Tenax heart drug fails to improve walking results in study, shares plunge

Aug. 10 (Reuters) - Tenax Therapeutics said on Monday its experimental drug did not significantly improve how far patients could walk compared with placebo in a late-stage trial testing TNX-103 for a difficult-to-treat form of heart failure.

Shares of the company plunged more than 85% in premarket trading following the update.

The company was testing TNX-103 in patients with pulmonary hypertension associated with heart failure with preserved ejection fraction, or HFpEF, a type of heart failure linked to high blood pressure in the lungs.

The trial did not show a significant improvement in how far patients could walk in six minutes compared with a placebo.

Patients treated with TNX-103 improved by 14 meters from baseline, compared with 10.4 meters for placebo, a difference of 3.5 meters, which was not statistically significant.

It also missed a key secondary goal measuring symptoms and quality of life.

"This readout did not go remotely how we thought it would," said Cantor analyst Olivia Brayer Saunders, adding that "the headline is ugly."

However, Tenax said patients who could walk less than 333 meters at the start of the trial, a marker of more advanced disease, showed a 26.3-meter improvement over placebo, at week 12.

"Having reviewed the available trial results, I am encouraged we have a clear path forward," said Stuart Rich, the company's chief medical officer, adding that the results point to "a meaningful beneficial treatment effect of TNX-103 in patients with more disease burden."

The company also pointed to a sharp drop in a blood marker of heart stress and a reduction in pressure in the lungs among all patients who took the drug.