Tenax Therapeutics reported new Phase 3 data for its drug TNX-103 (levosimendan) at the European Society of Cardiology Congress 2026 in Munich, with mixed results in a study targeting pulmonary hypertension associated with heart failure with preserved ejection fraction (HFpEF).
The LEVEL Phase 3 study randomized 241 patients across 41 centers in the United States and Canada. The primary endpoint—a change in 6-minute walk distance at week 12—did not achieve statistical significance, nor did the main secondary endpoint assessing symptom scores. However, in a predefined subgroup of patients with a baseline 6-minute walk distance below the median of 333 meters, TNX-103 demonstrated clinically meaningful improvements.
In this subgroup, treatment with TNX-103 resulted in a 26.3-meter improvement in walk distance compared to placebo (p = 0.0112). The drug also produced a 47% reduction in NT-proBNP levels versus placebo (p < 0.0001) and lowered right ventricular systolic pressure by 4.9 mmHg (p = 0.009). TNX-103 was reported as safe and well-tolerated across the study population, with no significant arrhythmias observed.
Tenax indicated it plans to refine the patient population for the follow-up LEVEL-2 study based on these findings. Levosimendan, the active ingredient in TNX-103, is already approved for intravenous use in 60 countries for acute decompensated heart failure, though it is not available in the United States or Canada.
