Orange Book: Therapeutic equivalence evaluations

Over the past half-century, the prescription medication industry has witnessed phenomenal growth. To combat sharp increments in drug costs during the 1970s, states deployed laws and developed guidance material with the help of the Food and Drug Administration, writes Dr Nicola Davies in her monthly exclusive FDA Blog for The Pharma Letter.

Initially, the laws directed for these guides to be in the form of lists, created individually for each state, allowing or disallowing the substitution of non-branded or generic (economical alternative drugs) in place of branded (expensive) counterparts. The permissible list was to be engineered using a Positive Formulary Approach (PFA), while the non-permissible list would use a Negative Formulary Approach (NFA). Drug prices could be regulated in this manner by substituting one drug for another according to a “bioavailability” or “bioequivalence” rating.

With over 50 states to tend to, the FDA quickly found itself lacking the necessary manpower and centralized approach for such a critical and large-scale endeavor. The first version of the “Orange Book” was formulated as a prototype in 1978 to assist all states with a single, countrywide, literary resource. A combination of both PFA and NFA conclusions, the Orange Book began to serve as a reference publication to aid interoperability of state administrations, businesses, and the industry. The list’s format has remained relatively unchanged since its conception, now comprising a how-to section for using the guide, lists of discontinued as well as OTC/prescription drugs, and an index of the products available in the market.