Immunocore fully enrolls 540-patient Phase 3 KIMMTRAK trial
Rhea-AI Filing Summary
Immunocore Holdings plc (IMCR) reports that it has achieved target enrollment of 540 patients in its global, randomized, registrational Phase 3 TEBE-AM trial of KIMMTRAK (tebentafusp) as monotherapy and in combination with pembrolizumab versus Investigator’s Choice in HLA-A*02:01-positive advanced melanoma after prior therapy. The primary endpoint is overall survival, and the company expects to share topline overall survival data as early as the end of 2026. KIMMTRAK, developed from Immunocore’s ImmTAC TCR bispecific platform, is already approved for HLA-A*02:01-positive adult patients with unresectable or metastatic uveal melanoma in multiple major markets.
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Filing Explained
TEBE-AM has moved from enrollment to follow-up: all
8-K Event Classification
2 items: 7.01, 9.01
2 items
Item 7.01
Regulation FD Disclosure
Disclosure
Material non-public information disclosed under Regulation Fair Disclosure, often investor presentations or guidance.
Item 9.01
Financial Statements and Exhibits
Exhibits
Financial statements, pro forma financial information, or exhibit attachments filed with this report.
Key Figures
TEBE-AM target enrollment: 540 patients
Potential advanced melanoma patients: 4,000 patients
CRS incidence with KIMMTRAK: 89%
+5 more
8 metrics
TEBE-AM target enrollment
540 patients
Target patient enrollment achieved in the Phase 3 TEBE-AM trial
Potential advanced melanoma patients
4,000 patients
Estimated HLA-A*02:01-positive previously treated advanced melanoma patients in US and Europe
CRS incidence with KIMMTRAK
89%
Patients receiving KIMMTRAK who experienced Cytokine Release Syndrome
Grade 3 or 4 CRS
0.8%
Patients treated with KIMMTRAK with grade 3 or 4 CRS
Skin reactions with KIMMTRAK
91%
Patients treated with KIMMTRAK experiencing skin reactions
Elevated liver enzymes
65%
Patients treated with KIMMTRAK who had elevations in liver enzymes
Common adverse reactions threshold
≥30%
Frequency threshold for listing common adverse reactions with KIMMTRAK
Common laboratory abnormalities threshold
≥50%
Frequency threshold for listing common laboratory abnormalities with KIMMTRAK
Key Terms
overall survival, registrational Phase 3 clinical trial, ImmTAC, Cytokine Release Syndrome, +2 more
6 terms
overall survival medical
"The primary endpoint is overall survival."
Overall survival is the average or median length of time patients remain alive after starting a treatment or entering a clinical study, measured regardless of cause of death. Investors care because it is a clear, hard measure of a therapy’s real-world benefit — like timing how long a new battery actually runs — and strong improvements in overall survival can drive regulatory approval, market adoption and revenue potential.
registrational Phase 3 clinical trial medical
"TEBE-AM is a global, randomized, registrational Phase 3 clinical trial"
A registrational phase 3 clinical trial is a large, late-stage study designed to show whether a new drug or medical treatment is safe and effective enough for regulators to approve it for widespread use. Think of it as a final, large-scale field test or exam: its size, design and results are intended to provide the main evidence regulators rely on, and those results strongly affect a product’s chances of approval, market access and commercial value.
ImmTAC medical
"bispecific biologics called ImmTAC (Immune mobilizing monoclonal TCRs Against Cancer)"
Cytokine Release Syndrome medical
"Cytokine Release Syndrome (CRS), which may be serious or life-threatening"
An intense immune overreaction in which the body's defense system releases a large surge of signaling proteins, causing fever, low blood pressure, breathing trouble or organ stress; imagine the immune system's alarm going into overdrive and flooding the body with emergency responders. Investors care because this side effect can slow or block regulatory approval, increase clinical trial costs and liabilities, limit how widely a therapy can be used, and therefore affect a drug's market value and sales potential.
uveal melanoma medical
"for the treatment of HLA-A*02:01-positive adult patients with unresectable or metastatic uveal melanoma"
A cancer that starts in the uveal tract of the eye — the iris, ciliary body or choroid — growing like an unwanted patch in the eye’s colored and surrounding tissues. It matters to investors because its rarity and serious course mean that successful drugs, surgical techniques, or diagnostic tests can shift patient care, regulatory approvals, and revenue prospects for healthcare companies in the oncology and ophthalmology markets.
HLA-A*02:01-positive medical
"for the treatment of HLA-A*02:01-positive patients with advanced melanoma"
HLA-A*02:01-positive means a person carries a specific version of a gene that helps the immune system present bits of proteins on the surface of cells—think of it as one particular lock shape on many cells that certain immune ‘keys’ can recognize. Investors should care because some drugs, vaccines and cell therapies only work or are tested in people with this lock shape, so it directly affects patient eligibility, trial size, market reach and the likelihood of a treatment’s success.
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What milestone did Immunocore (IMCR) announce for the TEBE-AM trial?
Immunocore announced it has achieved target enrollment of 540 patients in the Phase 3 TEBE-AM trial. This registrational study evaluates KIMMTRAK (tebentafusp) as monotherapy and in combination with pembrolizumab versus Investigator’s Choice in HLA-A*02:01-positive patients with previously treated advanced melanoma.
When does Immunocore (IMCR) expect topline data from the TEBE-AM study?
Immunocore expects to share topline overall survival data from the registrational Phase 3 TEBE-AM trial as early as the end of 2026. Patients who have been enrolled will continue to be followed for the planned overall survival analysis.
What patient population is targeted in Immunocore’s TEBE-AM Phase 3 trial?
The TEBE-AM trial targets HLA-A*02:01-positive patients with advanced melanoma whose disease has progressed following prior therapy. This includes second-line or later patients who have progressed on anti-PD1, received prior ipilimumab and, if applicable, a BRAF kinase inhibitor.
How large is the potential patient population for tebentafusp in advanced melanoma?
Immunocore believes tebentafusp could address a significant unmet need for up to 4,000 HLA-A*02:01-positive patients with previously treated advanced melanoma in the post-PD1 setting across the United States and Europe, if successfully developed and approved.
What is KIMMTRAK and where is it currently approved?
KIMMTRAK is a bispecific protein comprised of a soluble T cell receptor fused to an anti-CD3 effector function, targeting gp100 in melanocytes and melanoma. It is approved for HLA-A*02:01-positive adult patients with unresectable or metastatic uveal melanoma in the US, EU, Canada, Australia and the UK.
What is the primary endpoint of the TEBE-AM Phase 3 trial?
The primary endpoint of the TEBE-AM registrational Phase 3 trial is overall survival. The study compares KIMMTRAK (tebentafusp) as monotherapy and in combination with an anti-PD-1 versus an Investigator’s Choice control arm in previously treated advanced melanoma.
What are key safety concerns highlighted for KIMMTRAK in the filing?
Key safety points include Cytokine Release Syndrome (CRS) in 89% of patients (with 0.8% grade 3–4), skin reactions in 91%, and elevated liver enzymes in 65%. The text also notes embryo-fetal toxicity risk and lists common adverse reactions and laboratory abnormalities.
AI-generated analysis. How Rhea-AI works. Not financial advice.
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
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FORM 8-K
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CURRENT REPORT
Pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): September 14, 2026
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Item 7.01. Regulation FD Disclosure.
On September 14, 2026, Immunocore Holdings plc (the "Company") issued a press release announcing the achievement of target patient enrollment in its Phase 3 TEBE-AM clinical trial evaluating tebentafusp as monotherapy and in combination with pembrolizumab for the treatment of HLA-A*02:01-positive patients with unresectable or metastatic melanoma whose disease has progressed following prior therapy. A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference herein.
The information contained in Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, and shall not be deemed incorporated by reference into any of the Company’s filings under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.
Item 9.01. Financial Statements and Exhibits
Exhibit No. | Description | |||||||
99.1 | Press Release dated September 14, 2026. | |||||||
104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). | |||||||
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
Dated: September 14, 2026
IMMUNOCORE HOLDINGS PLC | |||||
By: | /s/ Bahija Jallal, Ph.D. | ||||
Name: Bahija Jallal, Ph.D. | |||||
Title: Chief Executive Officer | |||||
Immunocore announces achievement of target enrollment in registrational TEBE-AM trial with KIMMTRAK® (tebentafusp) in previously treated advanced melanoma
Topline overall survival data expected as early as end of 2026
(OXFORDSHIRE, England & CONSHOHOCKEN, PA & ROCKVILLE, MD, US, 14 September 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 the achievement of target patient enrollment (540 patients) in the TEBE-AM clinical trial (NCT05549297).
TEBE-AM is a global, randomized, registrational Phase 3 clinical trial evaluating KIMMTRAK (tebentafusp) as monotherapy and in combination with pembrolizumab, versus Investigator’s Choice, for the treatment of HLA-A*02:01-positive patients with advanced melanoma whose disease has progressed following prior therapy. The primary endpoint is overall survival.
"Achieving target enrollment 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. “We are grateful to the patients and investigators participating in the trial."
With target enrollment now achieved, patients enrolled in the trial will continue to be followed for the planned overall survival analysis.
The Company believes tebentafusp has the potential to address a significant unmet need for up to 4,000 HLA-A*02:01-positive patients with previously treated advanced melanoma in the post-PD1 setting, in the United States and Europe. The Company expects to be able to share topline data as early as the end of 2026.
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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 cancerous 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 the demonstrated mechanism of T cell infiltration into human tumors, the ImmTAC mechanism of action holds the potential to treat hematologic and solid tumors,
Page 1 of 5regardless of mutational burden or immune infiltration, including immune “cold” low mutation rate tumors.
About TEBE-AM - Phase 3 registrational trial with tebentafusp in previously treated advanced melanoma
The trial is evaluating tebentafusp in patients with second-line or later advanced melanoma who have progressed on an anti-PD1, received prior ipilimumab and, if applicable, received a BRAF kinase inhibitor. The study comprises three arms: tebentafusp as monotherapy, tebentafusp in combination with an anti-PD-1, and a control arm. The primary endpoint is overall survival.
About Cutaneous Melanoma
Cutaneous melanoma (CM) is the most common form of melanoma. It is the most aggressive skin carcinoma and is associated with the vast majority of skin cancer-related mortality. The majority of patients with CM are diagnosed before metastasis and survival remains poor for the large proportion of patients with metastatic disease. Despite recent progress in advanced melanoma therapy, there is still an unmet need for new therapies that improve first-line response rates and duration of response as well as for patients who are refractory to first-line treatments.
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. This is the first molecule developed using Immunocore’s ImmTAC technology platform, designed to redirect and activate T cells to recognize and kill tumor cells. KIMMTRAK has been approved for the treatment of HLA-A*02:01-positive adult patients with unresectable or metastatic uveal melanoma in the United States, European Union, Canada, Australia, and the United Kingdom.
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.
Page 2 of 5Skin 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 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
Page 3 of 5well 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 estimated size of the patient populations for the Company’s product candidates; the Company’s expectations regarding the design, progress, timing, enrollment, randomization, scope, expansion, and results of its TEBE-AM trial. 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 risks and uncertainties include, but are not limited to, the impact of worsening macroeconomic conditions, including as a result of health epidemics or pandemics, war in Ukraine, the conflict in the Middle East, or global geopolitical tension, on the Company’s business, financial position, strategy and anticipated milestones, including Immunocore’s ability to conduct ongoing and planned clinical trials; the Company’s ability to obtain a clinical supply of current or future product candidates or commercial supply of KIMMTRAK or any future approved products; the Company’s ability to obtain and maintain regulatory approval of KIMMTRAK and its other product candidates; the Company’s ability and plans in continuing to establish and expand a commercial infrastructure and to successfully launch, market and sell KIMMTRAK and any future approved products; the Company’s ability to successfully expand the approved indications for KIMMTRAK or obtain marketing approval for KIMMTRAK in additional geographies in the future; the delay of any current or planned clinical trials, whether due to patient enrollment delays or otherwise; the Company’s ability to successfully demonstrate the safety and efficacy of its product candidates and gain approval of its product candidates on a timely basis, if at all; competition with respect to market opportunities; unexpected safety or efficacy data observed during preclinical studies or clinical trials; actions of regulatory agencies, which may affect the initiation, timing and progress of clinical trials or future regulatory approval; Immunocore’s need for and ability to obtain additional funding, on favorable terms or at all, including as a result of worsening macroeconomic conditions, including changes in inflation and interest rates and unfavorable general market conditions, and the impacts thereon of the war in Ukraine, the conflict in the Middle East, and global geopolitical tension; Immunocore’s ability to obtain, maintain and enforce intellectual property protection for KIMMTRAK or any of its product candidates it or its collaborators are developing; and the success of Immunocore’s current and future collaborations, partnerships or licensing arrangements. These and other risks and uncertainties are described in greater detail in the section titled "Risk Factors" in Immunocore’s filings with the Securities and Exchange Commission, including Immunocore’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.
Page 4 of 5Contact Information
Immunocore
Sébastien Desprez, Head of Communications
T: +44 (0) 7458030732
E: sebastien.desprez@immunocore.com
Follow on LinkedIn: @Immunocore
Ryan Baker, Vice President, Investor Relations
T: +1 (215) 384-4781
E: ir@immunocore.com
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