Shares of Cara Therapeutic Inc. (NASDAQ: CARA) fell 31 percent on Friday after the company announced disappointing results on the CR845 oral medication from a phase 2b trial.

Cara is a biopharmaceutical company that focuses on developing medications to alleviate pain and pruritus. CR845, the company’s kappa opioid receptor agonist, was created to treat acute and chronic pain, in the hopes of replacing problematic opioids such as morphine and hydrocodone.

The drug failed to produce lower pain scores compared to a placebo. Patients taking 1.0 mg, 2.5 mg, or 5.0 mg of CR845 experienced as much pain as those not taking the medication with osteoarthritis (OA) of the knee or hip.

Cara attempted to bury the trial results under more upbeat but less important findings. Results cherry-picked by the corporation to lead the press release included the performance of the highest dose in patients with hip pain. The trial linked CR845 to a statistically significant improvement in pain scores within this subgroup of patients. However, without a rationale for why CR845 would treat pain in the hip but not the knee, the importance of this finding is questionable.

These trial results come a few days after Cara stock set an all-time record high, rising 40 percent in five days after Cara announced positive feedback on CR845.

“The drug was observed to be well tolerated over the treatment period and this overall data set will inform both our dose selection and patient population in designing our next trial of oral CR845 in OA patients,” Cara CMO Joseph Stauffer said in a statement.