Trial shows Celgene's oral psoriasis med works on patients who took Amgen's injectable Enbrel

Celgene ($CELG) touted postmarket study results of its oral antipsoriasis drug Otezla, which showed that the med works on those who switch over from Pfizer ($PFE) and Amgen's ($AMGN) injectable competitor Enbrel (etanercept). Celgene's med is taking on a top dog in Enbrel, whose 2013 sales ($8.8 billion) made it the world's second best selling drug.

The trial to evaluate the efficacy and safety of twice-a-day Otezla had an open-label extension phase during which all the placebo- and Enbrel-arm patients were switched to Otezla arm at week 16 of the 104-week trial.

Celegene says that 55% of those who switched from Enbrel to Otezla at week 16 (46 out of 83 patients) met the 52-week primary endpoint, as measured by their response to the Psoriasis Area and Severity Index, which incorporates the severity of three clinical signs of the skin condition as well the percentage of skin affected.

Slightly more than half (42 out of 83 patients) of patients randomized to Otezla at the initiation of the trial met the primary endpoint.

In general, patients who switched to from Otezla from Enbrel at week 16 had results comparable to those in the Otezla arm at trial initiation. Both groups demonstrated improvements in itching at week 16 and through week 52.

"Many patients with moderate to severe plaque psoriasis need treatment options that can help in managing multiple facets of the disease, including itching and impact on disease-related quality of life," said Dr. Kristian Reich of the SCIderm Research Institute in Hamburg, Germany, in a statement. "The encouraging findings presented at EADV (European Academy of Dermatology and Venereology Congress) add to the growing body of data which suggest that treatment benefits observed with Otezla at week 16 are maintained through week 52 of treatment."

Otezla was approved by the FDA for psoriasis in September 2014 and psoriatic arthritis in March of the same year.

The drug is expected to hit blockbuster territory by 2018, with $1.3 billion in sales by then, thanks in part to the convenience associated with pills, as opposed to injections. The oral formulation is a crucial form of product differentiation in an increasingly competitive therapeutic arena.

Otezla has hit some speed bumps this year though. In June, the U.K.'s federal gatekeeper, the National Institute for Health and Care Excellence (NICE), decided not to recommend Otezla to treat psoriatic arthritis. And in May German cost watchdog IQWiG said it doesn't see the added benefit of the med over treatments already on the market.

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