The following article features coverage from the Society of Immunotherapy of Cancer (SITC) 2020 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Retifanlimab, a programmed cell death 1 (PD-1) inhibitor, demonstrated antitumor activity and a tolerable safety profile among patients with previously treated endometrial cancer that had high microsatellite instability (MSI-H)/mismatch repair deficiency (dMMR), according to results of a phase 1 study presented at the virtual Society for Immunotherapy of Cancer (SITC) 35th Anniversary Annual Meeting.

Previous studies have demonstrated response rates of up to 57% with immune checkpoint inhibitors in endometrial cancer with MSI-H/dMMR. The purpose of this study was to evaluate retifanlimab in this population.

The open-label, phase 1 PODIUM-101 trial includes dose-escalation and dose-expansion phases. This interim analysis included a cohort of 44 patients with recurrent unresectable endometrial cancer with MSI-H/dMMR enrolled in the dose-expansion phase. Endpoints included safety and response.

At baseline, the median patient age was 63 years and 79.5% of patients were white. The majority of patients had undergone a prior surgery (90.9%) and radiotherapy (72.7%).


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Among the 31 patients evaluable for response, the objective response rate was 25.8%, including 1 patient who achieved a complete response. The disease control rate was 71%. Of the 8 patients who responded, 6 were ongoing responses.

Among the 44 patients evaluable for safety, grade 3 or higher treatment-related adverse events (TRAEs) occurred among 9.1% of patients, and 2.3% of patients experienced a serious TRAE. Treatment discontinuation due to adverse events occurred among 6.8% of patients, and 11.4% required a dose interruption.  The median duration of response was not yet reached.

The authors concluded that retifanlimab was well tolerated and showed preliminary activity among patients with MSI-H/dMMR endometrial cancer. They noted that these “results support further clinical investigation of retifanlimab in patients with endometrial cancer.”

Read more of Cancer Therapy Advisor‘s coverage of the SITC 2020 meeting by visiting the conference page.

Reference

Berton-Rigaud D, Vergote I, Pautier P, et al. A phase 1 study of retifanlimab (INCMGA00012), a PD-1 inhibitor, in patients with advanced solid tumors: preliminary results in recurrent MSI-high or dMMR endometrial cancer (PODIUM-101). Presented at: Society for Immunotherapy of Cancer 35th Anniversary Annual Meeting & Preconference Programs (SITC 2020); November 11-14, 2020. Abstract 268. J Immunother Cancer. 2020;8(Suppl 3):A656–A959.