Tenax Therapeutics reported negative results Monday from a late-stage clinical trial evaluating an experimental treatment for a type of heart failure associated with high blood pressure in the lungs.

Shares of the biotech company plunged 84% to $2 in early trading.

In the Phase 3 study called LEVEL, Tenax’s drug, an oral formulation of levosimendan, improved exercise capacity by 14 meters on a six-minute walking test compared to an improvement of 10.4 meters for a placebo. The difference was not statistically significant, failing to achieve the study’s primary efficacy goal, the company said.