Comparison of Serious Adverse Events Between the Original and a Generic Docetaxel in Breast Cancer Patients

Background: Generic formulations are not necessarily identical to the original in terms of efficacy and adverse events. Generic docetaxel has been available in Canada since 2011. Objective: To compare the occurrence of grade III to IV adverse events between original docetaxel and a generic formulation in breast cancer patients. Methods: A consecutive series of 400 patients were assessed retrospectively: 200 who received the original docetaxel and 200 who received a generic formulation. Patients who received both formulations or received their chemotherapy outside our center were excluded. The primary outcome was the occurrence of grade III to IV adverse events related to docetaxel (febrile neutropenia, hand and foot syndrome, intestinal perforation, thrombotic event, and death). Results: Three hundred-sixty-four patients were available for analysis (182/group). The use of a granulocyte colony-stimulating factor (G-CSF) was more frequent in the generic group (44.5% vs 28.8%), as well as treatment discontinuation (26.4% vs 14.8%). The occurrence of grade III to IV febrile neutropenia, hand and foot syndrome, intestinal perforation, thrombotic event, and docetaxel-related deaths were similar between the 2 formulations. However, grade IV febrile neutropenia was more frequent with the generic formulation (78.8% vs 56.3%). Limitations were the retrospective nature of the study and the variety of chemotherapy regimens. Conclusion: Adverse events occurrence was similar between the 2 formulations. However, febrile neutropenia was more serious with generic docetaxel, despite increased G-CSF use. Results suggest that the studied generic formulation may be safe, but more caution during treatments might be warranted, especially concerning febrile neutropenia events.