Comparison of adverse events following injection of original or generic docetaxel for the treatment of breast cancer.

Purpose: The approval of injectable generic drugs does not require bioequivalence testing. However, although generic products contain the same level of the active compound, the levels and types of additives present can differ from those used in the original product. Since docetaxel is highly lipophilic, polysorbate 80 (PS80), polyethylene glycol (PEG), and ethyl alcohol are employed to solubilize this anticancer agent. This retrospective study compared the safety of five docetaxel products (Taxotere, Docetaxel Hospira, Docetaxel Sandoz, Docetaxel Sawai, and Docetaxel EE).

Methods: The incidence and severity of adverse events were analyzed using the medical records of operable breast cancer patients (n = 363) treated with docetaxel (75 mg/m) in Showa University Hospital, Japan, from Jan 2013 to Mar 2016. Toxicities were graded using the Common Terminology Criteria for Adverse Events, version 4.0.

Results: Significant product-related differences were observed in the following non-hematological adverse events: injection site reaction (P = 0.0012), hand-foot syndrome (≥grade 3) (P = 0.0003), and oral mucositis (≥grade 3) (P = 0.0080). Multivariate logistic regression analyses of the associations between these adverse events and the total additive administered (g/m) identified significant negative effects of PS80 and ethyl alcohol.

Conclusions: Injectable docetaxel products had different adverse event profiles, which showed negative associations with the amounts of PS80 and ethyl alcohol present. This finding indicated that there might be additive-related pharmacokinetic and physiochemical differences among these products, suggesting a need for further pre- or post-approval testing of injectable generic products containing noticeable different levels of additives.