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Treatment-free remission following discontinuation of second-line nilotinib for chronic myeloid leukemia (CML) in chronic phase (CP) is safe and durable in the long term, according to research presented at the 2019 American Society of Clinical Oncology Annual Meeting held in Chicago, Illinois.
Researchers presented long-term follow-up data from the phase 2 ENESTop study (ClinicalTrials.gov Identifier: NCT01698905) that assessed the feasibility of discontinuing nilotinib in patients with CML-CP who achieved molecular response (MR). A prior analysis had been conducted at 144 weeks after discontinuation.
Patients initially received imatinib for 4 weeks followed by nilotinib for 2 or more years. All of the 126 patients enrolled achieved and maintained MR4.5 (defined as BCR-ABL1IS ≤ 0.0032%) for 1 year. If patients experienced loss of major MR (defined as BCR-ABL1IS ≤ 0.1%) or confirmed loss of MR4.5 (defined as BCR-ABL1IS ≤ 0.01%), they resumed treatment with nilotinib.
At data cutoff, 56 patients had achieved at least 192 weeks of treatment-free remission, 59 had resumed nilotinib treatment, and 11 had discontinued treatment. Among patients who resumed nilotinib, 56 regained MR4 and 55 regained MR4.5.
Among 62 patients who maintained treatment-free remission for at least 144 weeks, musculoskeletal pain adverse events occurred in 11.3% of patients during consolidation and in 53.2%, 21.0%, 14.5%, and 3.2% of patients during each subsequent 48-week period. Hypertension and arthralgia were the most common adverse events in patients who resumed nilotinib.
Since the prior analysis, no new patients experienced disease progression or death due to CML.
1. Hughes TP, Boquimpani C, Takahashi N, et al. ENESTop 192-week results: Treatment-free remission (TFR) in patients (pts) with chronic myeloid leukemia in chronic phase (CML-CP) after stopping second-line (2L) nilotinib (NIL). Presented at: 2019 ASCO Annual Meeting; June 1, 2019; Chicago, IL. Abstract 7005.