The US Food and Drug Administration has granted breakthrough therapy designation to Novartis' serelaxin as a treatment for patients with acute heart failure.

The agency has concluded that the drug qualifies as breakthrough based on a Phase III trial which showed that patients who received serelaxin, also known as RLX030, had a 37% reduction in mortality at six months after an AHF episode compared to those who received conventional treatment. If approved, it could be "the first treatment breakthrough for AHF patients in 20 years", Novartis says.

Breakthrough therapy designation is distinct from the FDA's other fast-track programmes, such as accelerated approval and priority review, (although these can also be granted) as it involves "more intensive FDA guidance on an efficient drug development programme". David Epstein, head of Novartis Pharma, said that "commonly-used medicines for AHF only improve the immediate symptoms, so the additional effect on survival observed with RLX030 offers hope".

Serelaxin, a recombinant form of the hormone relaxin-2 which is present in both men and women, is currently being assessed by the FDA and the European Medicines Agency. Although the late-stage data Novartis reported in November last year was mixed, the firm has stressed that there is a clear need for new treatments that help relieve patients’ symptoms and protect the vital organs against damage during an AHF episode.

Serelaxin is the second breakthrough therapy designation Novartis has received from the FDA; in March; the agency backed LDK378 for a rare type of lung cancer.