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

By Kamal Choudhury

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 for a difficult-to-treat form of heart failure, sending its shares down nearly 90%.

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

Patients treated with TNX-103 improved their six-minute walk distance by 14 meters from baseline at week 12, compared with 10.4 meters for placebo, a difference of 3.5 meters that 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.”

Tenax, however, said that the trial result masked a benefit in patients with more advanced disease.

Patients who could walk less than 333 meters at the start of the trial showed a 26.3-meter improvement over placebo.

“Tenax did not anticipate the impact disease burden would have on the treatment response,” Chief Executive Chris Giordano said on an analyst call.

“We did not fail to find a treatment effect… we diluted one.”

Tenax’s chief medical officer Stuart Rich said that the drug may have worked “too well” in healthier patients by lowering blood volume to a level that limited their ability to exercise.

The company also pointed to a sharp drop in a blood marker of heart stress and a reduction in pressure in the lungs.

It said TNX-103 was generally safe, with serious side effects occurring at similar rates in both groups.

There are no approved treatments specifically for the condition, which is typically managed with standard heart failure therapies and treatment of underlying conditions.

The company plans to ask the U.S. Food and Drug Administration for a meeting to discuss changing its development plan, including protocol amendments to an ongoing second study to exclude less-severe patients.

(Reporting by Kamal Choudhury in Bengaluru; Editing by Devika Syamnath)