The following article features coverage from the American Society of Clinical Oncology (ASCO) 2018 meeting.

Complete response (CR) to treatment with the checkpoint inhibitor atezolizumab in patients with locally advanced or metastatic urothelial carcinoma (mUC) appears to be durable, according to long-term follow-up data from phase 1/2 studies presented at the 2019 American Society of Clinical Oncology annual meeting in Chicago.

Yohann Loriot, MD, of Institut de Cancérologie Gustave Roussy in Villejuif, France, and colleagues looked at 3 small cohorts of patients with mUC who had CR to atezolizumab, which blocks programmed death ligand 1. After a median follow-up of more than 30 months, most patients who received atezolizumab were alive and had ongoing CR, the investigators reported in a poster presentation.

Their study included 12 patients from a phase 1 trial who received prior treatment with platinum-based chemotherapy (PCD cohort) and 2 cohorts from the phase 2 IMvigor210 trial: 10 patients with cisplatin-ineligible mUC (cohort 1), and 22 patients with platinum-treated mUC (cohort 2). Median CR duration was 37.5 months in the PCD cohort, not estimable in IMvigor210 cohort 1, and 28.4 months in the IMvigor210 cohort 2, Dr Loriot’s group reported. In these cohorts, 67%, 80%, and 55% of patients had ongoing CR, respectively, according to investigators. Patients who experienced CR had a first response by a median of 3.5 cycles. The median duration of atezolizumab treatment was 33.6, 21.5, and 32.6 months, respectively. The median time to CR was 8.1, 6.2, and 4.2 months, respectively.

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Reference

Loriot Y, Balar AV, Dreicer R, et al. Durability of complete response (CR) with atezolizumab (atezo) in locally advanced/metastatic urothelial carcinoma (mUC). Presented at the 2019 American Society of Clinical Oncology annual meeting in Chicago, May 31 to June 4. Abstract 4527.