The role of ponatinib in chronic myeloid leukemia in the era of treatment free remission

Patient-guided dose reduction of tyrosine kinase inhibitors in chronic myeloid leukaemia (RODEO study): study protocol for a prospective, multicentre, single-arm trial

BACKGROUND

Dose reduction of tyrosine kinase inhibitors (TKI) in patients with chronic myeloid leukaemia (CML) with an optimal response to TKIs may support cost-effective medication use by maintaining therapeutic effectiveness while reducing adverse events and medication costs. As the choice for dose reduction depends on patients' individual needs and preferences, a patient-centred approach is warranted. Therefore, a study to evaluate the effectiveness of patient-guided dose reduction in patients with CML who are in a major or deep molecular response is designed.

METHODS

This study is a prospective, multicentre, single-arm study. 147 patients with CML (aged ≥ 18 years) in chronic phase, who are treated with imatinib, bosutinib, dasatinib, nilotinib or ponatinib, and have reached at least major molecular response (defined as having BCR-ABL levels < 0.1% for an uninterrupted period of 6 months) are eligible. Patients will use an online patient decision aid and a shared decision making consultation will be held, after which patients who choose to will receive a personalised, lower TKI dose. Primary outcome is the proportion of patients with intervention failure at 12 months after dose reduction, defined as patients who have restarted their initial dose due to (expected) loss of major molecular response. For this, BCR-ABL1 levels will be analysed from blood samples drawn at baseline, 6 weeks after dose reduction and 3-monthly thereafter. Secondary outcomes include the proportion of patients with intervention failure at 6 and 18 months after dose reduction. Other outcomes include differences before and after dose reduction regarding the number and severity of patient-reported side effects; quality of life; beliefs about medicines; and medication adherence. Patients' level of decisional conflict and regret after choosing dose reduction will be assessed, as will the decisional process experienced by patients and healthcare providers.

DISCUSSION

Outcomes of this trial using a personalised approach will provide clinical and patient-reported data to guide future dose reduction of TKIs in CML. If the strategy appears to be effective, it may be implemented as another valid option to offer next to standard of care to prevent potential unnecessary exposure to higher TKI doses in this selected group of patients.

TRIAL REGISTRATION

EudraCT number 2021-006581-20.

Guidelines for the treatment of chronic myeloid leukemia from the NCCN and ELN: differences and similarities

Patients diagnosed with chronic myeloid leukemia (CML) in chronic phase can now have a life expectancy comparable to that of the general population thanks to the use of tyrosine kinase inhibitor (TKI) therapies. Although most patients with CML require lifelong TKI therapy, it is possible for some patients to achieve treatment-free remission. These spectacular results have been made possible by the development of superior treatment modalities as well as clinicians' efforts in strictly adhering to clinical guidelines such as the National Comprehensive Cancer Network (NCCN) and European Leukemia Network (ELN). CML treatment recommendations reported in these guidelines are the result of years of selecting and incorporating the most reliable evidence. In this review, we provide a synopsis of the differences and similarities that exist between the NCCN and ELN guidelines.

Current Management of Chronic Myeloid Leukemia Myeloid Blast Phase

Despite the major advancements in the management of chronic phase (CP) chronic myeloid leukemia (CML), blast crisis (BC) remains a major therapeutic challenge. BC can be myeloid, lymphoid, or mixed lineage with myeloid BC being the most common type. BC in CML is mediated by aberrant tyrosine kinase activity of the BCR::ABL fusion protein. The introduction of BCR::ABL tyrosine kinase inhibitor (TKI) has been a gamechanger in the treatment of CML and there has been a significant reduction in the incidence of BC. The main treatment goal in BC is to achieve a second CP and consolidate that with an allogeneic stem cell transplantation (SCT) in eligible patients. The outcomes in BC remain dismal even in the current era. In this review, we provide an overview of the biology and current therapeutic approach in myeloid BC.

Treatment-Free Remission in Chronic Myeloid Leukemia and New Approaches by Targeting Leukemia Stem Cells

The therapeutic landscape for chronic myeloid leukemia (CML) has improved significantly with the approval of tyrosine kinase inhibitors (TKIs) for therapeutic use. Most patients with optimal responses to TKIs can have a normal life expectancy. Treatment-free remission (TFR) after discontinuing TKI has increasingly become a new goal for CML treatment. However, TKI only "control" CML, and relapse after discontinuation has become a key factor hindering patient access to attempt TFR. In this study, we reviewed studies on TKI discontinuation, including both first and second-generation TKI. We also reviewed predictors of relapse, new monitoring methods, and strategies targeting leukemic stem cells.

A Treatment-free Interval Allowed by Ponatinib as Fourth-line Therapy

BACKGROUND

The third-generation tyrosine kinase inhibitor ponatinib has demonstrated high clinical efficacy in the setting of patients with resistant chronic phase chronic myeloid leukemia (CML), also inducing deep molecular responses. However, ponatinib-related cardiovascular toxicities make management challenging, especially of those patients with CML with previous cardiovascular comorbidities.

CASE REPORT

We report on the efficacy of ponatinib treatment used as fourth-line therapy in a 55-year-old woman affected by significant comorbidities (mainly cardiovascular) present before the diagnosis of CML. Ponatinib therapy induced a rapid and excellent clinical response, with the achievement of a durable deep molecular response that allowed us to propose a strategy of treatment discontinuation in order to reduce drug-related toxicities.

CONCLUSION

A strategy of a treatment-free interval might represent a useful clinical tool in those patients with CML who achieve a durable deep molecular response but are also affected by significant comorbidities in order to minimize the risk of ponatinib-related toxicities.

European LeukemiaNet 2020 recommendations for treating chronic myeloid leukemia

The therapeutic landscape of chronic myeloid leukemia (CML) has profoundly changed over the past 7 years. Most patients with chronic phase (CP) now have a normal life expectancy. Another goal is achieving a stable deep molecular response (DMR) and discontinuing medication for treatment-free remission (TFR). The European LeukemiaNet convened an expert panel to critically evaluate and update the evidence to achieve these goals since its previous recommendations. First-line treatment is a tyrosine kinase inhibitor (TKI; imatinib brand or generic, dasatinib, nilotinib, and bosutinib are available first-line). Generic imatinib is the cost-effective initial treatment in CP. Various contraindications and side-effects of all TKIs should be considered. Patient risk status at diagnosis should be assessed with the new EUTOS long-term survival (ELTS)-score. Monitoring of response should be done by quantitative polymerase chain reaction whenever possible. A change of treatment is recommended when intolerance cannot be ameliorated or when molecular milestones are not reached. Greater than 10% BCR-ABL1 at 3 months indicates treatment failure when confirmed. Allogeneic transplantation continues to be a therapeutic option particularly for advanced phase CML. TKI treatment should be withheld during pregnancy. Treatment discontinuation may be considered in patients with durable DMR with the goal of achieving TFR.