Pharmos pain drug produces mixed results

The lowest dose of cannabinor, a CB2 agonist, produced a statistically significant decrease in pain versus placebo, as measured by the primary endpoint. However, this drug effect was not seen in the higher dose groups. Pharmos said this was an unexpected pattern of results and it will continue to explore possible explanations.

Cannabinor activates the CB2 receptor, which is involved with pain relief, without activating the CB1 receptor, which is associated with the psychotropic effects caused by cannabis.

Pharmos recently completed a separate phase IIa study of intravenous cannabinor in experimentally induced pain in healthy volunteers. As previously reported, a 48mg dose of the drug was not active in reducing capsaicin-induced pain, the primary endpoint, but it was active in reducing the pain reaction to pressure-induced and heat-induced pain in normal skin.

“We are encouraged by the analgesic signal of cannabinor in the nociceptive pain study, but the pattern of the results is not that easily interpreted. Taken together with the results from the phase IIa experimentally induced pain study, the data do suggest that cannabinor has analgesic properties in acute pain models and the potential to be active in the targeted indications of neuropathic pain and chronic nociceptive pain where the drug would be given chronically,” said Arnon Aharon, senior director of Clinical Development.

Pharmos is developing its CB2 agonists as treatments for chronic pain and autoimmune diseases such as multiple sclerosis and rheumatoid arthritis.