SAN DIEGO Generic formulations of imatinib appear to be non-inferior to Novartis’s Gleevec brand formulation with respect to clinical efficacy and tolerability in patients with chronic myeloid leukemia in chronic phase (CML-CP), according to findings presented at the American Society of Hematology (ASH) 58th Annual Meeting and Exposition.1

“There are currently more than 20 generic formulations of imatinib available in Poland,” said lead investigator Tomasz Sacha, department of hematology, Jagiellonian University Hospital, Krakow, Poland. “The current price in the majority of hospitals is approximately 5% to 10% of the original drug.”

Researchers evaluated the efficacy and tolerability of imatinib generics among patients with newly diagnosed CML-CP and among patients who switched from Gleevec to imatinib generics.

For the 1-year, prospective, observation study, investigators analyzed data from 726 patients, of which 99 initially received imatinib generics and 627 switched from Gleevec to generic imatinib. The most common imatinib generics used in Poland are Nibix and Meaxin, comprising 94% of generic imatinib use.

Among newly-diagnosed patients who initiated therapy with imatinib generics, results showed that 53% achieved BCR-ABL reduction to less than 1% at 6 months and 53% achieved major molecular response at 12 months. Using EUTOS registry data, the investigators found that 57% and 41% of patients treated with Gleevec achieved complete cytogenetic response and major molecular response at 12 months, respectively.

“Among switched patients, molecular response under therapy with generics was sustained in 65% of patients, improved in 19%, and worsened in 15%,” Mr Sacha noted. “Complete cytogenetic response was lost in 0.3%, major molecular response was lost in 1.3%, and MR4.5 was lost in 10.3%.”

Researchers found that 4.5% of switched patients switched to second-generation tyrosine kinase inhibitors, mainly due to intolerance of first-line treatment.

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The study showed an acceptable safety profile for all generics. There was no increased switching rate from first-generation kinase inhibitors to second-generation kinase inhibitors among patients treated with imatinib generics compared with those given Gleevec.

Reference

  1. Sacha T, Gora-Tybor J, Szarejko M, et al. Imatinib generics in treatment of chronic myeloid leukemia: A prospective observation in large cohort of patients from Polish (PALG) Imatinib Generics Registry. Paper presented at: American Society of Hematology (ASH) 58th Annual Meeting and Exposition; December 3-6, 2016; San Diego, CA.