Key clinical point: First-line palbociclib plus letrozole treatment remains an effective and well-tolerated therapy in Japanese postmenopausal women with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2−) advanced breast cancer.
Major finding: The probability of progression-free survival (PFS) at 1 year was 75.6% (90% confidence interval, 62.4%-84.7%), median PFS was 35.7 (95% confidence interval [CI], 21.7-46.7) months, objective response rate was 47.6% (95% confidence interval, 32.0%-63.6%), and disease control rate was 85.7% (95% confidence interval, 71.5%-94.6%). The most common treatment-related adverse events included neutropenia, leukopenia, and stomatitis.
Study details: This open-label, single-group, Japanese phase 2 clinical trial included 42 patients with ER+/HER2– advanced breast cancer; the median duration of treatment was 33.0 (range, 1.8-49.2) months.
Disclosures: This study was sponsored by Pfizer Inc. Two coauthors are employees of Pfizer R&D Japan and one is an employee of Pfizer Japan Inc.
Takahashi M et al. Cancer Med. 2020 May 18. doi: 10.1002/cam4.3091.