TScan Therapeutics (TCRX) Study update summary

Strategic program updates

• Resources and strategic focus have shifted to in vivo TCR-T therapies for solid tumors, advancing PRAME and MAGE-A4 candidates into IND-enabling studies, with Phase 1 trials planned for Q4 2027.

• Heme malignancy and autoimmune programs are paused or on hold due to funding constraints, with ongoing patient follow-up and efforts to secure strategic partnerships.

• Workforce reduced by approximately 75% and internal manufacturing eliminated, resulting in $55 million in expected cost savings and extending the financial runway into Q4 2027.

Solid tumor program and technology

• Developed an in vivo lentiviral platform for efficient TCR gene delivery, eliminating patient-specific manufacturing and reducing costs.

• Lead candidates target PRAME (expressed in >90% of melanomas) and MAGE-A4 (prevalent in multiple cancers), addressing high unmet need.

• Preclinical models show in vivo-engineered TCR-Ts clear tumors as effectively as ex vivo products at lower doses.

• In vivo approach offers permanent T cell engineering, rapid expansion, and potential for long-term immune surveillance.

• Preclinical data and regulatory updates are expected in Q1 2027, with IND filing in Q3 2027 and Phase 1 trial initiation in Q4 2027.

Heme malignancy program update

• TSC-101 targets residual disease post-allogeneic HCT in high-risk AML, MDS, and ALL patients.

• Cohort C (14 patients) showed 79% relapse-free survival at six months, with all achieving complete donor chimerism.

• TSC-101 demonstrated a strong safety profile, with adverse events consistent with standard transplant procedures and no dose-limiting toxicities.

• Enrollment in the Phase 3 ALLOHA-2 study is paused due to capital constraints, but ongoing patient follow-up continues.

• Six-month data to be presented in Q4 2024; one-year follow-up data on 21 patients expected in Q2 2025.