FDA Proposes Withdrawal Of AMAG's Preterm Birth Drug Makena, Generics From Market

(RTTNews) - The FDA is proposing to withdraw AMAG Pharmaceuticals Inc.'s (AMAG) preterm birth drug Makena from the market because the required postmarket study failed to verify the clinical benefit of the drug.

Makena was granted accelerated approval by the FDA in 2011 to reduce the risk of preterm birth in women pregnant with a single baby who previously had spontaneous (unexplained) preterm birth. The companies whose drugs are approved under the "accelerated approval pathway" are required to conduct a post-approval confirmatory clinical trial to verify and describe clinical benefit. Only then, will the accelerated approval be converted into full approval.

In the case of Makena, the completed confirmatory trial, dubbed PROLONG, did not demonstrate a statistically significant difference between the treatment and placebo arms for the co-primary endpoints of reducing the risk of recurrent preterm birth or improving neonatal mortality and morbidity. The results of the PROLONG trial were announced last March.

Last October, an FDA panel, which met to review whether or not to allow Makena to remain in the market, voted 9-7 recommending withdrawal of the drug.

With the FDA's Center for Drug Evaluation and Research also now toeing the panel line, AMAG has 15 days to respond to the regulatory agency and also has the opportunity to request a hearing on the withdrawal.

If AMAG does request a hearing, and if its request is granted, a hearing would be conducted to decide whether to withdraw approval. This process can take months and during this time Makena and the approved generics of Makena will remain on the market, according to the FDA.

Makena and the generic equivalents are the only FDA-approved treatments available for pregnant women at risk for recurrent *preterm birth. (*delivery before 37 weeks of pregnancy). There are multiple approved generic equivalents of Makena.

As recently as October 1, AMAG agreed to be acquired by Switzerland-based Covis Group S.à r.l for $13.75 per share in cash, or approximately $498 million on a fully diluted basis and approximately $647 million on an enterprise basis, including debt obligations expected to be assumed or repaid net of cash. The transaction is expected to close in November.

AMAG is trading at $13.07, down 0.08%.