Multinational phase 1 trial of tebotelimab with or without margetuximab for solid tumors and hematologic cancers

Tebotelimab is a bispecific antibody that blocks both PD-1 and LAG-3. A multinational phase 1 trial evaluated tebotelimab as monotherapy or in combination with the anti-HER2 antibody margetuximab in patients with solid tumors or hematologic cancers. In the monotherapy cohort (n=269) 68% experience treatment-related adverse events (22% grade 3 or higher). No maximum tolerated dose was defined; the RP2D was 600 mg every two weeks. There were tumor decreases in 34% of response-evaluable patients, with objective responses in multiple solid tumor types. In the combination cohort (n=84), 74% had TRAEs (17% grade 3 or higher). The confirmed objective response rate was 19%, including responses in patients typically not responsive to anti-HER2/anti-PD-1 combination therapy.