A Diagnostics & Imaging Week
Epix Pharmaceuticals (Cambridge, Massachusetts) reported Monday that it has submitted a response to the "approvable" letter received from the FDA in January for MS-325.
MS-325 is anticipated to be the first in a new class of MRI blood pool contrast agents, and is specifically designed for magnetic resonance angiography (MRA).
The FDA indicated in the approvable letter that its principal questions related to the non-contrast MRA comparator scans used in the MS-325 clinical trials and to the statistical treatment of uninterpretable images. In the approvable letter, the FDA requested additional clinical studies to demonstrate efficacy prior to approval.
In its response, Epix provided new analyses of these issues, including analyses of the manner in which the non-contrast comparator scans were performed in the Phase III trials. The company said it believes these new analyses provide additional support for the conclusion that MS-325 is effective.
"In the response, we provided new analyses addressing each of the FDA's concern," CEO Mike Webb told listeners on a conference call Monday. "We believe that these new analyses provide additional support for the conclusion that MS-325 is effective based on data from the original four Phase III trials. We did not, however, include data from new clinical studies in our submission."
Webb said he wanted to give the FDA time to review Epix' response, and then "think about it, and discuss it with us."
He said that in the submission, the company included "new analyses of the manner in which the non-contrast comparator scans were performed in the Phase III trials."
"It is well-recognized that non-contrast MRA often produces poor quality images for a variety of reasons having to do with factors related to the physical limitations of the MRI scanners and patient characteristics such as vascular structure," Webb said in the call. "It is for that very reason that MS-325 was developed to improve the quality of MRA images. We believe our clinical trial results continue to demonstrate MS-325 is effective in improving the quality of MRA images."
Epix develops pharmaceuticals for imaging that are designed to transform the diagnosis, treatment and monitoring of disease. The company uses its Target Visualization Technology to create imaging agents targeted at the molecular level, designed to enable physicians to use MRI to obtain detailed information about specific disease processes.
The company's lead product candidate, MS-325, is the first imaging pharmaceutical specifically designed for MRA.
Schering AG (Berlin), a leader in MRI contrast agents, is the worldwide sales, marketing and development partner for MS-325. Schering AG submitted MS-325 for marketing approval in the European Union in June 2004. Epix also is collaborating with Schering in the development of its second drug candidate, EP-2104R, for imaging blood clots using MRI, and in a research partnership to discover novel compounds for MRI.