Pfenex Submits Follow-on Teriparatide for FDA Review

Pfenex announced this week that it submitted to the FDA a New Drug Application (NDA) for its PF708, a teriparatide follow-on referencing Eli Lilly’s Forteo for the treatment of osteoporosis.

“We are pleased to submit to the FDA an NDA for PF708 as a proposed therapeutic equivalent to Forteo, which achieved $1.7 billion in global sales in 2017,” Eef Schimmelpennink, CEO of Pfenex, said in a statement announcing the submission. Schimmelpennink added that the timing of the submission could allow for a commercial launch of the follow-on as early as the fourth quarter of 2019, should the FDA approve the product.

The data package for PF708 includes 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 (ADAs) at week 24, and secondary end points included the mean percentage changes in lumbar-spine bone mineral density (BMD) 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.

In total, 2 patients in the PF708 arm and 2 patients in the reference arm developed ADAs during the study period. The follow-on and reference teriparatide demonstrated comparable effects, with no statistically significant differences observed, on lumbar spine BMD and on both N-terminal propeptide of type 1 procollagen (a marker of bone formation) and cross-linked C-terminal telopeptide of type 1 collagen (a marker of bone reabsorption). There were no significant differences in the proportion of patients who experienced adverse events (AEs), or in the severity of AEs, between the 2 study arms.

While teriparatide follow-on products are regulated as biosimilars in the European Union (and biosimilars including Gedeon Richter’s Terrosa and Stada’s Movymia have already been approved for marketing), in the United States, such products are regulated as drugs. As such, Pfenex has submitted an 505(b)(2) NDA rather than an abbreviated Biologics License Application for the product.

A key feature of 505(b)(2) NDAs is that the pathway allows manufacturers to submit their drug products for FDA review by including data collected by the reference product sponsor, though, like the biosimilar approval pathway, the follow-on must be shown to be similar to the reference through bioanalytical testing, preclinical studies, and (in some cases) clinical trials. According to Pharmacy Times^®, a sister publication of The Center for Biosimilars^®, another key feature of the pathway is that drugs approved via 505(b)(2) NDAs are eligible for 3 to 5 years of market exclusivity (versus a potential 6 months of market exclusivity for drugs approved as first generics).