On December 9, 2024 TScan Therapeutics, Inc. (Nasdaq: TCRX), a clinical-stage biotechnology company focused on the development of T cell receptor (TCR)-engineered T cell (TCR-T) therapies for the treatment of patients with cancer, reported that updated results from the ongoing ALLOHA Phase 1 trial of TSC-100 and TSC-101 will be presented during an oral session at the 66th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition (Press release, TScan Therapeutics, DEC 9, 2024, View Source [SID1234648995]). TSC-100 and TSC-101 are designed to treat residual disease and prevent relapse in patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic cell transplantation (HCT) with reduced intensity conditioning.
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"Disease relapse is the leading cause of death in patients undergoing transplant following reduced intensity conditioning and represents a significant unmet medical need," said Chrystal U. Louis, M.D., Chief Medical Officer. "As the majority of patients enrolled in both the treatment and control arms were considered at very high risk for relapse, we are highly encouraged by the preliminary ALLOHA study results, which suggest that TSC-100 and TSC-101 have the potential to eliminate residual disease and prevent relapse in patients with AML, ALL, or MDS post-HCT."
"We are very excited by these data and, based on these results, we intend to launch a pivotal trial in the second half of 2025," said Gavin MacBeath, Ph.D., Chief Executive Officer. "Following recent feedback from the FDA, we believe we have a clear development path and will share our plans at our KOL event tomorrow morning."
In the ongoing ALLOHA Phase 1 trial (NCT05473910), patients receive either TSC-100 or TSC-101 post-HCT, whereas control-arm patients receive HCT alone as per standard of care. To date, 38 patients have been enrolled in the trial and undergone HCT, with 26 in the treatment arm and 12 in the control arm. The key endpoints in the trial are safety and efficacy, with exploratory endpoints including donor chimerism and minimal residual disease (MRD) status.
Key Presentation Highlights:
To date, event-free survival strongly favors the treatment arm (HR=0.30; p=0.04) and early trends suggest a lower probability of relapse (HR=0.28; p=0.14).
2 of 26 (8%) treatment-arm patients relapsed compared to 4 of 12 (33%) control-arm patients. One treatment-arm relapse and subsequent mortality occurred in a very high-risk patient who was taken to transplant without first achieving complete remission, and the other was an extramedullary relapse in the patient’s central nervous system with no evidence of systemic relapse.
Median time to relapse was not evaluable in the treatment arm versus 160 days in the control arm.
8 of 38 (21%) patients in the study had TP53 mutations, with 6 cases in the treatment arm and 2 cases in the control arm. Of the 4 patients in the treatment arm with these mutations who received TCR-T cell infusions, none has relapsed, and one patient has now been relapse-free for 22 months. Of the 2 patients in the control arm with mutated TP53, both relapsed within 6 months of transplant and died shortly thereafter.
TSC-100 and TSC-101 infusions were well-tolerated at all three dose levels with no dose-limiting toxicities. Observed adverse events were similar across the treatment and control arms and were generally consistent with post-HCT adverse events.
TSC-100 and TSC-101 TCR-T cells were detected at all timepoints in all treated patients, including those who have been on study for over a year, with clear evidence of a dose-persistence relationship.
A copy of the presentation materials will be made available on the "Publications" section of the Company’s website at tscan.com once the presentation has concluded.
Virtual Key Opinion Leader (KOL) Event
The Company will host a virtual KOL event featuring Ran Reshef, M.D., M.Sc., on Tuesday, December 10, 2024, at 8:00 a.m. ET to discuss the data presented at ASH (Free ASH Whitepaper), updates with regards to a potential registrational path for the program following its initial meeting with the U.S. Food and Drug Administration, as well as future plans to expand the program, in addition to an update on the Company’s PLEXI-T Phase 1 solid tumor trial.
Dr. Reshef is the Professor of Medicine and Director of the Cellular Immunotherapy Program at Columbia University Irving Medical Center. Details for attending the event can be found here.