First-line therapy with generic imatinib in chronic myeloid leukemia (CML) is associated with poorer outcomes compared with branded imatinib (Gleevec). Generic imatinib as second-line therapy does not, however, have a negative effect on outcomes, according to a study published in Clinical Lymphoma, Myeloma & Leukemia.1

The expiration of Novartis Pharmaceutical’s patent on imatinib mesylate led to recent approvals of generic products in numerous countries, offering a lower cost alternative for the treatment of patients with CML. But the long-term clinical outcomes in patients treated with generics remain unclear.

To evaluate outcomes of patients treated with first-line and second-line generic imatinib, investigators analyzed data from 41 patients treated between 2013 and 2016.

Of those, 27 were newly diagnosed patients receiving generic imatinib as first-line therapy and 14 were patients who received second-line generic imatinib after switching from frontline Gleevec.

With a median follow-up of 16 months, 85% of patients given first-line generic imatinib were alive at 36 months and 81% had achieved a complete cytogenetic response. Nearly half (48%) achieved a major molecular response by 24 months.

Fifty-two percent of patients who received generic imatinib as first-line therapy switched to nilotinib due to disease progression and intolerable side effects.

Among those who switched to generic imatinib after first-line Gleevec, 93% of patients sustained cytogenetic and molecular response at 36 months of generic treatment. The 1 patient who lost complete cytogenetic response and major molecular response was on Gleevec for 5 months before switching to generic imatinib.

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The authors concluded that first-line generic imatinib demonstrated suboptimal efficacy with branded imatinib, while second-line generic therapy did not have a negative impact on patient outcomes.

Reference

  1. Islamagic E, Hasic A, Kurtovic S, et al. The efficacy of generic imatinib as first- and second-line therapy: three year follow-up of chronic myeloid leukemia patients. Clin Lymphoma Myeloma Leuk. 2017 Feb 16. doi: 10.1016/j.clml.2017.02.001 [Epub ahead of print]