Tectonic reports Phase 1a safety data for TX2100 in HHT program

Tectonic Therapeutic announced topline results on September 29, 2026 from a Phase 1a trial of TX2100, an investigational antibody targeting the APJ receptor being developed for hereditary hemorrhagic telangiectasia (HHT), a rare inherited vascular disorder. The trial was designed to support further clinical development of TX2100 for HHT, a condition with no currently approved therapies.¹

The company said single ascending doses of TX2100, given intravenously and subcutaneously, were tolerated without major issues across all six planned dose cohorts.¹ Adverse events reported during the study were mild or moderate and temporary, with no deaths, serious adverse events, or severe adverse events at any dose level.¹ No clinically significant changes appeared in vital signs, lab results, or electrocardiograms.¹ Anti-drug antibody results are still pending.¹

On the regulatory front, the FDA cleared Tectonic's IND application for TX2100 in HHT in August 2026, allowing the company to proceed with a planned open-label Phase 1b trial in HHT patients in the U.S.¹ In September 2026, the FDA also granted TX2100 Fast Track Designation for HHT treatment.¹

Tectonic said it intends to advance TX2100 into two studies: an open-label Phase 1b trial in patients with hematologic-support dependent HHT, and a placebo-controlled Phase 2 trial in moderate-to-severe HHT patients, with the Phase 1b expected to start by year-end 2026 and the Phase 2 trial in early 2027.¹

The company plans to present detailed safety, tolerability, pharmacokinetic and anti-drug antibody results at the CureHHT 16th HHT International Scientific Conference, scheduled for October 12-16, 2026.¹