Immunocore presents new data on tebentafusp in metastatic cutaneous melanoma (mCM) and uveal melanoma (mUM) at the Society for Immunotherapy of Cancer (SITC) 36th Annual Meeting

PRESS RELEASE RESS RELEASE

Immunocore presents new data on tebentafusp in metastatic cutaneous melanoma (mCM) and uveal melanoma (mUM) at the Society for Immunotherapy of Cancer (SITC) 36th Annual Meeting

Tebentafusp in combination with checkpoint inhibitors had acceptable safety profile; preliminary evidence of clinical activity in anti-PD(L)1 relapsed/refractory mCM

Survival benefit for tebentafusp monotherapy in mUM observed for both high and low gp100 protein tumor expression

(OXFORDSHIRE, England & CONSHOHOCKEN, Penn. & ROCKVILLE, Md., US, 9 November 2021) Immunocore Holdings Plc (Nasdaq: IMCR), a late-stage biotechnology company pioneering the development of a novel class of T cell receptor (TCR) bispecific immunotherapies designed to treat a broad range of diseases, including cancer, infectious and autoimmune disease, will present six posters at the Society for Immunotherapy of Cancer (SITC) 36^th Annual Meeting, to be held in Washington, D.C. and virtually between November 10-14^th.

The Company will present a Phase 1b study of tebentafusp in combination with durvalumab (anti-PDL1) and/or tremelimumab (anti-CTLA4) in metastatic cutaneous melanoma (mCM) and new clinical data analyzing gene expression and overall survival from the metastatic uveal melanoma (mUM) tebentafusp monotherapy program. Four additional posters depicting new analyses from tebentafusp in metastatic uveal melanoma, as well as the Company’s proprietary soluble TCR bispecific ImmTAC® platform will be made available for on-demand viewing throughout the SITC 36^th Annual Meeting on the SITC website.

In a phase 1b trial in mCM of tebentafusp in combination with checkpoint inhibitors, in which the majority of patients had previously received prior anti-PD(L)1 therapy, the maximum target doses of tebentafusp (68 mcg) plus durvalumab (20 mg/kg) with and with/out tremelimumab (1 mg/kg) were tolerated in both doublet and triplet arms of the study. Preliminary evidence of tebentafusp clinical activity in mCM patients who received prior anti-PD(L)1 therapy, currently an unmet medical need, included 1-year overall survival (OS) rate of 76%. In mCM patients who were refractory (defined as best response of progressive disease) to prior anti-PD(L)1, the 1-year OS rate was 61%.

“At SITC, we build upon our previously released survival data in metastatic uveal melanoma with the clinical results of tebentafusp in combination with checkpoint inhibitors in metastatic cutaneous melanoma patients who previously received anti-PD(L)1 therapy. In this population with poor prognosis, and which is an unmet need, treatment with tebentafusp in combination with checkpoints resulted in a 76% one-year overall survival rate” said David Berman, Head of Research and Development at Immunocore.

In a new analysis of baseline gp100 protein expression by immunohistochemistry of tumor biopsies from the Phase 2 and Phase 3 tebentafusp monotherapy mUM trials, OS benefit was observed for both high and low gp100 protein tumor expression. Additionally, circulating tumor DNA (ctDNA) reductions were also observed for both high and low gp100 protein tumor expression, while high gp100 expression at baseline was associated with greater T cell infiltration into the tumor and greater IFNg, granzyme B and perforin expression.

“We are encouraged that the survival benefit from tebentafusp in metastatic uveal melanoma was independent of baseline gp100 tumor expression in this new analysis based on immunohistochemistry. This benefit, apparent even in patients with low gp100 protein expression, may reflect the high sensitivity of our TCR bispecific platform, which may be able to recognize cancer cells with very low target expression” said David Berman.

POSTER PRESENTATIONS

Title: Overall survival on tebentafusp in metastatic uveal melanoma (mUM) across the range of tumor gp100 expression levels

• Poster #: 868

• Author: Emma Leach

• Location: Poster Hall (Hall E)

• Date & Time: November 13^th - 12:30-2:00 pm and 7:00-8:30 pm ET

Title: Results from Phase Ib study of tebentafusp (tebe) in combination with durvalumab (durva) and/or tremelimumab (treme) in metastatic cutaneous melanoma

• Poster #: 546

• Author: Omid Hamid

• Location: Poster Hall (Hall E)

• Date & Time: November 13^th - 12:30-2:00 pm and 7:00-8:30 pm ET

Title: Updated survival of patients with previously treated metastatic uveal melanoma who received tebentafusp

• Poster #: 538

• Author: Joseph J. Sacco

Title: Selective affinity-enhanced T cell receptor bispecific targeting of KRAS^G12D neoantigen driven cancers

• Poster #: 882

• Author: Andrew Poole

• Location: Poster Hall (Hall E)

• Date & Time: November 13^th - 12:30-2:00 pm and 7:00-8:30 pm ET

Title: IL-2 Combination with ImmTAC Overcomes CD163+ Macrophage Inhibition of Redirected T Cell Killing of Tumour Cells

• Poster #: 571

• Author: Esra Güç

• Location: Poster Hall (Hall E)

• Date & Time: November 12^th - 12:40-2:10 pm and 7:00-8:30 pm ET

Title: Radiomic Markers Associated with Clinical Benefit in Advanced Uveal Melanoma Patients with Radiographic Progression on Tebentafusp

• Poster #: 819

• Author: Volkan Beylergil

Virtual ePosters presented at the conference will be made available throughout the SITC 36^th Annual Meeting on the SITC website.

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About Immunocore

Immunocore is a late-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, infectious and autoimmune. Leveraging its proprietary, flexible, off-the-shelf ImmTAX platform, Immunocore is developing a deep pipeline in multiple therapeutic areas, including five clinical stage programs in oncology and infectious disease, advanced pre-clinical programs in autoimmune disease and multiple earlier pre-clinical programs. Immunocore’s most advanced oncology therapeutic candidate, tebentafusp, has demonstrated an overall survival benefit in a randomized Phase 3 clinical trial in metastatic uveal melanoma, a cancer that has historically proven to be insensitive to other immunotherapies.

About Tebentafusp

Tebentafusp is a novel bispecific protein comprised of a soluble T cell receptor fused to an anti-CD3 immune-effector function. Tebentafusp specifically targets gp100, a lineage antigen expressed in melanocytes and melanoma, and is the first molecule developed using Immunocore’s ImmTAC technology platform designed to redirect and activate T cells to recognise and kill tumour cells. Tebentafusp has been granted Priority Review; Real Time Oncology Review; Breakthrough Therapy designation; Fast Track designation; and orphan drug designation by the FDA in the United States; orphan drug status in the European Union; and Promising Innovative Medicine (PIM) designation under the UK Early Access to Medicines Scheme for metastatic uveal melanoma. Tebentafusp has also been granted accelerated assessment by the EMA’s CHMP. Tebentafusp is being reviewed under the FDA’s Project Orbis initiative, which enables concurrent review by the health authorities in partner countries that have requested participation. For more information about enrolling in tebentafusp clinical trials for metastatic uveal melanoma, please visit ClinicalTrials.gov (NCT03070392).

About ImmTAC^® Molecules

Immunocore’s proprietary T cell receptor (TCR) technology generates a novel class of bispecific biologics called ImmTAC (Immune mobilising monoclonal TCRs Against Cancer) molecules that are designed to redirect the immune system to recognise and kill cancerous cells. ImmTAC molecules are soluble TCRs engineered to recognise 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 tumours, the ImmTAC mechanism of action holds the potential to treat hematologic and solid tumours, regardless of mutational burden or immune infiltration, including immune “cold” low mutation rate tumours.

About Uveal Melanoma

Uveal melanoma is a rare and aggressive form of melanoma, which affects the eye. Metastatic uveal melanoma typically has a poor prognosis and has no currently accepted optimal management or treatment. Although it is the most common primary intraocular malignancy in adults, the diagnosis is rare, with approximately 8,000 new patients diagnosed globally each year (1,600-2,000 cases per year in the United States). Up to 50% of people with uveal melanoma will eventually develop metastatic disease. When the cancer spreads beyond the eye, only approximately half of patients will survive for one year.

Forward Looking Statements

This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including, but are not limited to, statements regarding the efficacy, safety and therapeutic potential of tebentafusp; the clinical development of tebentafusp; and the expected benefits of tebentafusp including that tebentafusp would be a therapeutic option treatment for metastatic uveal melanoma. Any forward-looking statements are based on management’s current expectations of future events and are subject to a number of risks and uncertainties that could cause actual 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 impacts of the COVID-19 pandemic on the Company’s business, clinical trials and financial position; unexpected safety or efficacy data observed during preclinical studies or clinical trials; clinical trial site activation or enrolment rates that are lower than expected; the risk that initial or interim results from a clinical trial may not be predictive of the final results of the trial or the results of future trials; changes in expected or existing competition; changes in the regulatory environment; and the uncertainties and timing of the regulatory approval process. For a discussion of other risks and uncertainties, and other important factors, any of which could cause our actual results to differ from those contained in the forward-looking statements, see the section titled “Risk Factors” in the Company’s Annual Report on Form 20-F for the year ended December 31, 2020 filed with the Securities and Exchange Commission on March 25, 2021, as well as discussions of potential risks, uncertainties, and other important factors in the Company’s subsequent filings with the Securities and Exchange Commission. 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:

Immunocore
Debra Nielsen, Head of Communications
T: +1 (610) 368-8602
E: debra.nielsen@immunocore.com
Follow on Twitter: @Immunocore

Consilium Strategic Communications (corporate and financial)
Mary-Jane Elliott/ Chris Welsh/ Jessica Hodgson
T: +44 (0)203 709 5700
E: Immunocore@consilium-comms.com

Investor Relations
Clayton Robertson, Head of Investor Relations
T: +1 215-384-4781
E: ir@immunocore.com