Biotechnology firm Cara Therapeutics has enrolled first patients in a Phase II trial of an oral tablet formulation of its peripherally selective kappa opioid agonist CR845 to treat osteoarthritis (OA).
CR845 is a peripherally acting kappa opioid receptor agonist, which is currently in development to treat acute and chronic pain and pruritus.
Cara Therapeutics chief medical officer Dr Joseph Stauffer said: "The initiation of this osteoarthritis trial is an important step toward establishing the potential clinical utility of our oral CR845 formulation in the treatment of chronic inflammatory pain.
"CR845's novel peripheral mechanism of action may ultimately provide a safer, non-abusable alternative to NSAIDs and narcotic opioids, and satisfy a significant unmet need among osteoarthritis patients and potentially general chronic pain patients."
The trial is a single-blind, randomised and multiple ascending dose study designed to assess the safety, pharmacokinetics (PK) and effectiveness of oral CR845 tablets dosed over a two-week treatment period in OA patients experiencing moderate-to-severe pain.
The company intends to enrol around 80 OA patients at multiple sites in the US, who will be administered four tablet strengths, including 0.25mg, 0.5mg, 1.0mg, and 5mg twice a day.
Pharmacodynamics endpoints will comprise change from baseline in joint pain using the Numeric Rating Scale (NRS), change from baseline in the Western Ontario and McMaster Osteoarthritis Index (WOMAC) and Patient Global Assessment (PGA) of OA, in addition to safety and PK observations.
IV CR845 treatment resulted in statistically significant reductions in both pain intensity and opioid-related side effects in multiple randomised, double-blind, and placebo-controlled Phase II trials in patients undergoing laparoscopic hysterectomy or bunionectomy procedures.
Image:MRI of osteoarthritis in the knee, with characteristic narrowing of the joint space. Photo: courtesy of Scuba-limp.