On June 3, 2026 TransCode Therapeutics, Inc. (NASDAQ: RNAZ) a clinical stage company pioneering immuno-oncology and RNA for the treatment of high risk and advanced cancer, reported further results of the Phase 1a dose escalation clinical trial. The trial met its primary endpoint of safety, with positive tolerability, combined with disease stabilization in multiple patients, and the absence of dose-limiting toxicities with its lead therapeutic candidate TTX-MC138. TTX-MC138, an investigational inhibitor of the key metastatic driver, microRNA-10b, has shown durable disease control. These findings support advancing TTX-MC138 into Phase 2a clinical development to assess efficacy in patients with circulating tumor DNA (ctDNA) positive colorectal cancer following curative–intent therapy.
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TTX-MC138 has been administered to 16 patients who received 86 doses. The median treatment duration was 11.3 weeks, with a range of four to 52.4 weeks, representing 2 to 20 cycles of treatment.
Notably, three patients remain on trial, and continue to receive TTX-MC138. One patient is at 21 cycles of treatment, another is at 16 cycles, and the third one is at 14 cycles of treatment. (Table 1)
Table 1: Trial demographics, met safety primary endpoint
Cohort
Dose
Number of Patients
DLT’s1
1
0.8mg/kg
3
0
23
1.6mg/kg
3
0
33
3.2mg/kg2
7
0
43
4.8mg/kg
3
0
1 No significant treatment-related safety events or dose limiting toxicities were observed.
2 Optional backfill 3 with additional patients.
3 One patient in each of cohort 2, 3 and 4 currently on study.
TransCode believes these results support its selection of the recommended Phase 2a dose (RP2D) of 4.8mg/kg.
In addition, the assessment of the trial patient population underscored the potential for durable disease control in participants with metastatic cancer.
Based on Response Evaluation Criteria in Solid Tumors (RECIST) standardized criteria to measure tumor response to treatment using imaging to categorize lesions and assess changes in size over time, 9 out of 14 (64%) of evaluable patients achieved stable disease lasting six months, demonstrating a durable disease activity.
"From a clinical perspective, it is quite encouraging to see how well tolerated this agent has been at the exposures achieved through the Phase 1a dose-escalation study, without any dose-limiting toxicities. That, combined with the observation of disease stabilization in a population with such advanced disease supports continued clinical development" noted Keith Flaherty, MD, Director of Clinical Research at the Massachusetts General Hospital Cancer Center, Professor of Medicine at Harvard Medical School and TransCode’s Advisory Board member.
The pharmacokinetics profile from the analysis of plasma from patients receiving TTX-MC138 demonstrated evidence of drug bioavailability consistent with earlier preclinical studies.
One patient diagnosed with metastatic thyroid cancer was noted to have a dramatic decrease in their thyroglobulin levels, a tumor marker associated with cancer progression. The patient has now had demonstrated stable disease for the last 12 months and is one of the three patients who remain on study. We believe that the patient’s continued participation in the study, together with the decline in their thyroglobulin levels, provides further evidence of therapeutic activity from TTX-MC138.
A clinical study report is in process. Several presentations are planned at future scientific congresses.
"As the safety and tolerability primary objectives of the trial were met, the encouraging rates of disease stabilization provide the rationale to advance TTX-MC138 clinical development in our recently initiated Phase 2a trial. We continue to believe that TTX-MC138 may offer a promising therapeutic option, if approved, for patients with metastatic disease who have limited treatment alternatives," said Daniel Vlock, MD, TransCode Consulting Clinician.
Further information about the trial is available at www.clinicaltrials.gov, (NCT Identifier: NCT06260774).
About TTX-MC138
TTX-MC138 is a first-in-class therapeutic candidate designed to inhibit microRNA-10b (miR-10b), a microRNA widely believed to be critical to the emergence and progression of many metastatic cancers. TransCode’s Phase 0 clinical trial produced evidence of delivery of a radiolabeled version of TTX-MC138 to metastatic lesions.
(Press release, TransCode Therapeutics, JUN 3, 2026, View Source [SID1234666415])