TScan Therapeutics, Inc. 8-K

What Happened
On June 22, 2026, TScan Therapeutics (TCRX) filed a Form 8-K and issued a press release and updated presentation reporting initial results from Cohort C of the ongoing ALLOHA™ Phase 1 study of TSC-101 in patients with hematologic (heme) malignancies undergoing allogeneic hematopoietic cell transplantation (HCT). The cohort used the commercial-ready manufacturing process.

Key Details

• 19 patients enrolled in Cohort C; manufacturing success ~90% (17/19) with the commercial-ready process.
• 14 of 19 patients proceeded to transplant and received their first TSC-101 infusion; 10 of those 14 received the planned second infusion and 1 received a third. Three patients did not proceed to transplant for clinical reasons.
• Chimerism (measured by high-sensitivity NGS assay "Alloheme", assay cut-off 0.2%): 11 of 14 patients achieved complete donor chimerism within ~3 weeks of the first TSC-101 infusion; 2 of the remaining 3 are approaching complete donor chimerism.
• One patient with TP53‑mutated AML remained in complete donor chimerism 6 months post-HCT.
• TSC-101 infusions were generally well-tolerated; safety profile was consistent with Cohort A and with expected post‑HCT adverse events.
• Company filed Exhibits 99.1 (press release) and 99.2 (updated presentation) with the Form 8‑K.

Why It Matters
These are early clinical and manufacturing-readiness data reported by TScan showing high manufacturing success with the commercial-ready process and rapid achievement of donor chimerism in most treated patients—metrics the company highlights as important for its heme malignancies program. Investors should note the data are initial and from a small cohort; the filing also includes the company's forward‑looking statements and risk disclosures.