222185 Analysis of the Generic Drugs Approved by the US FDA between 1980 and 2009

Sunday, November 7, 2010

Rosa Rodriguez-Monguio, PhD , School of Public Health and Health Sciences, University of Massachusetts, Amherst, Amherst, MA
Jing Hao, MPH , School of Public Health and Health Sciences, University of Massachusetts, Amherst, Amherst, MA
OBJECTIVES: Generic market competition reduces drug prices and increases access to pharmaceuticals after expiration of patents and market exclusivity periods. This study assessed the characteristics of generic approvals and the time from originator drug approval to first generic entry for drugs approved by the FDA in the period 1980-2009. METHODS: The study included all new molecular entities (NMEs) and therapeutic biologic applications (BLAs) approved by the FDA in the study period. Data derived from the FDA and were updated through 12/31/2009. Differences between group means and between proportions were assessed using t-test and chi-square test, respectively. Significant level was set at 0.05. RESULTS: The FDA approved 739 NMEs and 75 BLAs during the study period. After excluding drugs discontinuations, the analysis included 625 marketed NMEs. The FDA approved at least one abbreviated new drug application (ANDA) for 39.4% of marketed NMEs. There were ANDA approvals for 3 discontinued drugs. BLAs had not generic competition because a process for approval of generic BLAs has not been passed by Congress. There were 175 Paragraph IV patent certifications (required for ANDAs for originator products with unexpired patents listed in the FDA Orange Book-OB) for the NMEs approved after the Hatch-Waxman Act (1984). Paragraph IV certifications were filed for 50.0% of the 180 ANDAs for marketed NMEs approved after the Hatch-Waxman Act implementation. The patent and market exclusivity of 28.5% of the NMEs with generic competition had not expired at the moment of ANDA approval. There were 130 marketed NMEs without patents and market exclusivity listed in the OB that did not have ANDA approval. Orphan drugs had a higher percentage of NMEs without patent and market exclusivity and without ANDA approvals (61.5%) than non-orphan drugs (40.8%) (p<.01). No significant differences were found in ANDA approvals between priority and standard review drugs. Time from NDA approval to generic entry was on average 11.94.2 years (n=249), and varied by therapeutic class from 9.43.4 years for musculo-skeletal ANDAs (n=17) to 16.54.1 for dermatological ANDAs (n=12)(p<0.001). The top classes by number of ANDA approvals were cardiovascular (n=54, 11.43.5 yrs), nervous system (n=50; 10.23.2 yrs) and antiinfectives (n=30; 14.04.3 yrs). CONCLUSIONS: A large percentage of ANDA approvals had Paragraph IV certifications for patents listed in the OB that were not valid or enforceable. Orphan drugs had less generic competition than drugs for larger patient populations. There is a need for establishing a regulatory system for biologic generic approval.

Learning Areas:
Public health or related public policy

Learning Objectives:
Analyze the characteristics of generic drug entries in the US in the period 1980-2009. Assess differences in the generic approvals and effective patent and market exclusivity periods between priority and standard review drugs, and between orphan drugs and non-orphan drugs approved by the FDA in the study period. Understand the impact of FDA drug regulatory policy in the approval of generic drugs. Discuss the implications of the lack of a regulatory procedure for FDA approval of biologic generic alternatives.

Keywords: FDA, Drugs

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have conducted the study
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.