Tenax Therapeutics plunges 85% as Phase 3 trial misses endpoints

Tenax Therapeutics' Phase 3 LEVEL trial of TNX-103 missed its primary endpoint in pulmonary hypertension with preserved ejection fraction, erasing about 85 percent of shareholder value and leaving a condition with no approved therapy without a new treatment candidate.

"The prespecified subgroup analyses demonstrate that there is a meaningful beneficial treatment effect of TNX-103 in patients with more disease burden, which is the patient population with the greatest unmet need," Stuart Rich, chief medical officer at Tenax, said.

The 241-patient trial, randomized across 41 sites in the United States and Canada, showed a 3.5-meter treatment difference in 6-minute walk distance at Week 12 (p=0.63) and a 0.1-point difference on the Kansas City Cardiomyopathy Questionnaire total symptom score. Prespecified exploratory analyses showed a 49 percent placebo-adjusted reduction in NT-proBNP (nominal p<0.0001) and a 3.5 mmHg reduction in right ventricular systolic pressure (nominal p=0.0045). Among patients with baseline walk distance below the trial median of 333 meters, TNX-103 improved 6-minute walk distance by 26.3 meters (nominal p=0.0112).

Tenax shares fell about 90 percent on the readout, cutting market value to roughly $503 million. The company plans a Type C meeting with the FDA to discuss an enriched patient population, after the agency previously agreed a single Phase 3 trial with a p-value of 0.01 could support an NDA submission.

Subgroup Signal vs. Primary Miss

The trial's overall result leaves TNX-103's registrational path uncertain. Tenax's own analysis showed the treatment effect concentrated in sicker patients: those aged 71 and older gained 27.1 meters (nominal p=0.0021), and the oldest tertile above 74 years gained 37.6 meters (nominal p=0.0013). A post hoc quartile analysis showed the effect reversed with better baseline exercise capacity — a 32.4-meter gain in the lowest quartile versus a 27.3-meter loss in the highest. Tenax cautioned the nominal p-values were not adjusted for multiplicity and the analyses do not establish efficacy.

Safety data were more balanced. Serious adverse events occurred in 10.8 percent of TNX-103 patients versus 10.7 percent on placebo, though overall adverse events (86.7 percent versus 71.9 percent) and treatment-related events (38.3 percent versus 17.4 percent) were more frequent with the drug.

What's at Stake for Investors

TNX-103 is oral levosimendan, a K-ATP channel activator and calcium sensitizer already approved for intravenous use in acutely decompensated heart failure in 60 countries, though not in the United States or Canada. Tenax holds global rights to develop and commercialize the drug for PH-HFpEF, the most prevalent form of pulmonary hypertension globally.

The company's balance sheet provides some cushion — zero debt and a current ratio of 15.07 — but it has no revenue and burns cash. Its GF Score of 22 out of 100 reflects weak profitability and momentum despite strong financial strength. Analysts had set price targets between $27 and $50 before the readout, with a median of $37.50. Levi & Korsinsky has notified investors of a pending investigation into potential securities law violations tied to the disclosure.

Full LEVEL results are scheduled for a Late-Breaking Clinical Science session at the ESC Congress 2026 in Munich from August 28-31. Tenax also plans to seek scientific consultation from the European Medicines Agency and continues its LEVEL-2 Phase 3 trial.

This article is for informational purposes only and does not constitute investment advice.