The combination elicited a complete response in patient with cervical cancer and a partial response in a patient with ovarian cancer.
The combination of etigilimab, an anti-TIGIT antibody, in combination with nivolumab (Opdivo) has demonstrated anti-tumor efficacy and acceptable safety data in patients with solid tumors, according to a press release on the interim results of the phase 1b/2 ACTIVATE trial by Mereo BioPharma Group plc.
The phase 1b/2 study (NCT04761198) has a target enrollment of 125 participants and an estimated study completion date of June 2023. The primary end point is objective response rate.
During the study, patients will receive an infusion of etigilimab every 2 weeks and an infusion of nivolumab every 2 weeks. Cohorts include squamous cell carcinoma of the head and neck, cervical cancer on or after chemotherapy, gastric or gastroesophageal junction adenocarcinoma, endometrial carcinoma, tumor burden high and microsatellite stable solid tumors, rare disease with high TIGIT expression, ovarian cancer, and endometrial carcinoma post standard of care therapy.
At the time of data cutoff, 22 patients were included in the safety analysis. Twenty patients were evaluable with a minimum of at least one scan and 15 were included in the efficacy analysis.
The analysis found that 1 patient in the cervical cancer cohort had a complete response. In the ovarian cancer cohort, 1 patient had a partial response. Four patients with stable disease was seen in ovarian cancer, cervical cancer, and uveal melanoma. Additionally, the ovarian cancer cohort has crossed futility for expansion into the second stage of the study.
The combination was found to be well tolerated, and no new safety signals were observed. Common adverse events included skin reactions, which were seen in 7 patients. No patients required systemic steroids. There was one reported case of immune diabetes mellitus.
“These early results from the ACTIVATE study are highly encouraging and support the further study of etigilimab in combination with an anti-PD-1 antibody in solid tumor types, especially in gynecologic malignancies,” said Denise Scots-Knight, PhD, chief executive officer of Mereo in a press release. “We are particularly excited by the complete response in the cervical cancer cohort and the partial response in one of the ovarian cancer patients treated to-date. In the efficacy analysis set, biomarker analysis showed a positive trend between baseline PVR expression and clinical benefit including in the absence of PD-L1 expression in the efficacy analysis population. Clinical benefit also occurred in tumor types with historically low response rates to anti-PD-1/PDL-1 antibodies. We look forward to providing additional updates on the study in 2022.”
In order to participate in the study, patients must have a confirmed diagnosis of a relevant tumor type and are not candidates for curative surgery or radiation therapy, have available tumor tissue, adequate hematological and end organ function, life expectancy greater than 12 weeks, and an ECOG performance status of 0 to 1.
Patients with a concurrent active malignancy, major surgery within 4 week of treatment, active or suspected autoimmune disease, prior treatment with anti-TIGIT antibodies, a history of immune-related adverse events, active HIV infection, or are pregnant are not eligible to participate.
The study is currently recruiting in Arizona, California, Florida, Massachusetts, Michigan, Minnesota, New York, North Carolina, Oklahoma, Tennessee, Texas, Utah, and Virginia.