ASCO 2019: Novel Targeted Therapy Active in Metastatic Breast Cancer
Posted: Wednesday, June 26, 2019
Phase III trial results showed that adding the targeted therapy pyrotinib to capecitabine yielded improved progression-free survival rates in women with HER2-positive metastatic breast cancer who were previously treated with taxanes and trastuzumab, compared with capecitabine alone. Pyrotinib monotherapy also showed antitumor activity, according to the work presented by Zefei Jiang, MD, of the Fifth Medical Center of Chinese PLA General Hospital, Beijing, China, and colleagues at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago (Abstract 1001).
The double-blind trial randomly assigned 185 women to receive pyrotinib and capecitabine and 94 to receive placebo and capecitabine. All patients received treatment on a 21-day cycle, receiving twice-daily capecitabine at 1,000 mg/m2 on days 1 to 14. The women in the treatment arm also received 400 mg daily of pyrotinib, an irreversible pan-ErbB receptor tyrosine kinase inhibitor.
Median progression-free survival, the study’s primary endpoint, was 11.1 months in the pyrotinib/capecitabine arm and 4.1 months in the placebo/capecitabine arm (P < .001). After disease progression with placebo/capecitabine, 71 women received subsequent pyrotinib; they demonstrated a single-agent response rate of 38.0% and a median progression-free survival of 5.5 months.
Some grade ≥ 3 treatment-related adverse events occurred in both study arms. The most frequent side effects were diarrhea (30.8% in the pyrotinib arm vs. 12.8% in the control arm) and hand-foot syndrome (15.7% vs. 5.3%, respectively).
Disclosure: The study authors’ disclosure information may be found at coi.asco.org.