TransCode reports updated Phase 1a data for TTX-MC138 in advanced solid tumors

TransCode Therapeutics announced updated clinical data on September 28, 2026 from its Phase 1a trial of TTX-MC138, its anti-miR-10b candidate, in patients with relapsed or refractory, unresectable locally advanced, or metastatic solid tumors.

At a data cutoff of September 1, 2026, 10 of 14 efficacy-evaluable patients, or 71.4%, achieved stable disease as their best overall response by investigator assessment.¹ The disease control rate was 57.1% (95% confidence interval, 28.9% to 82.3%) at Cycle 3 Day 1 and 35.7% (95% confidence interval, 12.8% to 64.9%) at Cycle 6 Day 1.¹ On durability, six of 14 efficacy-evaluable patients were progression-free at three months, three of 14 at six months, and three of 14 at nine and 12 months.¹

As of the cutoff, a total of 98 doses have been administered.¹ The company reported no dose-limiting toxicities were reported, no treatment-emergent adverse events led to treatment discontinuation, including the highest evaluated dose level of 4.8 mg/kg, and administration of TTX-MC138 for over a year was well tolerated and not associated with any dose-limiting toxicities.¹

In a post-hoc analysis, TransCode calculated a Growth Modulation Index, where 6 of 15 evaluable patients (40%) achieved a GMI greater than 1.3, indicating that treatment with TTX-MC138 resulted in at least a 30% longer progression-free interval than that achieved with the patient's immediately preceding therapy.¹

Exploratory blood RNA-sequencing showed encouraging on-treatment increases in an antitumor cytokine signature and dose-dependent immune effects, including cytotoxic effector activity and increased monocyte and M1-associated inflammatory activity, and patients with stable disease showed higher B-cell and monocyte fractions and enrichment of cytotoxic, phagocytic, and Type I interferon programs compared with patients with progressive disease.¹ The company cautioned that given the small sample size, the biomarker findings are hypothesis-generating and require confirmation in larger studies.¹

TransCode said it expects to incorporate the updated clinical findings into a clinical study report addendum and to continue evaluating safety, pharmacokinetics, pharmacodynamics, and antitumor activity.¹ The Phase 1a program's primary safety endpoint was already met, and TTX-MC138 is currently being evaluated in a Phase 2a clinical trial targeting ctDNA-positive colorectal cancer patients following curative-intent treatment.¹