Pemetrexed plus vinorelbine versus vinorelbine monotherapy in patients with metastatic breast cancer (KCSG-BR15-17): A randomized, open-label, multicenter, phase II trial

Metastatic breast cancer refractory to anthracycline and taxanes often shows rapid progression. The development of effective and tolerable combination regimens for these patients is needed. This phase II trial investigated the efficacy of pemetrexed plus vinorelbine in patients with metastatic breast cancer. This randomized, open-label, phase II trial was conducted in 17 centers in Korea. Patients with advanced breast cancer who had previously been treated with anthracyclines and taxanes were randomly assigned in a 1:1 ratio to receive either vinorelbine or pemetrexed plus vinorelbine. Randomization was stratified by prior capecitabine treatment and hormone receptor status. The primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included the objective response rate, overall survival, safety, and quality of life. Between March 2017 and August 2019, a total of 125 patients were enrolled. After a median follow-up duration of 14.1 months, 118 progression events and 88 death events had occurred. Sixty-two patients were assigned to the pemetrexed plus vinorelbine arm, and 63 were assigned to the vinorelbine arm. Pemetrexed plus vinorelbine significantly prolonged PFS compared to vinorelbine (5.7 vs. 1.5 months, p