Pfizer, Opko's growth hormone med en route to October FDA decision

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The Biologics License Application for somatrogon is based on a global phase 3 study that pitted somatrogon against Genotropin in 224 children with growth hormone deficiency who had not been treated before. (FDA)

Pfizer and Opko Health have filed their once-weekly growth hormone deficiency (GHD) treatment for FDA approval, a decision the agency expects to make by October this year. The news comes after a phase 3 study showed the drug put less of a burden on patients than the established medicine, Pfizer’s Genotropin.

Genotropin, a recombinant human growth hormone, has been on the market for decades for the treatment of people with GHD. But like other human growth hormone treatments, it must be injected daily, a burden that has spurred research into longer-acting alternatives.

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The FDA approved the first such treatment for adults with GHD in August 2020: Novo Nordisk’s Sogroya, which, like Pfizer and Opko’s drug, is injected once a week.

Pfizer and Opko teamed up in 2014 to develop somatrogon, with the latter running clinical development and the former getting the drug through approval and then onto the market.

Its Biologics License Application is based on a global phase 3 study that pitted somatrogon against Genotropin in 224 children with GHD who had not been treated before. The study met its primary endpoint, with somatrogon doing no worse than Genotropin on a measure called height velocity—the vertical growth of a child during a unit of time—after one year.

While somatrogon achieved noninferiority against Genotropin, there’s another drug in development that beat the incumbent. In a phase 3 study, children who took Ascendis Pharma’s once-weekly drug TransCon hGH grew 11.2 cm, on average, compared to children who received Genotropin, who grew 10.3 cm. The FDA accepted Ascendis’ regulatory filing in September and expects to make a decision by June 25.

RELATED: 2020's New Drug Approvals | Sogroya

In October last year, Pfizer and Opko presented more data on their prospect from a phase 3 trial that tested a 12-week course of somatrogon followed by 12 weeks of Genotropin or vice versa. The goal of the study was to gauge whether patients and caregivers found the once-weekly drug interfered less in their lives than the incumbent did.

The trial used a life interference scale with possible scores ranging from seven to 35. Higher numbers indicate a greater burden. Somatrogon scored 8.63 on the scale. Genotropin scored 24.13, indicating that patients found the once-weekly product less of a burden.