PD-L1 inhibitor shows promise as first-line therapy
Treatment provides durable responses in cisplatin-ineligible patients
New York—A recently approved treatment for urothelial carcinoma provides durable responses when used as first-line treatment in patients who are ineligible for cisplatin-based therapy, according to a recent study.
In addition, a separate analysis examined immune and genetic predictors of response to atezolizumab (Tecentriq) in the IMvigor 210 cohort of patients treated with atezolizumab as second-line therapy.
In May 2016, atezolizumab became the first PD-L1 inhibitor approved for the treatment of urothelial carcinoma. The indication was for use as second-line therapy in patients with locally advanced or metastatic disease that had progressed during or following platinum-based chemotherapy or that worsened within 12 months of receiving platinum-based neoadjuvant or adjuvant chemotherapy, and it was based on outcomes achieved in a cohort of 310 patients enrolled in the phase II IMvigor 210 trial (“Cohort 2”).
At the American Society of Clinical Oncology annual meeting in Chicago, Arjun V. Balar, MD, presented findings from a cohort of 119 patients in the same study (“Cohort 1”) on behalf of the IMvigor 210 investigators. He described the responses as “unprecedented.”
The objective response rate (ORR) was 24%, including 7% complete responses and 17% partial responses. At a median follow-up of 14.4 months (data cut-off, March 2016), 75% of the responses were ongoing, and the estimated median survival was 14.8 months, although the data were still immature (event rate was 47%). The estimated 12-month overall survival rate was 57%.
Subgroup analyses showed that the response rates, tumor regression rates, and estimated median survival were similar regardless of the level of PD-L1 expression on tumor-infiltrating immune cells (IC) and in patients with poor prognostic factors.