Shares of

Amag Pharmaceuticals

(AMAG) - Get Report

rocketed on Thursday after the company said the Food and Drug Administration will give a speedy review to its latest submission for an iron-replacement therapy.

Shares of AMAG, which achieved a new 52-week low this week, added back $12.78, or 70%, to $31.15 after the update on the company's lead prospect, ferumoxytol.

The FDA indicated earlier this year that it wanted more information before approving ferumoxytol for iron-deficiency anemia in patients with chronic kidney disease. That shook investor confidence, but Amag's CEO, Brian Pereira, had maintained that the company likely wouldn't have to conduct additional trials and that it still expected to launch the drug in the first quarter of 2009.

The company said the FDA is aiming to make a decision by Dec. 30, allaying more investor fears that ferumoxytol might receive a longer, six-month review period.