Keywords: Adhesion, non-inferiority, generic TDS
In June, 2016, the Office of Generic Drugs (OGD) published a draft guidance: “Assessing Adhesion with Transdermal Delivery Systems and Topical Patches for ANDAs”. Historically, OGD had published product-specific bioequivalence (BE) recommendations that included guidance to industry on the methods for comparative evaluation of adhesion performance for test (TEST) and reference listed drug (RLD) transdermal delivery systems (TDS) and topical patches. With the advance of adhesion technology and the recent prevalence of TDS drug products that are considered to be "well-adhering", the statistical approach historically recommended for evaluating non-inferiority (NI) of adhesion did not have sufficient power to pass well-adhering TDS products. This statistical issue, compounded by several related issues, increasingly impacted the approvability and availability of generic TDS products for the American public. This presentation will discuss the underlying causes for the low power of the historical statistical method, research on alternative statistical methods to improve power for well-adhering TDS products, and the impact of the new statistical approach recommended in the new draft guidance on regulatory evaluation of generic TDS and topical patches.