Tenax's TNX-103 misses primary endpoint in Phase 3 LEVEL trial for PH-HFpEF

Tenax Therapeutics announced on August 10, 2026 topline results from its Phase 3 LEVEL trial testing TNX-103, an oral form of levosimendan, in patients with pulmonary hypertension due to heart failure with preserved ejection fraction (PH-HFpEF).

The trial failed to reach its primary goal of improving six-minute walk distance compared with placebo, and also missed a key secondary endpoint measuring symptom scores on the Kansas City Cardiomyopathy Questionnaire.¹ At Week 12, the least-squares mean improvement in walk distance was 14.0 meters on TNX-103 versus 10.4 meters on placebo, a difference of 3.5 meters that was not statistically significant (p=0.63).¹

The study randomized 241 patients to receive TNX-103 at 1 mg twice daily, with titration to 1 mg three times daily beginning at Week 5 if tolerated, or to placebo.¹

In prespecified subgroup analysis, patients whose baseline walk distance was below the trial median of 333 meters showed a treatment difference of 26.3 meters versus placebo (95% CI 6.0 to 46.7, nominal p=0.0112).¹ Exploratory biomarker findings showed a 49% reduction in NT-proBNP relative to placebo across the full population (nominal p<0.0001)¹ along with a 3.5 mmHg reduction in right ventricular systolic pressure by echocardiography (nominal p=0.0045).¹

On safety, the drug was described as generally safe and well tolerated, with no new safety signals identified.¹ Serious adverse events were similar between groups, at 10.8% for TNX-103 versus 10.7% for placebo.¹

Tenax said it plans to request a Type C meeting with the FDA to discuss changes to the ongoing registrational development plan for TNX-103.¹ The company also said it intends to seek scientific consultation from the European Medicines Agency in parallel.¹ Full trial results are scheduled to be presented in a Late-Breaking Clinical Science session at the European Society of Cardiology Congress 2026 in Munich, Germany, from August 28 to 31.¹