Eye on Pharma: Pfenex Reports Results of Human Factors Study for Follow-on Teriparatide

Drug maker Pfenex announced this week that it has completed its comparative use human factors study for its follow-on teriparatide product, PF708, referencing the osteoporosis drug Forteo. The follow-on was approved by the FDA earlier this month.

According to Pfenex, the study included 102 untrained participants, 52 of whom were patients with osteoporosis and 50 of whom were caregivers. Of the 18 critical tasks assessed, patients using the follow-on had fewer user errors or the same number of errors for 12 (67%) of those tasks. Among caregivers, there were equal numbers of user errors or fewer errors for 15 (83%) of the tasks.

No error difference, in either of the user groups, exceeded the prespecified maximum allowable difference.

In a statement, Pfenex’s chief executive officer, Eef Schimmelpennink, said that the outcome of the study “demonstrates noninferiority between the user interfaces of our product and Forteo,” and that the company will present the data to the FDA as part of a package that the regulator will review to evaluate therapeutic equivalence of the product with its reference.

Because PF708 was approved under the 505(b)(2) approval pathway instead of the biosimilar approval pathway, Pfenex can 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, PF708 will be evaluated for a determination therapeutic equivalence rather than an interchangeable designation.

When the follow-on was first approved, Schimmelpennink noted that, in order to optimize patient and payer impact, Pfenex’s partner Alvogen will launch PF708 once the FDA has made its decision on therapeutic equivalence for the product.