New treatment options for advanced urothelial cancer: a combination of atesolizumab with chemotherapy

Background. Atezolizumab can induce sustained responses in metastatic urothelial carcinoma. We report the results of IMvigor130, a phase III trial that compared atezolizumab with or without platinum-based chemotherapy versus placebo plus platinum-based chemotherapy in first-line metastatic urothelial carcinoma.

Materials and methods. In this multicentre, phase III, randomised trial, untreated patients aged 18 years or older with locally advanced or metastatic urothelial carcinoma, from 221 sites in 35 countries, were randomly assigned to receive atezolizumab plus platinum-based chemotherapy (group A), atezolizumab monotherapy (group B), or placebo plus platinum-based chemotherapy (group C). Patients received 21-day cycles of gemcitabine (1000 mg/ml body surface area, administered intravenously on days 1 and 8 of each cycle), plus either carbo-platin (area under the curve of 4.5 mg/mL per min administered intravenously) or cisplatin (70 mg/ml body surface area administered intravenously) on day 1 of each cycle with either atezolizumab (1200 mg administered intravenously on day 1 of each cycle) or placebo. Group B patients received 1200 mg atezolizumab, administered intravenously on day 1 of each 21-day cycle. The co-primary efficacy endpoints for the intention-to-treat population were investigator-assessed Response Evaluation Criteria in Solid Tumours 1.1 progression-free survival (PFS) and overall survival (OS) (group A vs group C) and OS (group B vs group C), which was to be formally tested only if OS was positive for group A versus group C. The trial is registered with ClinicalTrials.gov, NCT02807636.

Results. Between July 15, 2016, and July 20, 2018, were enrolled 1213patients. 451 (37 %) were randomly assigned to group A, 362 (30 %) to group B, and 400 (33 %) to group C. Median follow-up for survival was 11.8 months (interquartile range 6.1—17.2 months) for all patients. At the time of final PFS analysis and interim OS analysis (May 31, 2019), median PFS in the intention-to-treat population was 8.2 months (95 % confidence interval (CI) 6.5—8.3) in group A and 6.3 months (95 % CI 6.2—7.0) in group C (stratified hazard ratio 0.82; 95 % CI 0.70—0.96; one-sided p = 0.007). Median OS was 16.0 months (95 % CI 13.9—18.9) in group A and 13.4 months (95 % CI 12,0—15.2) in group C (0.83; 95 % CI 0.69—1.00; one-sided p =0.027). Median OS was 15.7 months (95 % CI 13.1—17.8) for group B and 13.1 months (95 % CI 11.7—15.1) for group C (1.02; 95 % CI 0.83—1.24). Adverse events that led to withdrawal of any agent occurred in 156 (34 %) patients in group A, 22 (6 %) patients in group B, and 132 (34 %) patients in group C. 50 (11 %) patients in group A, 21 (6 %) patients in group B, and 27 (7 %) patients in group C had adverse events that led to discontinuation of atezolizumab or placebo.

Conclusion. Addition of atezolizumab to platinum-based chemotherapy as first-line treatment prolonged PFS in patients with metastatic urothelial carcinoma. The safety profile of the combination was consistent with that observed with the individual agents. These results support the use of atezolizumab plus platinumbased chemotherapy as a potentialfirst-line treatment option for metastatic urothelial carcinoma.