Evaluation of safety in clinical use of generic paclitaxel [NK] for injection

The introduction of generic drugs is a favored strategy in reducing medical costs, but some clinicians are often reluctant to use them because of lack of information with regard to their side effects. Generic paclitaxel [NK] differs from the proprietary version, Taxol®, in containing added citric acid and a more pure form of castor oil. However, little information exists regarding the effects of these additives on adverse events such as vascular pain, phlebitis, hypersensitivity and hepatic dysfunction. To compensate for this lack of information and to validate the safety of using generic paclitaxel, we investigated adverse events in response to generic paclitaxel [NK].

Our investigation focused on patients treated with both the proprietary formulation (Taxol® for injection) and the generic version(paclitaxel [NK] for injection)sequentially from April 2008 to March 2009. Adverse events were investigated retrospectively.

Incidence of vascular pain, phlebitis and hypersensitivity was similar to that with the original product. Although the expression of some liver enzymes was slightly increased and some gastrointestinal events were reduced following generic paclitaxel [NK] treatment there was no statistically significant difference. The profiles of other adverse events were not significantly different.

Increased vascular pain and phlebitis, predicted due to low pH conditions caused by citric acid, were not observed. Similarly, the pure castor oil included in generic paclitaxel [NK] did not influence hypersensitivity and hepatic function. We found no significant differences in our study of proprietary and generic paclitaxel [NK]. Thus, clinicians have no reason for prejudice against using generic paclitaxel [NK] on the basis of increased risk of side effects.