A look at treatment responses and the possibility of stopping imatinib

This study examined treatment responses to imatinib (Glivec) in chronic myeloid leukemia (CML) patients. Researchers reported that about half of patients achieved an optimal response to treatment that could allow patients to safely stop therapy.

Molecular response (MR) is a response to treatment where hardly any or no genetic abnormalities can be found in the blood or bone marrow. Many patients achieve this treatment goal with tyrosine kinase inhibitor (TKI) therapy, such as imatinib. TKIs are a type of targeted therapy that block enzymes called tyrosine kinases.

CML patients are generally expected to continue TKI therapy throughout their lives. This is because patients can lose their treatment response once treatment is stopped. Treatment-free remission (sustained MR after stopping therapy) is often considered the ultimate goal of CML treatment. However, it is often only attempted in clinical trials. More research is needed to help select patients that may successfully stop TKI therapy.

The records of 116 patients with chronic (early) phase CML were analyzed. All patients were treated with imatinib for an average of 91 months.  

93.1% of patients had achieved major MR at their last visit. 53.4% achieved deep MR or better. Among patients with a deep MR, 36.2% had received imatinib for more than 5.8 years and 26.7% for more tan 8 years. Patients with a deep MR or better were estimated to have the highest chance of staying in treatment-free remission after stopping treatment. Gender or age had no significant effect on the level of treatment response.

The results from this study support the possibility of treatment-free remission outside of clinical trials.

More studies are needed to confirm the safety of discontinuing TKI therapy.