PDG38 ASSESSMENT OF GENERIC COMPETITION FOR ORPHAN DRUGS MARKETED IN THE US (1993-2019)

Abstract

The Orphan Drug Act of 1982 created the orphan designation for drugs for the treatment of rare diseases that affect less than 200 thousand patients in the US. This study evaluated generic competition of orphan and non-orphan new molecular entities approved by the US US FDA in the period 1983-2019. Data for all new molecular entities (NME) and orphan drugs approved by the FDA in the period 1983-2019 were compiled from the USFDA website. The study compared orphan and non-orphan drugs as a percentage of drugs without patent or market exclusivity and generic competition, the number of abbreviated new drug applications (ANDA), and the difference between the approval of a new drug application (NDA) and the first ANDA. Descriptive analysis, linear and logistic regression were conducted using IBM SPSS vs.25. The FDA approved 628 NME in the period 1983-2019 that did not have patent or exclusivity protection as of December 31, 2019. The analysis included 506 (80.1%) that were marketed by December 31, 2019, of which 104 (20.1) were orphan drugs. Generic competition occurred for 65 (62.5%) orphan drugs and 352 (87.6%) non-orphan drugs (p<0.0001). The period from the NDA to the first ANDA approval was 12.7+4.6 years for non-oprhan drugs and 12.2+- 5.6 years for orphan drugs (NS). The number of ANDAs was lower for orphan (7.2+-6.6, median 7) than for non-orphan drugs (15.5+-12, median=11). After controlling for other factors, orphan designation was significantly and negatively associated with generic entry, and the number of ANDAs approved by the FDA. No significant differences in time from NDA to ANDA approval were observed between orphan and non-orphan drugs. Orphan drugs experience less generic competition and have a lower number of generic drugs than non-orphan drugs reducing affordability to essential therapeutic alternatives.