On November 6, 2026 Immunocore Holdings plc (Nasdaq: IMCR) ("Immunocore" or the "Company"), a commercial-stage biotechnology company pioneering and delivering transformative immunomodulating medicines to radically improve outcomes for patients with cancer, infectious diseases and autoimmune diseases, reported data from its Phase 1/2 trial evaluating brenetafusp alone and in combination with KIMMTRAK in HLA-A*02:01-positive patients with metastatic uveal melanoma (mUM), in a poster session at the 2026 Society for Immunotherapy of Cancer (SITC) (Free SITC Whitepaper) Annual Meeting. The data will also be presented in an oral session on Saturday, November 7, at 3:45 p.m. ET.

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KIMMTRAK and brenetafusp are ImmTAC molecules targeting gp100 and PRAME, respectively, with PRAME representing an established negative prognostic factor in mUM. KIMMTRAK is the first bispecific T cell receptor therapy to demonstrate survival benefit in a solid tumor and is the standard of care for HLA-A*02:01-positive adults with unresectable or metastatic uveal melanoma. Brenetafusp is an investigational candidate being evaluated in a range of tumors, including first-line cutaneous melanoma in the PRISM-MEL-301 Phase 3 trial. Adding brenetafusp to KIMMTRAK tests the hypothesis of whether the combination may improve outcomes in patients with HLA-A*02:01-positive mUM by increasing target engagement and enhancing T cell-mediated tumor killing.

"Immunocore continues to lead bispecific T cell engager innovation, having demonstrated the first overall survival benefit in metastatic uveal melanoma. We are now seeing the synergistic potential of combining two clinically active ImmTAC therapies. The 1- and 2-year overall survival data could be practice-changing, and I look forward to evaluating this combination in a randomized trial for patients with metastatic uveal melanoma," said Dr. Omid Hamid, Chief of Research & Immuno-Oncology, Co-Director, Cutaneous Malignancy Program at The Angeles Clinic & Research Institute.

"These encouraging Phase 1 data suggest combining brenetafusp with tebentafusp may offer a meaningful new option for HLA-A*02:01-positive patients with metastatic uveal melanoma," said Dr. Mohammed Dar, Executive Vice President, Clinical Development and Chief Medical Officer of Immunocore. "Building on our leadership with KIMMTRAK, we believe that targeting both gp100 and PRAME – a combined ImmTAC approach – offers the potential to deliver an even greater benefit for HLA-A*02:01-positive patients."

At the June 2026 data cut-off, 22 patients with mUM had received clinically active doses of brenetafusp monotherapy and 26 had received brenetafusp plus tebentafusp. The Company believes that this is the first data showing clinical activity and a manageable safety profile for a combination of two T cell engagers in a solid tumor.

Across the 17 evaluable first-line patients who received the combination, overall response rate (ORR) was 29% with a median duration of response (mDoR) of 24.1 months. The disease control rate (DCR) was 71% and median progression-free survival (mPFS) was 8.1 months. At the data cut-off, median overall survival (mOS) had not been reached at a median follow-up of 29 months. OS rates were 88% at one year and 70% at two years with 10 of the 17 patients remaining on study. The majority of patients with OS >2 years (64%; 7 out of 11) had received only the brenetafusp and tebentafusp combination.

In the 16 evaluable patients who received brenetafusp monotherapy in the second-line or later setting, ORR was 19%, mDoR 14.5 months, DCR 63%, mPFS 4.2 months, and mOS 20.3 months. OS rates were 63% at one year and 31% at two years.

The safety profile of brenetafusp as monotherapy and in combination with tebentafusp was generally well tolerated and consistent with that observed for the individual agents, with no new safety signals reported. The most frequent treatment-related adverse event (TRAE) was reversible and manageable cytokine release syndrome (CRS), observed in 77% of combination patients and 73% of monotherapy patients, with the majority being Grade 1 or 2 (no Grade 3/4 CRS for the combination and 5% Grade 3 CRS for brenetafusp monotherapy). Grade 3 or 4 TRAEs were reported in 38% of combination patients and 41% of monotherapy patients, with the most frequent being transient lymphocyte count decrease that resolved without intervention. No TRAE led to discontinuation or death in either group.

The data also demonstrated molecular responses for the combination. Out of the nine patients who were evaluable for ctDNA response, eight (89%) had a molecular response, and four (44%) achieved ctDNA clearance.

The Company is planning to start DUET-UVEAL, a randomized Phase 2/3 trial, to further evaluate the combination for the treatment of HLA-A*02:01-positive adults with unresectable or metastatic uveal melanoma.

The data presented at SITC (Free SITC Whitepaper) come from an ongoing Phase 1/2 trial (NCT04262466; EudraCT 2019-004046-16) evaluating brenetafusp as monotherapy as well as in combination across a number of solid tumors, including HLA-A*02:01-positive patients with unresectable or metastatic uveal melanoma. Brenetafusp and tebentafusp were administered by weekly intravenous infusion with step-up dosing.

Presentation details

Title: Phase 1 evaluation of brenetafusp alone and in combination with tebentafusp in metastatic uveal melanoma (Abstract number: 1177)

Poster session: Poster Hall
Date and Time: Friday, November 6, 2026, 10:00 a.m. MST / 12:00 p.m. EST

Clinical oral abstract session: Session 2
Date and Time: Saturday, November 7, 2026, 1:45 p.m. MST / 3:45 p.m. EST

(Press release, Immunocore, NOV 6, 2026, View Source [SID1234674392])