ASCO20: Which Women With HER2-Positive Early Breast Cancer May Avoid Chemotherapy?
Posted: Tuesday, June 16, 2020
Javier Cortes, MD, PhD, of the IOB Institute of Oncology, Barcelona, and colleagues across Europe, used FDG-PET/CT (F-PET) to identify women with HER2-positive early breast cancer who might likely benefit from chemotherapy-free dual HER2 blockade. In the randomized PHERgain trial, response to combined trastuzumab and pertuzumab was assessed. The results were presented during the ASCO20 Virtual Scientific Program (Abstract 503).
“This strategy could select a group of HER2-positive early breast cancer patients who would not need chemotherapy,” stated Dr. Cortes in an ASCO press release.
A total of 376 patients with stage I–III HER2-positive early breast cancer were enrolled in the study. Patients were randomly assigned in a 1:4 ratio, stratified by hormone receptor status, and divided into three cohorts. Cohort A (71 patients) received trastuzumab plus pertuzumab, carboplatin, and docetaxel, for a total of six treatment cycles. Cohort B (285 patients) received trastuzumab plus pertuzumab with or without endocrine therapy. Cohort C (20 patients) had subclinical metastases and received six cycles of trastuzumab plus pertuzumab, carboplatin, and docetaxel (data not assessed in this analysis). Response was evaluated by F-PET before randomization and after two treatment cycles.
If patients in cohort B responded to treatment, they were given a total of six cycles; if not, they were switched to cohort A’s protocol. Responders who did not achieve pathologic complete response were also given six cycles of cohort A’s protocol.
Pathologic complete response was attained by 57.7% of patients in cohort A and 35.4% of patients in cohort B. Although 79.6% of patients in cohort B were responders on F-PET, 37.9% achieved pathologic complete response, and 25.9% of those who did not still achieved pathologic complete response after switching protocols. Patients in cohort A also reported more adverse events than those in cohort B, with 58.8% versus 12% being ≥ grade 3, and 29.4% versus 4.6% being serious adverse events, respectively.
Researchers are continuing to follow-up on the 3-year invasive disease–free survival co-endpoint.
Disclosure: For full authors’ disclosures, visit coi.asco.org.
