TScan Therapeutics, Inc. announced that the U.S. Food and Drug Administration (FDA) has cleared its investigational new drug (IND) applications for T-Plex, TSC-204-A0201, and TSC-204-C0702. T-Plex will now serve as the primary IND for TScan's solid tumor program, enabling customized combinations of TCR-Ts to be administered to patients based on the targets and HLAs expressed in their tumors. The specific TCRs for each patient will be chosen from the Company's ImmunoBank, consisting of high-affinity, naturally occurring TCRs that recognize a variety of prevalent cancer-specific targets and are associated with various common HLA types.

Each unique TCR-T will be filed as a secondary IND and will reference the primary T-Plex IND. In addition to the T-Plex IND, TScan filed secondary INDs for two initial TCR-T products, TSC-204-A0201 and TSC-204-C0702, that target melanoma-associated antigen 1 (MAGE-A1) on HLA types A*02:01 and C*07:02. MAGE-A1 is a cancer-associated antigen overexpressed in 45% of head and neck cancers and 50% of melanoma, cervical, and non-small cell lung cancers.

TScan believes that TSC-204-C0702 is the first clinical program in MAGE-A1 for an HLA type other than A*02:01. With these INDs cleared, TScan is now working to open a multicenter Phase 1 clinical trial to establish the safety, preliminary efficacy, and feasibility of repeat dosing of multiplexed TCR-T. The trial will include patients with non-small cell lung cancer, melanoma, head and neck cancer, ovarian cancer, and cervical cancer. In the Phase 1 trial design, each TCR-T will initially be evaluated as singleplex therapy at two successive dose levels.

Once single agent safety is established, each TCR becomes eligible for combination with any other TCR that has passed this threshold. The protocol has an interval 3+3 design, potentially allowing for a rapid path to multiplexing. The trial design also features a screening protocol, which pre-identifies patients whose tumors have a combination of targets and HLAs that would qualify them for the interventional study.

The screening protocol is expected to initiate in second quarter 2023.