CML: Study Evaluates Long-term Outcomes After Imatinib Discontinuation

Imatinib discontinuation in patients with chronic myeloid leukemia in chronic phase (CML-CP) who achieved undetected minimal residual disease (UMRD) after frontline imatinib therapy led to favorable long-term outcomes with respect to safety and feasibility, a study published in the journal Acta Haematologica has shown.¹

Because limited data exist on the long-term outcomes following imatinib discontinuation in patients treated with first-line imatinib therapy, researchers in South Korea sought to assess the long-term outcomes of patients with CML-CP and UMRD who discontinue imatinib.

For the study, researchers enrolled 19 patients with CML-CP who discontinued imatinib after achieving UMRD for 12 or more months between June 2009 and January 2013.

Results showed that after imatinib was discontinued, 74% of patients lost UMRD after a median of 4.0 months. Of those, 14 patients relapsed within the first 9 months after imatinib discontinuation and the other 2 patients relapsed at 20.5 and 22.8 months, respectively.

With a median follow-up of 58.1 months, researchers estimated the 5-year persistence rate to be 23.7%. All patients who had a molecular relapse were retreated with imatinib, and 12 of those 14 patients re-achieved UMRD at a median of 5.3 months.

The study also demonstrated that a high-risk Sokal score, delayed UMRD achievement, and short-term treatment with imatinib were significantly associated with molecular relapse.

Imatinib is a tyrosine kinase inhibitor indicated for the treatment of newly diagnosed adult and pediatric patients with Philadelphia chromosome (Ph)-positive CML-CP, as well those in accelerated phase, chronic phase, or blast crisis after failure of interferon-alpha therapy.

Reference

1. Yhim H-Y, Lee N-R, Song E-K, et al. Long-term outcomes after imatinib mesylate discontinuation in chronic myeloid leukemia patients with undetectable minimal residual disease. Acta Haematol. 2016;135:133-139.