Although the FDA will not grant a request by Epix Pharmaceuticals to approve its MR blood-pool agent for marketing in the U.S., more testing may not be necessary to ultimately gain the agency’s approval. Instead, a blinded reread of the images obtained from the previously completed phase III clinical trials of Vasovist -- assuming the results are positive -- may be enough to win approval.
Although the FDA will not grant a request by Epix Pharmaceuticals to approve its MR blood-pool agent for marketing in the U.S., more testing may not be necessary to ultimately gain the agency's approval. Instead, a blinded reread of the images obtained from the previously completed phase III clinical trials of Vasovist - assuming the results are positive - may be enough to win approval.
"While the FDA has denied our appeal for immediate approval, its response does indicate a potential path that does not require additional clinical trials," said Dr. Andrew Uprichard, Epix president and head of R&D, in an investor conference call June 19. "This is the first time since we began the appeals process that the FDA has indicated that image quality might be sufficient to potentially provide substantial evidence for efficacy of Vasovist."
The company does not expect Vasovist to reach the U.S. market, however, until the end of 2008. In the meantime, three steps, each taking six months, need to occur. The first is agreeing with regulators on the methodology for the rereading. The second is analyzing the data again, and then summarizing the study conclusions. The third is FDA review of the submitted data and conclusions.
The successful outcome of this approach depends on the quality of the images acquired during the four previously conducted phase III studies. In its response to Epix, the FDA recommended that the currently available images from the pivotal studies be re-analyzed to support the potential approval of Vasovist, according to the company. The agency did not say whether the data were of sufficient quality to provide such support.
Epix faces other uncertainties as well. During the conference call, company executives stated that the MR contrast agent would be "monetized" to its partner - a financial euphemism meaning that the rights to Vasovist would be sold to Bayer Schering Pharma, which currently owns the drug's marketing rights.
Although founded as an imaging company, Epix has since turned to the development of therapeutics. Vasovist may no longer be in sync with the corporate mission, but it could provide an extraordinary infusion of capital.
Dr. Michael G. Kauffman, Epix CEO, estimated that the current market for MR angiography is about $100 million in the U.S., noting that the drugs satisfying this demand are being sold off label and without marketing.
"We expect Vasovist to be a significant product and are excited about it," he said.
Kauffman noted that analysts have predicted sales for MR angiography could go beyond $200 million, if such a blood-pool agent were commercially available in the U.S.
Vasovist has been approved in 32 countries, including members of the European Union, as a contrast agent to help visualize noncoronary vascular disease.
Epix will begin working with the FDA's Division of Medical Imaging and Hematology Products to develop a jointly agreed-upon protocol for the blinded re-analysis of images.