505(b)(2) Approval Pathway: Not Necessarily Shorter Approval Times
With a goal of avoiding unnecessary duplication of studies performed on a previously approved drug, the 505(b)(2) pathway allows for a more streamlined development and approval process, but for new drug applications (NDAs), the pathway has not led to shorter approval times, according to a recent analysis conducted by the Tufts Center for the Study of Drug Development.
Background
Established under the Hatch-Waxman Amendments of 1984 to the Federal Food, Drug, and Cosmetic Act, the 505(b)(2) pathway expressly permits the US Food and Drug Administration (FDA) to rely, for approval of NDAs, on data not developed by the applicant.
In terms of the type of information an applicant can rely on in an application that is based upon studies “not conducted by or for the applicant and for which the applicant has not obtained a right of reference,” FDA guidance points to: Published literature or the agency’s finding of safety and effectiveness for an approved drug,
The pathway is attractive to drugmakers because it can shorten the development time and decrease costs, and 505(b)(2) applicants may also qualify for three to five years of market exclusivity.
New Tufts Review
From 2009 to 2015, Tufts found that 63% of 451 original new drug applications approved by FDA were for drugs approved via the 505(b)(2) pathway, but mean approval times for such applications was nearly five months longer than that for new molecular entities (NMEs).
Part of that lag can be attributed to 505(b)(2) applications receiving fewer expedited review designations from FDA than NMEs during the time period studied, though it also seems these 505(b)(2) applications were not as ready for approval as their NME counterparts. Tufts found about half of 505(b)(2) applications were approved on the first cycle during 2009-15, compared to 78% of all NME applications for 2014 and 85% for 2015.
"Our findings suggest that drug developers should not anticipate a 505(b)(2) application will necessarily result in a shorter approval time or limited FDA requirements," said Joseph A. DiMasi, director of economic analysis at Tufts CSDD and principal investigator for the study. "As with any drug development program, it's important to engage proactively with the FDA to better understand the data needed to bridge a 505(b)(2) program with the approved reference product."
The Tufts report offers similar results to a study from Thomson Reuters from 2015 that found median approval times for 505(b)(2) reviews were slower by 46 days for standard-review drugs and 24 days for expedited-review drugs.