Tenax Therapeutics on Friday presented additional Phase 3 trial data for its experimental drug TNX-103 (levosimendan) in pulmonary arterial hypertension associated with heart failure with preserved ejection fraction (PH-HFpEF). The results were shared at the European Society of Cardiology Congress 2026 in Munich.
The Phase 3 LEVEL clinical trial randomized 241 patients across 41 sites in the United States and Canada. The primary endpoint—a change in 6-minute walk distance at Week 12—did not achieve statistical significance. Similarly, the key secondary endpoint assessing symptom scores also fell short of significance. The trial’s median baseline 6-minute walk distance was 333 meters, with the patient population’s baseline performance roughly 50–60 meters higher than in prior PH-HFpEF studies.
A pre-specified subgroup analysis of patients with a baseline 6-minute walk distance below the trial median revealed notable improvements. In this group, TNX-103 demonstrated a 26.3-meter improvement in 6-minute walk distance compared to placebo (p = 0.0112). The drug also reduced NT-proBNP levels by 47% versus placebo (p < 0.0001) and lowered right ventricular systolic pressure by 4.9 mmHg relative to placebo (p = 0.009). TNX-103 was reported as safe and well-tolerated across the overall trial population, with no significant arrhythmias observed.
Levosimendan, the active ingredient in TNX-103, has received market authorization in 60 countries for intravenous use in hospitalized patients with acutely decompensated heart failure, though it remains unavailable in the United States and Canada. Tenax Therapeutics, based in Chapel Hill, North Carolina, intends to use these findings to enrich the population in its planned LEVEL-2 follow-up trial while continuing global development efforts.
