Remission rates after discontinuation of imatinib

This study examined outcomes after discontinuation of imatinib (Gleevac) in patients with chronic myeloid leukemia (CML). Researchers reported that some CML patients can safely discontinue imatinib after achieving a deep treatment response. Factors such as detectable residual leukemia cells after treatment affect the risk of losing treatment response.

Major molecular response (MMR) is a response to treatment where hardly any genetic abnormalities can be found in the bone marrow. Patients with major or deep molecular response (showing no more genetic abnormalities in the bone marrow) have a near-normal life expectancy. About one-half of CML patients achieve deep molecular response with tyrosine kinase inhibitor (TKI) therapy, such as imatinib. This refers to a type of targeted therapy that block enzymes called tyrosine kinases.

However, CML patients are generally expected to continue TKI treatment throughout their lives. Many patients lose their treatment response once TKI therapy is stopped. More studies are needed to better understand outcomes after discontinuation of imatinib.

The aim of this study was to evaluate remission rates after discontinuation of imatinib.

68 CML patients were included. All patients were treated with imatinib for at least 3 years and showed deep molecular response for at least 2 years. Patients then discontinued imatinib and were followed for an average of 36 months.

At 12 months, 46 patients (67.6%) were in treatment-free remission (no disease relapse after end of treatment). The remaining 22 patients lost MMR during the first 12 months. All 22 patients regained MMR after restarting treatment. Three-year treatment-free survival was estimated at 64.6%.

Patients who had no detectable signs of leukemia cancer cells on a molecular level after treatment were significantly less likely to lose MMR. Overall, the risk of losing MMR was 64% lower. Estimated 3-year treatment-free survival was 72.2% for these patients. In contrast, estimated 3-year treatment-free survival was 35.7% for patients where residual leukemia cancer cells could be detected.

This study concluded that CML patients with no detectable residual leukemia cells can safely discontinue imatinib therapy. Authors advised that treatment-free remission could be a valuable goal for CML treatment.

Further studies are needed to confirm these preliminary results.