Adaptimmune’s pivotal Phase II trial of its investigational T cell therapy lete-cel has met its primary endpoint, with the company now eyeing up its second sarcoma approval. 

UK-based Adaptimmune will submit a rolling Biologics License Application (BLA) to the US Food and Drug Administration (FDA) for lete-cel for the treatment of advanced or metastatic synovial sarcoma and myxoid/round cell liposarcoma (MRCLS) by the end of 2025.  

Data from the Phase II IGNYTE-ESO trial (NCT03967223) showed that 42% of patients treated with lete-cel achieved a response. In synovial sarcoma, the median response lasted for 18.3 months, while in MRCLS, the median response was 12.2 months. All patients experienced treatment-emergent adverse events (TEAEs), including cytopenia, cytokine release syndrome and rash. Adaptimmune said that safety findings were consistent with previous data, showing no unexpected adverse events. 

The primary analysis of the IGNYTE-ESO trial comprises data from 64 patients with either synovial sarcoma or MRCLS. Investigators will share detailed results from the trial on 16 November at the Connective Tissue Oncology Society (CTOS) 2024 annual meeting in San Diego, US. 

Synovial sarcoma and MRCLS are rare and often aggressive cancers with limited treatment options. Synovial sarcoma is a soft tissue cancer that arises in the limbs, primarily affecting young adults. MRCLS is a subtype of liposarcoma that can spread quickly and prove challenging to treat with conventional methods like surgery, chemotherapy, and radiotherapy.  

Adaptimmune is on its way to building a portfolio of sarcoma treatments. The company achieved its first FDA approval in August 2024 for Tecelra (afami-cel), a T cell receptor (TCR) therapy for adults with metastatic synovial sarcoma. This approval marked several firsts, including the first engineered cell therapy for solid tumours, and the first new therapy for synovial sarcoma in over a decade. 

According to a GlobalData analyst, the approval of lete-cel would multiply the US addressable market by 2.5 times, from 400 patients annually with Tecelra to 1,000. The treatments could be combined or administered sequentially, as lete-cel targets another antigen. 

GlobalData is the parent company of Pharmaceutical Technology. 

Adaptimmune has actively engaged in several partnerships to bolster its position in the cell therapy space. In 2021, the company teamed up with Roche’s subsidiary Genentech on T cell therapy development – a five-year agreement with a potential value exceeding $3bn. However, Genentech walked away from the partnership in April 2024 for reasons that were not disclosed. The cell therapy company quickly pivoted, securing a $665m deal with Galapagos just seven weeks later. This deal, including a $100m upfront payment, granted Adaptimmune rights to uza-cel, a MAGE-A4 T cell therapy. 

The company has further partnered with Agilent Technologies to develop the MAGE-A4 ICH 1F9 pharmDx companion diagnostic, which won FDA approval in August, as well as with Thermo Fisher Scientific to include Tecelra in the labelling for their SeCore CDx HLA-A Locus Sequencing System.