Objective. To assess the clinical effectiveness of trastuzumab among metastatic breast cancer (MBC) patients and compare the results to those reported in the two pivotal clinical trials and product monograph.
Design. Retrospective chart review of all patients who had initiated trastuzumab monotherapy or combination therapy for MBC within the Alberta Cancer Board (ACB) from August 1998 to May 2001.
Setting. Two public tertiary cancer centres in the Canadian province of Alberta.
Patients. Of 90 patients reviewed within the ACB, 72 women were eligible for the study.
Main outcome measures. The primary endpoints measured were time to treatment failure (TTF) and survival. Secondary end-points measured included adverse events and compliance with ACB guidelines for trastuzumab administration.
Results. Among all 72 patients, median TTF was 7.6 months and median survival was 14.4 months. Trastuzumab combination therapy was associated with a significantly longer median TTF compared to trastuzumab monotherapy (P= 0.011). With respect to survival, no significant advantage was seen with combination therapy over monotherapy (P= 0.438). Infusion-related reactions were reported in 11.1% of our patients, while cardiotoxicity was reported in12.5%.
Conclusions. Overall, we found that trastuzumab performs better in the clinical setting than it did in the pivotal trials with respect to TTF (2.5 vs. 2.4 months and 8.2 vs. 6.9 months), but not as well with respect to survival (10.0 vs. 13.0 months and 21.0 vs. 25.1 months). In comparison to the product monograph, we report a significantly lower incidence of infusion-related reactions and a slightly higher incidence of cardiotoxicity.
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