Do chronic myeloid leukemia patients with late "warning" responses benefit from "watch and wait" or switching therapy to a second generation tyrosine kinase inhibitor?

In the latest recommendations for the management of chronic-phase chronic myeloid leukemia suboptimal responses have been reclassified as "warning responses." In contrast to previous recommendations current guidance advises close monitoring without changing therapy. We have identified 198 patients treated with first-line imatinib, with a warning response after 12 months of treatment (patients with a complete cytogenetic response but no major molecular response [MMR]). One hundred and forty-six patients remained on imatinib, while 52 patients changed treatment to a second generation tyrosine kinase inhibitor (2GTKI). Changing therapy did not correlate with an increase in overall survival or progression-free survival. Nevertheless, a significant improvement was observed in the probability of a MMR: 24% vs. 42% by 12 months and 43% vs. 64% by 24 months (P = 0.002); as well as the probability of achieving a deep molecular responses (MR(4.5) ): 1% vs. 17% and 7% vs. 23% by 12 and 24 months, respectively (P = <0.001) .The treatment change to 2GTKI remained safe; however, we have observed a 19% of treatment discontinuation due to side effects. We have observed an improvement of molecular responses after changing treatment to 2GTKI in patients with late suboptimal response treated with imatinib first line. However, these benefits were not correlated with an improvement of progression free survival or overall survival.

Toxicity of Asciminib in Real Clinical Practice: Analysis of Side Effects and Cross-Toxicity with Tyrosine Kinase Inhibitors.

(1) Background: Despite the prognostic improvements achieved with tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML), a minority of patients still fail TKIs. The recent introduction of asciminib may be a promising option in intolerant patients, as it is a first-in-class inhibitor with a more selective mechanism of action different from the ATP-competitive inhibition that occurs with TKIs. Therefore, our goal was to analyze toxicities shown with asciminib as well as to study cross-toxicity with previous TKIs. (2) Methods: An observational, multicenter, retrospective study was performed with data from 77 patients with CML with therapeutic failure to second-generation TKIs who received asciminib through a managed-access program (MAP) (3) Results: With a median follow-up of 13.7 months, 22 patients (28.5%) discontinued treatment: 32% (7/22) due to intolerance and 45% (10/22) due to resistance. Fifty-five percent of the patients reported adverse effects (AEs) with asciminib and eighteen percent grade 3-4. Most frequent AEs were: fatigue (18%), thrombocytopenia (17%), anemia (12%), and arthralgias (12%). None of the patients experienced cardiovascular events or occlusive arterial disease. Further, 26%, 25%, and 9% of patients required dose adjustment, temporary suspension, or definitive discontinuation of treatment, respectively. Toxicities under asciminib seemed lower than with prior TKIs for anemia, cardiovascular events, pleural/pericardial effusion, diarrhea, and edema. Cross-toxicity risk was statistically significant for thrombocytopenia, anemia, neutropenia, fatigue, vomiting, and pancreatitis. (4) Conclusion: Asciminib is a molecule with a good safety profile and with a low rate of AEs. However, despite its new mechanism of action, asciminib presents a risk of cross-toxicity with classical TKIs for some AEs.