A phase III, multicenter, randomized trial of maintenance versus observation after achieving clinical response in patients with metastatic breast cancer who received six cycles of gemcitabine plus paclitaxel as first-line chemotherapy (KCSG-BR 0702, NCT00561119).

Abstract

1003 Background: Chemotherapy provides a survival benefit in patients with metastatic breast cancer (MBC), but the optimal duration of chemotherapy remains controversial. Primary purpose of the study was to evaluate whether the maintenance chemotherapy with gemcitabine/paclitaxel (GP), which is one of the two regimens which showed a survival gain from a randomized trial, is superior to observation in terms of progression free survival (PFS) in responding patients with MBC after 6 cycles of GP as first-line treatment. Methods: This study is a prospective, randomized, multi-center, phase III study. Patients who achieved response (CR+PR+SD) following 6 cycles of GP chemotherapy (gemcitabine 1250 mg/m2 on day 1 and 8 plus paclitaxel 175 mg/m2 on day 1 every 3 weeks) randomized to maintenance till progression or observation arm. The trial was conducted by the Korean Cancer Study Group (KCSG). Results: Among total 324 patients enrolled between 2007 and 2010 from 10 centers, 231 responding patients to were randomly assigned to maintenance chemotherapy (n=116) or observation (n=115). Median age was 49 (range 28-76). The numbers of hormone receptor (HR)+ve and HR-ve patients were 172 (74.5%) and 59 (25.5%), respectively. The median No. of chemotherapy cycles in maintenance group was 12 (range 6-32). During median 33 months of follow-up, median PFS was superior in maintenance than in observation (12.0 vs. 8.3 months, p=0.030). Patients < age 50 years (hazard ratio 0.50, p=0.001) and HR-ve patients (hazard ratio 0.52, p=0.019) received more benefit from maintenance chemotherapy in terms of PFS. Median OS was superior in maintenance than in observation (36.8 vs 28.0 months, p=0.047). Neurotoxicity (≥ grade 2) was more common in maintenance than in observation without statistical significance (41.7% vs 33.3%, p=0.210). Serial assessment of Quality of Life (QoL) did not show any significant difference between two groups. Conclusions: Maintenance GP chemotherapy for responding patients with MBC showed clinical benefit in terms of PFS and OS without impairment of QoL.