What happened

Shares of Cara Therapeutics Inc. (NASDAQ:CARA), a clinical-stage biopharmaceutical company focused on pain and pruritus relief, surged about 14% higher after the opening bell before tapering off to a 5.8% gain as of 11:30 a.m. EDT during Wednesday's session. Results from a safety study with a tablet form of its non-euphoria inducing opioid candidate present some interesting options for the company.

So what

Wednesday morning Cara Therapeutics announced early stage clinical trial results that show tablet strengths of its lead candidate ranging all the way up to 2.5 mg were well tolerated when swallowed either daily or after dialysis three times per week. The company also noted the plasma levels of orally administered CR845 were in line with those observed with the intravenously delivered version during a previously successful study as a reliever of chronic itching among patients with kidney disease.

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So far, it looks like the IV version of Cara's lead candidate has a solid shot at becoming the first itch reliever for a growing population of dialysis patients, but an easy to swallow tablet would be a lot easier to commercialize if eventually approved. There's an unmet need for relief of itching associated with chronic kidney disease, and, if approved, a tablet version of CR845 could probably generate more than $300 million in annual sales.

Now what

Late last month, the market clubbed Cara's stock after it failed to impress as a pain reliever for patients with osteoarthritis of the hip or knee. Patients with affected hips reported joint pain scores just low enough to suggest a statistically significant benefit when given 5 mg twice daily. When scores from those with pain in the knee and hip were combined, though, the reported benefit didn't hit the mark. 

It's a long shot, but I wouldn't score CR845's chances of eventually succeeding as a chronic pain reliever at zero. Cara pointed out that patients treated with CR845 did report significant osteoarthritis improvements. Wednesday's safety data showed adverse events in the group of dialysis patients receiving 2.5 mg three times daily was comparable to the rate of side effects seen in the placebo group. I wouldn't be surprised if Cara eventually takes another shot at a chronic pain indication with a stronger dose.

Cory Renauer has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.