Pfenex Announces Positive Top-Line Results for Proposed Follow-on Teriparatide

Drug maker Pfenex has announced positive top-line results from its phase 3 PF708-301 study, which showed comparable overall profiles between reference teriparatide (Forteo) and Pfenex’s proposed follow-on, PF708, in patients with osteoporosis. Teriparatide, a recombinant human parathyroid hormone, is an anabolic agent that stimulates bone formation.

The study enrolled 181 patients with osteoporosis who were randomized to receive either the proposed follow-on or the reference Forteo. In total, 82 patients in the follow-on arm and 81 patients in the reference arm completed the 24-week study.

The primary study endpoint was incidence of anti-drug antibodies (ADAs) at 24 weeks of treatment, and secondary endpoints included the mean percentage changes in lumbar-spine bone mineral density (BMD) and median percentage changes in bone turnover markers after 24 weeks, as well as pharmacokinetic parameters for up to 4 hours after the first dose. Safety was also assessed, using the incidence of adverse events (AEs).

In total, 2 patients in the follow-on arm and 2 patients in the reference arm developed ADAs during the study period, and “these low rates of immunogenicity are consistent with historical Forteo results,” as well as “with observations in follow-on biologics and biosimilars approved in the United States,” says the company.

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).

Pfenex also reported that there were no significant differences in the proportion of patients who experienced 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, they are regulated as drugs. As such, Pfenex will submit to the FDA a New Drug Application (NDA), rather than a Biologics License Application, for PF708. Pfenex says it will submit its NDA in the third quarter of 2018.

Other drugs in Pfenex’s follow-on and biosimilars pipeline include ranibizumab (referencing Lucentis), pegfilgrastim (referencing Neulasta), and Pegaspargase (referencing Oncaspar). The company is also developing novel anthrax vaccine candidates, funded by HHS, in an effort to meet the US government’s demand for dose-sparing anthrax vaccines.