Shares of Pharmos Corp. slid 10 percent after its intravenous cannabinoid drug, cannabinor, missed its endpoint in a Phase IIa study in capsaicin-induced pain, but the company said it is moving ahead with an oral version of the compound in neuropathic pain.
Results from the trial indicated that 48 mg of intravenous cannabinor failed to show efficacy over placebo in analgesic effects in 24 healthy male volunteers with capsaicin-induced allodynia and hyperalgesia, though the drug was found to be safe and well tolerated with no serious adverse events. That news dropped Pharmos' stock (NASDAQ:PARS) 20 cents Friday to close at $1.61.
Company officials could not be reached for comment, but Pharmos Chairman and CEO Haim Aviv said in a press release that the disappointing results would not preclude the firm from advancing into the clinic with an orally administered cannabinor, which demonstrated promising activity in neuropathic pain in preclinical studies. Pharmos recently finished the toxicology and pharmacology studies needed to support plans for a Phase I trial in healthy volunteers.
The company also expects to wrap up an ongoing Phase IIa trial of the intravenous formulation in nociceptive pain. That single administration study, anticipated to conclude later this quarter, will compare cannabinor vs. placebo in 100 healthy male subjects experiencing pain following third molar dental extraction.
Cannabinor, a synthetic CB2-selective agonist, is the lead compound to emerge form Pharmos' cannabinoid research program, which is focused on developing CB2 agonists designed to inhibit inflammatory and autoimmune processes. The company has reported efficacy in preclinical models with a number of second-generation CB2-selective receptor agonists in the areas of pain, inflammation, immunologic dysfunction and psychiatric disease.
Pharmos has reported better news with its lead drug candidate, dextofisopam, an R-enantiomer of racemic tofisopam, which successfully completed a Phase IIa study in irritable bowel syndrome and is expected to move into a Phase IIb trial this year.
Dextofisopam was developed by Ewing, N.J.-based Vela Pharmaceuticals Inc., which was acquired by Pharmos last year in a cash and stock deal valued at about $30 million. (See BioWorld Today, March 16, 2006.)
The company also is continuing work on its NanoEmuslion topical drug delivery technology. In November, Pharmos reported positive results from a Phase I study of the technology formulated with diclofenac, an approved nonsteroidal anti-inflammatory drug, which showed low systemic exposure with no drug accumulation after repeated daily administrations.