Shares of biopharma firm Cara Therapeutics (CARA 17.90, -7.61) gap about 29.8% lower today, retracting the recent five (or so) session surge in the stock as data from the company’s Phase 2b Trial of oral CR845 in chronic pain patients with osteoarthritis of the hip or knee.
The aforementioned Phase 2b trial was a randomized, double-blind, placebo-controlled trial of three tablet strengths of CR845, 1.0 mg, 2.5 mg and 5.0 mg, dosed twice a day (BID) over an eight-week treatment period in 476 patients with osteoarthritis of the hip or knee experiencing moderate-to-severe pain.
Some highlights from the data include:
- The primary efficacy endpoint was the change from baseline at week eight, with respect to the weekly mean of the daily pain intensity score using a numerical rating scale (NRS).
- The trial design incorporated a four-week titration period for a response, followed by a four-week maintenance period. Sixty-seven percent of CR845-treated patients in the maintenance period titrated to the 5.0 mg dose after the four-week titration period, based on change in the observed mean joint pain score (NRS).
- Patients with OA of the hip maintained on the 5.0 mg dose to the end of the eight-week treatment period exhibited a statistically significant 39% reduction in mean joint pain score (p=0.043 vs. placebo); all patients (OA of the knee or hip) maintained on the 5.0 mg dose to the end of the eight-week treatment period exhibited a 35% reduction in mean joint pain score (p=0.111 vs. placebo).
- Patients maintained on the 1.0 mg and 2.5 mg tablet strengths did not exhibit significant reductions in mean joint pain scores compared to placebo.
- For patients maintained on the 5.0 mg dose, there was a statistically significant increase in the proportion of patients whose OA was “very much improved” or “much improved” as indicated by Patient Global Assessment score in both the total patient group (p <0.005 vs. placebo) and in patients with primary OA of the hip (p<0.006 vs. placebo).
- The reduction in pain score in the 5.0 mg dose group in hip patients was accompanied by a reduction in mean rescue medication of 41 percent at week eight versus placebo.
- An overall improvement of 62 percent from baseline in WOMAC scores was observed over the eight-week treatment period for the 5.0 mg dose group in hip patients.
Despite effectively missing its endpoint on the ‘845 trial, many on the street still hold bullish views on the stock. Many hold that the results represent proof of concept in oral kappa opioids. While the company may benefit from another trial, paramount to the results should be changes to the trial parameters in order to demonstrate a clearer picture for investors how efficient ‘845 actually is.