Parsing Roche's IPF bet
How Roche can use mortality data, new indications to create Esbriet blockbuster
InterMune Inc.'s third Phase III trial transformed it from a forgotten company with $70.3 million in 2013 sales of one Orphan product to a takeout play worth $8.3 billion to Roche. The question now is whether the mortality data on Esbriet pirfenidone in idiopathic pulmonary fibrosis will be good enough to monetize the pharma's acquisition. The key might be expanding into other indications.
In 2009, InterMune reported mixed data from two Phase III trials. Esbriet met the primary endpoint of improving mean change in forced vital capacity (FVC) at 72 weeks in the CAPACITY2 trial, but missed the same endpoint in CAPACITY1. The data were enough to get Esbriet approved in Europe in 2011 and Canada in 2012. But in a 2010 complete response letter, FDA asked for a third Phase III trial, the ASCEND study, despite a positive recommendation from its Pulmonary-Allergy Drugs Advisory Committee.
In February, InterMune said Esbriet met ASCEND's primary endpoint of reducing the proportion of patients experiencing a more than 10% reduction from baseline in FVC or death at week 52 vs. placebo (16.5% vs. 31.8%, p<0.000001).
A second component of the primary endpoint showed that Esbriet improved the proportion of patients with no reduction in FVC from baseline vs. placebo (22.7% vs. 9.7%, p<0.000001).
In addition, a pre-specified pooled analysis of ASCEND and the two CAPACITY studies showed Esbriet significantly reduced all-cause mortality and treatment emergent IPF-related mortality vs. placebo at week 52 (HR=0.52, log rank p=0.0107; HR=0.32, log rank p=0.0061).
What cannot be said with certainty is how much longer patients treated with Esbriet would survive vs. placebo, as the data only measured survival at one year.
Both the ASCEND data and the pooled analysis have been added to an NDA that InterMune resubmitted in May. The PDUFA date is Nov. 23. FDA granted breakthrough therapy designation in July.