Tenax’s TNX-103 fails primary endpoint in Phase 3 PH-HFpEF trial

Aug 10, 2026

Tenax Therapeutics shares collapsed by 84% to 87% on August 10, 2026, after its Phase 3 LEVEL trial of TNX-103 (oral levosimendan) failed to meet its primary endpoint. The drug showed a non-significant 3.5-meter walking improvement over placebo (p=0.63) and missed its key secondary symptom endpoint. While exploratory analyses revealed positive biomarker trends and benefits in a sicker subgroup of 119 patients, the failure wiped out $425 million in equity value, leaving the cash-burning biotech to re-evaluate its regulatory path.

Phase 3 LEVEL trial failure

▪In the Phase 3 LEVEL trial, patients treated with TNX-103 improved their six-minute walk distance by 14.0 meters from baseline compared to 10.4 meters for placebo, representing a non-significant difference of 3.5 meters.
▪The Phase 3 LEVEL trial enrolled 241 patients with pulmonary hypertension associated with heart failure with preserved ejection fraction across 41 sites in the United States and Canada.
▪The Phase 3 LEVEL trial of TNX-103 missed its key secondary endpoint measuring improvement in the Kansas City Cardiomyopathy Questionnaire total symptom score.
▪Tenax Therapeutics reported on August 10, 2026, that its Phase 3 LEVEL trial of TNX-103 did not meet its primary endpoint of a statistically significant improvement in six-minute walk distance compared to placebo.

Subgroup exploratory analyses

▪A prespecified subgroup analysis of the LEVEL trial showed that patients with a baseline six-minute walk distance below 333 meters achieved a placebo-adjusted improvement of 26.3 meters at week 12.
▪Tenax Therapeutics stated that the exploratory subgroup p-values are nominal, not adjusted for multiple comparisons, and are insufficient to demonstrate efficacy.

Biomarker exploratory analyses

▪In prespecified exploratory analyses of the LEVEL trial, TNX-103 treatment resulted in a 49% greater reduction in the cardiac stress biomarker NT-proBNP compared to placebo.
▪In exploratory analyses of the LEVEL trial, TNX-103 treatment reduced right-ventricular systolic pressure by an estimated 3.5 mmHg compared to placebo.

Stock price collapse

▪Tenax Therapeutics shares fell approximately 84% to 87% in premarket and early trading on August 10, 2026, following the announcement of the LEVEL trial results.
▪The collapse in Tenax Therapeutics stock on August 10, 2026, occurred despite positive pre-market indicators in the broader S&P 500 futures, which were up 0.03%.
▪Prior to the LEVEL trial readout, nine Wall Street brokerages held an average price target of $37.67 on Tenax Therapeutics stock, with targets ranging up to $50.

Safety profile

▪In the LEVEL trial, serious adverse events occurred at similar rates of 10.8% in the TNX-103 group and 10.7% in the placebo group.
▪Overall adverse events were reported in 86.7% of patients on TNX-103 compared to 71.9% on placebo, while treatment-related adverse events occurred in 38.3% of the treatment group versus 17.4% on placebo.

Market capitalization impact

▪Tenax Therapeutics reported having $118.0 million in cash and restricted cash as of June 30, 2026, which the company previously estimated would fund operations through mid-2028.
▪The premarket stock drop on August 10, 2026, wiped out approximately $425 million in core equity value, reducing Tenax Therapeutics' market capitalization from nearly $503 million to about $77.8 million.