Exhibit 99.1

Immunocore reports first quarter financial results and provides a business update

KIMMTRAK^® (tebentafusp-tebn) Q1 net sales of $106.7 million, growing by 14% year-over-year

Oral presentation at AACR: KIMMTRAK doubles likelihood of being alive at five years for patients with HLA-A*02:01 positive metastatic uveal melanoma

Cash, cash equivalents and marketable securities of $845 million as of March 31, 2026

(OXFORDSHIRE, England & RADNOR, Penn. & GAITHERSBURG, Md., US, 6 May 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 its financial results for the first quarter ended March 31, 2026, and provided a business update.

“We are proud to report another quarter of strong commercial performance, with KIMMTRAK generating $107 million in net revenues in Q1 2026,” said Bahija Jallal, CEO of Immunocore. “The five-year overall survival (OS) data from our Phase 3 trial presented at AACR is a landmark moment. It is the longest OS follow-up ever reported in a randomized trial in metastatic uveal melanoma and underscores the long-term benefit KIMMTRAK delivers to patients. In parallel, we are executing with discipline across our pipeline."

Financial Results

For the first quarter of 2026 (Q1 2026), total net product revenue (or ‘net sales’) arising from the sales of KIMMTRAK was $106.7 million, compared to $93.9 million for the same period in 2025. Q1 2026 sales were $67.4 million in the United States, $34.4 million in Europe, and $4.8 million in international regions. The increase in net product sales was due to increased volumes in the United States and Europe as well as global country expansion.

Research & development (R&D) expenses for Q1 2026 were $61.1 million, compared to $56.5 million for Q1 2025. This increase was primarily due to clinical expenses related to the progression of our Phase 3 trials, primarily PRISM-MEL-301.

Selling, general and administrative (SG&A) expenses for Q1 2026 were $37.9 million, compared to $40.2 million for Q1 2025. This decrease was primarily due to increases in forfeitures of share-based compensation.

Net income for Q1 2026 was $13.0 million compared to $5.0 million for Q1 2025.

The Q1 2026 diluted income per share was $0.25 compared to $0.10 for Q1 2025.

Cash, cash equivalents and marketable securities were $844.9 million as of March 31, 2026.

The Company’s lead product, KIMMTRAK^® (tebentafusp), is approved in 39 countries and has been launched in over 30 countries globally to date for HLA-A*02:01 positive people with unresectable or metastatic uveal melanoma (mUM). KIMMTRAK continues to be the standard of care in most markets where it is launched.

The Company sees three key growth areas as it plans to expand patient reach for KIMMTRAK, including continued US community and global market penetration in mUM, the potential expansion into 2L+ advanced cutaneous melanoma (CM), and the potential expansion into adjuvant uveal melanoma.

Metastatic uveal melanoma

2L+ advanced cutaneous melanoma

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There is great unmet need in second- and later-line cutaneous melanoma, with no therapy having shown, to date, an OS improvement post checkpoint inhibitors in a randomized clinical trial. The Company estimates that there is a potential to address up to 4,000 previously treated advanced HLA-A*02:01 positive CM patients.

Adjuvant uveal (or ocular) melanoma

Brenetafusp is the Company’s lead PRAME-A02 ImmTAC bispecific candidate. Brenetafusp is being evaluated in combination with nivolumab in a Phase 3 registrational trial (PRISM-MEL-301) in patients with first-line, advanced cutaneous melanoma, and in a Phase 1/2 clinical trial as monotherapy and in combination across multiple tumor types, including ovarian cancer and non-small cell lung cancer (NSCLC).

PRISM-MEL-301 – First PRAME Phase 3 clinical trial with brenetafusp in first-line, advanced cutaneous melanoma

Phase 1/2 clinical trials of brenetafusp and IMC-P115C (PRAME-A02 Half-Life Extended) in multiple solid tumors

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The Company expects to present initial data in 2027.

The Company’s bispecific TCR technology platform has the potential to offer a new approach for the treatment of certain chronic infections and aims to eliminate evidence of remaining virus in circulation after the patient stops taking medication – known as a ‘functional cure’. The Company is studying an investigational candidate for people living with human immunodeficiency virus (HIV).

Phase 1/2 trial of IMC-M113V (Gag-A02) for people living with HIV

The key differentiator of the ImmTAAI platform is tissue-specific, down modulation of the immune system, as the candidates suppress pathogenic T cells via PD1 receptor agonism only when tethered to the target tissue.

The Company will present the following two posters at the 2026 American Society of Clinical Oncology Meeting:

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, regardless of mutational burden or immune infiltration, including immune “cold” low mutation rate tumors.

ImmTAV (Immune mobilizing monoclonal TCRs Against Virus) molecules are novel bispecifics that are designed to enable the immune system to recognize and eliminate virally infected cells. Immunocore is advancing a clinical candidate, aiming to achieve sustained control of HIV after people living with HIV stop anti-retroviral therapy (ART), without the risk of virological relapse or onward transmission. This is known as ‘functional cure’.

ImmTAAI (Immune mobilizing monoclonal TCRs Against AutoImmune disease) molecules are novel bispecifics that are designed for tissue-specific down modulation of the immune system. When tethered to the tissue of interest, ImmTAAI candidates suppress pathogenic T cells via PD1 receptor agonism. The Company is currently advancing two candidates for autoimmune diseases, including type 1 diabetes and inflammatory dermatological diseases.

The Phase 3 registrational trial is randomizing HLA-A*02:01-positive patients with previously untreated, advanced or metastatic cutaneous melanoma, to brenetafusp 160 mcg + nivolumab or a control arm of either nivolumab or nivolumab + relatlimab. The primary endpoint of the trial is progression free survival (PFS) by blinded independent central review (BICR), with secondary endpoints of overall survival (OS) and overall response rate (ORR).

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. The Phase 1 dose escalation 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), a bispecific protein built on Immunocore’s ImmTAC technology, and the Company’s first molecule to target the PRAME antigen. The Company is currently focusing on enrolling patients in combination arms with standards-of-care across multiple tumor types.

The trial is randomizing patients with second-line or later advanced cutaneous melanoma who have progressed on an anti-PD1, received prior ipilimumab and, if applicable, received a BRAF kinase inhibitor. Patients are randomized to one of three arms, including tebentafusp – as monotherapy or in combination with an anti-PD1 – or a control arm. The primary endpoint is overall survival.

The EORTC-sponsored Phase 3 clinical trial will include sites in 10 EU countries and the United States and is randomizing HLA-A*02:01-positive patients with high-risk primary uveal melanoma after definitive treatment, by surgery or radiotherapy, and no evidence of metastatic disease on imaging. The trial is expected to enroll a total of 290 patients who will be randomized 1:1 to one of two arms: tebentafusp as monotherapy or observation. The primary endpoint of the trial is relapse-free survival (RFS), with secondary objectives of overall survival and safety and tolerability of tebentafusp. Exploratory objectives include the comparison of the health-related quality of life between the treatment arms and the evaluation of the role of circulating tumor DNA (ctDNA) as a biomarker for the presence of residual disease.

Uveal melanoma is a rare and aggressive form of melanoma, which affects the eye. This is the most common primary intraocular malignancy in adults and up to 50% of people with uveal melanoma will eventually develop metastatic disease. Unresectable or metastatic uveal melanoma typically has a poor prognosis and had no approved treatment until KIMMTRAK.

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 but 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.

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.

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).

Immunocore is committed to helping patients who need KIMMTRAK obtain access via its KIMMTRAKConnect program. The US program provides services with dedicated nurse case managers who provide personalized support, including educational resources, financial assistance, and site of care coordination. To learn more, visit KIMMTRAKConnect.com or call 844-775-2273.

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.

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 Company’s ability to reach more patients for KIMMTRAK, including continued U.S. community and global market penetration in mUM, the potential expansion into 2L+ advanced cutaneous melanoma, and the potential expansion into adjuvant uveal melanoma; the Company’s ability to grow and advance its clinical pipeline; the estimated size of the patient populations for the Company’s product candidates; expectations regarding the design, progress, timing, enrollment, randomization, scope, expansion, and results of the Company’s and its collaborators’ existing and planned clinical trials; the timing and sufficiency of clinical trial outcomes to support potential approval of any of the Company’s product candidates or those of, or combined with, its collaboration partners; the expected submission of clinical trial applications or investigational new drug applications; the potential regulatory approval, and expected clinical benefits and availability of the Company’s product candidates. 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.

Immunocore

Sébastien Desprez, Head of Communications

T: +44 (0) 7458030732

E: sebastien.desprez@immunocore.com

Follow on LinkedIn: @Immunocore

Investor Relations

Morgan Morse

T: +1 (215) 384-4781

E: ir@immunocore.com

Immunocore Holdings plc

Condensed Consolidated Statement of Operations

Comparison of the Quarters Ended March 31, 2026 and 2025

(In thousands, except share and per share data)

(Unaudited)

Immunocore Holdings plc

Condensed Consolidated Balance Sheets

As of March 31, 2026 and December 31, 2025

(In thousands)

(Unaudited)

Immunocore Holdings plc

Summary Condensed Consolidated Statements of Cash Flows

For the Three Months Ended March 31, 2026 and 2025

(In thousands)

(Unaudited)

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