Adaptimmune Presents MAGE-A4 Expression Data from its Screening Protocol at AACR Confirming Expression Across a Broad Range of Solid Tumors

Adaptimmune Therapeutics plc (Nasdaq: ADAP), a leader in cell therapy to treat cancer, presented data from the multinational, multicenter, screening protocol (NCT02636855) at the American Association for Cancer Research (AACR) annual meeting in a poster entitled “Identifying MAGE-A4-Positive Tumors for SPEAR T-Cell Therapies in HLA-A*02–Eligible Patients”.

“This large clinical dataset continues building the science around MAGE-A4 expression, and provides a broad, real-world understanding of patient eligibility for our clinical trials with SPEAR T-cell therapies targeting MAGE-A4,” said Elliot Norry, Adaptimmune’s Chief Medical Officer. “This information confirms the potential of our MAGE-A4 franchise and our continued commitment to patients and clinicians.”

The screening protocol prospectively evaluated HLA types and MAGE-A4 expression levels to determine eligibility for the Company’s clinical trials with SPEAR T-cells targeting MAGE-A4 across a broad range of solid tumors. To be eligible, patients are required to be HLA-A*02 positive1 and tumor samples need to meet protocol-defined MAGE-A4 expression levels2 . Data were collected for screening in the Phase 1 trial of afami-cel (formerly ADP-A2M4; closed to enrollment) as well as the ongoing Phase 1 SURPASS trial.

Results from this large dataset are consistent with data previously shared by the Company and support MAGE-A4 as an important cancer target within the tumor types currently included in ongoing clinical trials of afami-cel and ADP-A2M4CD8.

Across sites in the US, Canada, and Spain, a total of 6167 patients had their HLA-A type accurately determined and 2729 (44.3%) were eligible based on protocol-defined criteria. Among HLA-eligible patients, 1543 had tumor samples evaluable for MAGE-A4 with 313 (20%) meeting the requirements for MAGE-A4 expression.

The rate of eligible MAGE-A4 expression levels was highest in synovial sarcoma (67%) and ranged from 20% to 35% across the following solid tumor indications: squamous small cell lung (35%); bladder (32%), esophagogastric junction (26%), ovarian (24%), head and neck squamous cell (22%), and esophageal (21%) cancers.

About AdaptimmuneAdaptimmune is a clinical-stage biopharmaceutical company focused on the development of novel cancer immunotherapy products for people with cancer. The Company’s unique SPEAR (Specific Peptide Enhanced Affinity Receptor) T-cell platform enables the engineering of T-cells to target and destroy cancer across multiple solid tumors. 

Forward-Looking StatementsThis release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 (PSLRA). These forward-looking statements involve certain risks and uncertainties. Such risks and uncertainties could cause our actual results to differ materially from those indicated by such forward-looking statements, and include, without limitation: the success, cost and timing of our product development activities and clinical trials and our ability to successfully advance our TCR therapeutic candidates through the regulatory and commercialization processes. For a further description of the risks and uncertainties that could cause our actual results to differ materially from those expressed in these forward-looking statements, as well as risks relating to our business in general, we refer you to our Annual Report on Form 10-K filed with the Securities and Exchange Commission for the year ended December 31, 2021, our Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and other filings with the Securities and Exchange Commission. The forward-looking statements contained in this press release speak only as of the date the statements were made and we do not undertake any obligation to update such forward-looking statements to reflect subsequent events or circumstances.

Adaptimmune Contacts:

Media Relations:

Sébastien Desprez — VP, Corporate Affairs and CommunicationsT: [phone]M: [phone] [e-mail]

Investor Relations:

Juli P. Miller, Ph.D. — VP, Investor RelationsT: [phone]M: +1 215 460 [e-mail]

__________________1 HLA-A*02:01P, 02:02P, 02:03P, and 02:06P alleles are eligible; A*02:05P is excluded2 MAGE-A4 expression level is defined by protein (P) score, which is the percentage of tumor cells staining at 2+, 3+ by immunohistochemistry (IHC) using the clinical trial assay. Tumor samples with P scores ≥30% are considered eligible per protocol. Of note, P score is a quantification used internally at Adaptimmune. H-score is assessed as part of the Company’s translational research but is not used for eligibility.