Tectonic Therapeutic said its lead hereditary hemorrhagic telangiectasia program, TX2100, cleared a key early clinical hurdle with phase 1a data showing the drug was generally safe and well tolerated across all six planned single-dose cohorts in 48 healthy adult volunteers.
The company reported no deaths, serious adverse events or severe treatment-emergent adverse events at any dose. Adverse events were described as mild or moderate and transient, and there were no clinically significant changes in vital signs, laboratory tests or electrocardiograms.
The trial tested six cohorts: 0.1 mg/kg IV, 0.3 mg/kg IV, 100 mg SC, 1 mg/kg IV, 300 mg SC and 600 mg SC. The study enrolled 48 participants, with eight in each cohort and a 3:1 randomization to TX2100 or placebo.
On the pharmacokinetic side, Tectonic said the results showed target-mediated drug disposition at low concentrations, which it said confirmed high-affinity binding to the APJ receptor and clearance through that mechanism. The company said the data support once-weekly and every-other-week subcutaneous dosing in future studies.
Tectonic also said it has already moved through two regulatory milestones: the FDA cleared its IND in August 2026 and granted fast track designation in September 2026.
The next steps are laid out on a tight timeline. Tectonic plans to start an open-label phase 1b study in hematologic-support-dependent HHT patients by year-end 2026, and a placebo-controlled phase 2 trial in moderate-to-severe HHT patients in early 2027. The company said the two trials are planned to run in parallel.
The phase 1b study will look at changes in iron and red blood cell support as well as hematologic parameters. The phase 2 trial is expected to assess epistaxis, hemoglobin, hematologic support and other HHT-related endpoints.
Part b of the phase 1a study is already underway. Tectonic said enrollment is complete in the multiple-dose cohort, which is evaluating six healthy volunteers dosed with 600 mg SC on day 1, followed by 200 mg SC on day 8 and day 15.
TX2100 is being developed as a selective APJ receptor antagonist for a disease with no approved therapies. HHT affects an estimated 75,000 people in the U.S. and is associated with recurrent bleeding, chronic anemia and, in some patients, AVMs in the lungs, brain and liver. As a result of these announcements, the company's shares have moved -0.72% on the market, and are now trading at a price of $23.34. For more information, read the company's full 8-K submission here.
