Immunocore (the “Company”), a late-stage biotechnology company pioneering the development of a novel class of TCR bispecific immunotherapies designed to treat a broad range of diseases, including cancer, infectious and autoimmune, today announced that its Phase 3 IMCgp100-202 clinical trial of tebentafusp (IMCgp100) vs. investigator choice in metastatic uveal melanoma (mUM) has met the pre-defined boundaries for statistical significance of the primary endpoint of Overall Survival (OS) in its first pre-planned interim analysis conducted by the independent data monitoring committee. The OS Hazard Ratio (HR) in the intent-to-treat population favored tebentafusp, HR=0.51 (95% CI: 0.36, 0.71); p< 0.0001, over investigator’s choice (82% pembrolizumab; 12% ipilimumab; 6% dacarbazine). Although not yet mature, the Kaplan-Meier estimates suggest a 1-year OS rate of approximately 73% vs 58%, respectively. The efficacy data confirm the promising OS observed in the phase 2 study IMCgp100-102 in previously treated mUM which will be presented next month at the ESMO Immuno-Oncology Virtual Congress 2020.

Bahija Jallal, Chief Executive Officer of Immunocore said: “A positive survival benefit for tebentafusp represents a major step towards bringing a potential new treatment for cancer patients with a high unmet need. If approved, tebentafusp would be the first new therapy to improve overall survival in 40 years and to be specifically indicated for metastatic uveal melanoma, a disease with poor survival and where new therapies are urgently needed. We look forward to sharing these data with the medical community and Health Authorities in the near future.”

Tebentafusp is a novel bispecific protein comprised of a soluble T cell receptor fused to an anti-CD3 immune-effector domain. It is engineered to specifically target gp100, a lineage antigen expressed in melanocytes and melanoma, and is the first molecule developed using Immunocore’s ImmTAC technology platform designed to redirect and activate T cells to recognize and kill tumor cells. Tebentafusp has been granted Fast Track Designation by the U.S. Food and Drug Administration (FDA) and has previously been granted orphan drug designation for uveal melanoma by the FDA and Promising Innovative Medicine designation under UK Early Access to Medicines Scheme

“To our knowledge, this is the first survival benefit for any TCR therapeutic and for any bispecific in a solid tumor. The survival benefit observed in a randomized trial against checkpoint inhibitors validates our ImmTAC platform as we expand to study other cancers with high unmet need,” said David Berman, Head of R&D, “Uveal melanoma has one of the lowest tumor mutational burdens (TMB) and these results suggest our ImmTAC platform should be evaluated in tumors with low or high TMB status.”

The Phase 3 IMCgp100-202 clinical trial is designed to evaluate the OS of tebentafusp compared to investigator’s choice (either dacarbazine, ipilimumab or pembrolizumab) in patients with previously untreatedmUM. 378 patients were randomized in a 2:1 ratio to either tebentafusp or investigator’s choice. Final results from IMCgp100-202 are expected to be presented at an upcoming scientific conference and to be submitted for publication in a peer-reviewed journal.