Consistent Cohort C Results Significantly Derisk The Upcoming Phase III

Research evidence excerpt

Consistent Cohort C Results Significantly Derisk The Upcoming Phase III

TD Cowen TScan Therapeutics

Global Research June 22, 2026

There was one other patient (Patient 3) that achieved a complete chimerism response initially,

but subsequently developed mixed chimerism. This patient was incredibly difficult-to-treat

with MECOM-rearranged AML, which the KOL noted typically has a 3% survival rate. Therefore,

the KOL was impressed that this patient even achieved an initial response. Additionally,

the company treated this patient at DL3, which was per protocol as this patient was the

first in Cohort C to have a mismatched unrelated donor. The four remaining patients with

mismatched unrelated donors in Cohort C achieved complete chimerism at 3 weeks with DL4.

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These Strong Results Are Even More Impressive Given The Difficult-To-Treat Nature Of These

Patients

These results are particularly impressive when considering the difficult to treat nature of

these patients based on MRD positivity and TP53 mutations. Notably, in Cohort C, only

14% of patients (n=2/14) achieved complete chimerism immediately following transplant,

compared to 37% (n=7/19) in Cohort A and 24% (n=4/17) in the control arm. Additionally, 75%

(n=9/12) patients were MRD+ post-transplant compared to 63% in Cohort A and 53% in the

control arm. Lastly, 21% (n=3/14) of patients had TP53 mutations, which is typically a negative

prognosticator for long-term survival. The KOL reaffirmed this by stating that they have a

difficult time prescribing transplants to patients with TP53 mutations due to the uncertainty of

responses; however, strong results in these patients would be viewed even more positively.

101's Favorable Safety Profile Supports Outpatient Administration Of The Second Dose