Tenax's Only Drug Fails Phase 3 LEVEL Trial; Stock Loses 90% of Its Value

Tenax Therapeutics (Nasdaq: TENX) announced Monday that TNX-103, its oral levosimendan program and the company’s only clinical asset, failed the primary endpoint of the Phase 3 LEVEL trial in pulmonary hypertension with preserved ejection fraction. The stock lost roughly 90% of its value intraday, shrinking the company’s market cap from about $500 million to approximately $50 million. TENX closed at $13.44 on Friday.

The numbers leave no room for interpretation. TNX-103 improved 6-minute walk distance by 14.0 meters versus 10.4 meters for placebo, a 3.5-meter treatment difference with a p-value of 0.63. The key secondary endpoint, the KCCQ symptom score, improved by 6.6 points versus 6.5 points for placebo, a difference of 0.1. Both primary and secondary endpoints missed cleanly in the 241-patient trial.

The subgroup story. Management highlighted prespecified subgroup data to argue the drug showed activity in sicker patients. Among the 119 patients with baseline walking distance below 333 meters, TNX-103 produced a 26.3-meter placebo-adjusted improvement (nominal p=0.0112). Patients over 71 years old showed a 27.1-meter benefit. The heart failure biomarker NT-proBNP fell 49% relative to placebo across the full population (nominal p<0.0001). But the company explicitly noted that subgroup and biomarker analyses do not establish efficacy, and the FDA had previously agreed that a single Phase 3 trial reaching p=0.01 could support an NDA. The actual primary endpoint p-value was 0.63, two orders of magnitude short.

What comes next. Tenax plans to request a Type C meeting with the FDA to discuss an enriched patient population strategy and revisions to the ongoing LEVEL-2 trial, the company’s second registrational study. Whether regulators will accept a protocol reboot after a cleanly negative trial is uncertain. Full LEVEL data was presented in a Late-Breaking session at ESC Congress 2026 in Munich on August 29, 2026, with additional analyses showing a 26.3-meter placebo-adjusted 6MWD benefit (p=0.0112), a 47% NT-proBNP reduction, and a 4.9 mmHg RVSP improvement in the subgroup with baseline walking distance below 333 meters. The overall primary endpoint missed cleanly at p=0.63.

Why this matters beyond Tenax. PH-HFpEF affects over 1.6 million people in North America and has no FDA-approved therapies. Merck’s sotatercept showed encouraging signals in the Phase 2 CADENCE trial in a related HFpEF population at ACC 2026, and that program is now the most advanced candidate in the class, but the field remains wide open. Tenax was the most advanced oral therapy in development.

For Tenax specifically, this is an existential outcome. TNX-103 is the company’s only drug. TNX-101 (the intravenous formulation) and TNX-102 are the same active ingredient, levosimendan, in different delivery forms. There is no pipeline diversification. The cash runway and any remaining value in the stock now depend entirely on whether the FDA sees a path forward in the LEVEL-2 enrichment strategy.

For a primer on how to interpret the numbers in a readout like this one, see our guide to clinical trial press releases.