SAN DIEGO – Tyrosine kinase inhibitor (TKI) cessation appears feasible and safe in patients with chronic myeloid leukemia in chronic phase (CML-CP), according to findings presented at the American Society of Hematology (ASH) 58th Annual Meeting and Exposition.1
“Stopping treatment is an emerging goal of CML management and several studies have demonstrated the feasibility of stopping treatment,” said Francois-Xavier Mahon, MD, PhD, University of Bordeaux, France. “Consistent results over time with consistent follow-up from the STIM study validated the concept of treatment-free remission, though the exact preconditions for stopping CML treatment are not yet defined.”
For the multicenter, open-label, EURO-SKI study (ClinicalTrials.gov Identifier: NCT01596114), researchers assessed the duration of major molecular response (MMR) or better after stopping TKI therapy in a large cohort of patients with CML-CP. They enrolled 755 patients with very deep molecular responses for at least 1 year or at least 3 years of TKI treatment to stop TKI therapy.
During a median follow-up of 14.9 months, 373 of the evaluable 755 patients had a loss of major molecular response, including 296 who had molecular recurrence within the first 6 months of TKI cessation.
Forty-seven percent of patients were free of molecular recurrence at 36 months. The cumulative incidence of molecular recurrence at 36 months was 52%.
“The proportion of patients without recurrence after 6 months was 61% and 55% after 12 months,” noted Dr Mahon.
Seventy-two patients had a rise in BCR-ABL levels to greater than 1%; 11 patients lost complete cytogenetic response. No patients progressed to accelerated phase or blast crisis, and there were no CML-related deaths.
“Predicted probabilities to be in major molecular response at 6 months depends on MR4 duration,” Dr Mahon added. “Longer duration of imatinib therapy, optimally 5.8 years or longer prior to cessation, correlates to a higher probability of recurrence-free survival at 6 months.”
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TKI cessation saved approximately 22 million Euros over the course of the trial for 596 assessable patients.
“Our study would be useful and support the opportunity to edit new European Leukemia Net (ELN) recommendations taking account cessation of TKIs,” concluded Dr Mahon.
- Mahon FX, Richter J, Guilhot J, et al. Cessation of tyrosine kinase inhibitors treatment in chronic myeloid leukemia patients with deep molecular response: Results of the Euro-Ski trial. Paper presented at: American Society of Hematology (ASH) 58th Annual Meeting and Exposition; December 3-6, 2016; San Diego, CA.