Top Line: The initial analysis of the Italian phase 3 ShortHER trial failed to demonstrate noninferiority in disease-free survival with a shorter regimen of trastuzumab for HER2+ breast cancer.
The Study: As a reminder, we have seen successful trastuzumab de-escalation to six months. In practice, however, we’ve seen more of a de-escalation in chemo with dropping the anthracycline while keeping a year of trastuzumab. In ShortHER, 1254 women with HER2+ breast cancer receiving adjuvant anthracycline-taxane combos were randomized to the addition of trastuzumab x 1 year versus 9-weeks. We now have 10-year reporting with outcomes on the secondary endpoint of overall survival. At 10 years, disease-free survival was 78% after long-course versus 77% after short-course trastuzumab, and overall survival was 89% versus 88%. While your gut may say these outcomes appear pretty darn similar, a limited number of events (with half the target enrollment) again led to a confidence interval that surpassed the prespecified threshold.
TBL: “Nevertheless, these long-term data can reassure clinicians in case of early discontinuation of adjuvant trastuzumab (for any reason) in patients at low risk.” | Conte, J Clin Oncol 2023
The Study: As a reminder, we have seen successful trastuzumab de-escalation to six months. In practice, however, we’ve seen more of a de-escalation in chemo with dropping the anthracycline while keeping a year of trastuzumab. In ShortHER, 1254 women with HER2+ breast cancer receiving adjuvant anthracycline-taxane combos were randomized to the addition of trastuzumab x 1 year versus 9-weeks. We now have 10-year reporting with outcomes on the secondary endpoint of overall survival. At 10 years, disease-free survival was 78% after long-course versus 77% after short-course trastuzumab, and overall survival was 89% versus 88%. While your gut may say these outcomes appear pretty darn similar, a limited number of events (with half the target enrollment) again led to a confidence interval that surpassed the prespecified threshold.
TBL: “Nevertheless, these long-term data can reassure clinicians in case of early discontinuation of adjuvant trastuzumab (for any reason) in patients at low risk.” | Conte, J Clin Oncol 2023