FDA rejects Novartis' 'breakthrough' cardio drug serelaxin

The FDA's still-fledging Breakthrough Therapy Designation promises a speedy review and a front-row seat with regulators, but, as Novartis ($NVS) found out, it doesn't guarantee approval. The agency rejected the heart drug serelaxin, the latest blow to a treatment Novartis hoped would be a cornerstone of a cardiovascular franchise.

In its letter, the FDA said it needed more evidence of efficacy before it could approve the treatment, a synthetic form of the the hormone relaxin designed to ease blood vessels and treat acute heart failure. That means holding out for data from Novartis' ongoing Phase III trial, a 6,300-patient outcomes study with results expected by 2016.

The agency's move comes as little surprise after a panel of FDA advisers voted unanimously against recommending approval for serelaxin in March, taking the drugmaker to task over the design of its pivotal trial, gaps in the provided data and serious questions over serelaxin's efficacy. Echoing a particularly harsh review from FDA staff, the panel said Novartis failed to confirm the drug's effect on shortness of breath and the rate of heart failure.

Despite the setback--and a January rejection from the European Medicines Agency--Novartis remains confident in its cardio drug, believing it can eventually launch the treatment worldwide and dull the effects of patent losses to top-sellers like Diovan and Gleevec.

"We continue to believe [serelaxin] has the potential to be an important treatment for AHF and have been encouraged by feedback from FDA advisory committee members noting the data are intriguing," Global Head of Development Tim Wright said in a statement. "In accordance with the FDA's advice, we will continue to expedite our clinical trial program to build the supporting body of evidence."

Serelaxin was among the first drugs added to the FDA's stable of so-called breakthrough therapies, joining a program that has shepherded the likes of Roche ($RHHBY), Johnson & Johnson ($JNJ) and Gilead Sciences ($GILD) to early approvals. Novartis long touted the drug as a blockbuster in the making, expecting sales to peak well above $1 billion a year.

- read the statement