Pfizer’s bid to buttress its presence in a pediatric rare disease has hit a snag, giving competitor Acendis Pharma a longer runway to gather speed with a newly approved treatment.
The FDA has rejected somatrogon, a potential treatment for pediatric growth hormone deficiency, Pfizer and partner OPKO Health said Monday.
The complete response letter came as a surprise, given the drug is approved for that condition under the brand name Ngenla in Japan, Australia and Canada. An official go-ahead in Europe is also expected soon after the European Medicines Agency’s Committee for Medicinal Products for Human Use doled out a positive opinion in December.
Pfizer didn’t offer details on the nature of the problem but said it’s evaluating the FDA’s comments and will work with the agency to find the right path forward.
Ngenla is a recombinant growth hormone designed to compensate for inadequate production in patients. While existing hormone products require daily injections, Ngenla comes as a once-weekly treatment. The disease, which is estimated to affect about one in 4,000 to 10,000 children, can cause unusually slow body growth and short stature in adulthood.
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In a global phase 3 study in 224 previously untreated children, once-weekly Ngenla showed comparable efficacy to Pfizer’s own once-daily Genotropin in terms of patients’ annual height growth rate after one year
Pfizer lost a first-mover advantage for a long-acting pediatric growth hormone deficiency drug in the U.S. when Ascendis Pharma won an FDA go-ahead in August for Skytrofa, which is also given once every week. Skytrofa earned that nod with one-year phase 3 head-to-head data against Genotropin.
Ngenla’s efficacy and safety data looked similar to Skytrofa’s, Jefferies analyst Maury Raycroft, Ph.D., said in a Monday note.
In hindsight, Pfizer did face additional risk after the FDA delayed a decision in September and requested longer-term data, Raycroft noted. At that time, OPKO said Pfizer had submitted longer-term phase 2 and phase 3 data from open-label extension analyses.
There were concerns about development of anti-drug antibodies in some patients. But Raycroft pointed out that these antibodies didn’t seem to affect Ngenla’s efficacy or safety.
Besides the drug itself, manufacturing or quality problems might have driven Pfizer's complete response letter, too, Raycroft added.
Pfizer licensed Ngenla through a 2014 tie-up with OPKO for $295 million up front. Even though the two companies share some of the drug’s earnings, Pfizer has every reason to get Ngenla approved and launched aggressively, given its shrinking share with daily Genotropin, Raycroft said.
Although Ascent’s Skytrofa’s launch seemed slower than expected at this point, the market will eventually switch to weekly options, the Jefferies analyst concluded.