Effective Patent Life of Antiretroviral Drugs in the U.S 1987-2006

Abstract

Society is faced with balancing the reward from innovation for finding new drugs with adequate access to affordable drugs, especially for drugs targeting life-threatening diseases. This study examines the effective patent life periods of antiretroviral (ARV) new molecular entities (NMEs) approved for marketing in the United States between 1987 and 2006.

The study included all NMEs approved during the period 1987-2006 with at least one patent listed in the FDA Orange Book (OB). Drugs discontinued from the market were excluded from the analysis. The main sources of data were the FDA and the U.S. Patent Office. Data was updated to December 31, 2006. Summary descriptive statistics by year were computed for the variables included in the analysis. A comparison between the effective patent life (time from FDA drug approval to patent expiration) of ARVs and other NMEs was performed. The first and last patents were used to estimate the minimum and maximum effective patent life when several patents were listed in the OB for an NME. Group differences were assessed using group comparison t-tests. SPSS vs. 14 was used for the analysis.

A total of 532 NMEs were approved by the FDA during the study period. 105 NMEs did not have a patent listed in the OB and 43 were discontinued. All ARVs NMES (n=21) and 363 NMEs from other therapeutic classes were included in the analysis. An average of 4.10±3.48 patents for ARVs and 2.80 ±2.17 patents for other NMEs were listed in the OB. ARVs were more likely than other NMEs to be review by the FDA using fast track (85.7% AVRs vs. 9.6% other NMES) and priority review (95.2% vs. 38.0%) procedures.

The study found a statistically significant difference (p<0.01) in effective patent life of ARVs versus other therapeutic classes. ARVs had an average of 13.8±3.3 years of effective patent life for the first patent vs. the 10.9±4.2 year for other NMEs. Also, the ARVs had an average of 17.61±3.57 years of effective patent life for the first patent vs. the 14.82±4.73 year for other NMEs. The effective patent life listed in the OB for the last patent of 7 ARVs (33.3%) exceeded 20 years.

This different in post-marketing effective patent life derived from a shorter ARV development time and a statistically significant shorter ARV FDA review time (0.5±0.2 years for ARVs vs. 1.9±.1.4 years for other NMEs).

Differences in patent life between ARVs and other NMEs are explained by a shorter pre-NDA time and FDA NDA review time. Shortening the drug approval process increased post-NDA patent life and facilitated faster entry to new drugs into the market. Pharmaceutical companies marketing ARVs have an average of 3 more years of patent protection than other therapeutic classes in the U.S., and therefore a longer period without generic competition in the market to recover the investment in ARVs research and development. On the other side, longer protection limits competition and consumers end up paying higher prices for patented ARVs than they would have paid otherwise for generic substitutes.

Keywords: antiretroviral drugs, new molecular entities, patents, exclusivity, U.S.FDA.

JEL Classification: I10, I19, I12