The US Food and Drug Administration (FDA) on Tuesday unveiled one revised draft guidance and another new draft guidance to help advance the development of generic transdermal and topical delivery systems (TDS).
Applied to a patient’s skin, TDS products are expected to deliver the correct medication dose consistently and for the expected length of time while adhering consistently and uniformly to the skin, even if exposed to water, humidity and movement.
“Because of the inherent complexity of delivering a drug through a TDS, making generic copies of these complex drugs can be especially hard,” FDA Commissioner Scott Gottlieb said, noting that many TDS products like drug patches have not faced timely generic competition.
Other new policies to help complex generics include the development of “new analytical tools and in vitro tests that may be more accurate and sensitive, and reproducible tools to demonstrating sameness between a generic and branded version of a complex drugs,” he added. “We’ll also be issuing an umbrella guidance to help generic drug developers address some of the most challenging regulatory and scientific issues encountered when they try to make generic copies of complex drugs. This umbrella guidance will be followed by a series of more targeted guidances to help address legal questions that may be blocking generic competition.”
Irritation and Sensitization
This 12-page guidance provides recommendations for Abbreviated New Drug Application (ANDA) sponsors on the design and conduct of studies to evaluate the in vivo skin irritation and sensitization (I/S) potential of a proposed transdermal or topical delivery system (collectively referred to as TDS).
Applicants should perform a comparative assessment of the generic and reference TDS products using an appropriately designed skin I/S study with human subjects, the draft notes, to demonstrate that the potential for a skin irritation or sensitization reaction with the T TDS is no worse than the reaction observed with the R TDS.
Study design and conduct, considerations for statistical analysis, overall assessment of adverse event data and format of data submissions are all outlined in the draft guidance.
“The recommendations relating to the design and conduct of I/S studies described in this guidance replace the recommendations related to I/S studies provided in product-specific guidances published before this guidance,” the agency adds.
This revised 9-page draft guidance supersedes a draft from June 2016 and provides recommendations for the design and conduct of studies evaluating the adhesive performance of a TDS.
“Depending on the objectives of a TDS product development program, applicants may choose to evaluate TDS adhesion in clinical studies performed to evaluate TDS adhesion only or in clinical studies performed with a combined purpose (e.g., for the simultaneous evaluation of adhesion and bioequivalence (BE) with pharmacokinetic (PK) endpoints),” the revised draft says.
Topics covered in the revised draft include the study design and conduct, considerations for statistical analysis, as well as recommendations on the combined evaluation of adhesion and bioequivalence.
Assessing the Irritation and Sensitization Potential of Transdermal and Topical Delivery Systems for ANDAs: Draft Guidance for Industry
Assessing Adhesion With Transdermal and Topical Delivery Systems for ANDAs: Draft Guidance for Industry