This morning Novartis (NVS) reported that its 4-year study of the heart drug serelaxin had flubbed the primary endpoint, failing to significantly cut the rate of cardiovascular death or reduce worsening heart failure among patients with acute heart failure.

Written by John Carroll (ENDpts.com)

Novartis Chief Medical Officer Vas Narasimhan said that the pharma giant will continue to look over the data to determine next steps but that the R&D journey would appear to be over.

Despite winning one of the first breakthrough drug designations at the FDA for this program, an FDA panel wasn’t persuaded by the data that Novartis offered. The agency formally rejected the drug in the spring of 2014, looking for the outcomes data from the 6,600 patients recruited for RELAX-AHF-2. The EU followed up soon after with a thumbs down as well.

Novartis execs had been convinced that serelaxin would be the next big thing in heart drugs, set on a course to blockbuster status. The data, however, wouldn’t cooperate with their plans and Leerink’s Seamus Fernandez was ready with the last rites:

Given the post-hoc nature of the previous analyses, relatively small number of clinical events, and lack of historical success for other agents in large acute HF trials, we had previously been cautious on the chances for a favorable benefit on mortality outcomes. According to previous discussions with MEDACorp KOLs, success in this trial would have created a strong ethical mandate for use; however we believe the failure essentially terminates all enthusiasm for the drug.

The latest and perhaps last setback on this drug leaves Novartis’ cardio division dependent on Entresto for its future. That drug has jumped off to a slow start, though, leaving analysts scratching their heads over the drug’s potential earnings. Entresto earned just $170 million last year, despite the company’s commitment to pay-for-performance contracts and a relentless effort to build the data and payer deals needed to make the drug a success.

As Amgen, Inc. (AMGN) and the Regeneron Pharmaceuticals, Inc. (REGN)/Sanofi S A (SNY) team found out the hard way with PCSK9 drugs, trying to market a new drug aimed at heart disease can be a devilishly difficult task.

That kind of resistance will make it increasingly hard for large players to tackle the big and expensive late-stage efforts that are needed to get these drugs across the finish line. Serelaxin may ultimately exercise exactly the opposite kind of influence that Novartis was looking for.