AI Summary
The content is a reply to a comment on an analysis of the use of pertuzumab and trastuzumab without chemotherapy for ERBB2-positive metastatic breast cancer. The comment discusses the issue of survival and suggests that there was a 4-month benefit in favor of the chemotherapy arm between 24 to 72 months. The reply explains that the study was a phase 2 trial with overall survival at 24 months as the primary endpoint. The results showed similar proportions of patients alive at 2 years in both treatment arms.
In Reply We thank Sun and Wei for raising the important issue of survival with regard to de-escalation of chemotherapy in the presence of highly effective targeted anti-ERBB2 (formerly HER2) therapy. In their comments on our analysis, Sun and Wei conclude that between the time period of 24 to 72 months, reconstructed survival data looking at the area under the curve suggest a 4-month benefit in favor of the chemotherapy arm compared to those having had anti-ERBB2 therapy alone. The PERNETTA trial was an open-label, phase 2, noncomparative parallel-design with confidence interval approach in patients with centrally confirmed newly diagnosed ERBB2-positive metastatic breast cancer. Overall survival (OS) at 24 months was chosen as the primary end point, and the sample size relied on an assumed median OS of 32 months in both arms based on data from the most recent trials at the time the trial was planned. Our results show that the proportion of patients known to be alive at 2 years was 79.0% (90% CI, 71.4%-85.4%) and 78.1% (90% CI, 70.4%-84.5%) for arm A without and arm B with additional chemotherapy, respectively, with overlapping CIs.