8-K: Tenax Therapeutics' TNX-103 Fails Phase 3 Primary Endpoint

Tenax Therapeutics announced topline results from its Phase 3 LEVEL trial of TNX-103 for PH-HFpEF, which did not meet its primary endpoint for improving 6-minute walk distance.

Summary

• Tenax Therapeutics announced topline results from its Phase 3 LEVEL clinical trial for TNX-103 in patients with PH-HFpEF.
• The trial did not meet its primary endpoint of improvement in 6-minute walk distance (6MWD) compared to placebo.
• A key secondary endpoint, the Kansas City Cardiomyopathy Questionnaire total symptom score (KCCQ-TSS), was also not met.
• However, prespecified exploratory analyses showed a 49% reduction in NT-proBNP and a 3.5 mmHg reduction in right ventricular systolic pressure (RVSP) compared to placebo in the overall population.
• In a prespecified subgroup of patients with a baseline 6MWD below the trial median (333 meters), TNX-103 showed a statistically significant improvement of 26.3 meters.
• TNX-103 was generally safe and well-tolerated, with serious adverse events and clinical worsening events balanced across treatment arms.
• The company plans to request a Type C meeting with the FDA to discuss revisions to the ongoing development of TNX-103.

Sentiment

Score: 3

Explanation: StockSavvy.ai views this as a negative development due to the failure to meet the primary endpoint in the Phase 3 trial, despite some positive subgroup results.

Positives

• TNX-103 demonstrated a statistically significant improvement of 26.3 meters in 6-minute walk distance in patients with a baseline 6MWD below the trial median (333 meters).
• In the overall trial population, treatment with TNX-103 resulted in a 49% greater reduction in NT-proBNP compared to placebo (nominal p<0.0001).
• A reduction of 3.5 mmHg in right ventricular systolic pressure was observed compared to placebo (nominal p=0.0045).
• TNX-103 was generally safe and well-tolerated.
• Serious adverse events and adjudicated clinical worsening events were balanced across treatment arms.
• The company confirmed the therapeutic dose and demonstrated the safety and favorable pharmacokinetic profile of oral levosimendan.

Negatives

• The Phase 3 LEVEL clinical trial did not meet its primary endpoint of improvement in 6-minute walk distance (6MWD) versus placebo.
• The key secondary endpoint, improvement in Kansas City Cardiomyopathy Questionnaire total symptom score (KCCQ-TSS), was also not met.
• Adverse events were reported in 86.7% of patients on TNX-103 versus 71.9% on placebo.
• Treatment-related adverse events were reported in 38.3% of patients in the TNX-103 group versus 17.4% on placebo.
• Tenax Therapeutics will need to revise its development plan based on these results.

Risks

• Failure to meet primary and key secondary endpoints in the Phase 3 LEVEL trial may impact regulatory approval.
• The broad enrollment criteria included patients with less severe disease, potentially diluting the treatment effect.
• Higher rates of treatment-related adverse events, dose reductions, and discontinuations were observed in the TNX-103 group.
• Future trial designs may need to incorporate enrichment strategies to focus on patient populations with a demonstrated treatment effect.
• Delays in regulatory review and approval of product candidates.
• Risks related to formulation, production, marketing, customer acceptance, and clinical utility of product candidates.

Future Outlook

Tenax Therapeutics intends to request a Type C meeting with the FDA to discuss revisions to the ongoing registrational development of TNX-103 for PH-HFpEF, aiming to enrich the study population based on observed subgroup findings. The company will also seek scientific consultation from the European Medicines Agency. Full results will be presented at the ESC Congress 2026.

Management Comments

• "Having reviewed the available trial results, I am encouraged we have a clear path forward. 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."
• "Our entry criteria enrolled a broad population, including too many patients with less severe disease."
• "In a prespecified subgroup analysis of patients who walked less than the trial median of 333 meters at baseline, the improvement in the levosimendan group compared to placebo was 26.3 meters (95% confidence interval 6.0, 46.7 meters), demonstrating a strong result in a more characteristic HFpEF population that needs this therapy."
• "Based on the results from LEVEL, we are moving quickly to strengthen the development plan for TNX-103 to generate data we believe will support regulatory submissions."
• "The data from LEVEL provide us with a key insight into the population that exhibits the treatment effect of TNX-103. These trial results also confirm we had the appropriate dosing in HFpEF patients, illustrate a very favorable overall pharmacokinetic profile of oral levosimendan, and demonstrate the safety of oral levosimendan."

Industry Context

StockSavvy.ai notes that the failure to meet primary endpoints in Phase 3 trials is a significant setback for drug developers, especially in a therapeutic area with high unmet needs like PH-HFpEF. While positive biomarker and subgroup data can offer a path forward, they often face higher scrutiny from regulatory bodies compared to statistically significant primary endpoint results.

Stakeholder Impact

• Shareholders may react negatively to the failure to meet the primary endpoint, potentially impacting the stock price.
• Patients with PH-HFpEF, who are seeking new treatment options, will have to wait longer for potential therapies as development plans are revised.
• Healthcare providers and researchers involved in the trial will need to analyze the nuanced results to understand the drug's potential in specific patient subgroups.

Next Steps

• Request a Type C meeting with the U.S. Food and Drug Administration (FDA) to discuss revisions to the ongoing registrational development of TNX-103.
• Seek scientific consultation from the European Medicines Agency (EMA).
• Enrich the study population in future development to ensure a robust treatment effect.
• Present full results from the LEVEL trial at the European Society of Cardiology (ESC) Congress 2026.
• Publish full results from the LEVEL trial.

Key Dates

Recommendation

The failure to meet the primary endpoint in a Phase 3 registrational trial is a significant negative event. While there are some positive signals in subgroup analyses and biomarker data, the lack of statistical significance on the key measures of efficacy makes the drug's path to approval highly uncertain and increases the risk profile considerably. This warrants a 'sell' recommendation until a clearer, de-risked path to regulatory approval is established.

Keywords

PH-HFpEF, TNX-103, Levosimendan, Phase 3 Trial, Clinical Trial Results, Pulmonary Hypertension, Heart Failure, Cardiology