Tectonic Therapeutic (TECX) investor relations material

Study design and patient population

• Phase 1B Part B was a single-dose, open-label trial in 14 PH-HFrEF patients, enriched for CpcPH (PVR ≥3 WU), with baseline LVEF around 34% and all on standard HFrEF therapy.

• TX45 is a long-acting Fc-relaxin fusion protein targeting vasodilatory, lusotropic, antifibrotic, and anti-inflammatory effects via RXFP1.

• Baseline hemodynamics showed elevated PCWP, PVR, and mPAP, consistent with PH-HFrEF.

• Dosing ranged from 0.3 to 3 mg/kg, with most patients receiving the highest dose.

• The study included subgroups with CpcPH and IpcPH, aiming for 70% CpcPH.

Safety and tolerability

• TX45 was well tolerated with no serious or severe adverse events, discontinuations, or infusion reactions.

• All adverse events were mild or moderate and self-limited, most commonly procedural back pain.

• No clinically significant changes in vital signs, ECG, physical exams, or laboratory values; transient, asymptomatic decreases in systolic BP observed.

• No signs or symptoms of congestion or worsening heart failure; no fatigue-related adverse events in Part B.

• DSMB review found no safety concerns, and the study continued without alterations.

Hemodynamic and echocardiographic outcomes

• TX45 led to improvements in all hemodynamic measurements, including a >6 mmHg (29%) reduction in wedge pressure and a 29.2% decrease in TPR.

• PVR reduced by 19.7% in CpcPH patients (PVR ≥3 WU); mean reduction for PVR ≥2 WU was 10.3%.

• Cardiac output increased by 17.3%, mean pulmonary artery pressure dropped by 19.3%, and right atrial pressure decreased by 29%.

• Echocardiography at day 29 showed LVEF improved by 19.4% (to ~40.3%), TAPSE/SPAP increased by 36.3%, and RVFAC improved by 20.3%.

• Improvements were sustained through day 29 post-dose.