PTC notches up full house of failures in CF with ataluren, dumps program

The biotech's shares were hammered this morning on the news.

PTC Therapeutics has seen its Europe-approved Duchenne muscular dystrophy (DMD) drug ataluren flop spectacularly in its key phase 3 cystic fibrosis test, as it now plans to can all trials and attempts to get it onto the market in this disease setting.

The biotech was gunning for success in nonsense mutation cystic fibrosis (nmCF), but data out this morning showed a double whammy of bad news as it failed to hit both the primary and secondary endpoints across nearly 300 patients.

The primary endpoint was centered on lung function while the secondary was the rate of pulmonary exacerbations, but PTC’s drug failed to beat out placebo in statistical significance on both of these counts.   

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Given this flop, unsurprisingly PTC said it “plans to discontinue current clinical development of ataluren in cystic fibrosis, close ongoing extension studies and withdraw its application for marketing authorization in cystic fibrosis in Europe.”

Ataluren did recently gain European approval in DMD under the name Translarna (although this came off the back of some poor trial data).

But it is not approved in the U.S., where the FDA said it wouldn’t even look at the med, although PTC is still fighting that decision.

“We are disappointed with the outcome of this trial as there are no treatments that target the underlying cause of nonsense mutation cystic fibrosis, one of the most difficult forms to treat,” said Stuart Peltz, Ph.D., CEO of PTC Therapeutics. “We are particularly grateful to patients and investigators who participated in our trials. We remain committed to patients receiving ataluren in other indications.”

PTC is also working on RG7916, a candidate hoping to rival Biogen and Ionis in the rare, fatal infant disease SMA. The candidate is backed by Roche. 

Analysts at Barclays said in a note to clients: "Given the negative CF headline and modest expectations of success, we would expect PTCT shares to be weak, down potentially ~$3/share, but notably value in nmDMD and to a lesser degree SMA should provide a floor for the stock. The company provided few other details around the miss, but noted that work continues in the nmDMD program, including sales in the EU and SMA program partnered with Roche."

The company dropped 18% premarket on the news.