TransCode Therapeutics reports sustained disease control with TTX-MC138 in Phase 1a, including stable disease in 10 of 14 patients and no dose-limiting toxicities.
Written By: Aasritha Thippavajjala, PharmD
Reviewed By: Pharmacally Editorial Team
TransCode Therapeutics released updated results on September 28, 2026, from its Phase 1a trial of TTX-MC138, an investigational anti-miR-10b therapeutic candidate, in patients with relapsed or refractory, unresectable locally advanced, or metastatic solid tumors. At the September 1, 2026 data cutoff, 10 of 14 efficacy-evaluable patients achieved stable disease, three remained progression-free at one year, and no dose-limiting toxicities were reported across evaluated dose levels.
Phase 1a Trial Design and Data Snapshot
The first-in-human Phase 1a study (NCT06260774) is evaluating TTX-MC138 in patients with advanced, heavily pretreated solid tumors. The study uses a dose-escalation design to assess safety and tolerability while characterizing pharmacokinetics, pharmacodynamics, and antitumor activity.
The September 1 data snapshot included 14 efficacy-evaluable patients. The company reported that the primary endpoint of the study was met, with no dose-limiting toxicities reported across the evaluated dose levels. TTX-MC138 is designed to inhibit microRNA-10b (miR-10b), a target being investigated in metastatic cancer.
Disease Control and Durability
Ten of 14 efficacy-evaluable patients, or 71.4%, achieved stable disease as their best overall response by investigator assessment.
The disease control rate was 57.1% at Cycle 3 Day 1 (95% confidence interval, 28.9% to 82.3%) and 35.7% at Cycle 6 Day 1 (95% confidence interval, 12.8% to 64.9%). The company’s release also contains a 36.7% figure in its summary bullets, but the detailed clinical results report 35.7%. Pharmacally should use 35.7% consistently rather than mixing the two figures.
Six of 14 patients were progression-free at three months, three of 14 at six months, and three of 14 at both nine and 12 months. These findings indicate prolonged disease control in a subset of patients, although the small, non-randomized Phase 1 population limits interpretation of clinical activity.
Safety and Tolerability
As of September 1, 2026, a total of 98 doses had been administered. No dose-limiting toxicities were reported, and no treatment-emergent adverse events led to treatment discontinuation, including at the highest evaluated dose of 4.8 mg/kg.
The company also reported that treatment with TTX-MC138 for more than one year was well tolerated and was not associated with dose-limiting toxicities. Further evaluation in larger patient populations will be required to characterize the safety profile more fully.
Post-hoc Growth Modulation Index Analysis
A post-hoc Growth Modulation Index (GMI) analysis compared progression-free survival on TTX-MC138 with the progression-free interval achieved with each patient’s most recent prior systemic anticancer therapy.
In this analysis, six of 15 evaluable patients (40%) achieved a GMI greater than 1.3, indicating a progression-free interval at least 30% longer than that achieved with the immediately preceding therapy.
Importantly, the GMI analysis evaluated 15 patients, whereas the primary efficacy analysis included 14 efficacy-evaluable patients. This separate denominator should be retained to avoid conflating the two analysis populations. Because the GMI assessment was post-hoc and involved a small population, it should be considered exploratory.
Exploratory RNA-Sequencing Findings
Exploratory RNA sequencing of peripheral blood identified treatment-associated immune effects without major dysregulation of the global immune landscape. Findings included increases in an antitumor cytokine signature, cytotoxic effector activity, and monocyte and M1-associated inflammatory activity.
Compared with patients whose disease progressed, those with stable disease showed higher B-cell and monocyte fractions and enrichment of cytotoxic, phagocytic, and Type I interferon programs. The company described these findings as supporting biological activity associated with TTX-MC138. Given the small sample size, the biomarker findings remain hypothesis-generating and require confirmation in larger studies.
Development Path
TransCode is evaluating dose-expansion strategies to further assess TTX-MC138 in selected cancers and molecularly defined patient populations. The company also plans to incorporate the updated findings into a clinical study report addendum while continuing to evaluate safety, pharmacokinetics, pharmacodynamics, and antitumor activity.
TTX-MC138 is also being evaluated in a Phase 2a program involving patients with ctDNA-positive colorectal cancer following curative-intent treatment. The candidate remains investigational, and its safety and efficacy have not been established by the FDA or any other regulatory agency.
Reference
TransCode Reports Continued Disease Stabilization and Extended Treatment Duration with TTX-MC138 in Ongoing Phase 1a Clinical Trial Follow-Up, Transcode Therapeutics, 28 September 2026
Study of TTX-MC138 in Subjects with Advanced Solid Tumors, ClinicalTrials.gov ID NCT06260774
About the Writer
Aasritha Thippavajjala (Linkedin) is a pharm D student and aspiring medical writer with medical writing, clinical training experience and a strong interest in clinical research and patient safety She has hands-on exposure to clinical pharmacy activities including medication profile assessment, clinical case review, identification of potential drug-related problems, ADR awareness, patient counselling, and clinical documentation. She has also gained experience in medical literature review, evidence synthesis, and scientific communication through her published review article on digital twin-based patient simulation and her poster presentation at the 74th Indian Pharmaceutical Congress. Certified in ICH Good Clinical Practice (E6(R3)) and Scientific Writing in Health Research, she is passionate about applying her clinical knowledge and research skills to medical writing ,clinical research and contributing to accurate, evidence-based healthcare.