The tyrosine kinase inhibitors (TKI) used in chronic myeloid leukemia (CML) treatment have dramatically changed the disease outcome. Glivec/Gleevec (branded imatinib) was the first TKI developed and has proven to be effective and safe in the long term (Hochhaus et al., 2017).
After the Glivec patent expired, many countries approved generic imatinib for CML treatment. Generic formulations are less expensive and, therefore, more affordable and available for limited resources countries.
Generic formulations of imatinib are used in India since the early 2000s (Parikh et al. 2002) and in most countries since 2016. In Brazil, generics replaced Glivec in 2013 in the first-line treatment patients with CML treated at the Public Health System.
There are still conflicting results about safety and efficacy in the published studies. Regarding pharmacological properties and bioequivalence, several studies compared branded with generic imatinib showing similarity (Malhotra et al., 2014; Arora et al., 2016, Natarajan et al., 2019).
Switching from branded to generic imatinib appears to maintain efficacy and safety (Skazan et al., 2019; Scalzulli et al., 2019; Dalle et al., 2019; Gemelli et al., 2020). However, some studies showed that patients reported new or worsening side effects after switching, primarily mild and moderate, such as nausea, edema, diarrhea, and fatigue (Abudalli et al., 2019, Scalzulli et al., 2020).
In the first-line setting, retrospective and prospective studies compared branded with generic imatinib. A recent study from China compared 236 pts treated with generic with 206 pts treated in first line with branded imatinib and did not find differences in toxicity, responses and overall survival (OS) and progression-free survival in 4 years (Dou, 2020). An updated analysis of a Brazilian study compared the outcomes of a retrospective cohort treated with Glivec with a prospective cohort treated with generics. There was a similar rate of major molecular responses and toxicity at 12 months, OS and PFS survival. (personnal communication).
In terms of health care costs, real-life studies demonstrated that generics use reduced the cost of CML treatment and are more cost-effective than branded imatinib. In the last ELN 2020 recommendations, generic imatinib is indicated as one of the options for first-line treatment in CML, if the drug has quality control of production, similar bioavailability, and efficacy (Hochaus 2020). Monitoring of the short and long-term efficacy and safety is essential.
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