Massachusetts-based biotech AMAG Pharmaceuticals announced U.S. health regulators had sent them a “complete response letter” in answer to the company´s marketing application for their anemia drug Ferumoxytol.

Since August, the Food and Drug Administration (FDA) issues the complete response letter for drugs not ready for approval, instead of the approvable and non-approvable letters.

In the past, an approvable letter was seen as a sign that the drug could be approved if certain conditions were met. A not-approvable letter was seen as indication of more serious problems.
An AMAG spokeswoman said the company was not giving any details of the letter, but believed they could meet the FDA requirements without having to resort to additional clinical trials.

Analysts were a little jittery at the announcement, as they pointed out that both conditions – lack of detail and a challenge to the application – did not bode well for the company’s stock. However, on a whole they remained upbeat, and based on the company announcement, it seemed unlikely there would be a long delay for an approval of ferumoxytol.

AMAG said it continues preparations for the intended launch of ferumoxytol to treat iron deficiency anemia in chronic kidney disease patients during the first quarter of 2009.