Immunocore will present Phase 1 data for brenetafusp plus KIMMTRAK® (tebentafusp-tebn) in metastatic uveal melanoma, during a late-breaking oral session at the 2026 SITC meeting

Immunocore will present Phase 1 data for brenetafusp plus KIMMTRAK ® (tebentafusp-tebn) in metastatic uveal melanoma, during a late-breaking oral session at the 2026 SITC meeting

Clinical data for first combination of two T cell engagers in a solid tumor will be presented in a poster on Friday, November 6, and an oral presentation on November 7

(OXFORDSHIRE, England & RADNOR, PA & GAITHERSBURG, MD, US, October 29, 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, today announced that it will present 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, in a poster and oral session at the 2026 Society for Immunotherapy of Cancer (SITC) Annual Meeting.

The poster and oral presentations will include additional safety and efficacy data. The Company will issue a release on Friday, November 6, at 12:00 p.m. ET / 5:00 p.m. UK time when the poster session starts.

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

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About ImmTAC ® molecules for cancer

Immunocore’s proprietary T cell receptor (TCR) technology generates a novel class of bispecific biologics called ImmTAC (Immune mobilizing monoclonal TCRs Against Cancer) molecules that are designed to redirect the immune system to recognize and kill cancer cells. ImmTAC molecules are soluble TCRs engineered to recognize intracellular cancer antigens with ultra-high affinity and selectively kill these cancer cells via an anti-CD3 immune-activating effector function. Based on demonstrated T cell infiltration into human tumors, the ImmTAC mechanism of action holds the potential to treat hematologic and solid tumors, regardless of mutational burden or immune infiltration, tumors that are characterized as immune “cold” or having low mutation burden.

About the IMC-F106C-101 Phase 1/2 trial

IMC-F106C-101 is a first-in-human, Phase 1/2 dose escalation trial in patients with multiple solid tumors, including non-small cell lung and ovarian cancers, as well as uveal melanoma, evaluating brenetafusp both as monotherapy and in combination arms with standards-of-care. The Phase 1 dose escalation portion of the trial was designed to determine the maximum tolerated dose (MTD), as well as to evaluate the safety, preliminary anti-tumor activity and pharmacokinetics of IMC-F106C (brenetafusp) both as monotherapy and in combination with standards-of-care. Brenetafusp is a bispecific protein built on Immunocore’s ImmTAC technology, and the Company’s first molecule to target the PRAME antigen.

About KIMMTRAK

KIMMTRAK is a novel bispecific protein comprised of a soluble T cell receptor fused to an anti-CD3 immune-effector function. KIMMTRAK specifically targets gp100, a lineage antigen expressed in melanocytes and melanoma.

IMPORTANT SAFETY INFORMATION

Cytokine Release Syndrome (CRS), which may be serious or life-threatening, occurred in patients receiving KIMMTRAK. Monitor for at least 16 hours following first three infusions and then as clinically indicated. Manifestations of CRS may include fever, hypotension, hypoxia, chills, nausea, vomiting, rash, elevated transaminases, fatigue, and headache. CRS occurred in 89% of patients who received KIMMTRAK, with 0.8% being grade 3 or 4. Ensure immediate access to medications and resuscitative equipment to manage CRS. Ensure patients are euvolemic prior to initiating the infusions. Closely monitor patients for signs or symptoms of CRS following infusions of KIMMTRAK. Monitor fluid status, vital signs, and oxygenation level and provide appropriate therapy. Withhold or discontinue KIMMTRAK depending on persistence and severity of CRS.

Skin Reactions

Skin reactions, including rash, pruritus, and cutaneous edema occurred in 91% of patients treated with KIMMTRAK. Monitor patients for skin reactions. If skin reactions occur, treat with antihistamine and topical or systemic steroids based on persistence and severity of symptoms. Withhold or permanently discontinue KIMMTRAK depending on the severity of skin reactions.

Elevated Liver Enzymes

Elevations in liver enzymes occurred in 65% of patients treated with KIMMTRAK. Monitor alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total blood bilirubin prior to the start of and during treatment with KIMMTRAK. Withhold KIMMTRAK according to severity.

Embryo-Fetal Toxicity

KIMMTRAK may cause fetal harm. Advise pregnant patients of potential risk to the fetus and patients of reproductive potential to use effective contraception during treatment with KIMMTRAK and 1 week after the last dose.

The most common adverse reactions (≥30%) in patients who received KIMMTRAK were cytokine release syndrome, rash, pyrexia, pruritus, fatigue, nausea, chills, abdominal pain, edema, hypotension, dry skin, headache, and vomiting. The most common (≥50%) laboratory abnormalities were decreased lymphocyte count, increased creatinine, increased glucose, increased AST, increased ALT, decreased hemoglobin, and decreased phosphate.

For more information, please see full Summary of Product Characteristics (SmPC) or full U.S. Prescribing Information (including BOXED WARNING for CRS).

About Immunocore

Immunocore is a commercial-stage biotechnology company pioneering the development of a novel class of TCR bispecific immunotherapies called ImmTAX – Immune mobilizing monoclonal TCRs Against X disease – designed to treat a broad range of diseases, including cancer, autoimmune diseases and infectious diseases. Leveraging its proprietary, flexible, off-the-shelf ImmTAX platform, Immunocore is developing a deep pipeline in multiple therapeutic areas, including clinical and pre-clinical programs in oncology, infectious diseases, and autoimmune diseases. The Company’s most advanced oncology TCR therapeutic, KIMMTRAK, has been approved for the treatment of HLA-A*02:01-positive adult patients with unresectable or metastatic uveal melanoma in 39 countries, including the United States, European Union, Canada, Australia, and the United Kingdom.

Forward Looking Statements

This press release contains “forward-looking statements” within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Words such as “may”, “will”, “believe”, “expect”, “plan”, “anticipate”, “aim”, “continue”, “target” and similar expressions (as well as other words or expressions referencing future events or circumstances) are intended to identify forward-looking statements. All statements, other than statements of historical facts, included in this press release are forward-looking statements. These statements include, but are not limited to, statements regarding the data from the Phase 1/2 trial evaluating brenetafusp alone and in combination with KIMMTRAK. Any forward-looking statements are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual events or results to differ materially and adversely from those set forth in or implied by such forward-looking statements, many of which are beyond the Company’s control. These and other risks and uncertainties are described in greater detail in the section titled "Risk Factors" in the Company’s filings with the Securities and Exchange Commission, including the Company’s most recent Annual Report on Form 10-K for the year ended December 31, 2025, filed with the Securities and Exchange Commission on February 25, 2026, as well as discussions of potential risks, uncertainties, and other important factors in the Company’s subsequent filings with the SEC. All information in this press release is as of the date of the release, and the Company undertakes no duty to update this information, except as required by law.

Contact Information

Immunocore Sébastien Desprez, Vice President, Communications T: +44 (0) 7458030732 E: [email protected] Follow on LinkedIn: @Immunocore

Ryan Baker, Vice President, Investor Relations T: +1 (215) 384-4781 E: [email protected]

Source: Immunocore Holdings plc Released October 29, 2026