Data Updates from Ongoing MAGE-A10 Studies and MAGE-A4 Study to be presented at the European Society for Medical Oncology (ESMO) 2018 Congress

October 8, 2018

PHILADELPHIA and OXFORD, United Kingdom, Oct. 08, 2018 (GLOBE NEWSWIRE) -- Adaptimmune Therapeutics plc (“Adaptimmune”) (Nasdaq: ADAP), a leader in T-cell therapy to treat cancer, today announced further details about two poster presentations at the upcoming ESMO congress, as follows:

MAGE-A10 poster for discussion presentation details:

-- A late-breaking abstract with data from the two ongoing MAGE-A10 studies (“triple tumor” and lung) was accepted for poster discussion, with the full abstract and data to be made available at the time of presentation. -- Title: Safety and Anti-Tumor Effects of MAGE-A10c796TCR T-cells in Two Clinical Trials (Poster #LBA38) -- Poster discussion session: Immuno 1 in ICM room 14b -- Time: Saturday, October 20 from 16:45 to 17:45 CEST (10:45 to 11:45 EDT)

MAGE-A4 poster presentation details:

-- The full abstract for the MAGE-A4 poster is now available online (https://bit.ly/2NMBC3d) and is summarized below -- Title: Initial Safety Assessment of MAGE-A4 SPEAR T-cells (Poster #1156P) -- Poster display session (ID 259): Immunotherapy of cancer in Hall A3 poster networking Hub -- Time: Saturday, October 20 from 12:30 to 13:30 CEST (06:30 to 07:30 EDT)

Brief summary of abstract (data cut-off 25 April 2018):Background:

-- Ongoing study (NCT03132922) to evaluate safety and tolerability of SPEAR T-cells directed towards a MAGE-A4 peptide expressed on tumors in the context of HLA-A*02


-- Modified 3+3 design -- Patients have inoperable or metastatic (advanced) non-small cell lung cancer (NSCLC), urothelial (“bladder”), melanoma, synovial sarcoma, myxoid/round cell liposarcoma (MRCLS), head & neck, ovarian, gastric, or esophageal cancers expressing MAGE-A4 -- Lymphodepletion regimen: o Cohorts 1, 2: [fludarabine (Flu) 30 mg/m2/day and cyclophosphamide (Cy) 600 mg/m2/day] x 3 days o Cohort 3: [Flu 30 mg/m2/day] x 4 days + [Cy 600 mg/m2/day] x 3 days o Expansion Cohort: [Flu 30 mg/m2/day] x 4 days + [Cy 600 mg/m2/day] x 3 days -- Dose: o Cohort 1: target 100 million (M) transduced cells; range 80 to 120 M transduced cells o Cohort 2: target 1 billion (B) transduced cells; range 0.5 to 1.2 B transduced cells o Cohort 3: target 5 B transduced cells; range 1.2 to 6.2 B transduced cells o Expansion Cohort: target 5 B transduced cells; range 1.2 to 10 B transduced cells


-- Three patients were treated with 100 M MAGE-A4 SPEAR T-cells, and transduced cells were detectable in peripheral blood -- Adverse events (AEs) for the first 2 patients reported at grade (G) ≥3 included anemia, hypoglycemia, hyponatremia, lymphopenia, neutropenia, and thrombocytopenia -- Serious AEs included G4 hyponatremia, G3 atrial fibrillation, G3 syncope (unrelated to T-cell therapy), G1 CRS and G2 encephalopathy syndrome (both related), and G2 generalized muscle weakness (possibly related) -- None of the events were considered dose limiting toxicities (DLTs) by the Safety Review Committee


-- MAGE-A4 SPEAR T-cells at the 100 M transduced cell dose appear to show no evidence of on‑target or off-target toxicity -- Preliminary data support continued investigation of the T-cell receptor (TCR), and this trial is ongoing

About AdaptimmuneAdaptimmune is a clinical-stage biopharmaceutical company focused on the development of novel cancer immunotherapy products. The Company’s unique SPEAR (Specific Peptide Enhanced Affinity Receptor) T‑cell platform enables the engineering of T-cells to target and destroy cancer, including solid tumors. Adaptimmune is currently conducting clinical trials with SPEAR T-cells targeting MAGE-A4, MAGE-A10, and AFP across multiple solid tumor indications. The Company is located in Philadelphia, USA and Oxfordshire, U.K. For more information, please visit http://www.adaptimmune.com

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 Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) on August 2, 2018, and our other SEC filings. 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, Communications and Investor RelationsT: +44 1235 430 583M: +44 7718 453 176 Sebastien.Desprez@adaptimmune.com

Investor Relations: Juli P. Miller, Ph.D. – Director, Investor RelationsT: +1 215 825 9310M: +1 215 460 8920 Juli.Miller@adaptimmune.com

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