Immunocore completes TEBE-AM enrolment as tebentafusp Phase 3 matures
Immunocore has reached target enrolment of 540 patients in TEBE-AM, its global, randomised Phase 3 trial evaluating KIMMTRAK (tebentafusp) in HLA-A*02:01-positive adults with previously treated advanced melanoma. The Oxfordshire-based company said topline overall survival data could be available as early as the fourth quarter of 2026, a readout that will determine whether the therapy can expand beyond its existing approved indication in uveal melanoma.
TEBE-AM (NCT05549297) is structured around three arms: tebentafusp as monotherapy, tebentafusp in combination with pembrolizumab, and an Investigator's Choice control. Eligible patients must have progressed on an anti-PD-1 regimen, received prior ipilimumab, and, where relevant, prior BRAF kinase inhibitor therapy. Overall survival is the primary endpoint, a regulatory-grade bar that the FDA and EMA have come to regard as the gold standard for confirmatory oncology trials.
"Achieving target enrolment in TEBE-AM is an important milestone for Immunocore and a critical step toward addressing the substantial unmet need in previously treated, post-PD1 advanced melanoma, a setting with limited treatment options," said Mohammed Dar, Chief Medical Officer of Immunocore.
The science behind tebentafusp
Tebentafusp is a bispecific protein built on Immunocore's ImmTAC platform. It combines a soluble T cell receptor engineered to bind gp100, a lineage antigen expressed on melanocytes and melanoma cells, with an anti-CD3 effector domain that recruits and activates T cells at the tumour site. The mechanism differs from conventional checkpoint inhibitors in that it targets an intracellular peptide presented on the cell surface via HLA, rather than a surface-expressed protein. This approach is, in principle, applicable to tumours with low mutational burden and limited immune infiltration, categories that have historically responded poorly to PD-1 blockade.
KIMMTRAK is already approved in multiple major markets, including the United States, European Union, United Kingdom, Canada, and Australia, for unresectable or metastatic uveal melanoma. A positive TEBE-AM readout would mark the drug's first expansion into cutaneous melanoma, a substantially larger patient population. Immunocore estimates the addressable post-PD-1 cutaneous melanoma segment at up to 4,000 HLA-A*02:01-positive patients annually across the US and Europe.
Competitive and regulatory context
The post-PD-1 advanced melanoma space has attracted considerable development activity, with relatlimab combinations, tumour-infiltrating lymphocyte (TIL) therapies such as Iovance Biotherapeutics' lifileucel, and a number of investigational agents competing for patients who have exhausted standard checkpoint regimens. Tebentafusp's HLA restriction, which limits eligibility to roughly half of the melanoma population of European ancestry, is both a precision-medicine differentiator and a commercial constraint that will shape the drug's peak sales potential regardless of efficacy outcomes.
From a regulatory standpoint, the FDA approved KIMMTRAK for uveal melanoma on the basis of overall survival data from the IMCgp100-202 Phase 3 trial, a precedent that aligns well with TEBE-AM's primary endpoint design. Should topline data arrive in late 2026, a regulatory submission in the cutaneous melanoma indication could follow in 2027, assuming the data package is complete. The EMA pathway would likely run in parallel. Investors will be watching closely, as an expanded label would materially alter the drug's commercial trajectory and Immunocore's revenue outlook beyond its existing rare-disease base in uveal melanoma.