Final Results from SAUL, a Single-arm International Study of Atezolizumab in Unselected Patients with Pretreated Locally Advanced/Metastatic Urinary Tract Carcinoma.

Background and objective: We assessed the safety of atezolizumab in unselected patients (including understudied populations typically excluded from clinical trials) with pretreated urinary tract carcinoma (UTC). The prespecified final analysis updates previously reported safety and efficacy data.

Methods: The single-arm prospective SAUL study (NCT02928406) enrolled 1004 patients with locally advanced/metastatic urothelial/non-urothelial UTC that had progressed during/after one to three prior treatment lines for advanced UTC (or <12 mo after [neo]adjuvant therapy). Broad eligibility criteria allowed enrollment of patients with complex comorbidities approximating the real-world setting. Patients received atezolizumab 1200 mg every 3 wk until disease progression or unacceptable toxicity. The primary endpoint was safety. Secondary endpoints included duration of response and overall survival (OS).

Key findings and limitations: The treated cohort included 10% of patients with poor performance status, 5% with creatinine clearance <30 ml/min, and 4% with autoimmune disease. At median follow-up of 55 mo, median atezolizumab duration was 2.8 mo (range 0-62); 68 patients (7%) continued atezolizumab for >4 yr. Treatment-related grade ≥3 adverse events occurred in 16% of patients (death in 1%); 8% discontinued atezolizumab for adverse events. Median OS was 8.6 mo (95% confidence interval 7.8-9.7) and 136 patients (14%) had OS longer than 4 yr. Limitations include the small sample size for some subgroups of special interest.

Conclusions and clinical implications: Long-term safety and efficacy data continue to show a benefit of atezolizumab in unselected patients with UTC. Remarkably, 14% of patients lived for >4 yr after starting atezolizumab. These results can inform multidisciplinary team discussions and treatment decision-making for patients with UTC with complex comorbidities.

Patient summary: The SAUL study looked at how well tolerated a drug called atezolizumab was in patients with urinary tract cancer who had already received up to three previous treatments for their cancer, including people who are usually not included in clinical trials because of other medical conditions. The length of survival after starting treatment was also assessed. Overall, the results show that atezolizumab was well tolerated. People for whom other therapies had failed lived for about 8.6 months on average after starting treatment, and 14% of the patients were still alive after 4 years.