Merck and Pfizer Inc
Patients with unresectable locally advanced or metastatic UC treated with Cisplatin + gemcitabine or Carboplatin + gemcitabine chemotherapy (4-6 cycles) and obtained a CR, PR, or SD that was maintained for 4-10 weeks were entered into the study. They were randomized (1:1) between IV Avelumab (anti PDL-1) given every 2 weeks or best supportive care.
Platinum-based combination chemotherapy has remained the standard-of-care as first-line treatment for advanced urothelial carcinoma (UC). However, durations of progression-free survival (PFS) and overall survival (OS) are limited by chemotherapy resistance
The primary endpoint was overall survival. Primary analysis populations included all randomized patients and separately the PD-L1+ population. Secondary endpoints included PFS and objective response per RECIST 1.1, Safety and tolerability and patient reported outcomes.
This Late Breaking Abstract was presented at the ASCO plenary session. Switch maintenance avelumab significantly prolonged overall survival vs best supportive care alone in selected patients with UC whose disease had not progressed on first line platin based chemotherapy. These results are practice changing. Based on these results, this concept has already been approved by the FDA on June 30, 2020.
Maintenance avelumab significantly prolonged overall survival compared to best supportive care alone. The overall survival at 1 year was 71.3% vs 58.4%, and median overall survival was 21.4 vs 14.3 months (HR 0.69; 95% CI, 0.56, 0.86; 1-sided P<0.001). Avelumab also significantly prolonged overall survival in the PD-L1+ population as the overall survival at 1 year was 79.1% vs 60.4% (HR 0.56; 95% CI, 0.40, 0.79; 1-sided P<0.001). Adverse events occurred in 98.0% of patients in the avelumab arm and 77.7% of patients in the best supportive care alone arm, including grade ≥3 events in 47.4% and 25.2%, respectively.