In a poster presentation at the 2021 ASCO GU Cancers Symposium, Dr. Norihiko Tsuchiya and colleagues present subgroup data from this trial among Japanese patients. To briefly recap, this study enrolled patients with advanced urothelial carcinoma, defined as those with unresectable locally advanced disease or metastatic disease. To be eligible, patients had to have received platinum based induction chemotherapy with either cisplatin or carboplatin in combination with gemcitabine and have not had disease progression after 4-6 cycles of therapy. Among these patients with responsive or stable disease on induction chemotherapy, enrolled patients were randomized to avelumab and best supportive care (BSC) or best supportive care alone. The primary endpoint was overall survival, in all patients and in those with PD-L1+ tumors.
In this subset analysis, the authors examined 73 Japanese patients who were randomized to receive avelumab + BSC (n=36) or BSC alone (n=37), with PD-L1+ tumors found in 52.8% and 62.2%, respectively.
Assessing the primary outcome among all randomized Japanese patients, median OS (95% CI) was 24.7 months (18.2-not estimable [NE]) among patients randomized to avelumab + BSC as compared to 18.7 months (12.8-33.0) to those randomized to BSC alone (hazard ratio 0.81 [95% CI; 0.409-1.585]). Among Japanese patients with a PD-L1+ tumor, median overall survival was 18.6 months (9.4-NE) in patients randomized to avelumab + BSC compared to 19.4 months (11.7-33.0) in those randomized to BSC alone (hazard ratio 1.00 [95% CI, 0.413-2.412]).
Median PFS (95% CI) was similarly prolonged among patients randomized to avelumab + BSC (5.6 months [1.9-9.4]) compared to BSC alone (1.9 months [1.9-3.8]; hazard ratio, 0.63 [95% CI, 0.358-1.113]) in all randomized patients and in those with PD-L1+ tumors (5.6 months vs 1.9 months; hazard ratio 0.62 [95% CI, 0.298-1.301]).
Treatment-related adverse events were similar to the overall cohort: pyrexia (10 [27.8%]; 0), nasopharyngitis (7 [19.4%]; 0), and anemia (7 [19.4%]; 4 [11.1%]).
The authors conclude that this subgroup analysis supports the overall study interpretation in terms of both efficacy and tolerability.
Presented by: Norihiko Tsuchiya, MD, Department of Urology, Yamagata University
Written by: Christopher J.D. Wallis, Urologic Oncology Fellow, Vanderbilt University Medical Center Contact: @WallisCJD on Twitter during the 2021 ASCO Genitourinary Cancers Symposium (ASCO GU), February 11th to 13th, 2021