FDA Approves Pfenex's Follow-on Teriparatide, PF708

The FDA has approved Pfenex’s follow-on teriparatide, PF708, referencing Forteo, for the treatment of osteoporosis in patients at high risk for fractures.

“We believe PF708 has the potential to significantly enhance patient access to an important therapy as a cost-effective alternative to Forteo, which had $1.6 billion in global sales in 2018,” said Eef Schimmelpennink, chief executive officer of Pfenex, in a statement announcing the product’s approval.

The data package that supported approval of PF708 included data from a 24-week study in 181 patients with osteoporosis, results of which were announced earlier this year. The primary end point of the study was incidence of antidrug antibodies at week 24, and secondary end points included the mean percentage changes in lumbar-spine bone mineral density and median percentage changes in bone turnover markers after week 24, as well as pharmacokinetic parameters for up to 4 hours after the first dose.

Now that Pfenex has cleared its regulatory hurdle, next for the drug maker is a $2.5 million milestone payment from its partner, Alvogen, for having attained FDA approval. Alvogen will commercialize and manufacture the follow-on in the United States.

Although many products that are currently treated as drugs by the FDA, including insulins and hormones, will be regulated as biologics beginning in 2020, teriparatide is not on the FDA’s preliminary list of products that will make that regulatory transition. As such, Pfenex submitted an 505(b)(2) New Drug Application for PF708 rather than an abbreviated Biologics License Application.

As a result of following the 505(b)(2) approval pathway, the partnership can now also seek pharmacy-level substitutability for the product without having to undertake the kinds of extra clinical studies that a biosimilar would be subject to if seeking an interchangeable designation; because it is a follow-on and not a biosimilar, Pfenex and Alvogen can seek a determination of therapeutic equivalence, rather than an interchangeable designation, from the FDA.

According to Schimmelpennink, in order to optimize patient and payer impact, Alvogen will launch PF708 once the FDA has made its decision on a therapeutic equivalence rating. The company expects to file a comparative human factors study report with the FDA as early as this month.

In Europe, where the partnership has also filed for approval of PF708, teriparatide follow-ons are treated as biosimilars. If approved in Europe, the product will compete with Gedeon Richter’s already approved and launched Terrosa, also sold as Movimya.