TScan Therapeutics (TCRX) H.C. Wainwright 4th Annual Cell Therapy Virtual Conference summary

Pipeline overview and clinical progress

• Lead program targets heme malignancies post-bone marrow transplant, aiming to prevent relapse; phase III trial launching this month after FDA agreement on pivotal design.

• Solid tumor program uses in vivo T cell engineering with lentiviral particles, targeting antigens like PRAME and MAGE-A4; clinical entry expected mid-next year.

• Early donor chimerism is a strong predictor of long-term relapse-free survival, supported by sensitive assays and external validation.

• Cohort A shows mature, long-term data with 100% relapse-free survival at three years versus 0% in control; cohort C uses a new manufacturing process and includes higher-risk patients.

• Cohort C data, though less mature, shows no relapses to date among a higher proportion of MRD-positive patients.

Manufacturing and process improvements

• Transitioned from a 17-day magnetic bead-based process to a 12-day drug selection process, improving efficiency and reducing costs.

• New process yields younger, more active T cells with higher proliferation and activation markers, potentially enhancing clinical outcomes.

Pivotal trial design and regulatory alignment

• Pivotal trial excludes ALL patients, focuses on AML and MDS, and allows broader donor types for accessibility.

• Biological assignment (HLA-A*02:01 status) replaces randomization; large CIBMTR database analysis shows no outcome difference between arms.

• Stratification by disease and genotype, with interim checks at 50% enrollment to ensure balance between arms.

• Maintenance therapies allowed with timing adjustments to avoid interference with T cell therapy.