FDA rejects Novartis' breakthrough heart failure drug

It seems breakthrough status is no guarantee of an easy ride at the FDA, as the US regulator showed a red light to Novartis' acute heart failure drug serelaxin and asked for more data.

The FDA's decision that it needs further clinical evidence of serelaxin's efficacy was, however expected, given that the drug was rejected by an advisory committee earlier this year.

Novartis filed for approval of the relaxin receptor agonist on the strength of a single phase III trial called RELAX-AHF. This trial indicated the drug was effective in improving shortness of breath and delayed worsening of AHF after hospitalisation.

However, the design of the trial was criticised by FDA reviewers who were concerned that the drug – which has been given the proposed brand name Reasanz - had little impact on other heart failure symptoms.

Now Novartis is conducting a second late-stage trial of serelaxin, which will enrol more than 6,000 patients but is unlikely to generate results for a couple of years.

Novartis remains confident that serelaxin will eventually make it to market, with global head of development Tim Wright saying: "We continue to believe RLX030 has the potential to be an important treatment for AHF."

The feedback from the advisory committee that the RELAX-AHF data are "intriguing" has encouraged the company to press ahead with a second study, which will be called RELAX-AHF 2.

Serelaxin was also knocked back by the EMA's Committee for Medicinal Products for Human Use (CHMP) earlier this year, although Novartis said it planned to refile the dossier seeking conditional approval on the strength of new data analyses while it waits for results of the second phase III trial.

The FDA granted breakthrough status to serelaxin last June on the grounds that there has been no treatment advance in AHF for more than two decades. Analysts have predicted the drug could make peak sales of between $500m and $1.5bn a year if it eventually reaches the market.