNet laboratory recommendations for the diagnosis and management of chronic myeloid leukemia

From the laboratory perspective, effective management of patients with chronic myeloid leukemia (CML) requires accurate diagnosis, assessment of prognostic markers, sequential assessment of levels of residual disease and investigation of possible reasons for resistance, relapse or progression. Our scientific and clinical knowledge underpinning these requirements continues to evolve, as do laboratory methods and technologies. The European LeukemiaNet convened an expert panel to critically consider the current status of genetic laboratory approaches to help diagnose and manage CML patients. Our recommendations focus on current best practice and highlight the strengths and pitfalls of commonly used laboratory tests.

Asciminib in the Treatment of Philadelphia Chromosome-Positive Chronic Myeloid Leukemia: Focus on Patient Selection and Outcomes

Tyrosine kinase inhibitors (TKIs) have significantly changed the treatment of chronic myeloid leukemia (CML) and improved outcomes for patients with CML in chronic phase (CML-CP) and accelerated phase (AP). Now armed with numerous effective therapeutic options, clinicians must consider various patient- and disease-specific factors when selecting the most appropriate TKI across lines of therapy. While most patients with CML expected to have a near-normal life expectancy due to the success of TKIs, emphasis has expanded beyond response and survival to include factors like quality of life, tolerability, and long-term toxicity management. Importantly, a subset of patients can achieve sustained deep molecular response and can attain treatment-free remission. Despite these successes, unmet needs remain related to CML treatment, including the persistent challenge of treatment resistance and intolerance, broadening treatment options for patients with resistance mutations or serious comorbidities, and focus on specific populations such as children and young adults. In particular, the only previously available treatments for patients with CML-CP with the T315I mutation were ponatinib, olverembatinib (exclusively approved for use in China at the time of this writing), omacetaxine, and hematopoietic stem cell transplantation. Asciminib has entered the CML treatment landscape as a new option for adult patients with CML-CP who have received ≥2 prior TKIs or those with the T315I mutation. Asciminib's unique mechanism of action, Specifically Targeting the ABL Myristoyl Pocket, sets it apart from traditional adenosine triphosphate-competitive TKIs. While asciminib may overcome unmet needs for patients with CML-CP and continues to be studied in other novel settings, guidance on how to integrate asciminib in treatment algorithms is needed. This review focuses on clinical data and how asciminib can overcome current unmet needs, discusses how to individualize patient selection, and highlights future directions to investigate asciminib in earlier lines of therapy and in children and adolescents.

Italian Physicians' Perceptions about the Role of Asciminib in Later Lines Chronic Myeloid Leukemia in Clinical Practice: A GIMEMA Survey

Unmet needs remain in later lines chronic myeloid leukemia (CML): the response rate and the overall survival of resistant patients in the chronic phase who changed a second-generation TKI in the second line with another TKI with similar action are usually poor, while the off-target toxicities and the potential development of mutations increase. The recent approval of asciminib, a STAMP inhibitor, in the third line, has the potential to soon change the therapeutic algorithm for this subset of patients. Here, we report the results of a GIMEMA survey assessing the number of patients currently treated in the third line in Italy, the current approach in later lines by Italian physicians, and the future role of this drug according to the reason to switch to asciminib (resistance and/or intolerance), as well as the perceptions about the future position of this agent.