FDA spurns Pharming's Rhucin app in fresh setback

A few days ago Pharming announced plans for a Phase IIIb study of Rhucin, an experimental therapy produced in transgenic rabbits, in anticipation of running into fresh regulatory challenges. And it turns out the biotech didn't have far to go before learning the new study will be required to clear a new regulatory roadblock.

This morning Pharming and its partner Santarus announced that the FDA had handed back their biologics license application on Rhucin, saying it hadn't provided enough data on a sufficient number of patients for a complete review. The "refusal to file" letter was the latest in a series of setbacks on the drug, and drove down Pharming shares by 22 percent as investors got a chance to digest the news.

San Diego-based Santarus paid Pharming $15 million upfront for North American licensing rights to the therapy, intended for use against a rare genetic swelling ailment. At least for now, though, it doesn't have to fret over the $5 million milestone it agreed to pay once the app was accepted. Investigators plan to recruit 50 patients for the new study, which will run for 12 months to 18 months.

"In reaching its conclusion, the FDA indicated that the previously conducted studies evaluating Rhucin for the treatment of acute attacks of Hereditary Angioedema did not provide data for a sufficient number of subjects to support the proposed dose of 50 U/kg and lacked prospective validation of the visual analog scale used in measuring the clinical effects of Rhucin," the company reported. "The FDA also provided other comments on the prior clinical studies and indicated that they will provide additional feedback on the design of the ongoing Phase IIIb clinical study, which had been initiated based on previous discussions with the FDA. In addition, the FDA requested that the results of the Phase IIIb clinical study be included in any future BLA submission for Rhucin."

- see the Pharming/Santarus release
- check out the story from Reuters