The short version
- The average number of patents per small-molecule drug tripled between 1990 and 2019, driven largely by nonprimary filings.
- These secondary patents extended the period of market exclusivity by approximately four years on average, delaying affordable generic entry.
- Researchers recommend regulatory reforms to curb patent thickets that lack meaningful therapeutic innovation.
A significant shift in pharmaceutical intellectual property strategy has substantially prolonged the period during which brand-name drug manufacturers maintain market exclusivity. Research published recently in the Journal of the American Medical Association indicates that the proliferation of secondary patents has extended protection periods from an average of two years in 1990 to more than six years by 2019. This expansion occurs without corresponding advancements in clinical efficacy, effectively delaying the introduction of lower-cost generic alternatives and sustaining higher prices for patients and insurers.
The study, led by S. Sean Tu of the University of Alabama, analyzed data on small-molecule drugs approved by the Food and Drug Administration between 1990 and 2019. During this thirty-year window, the average number of patents associated with each approved drug rose from 2.1 to 6.9. The vast majority of this growth stemmed from nonprimary patents, which accounted for 84 percent of the 10,940 total patents filed on the 1,981 drugs examined. These secondary filings typically cover minor adjustments to inactive ingredients, new methods of administration, or design features of delivery devices such as auto-injectors, rather than the active pharmaceutical ingredient itself.
This accumulation of intellectual property claims creates what legal and economic experts term a patent thicket. By layering multiple patents around a single therapeutic product, manufacturers can complicate the regulatory landscape for generic competitors. Even if the primary patent on the active ingredient expires, secondary patents may still block market entry. The researchers noted that this strategy allows brand-name firms to charge monopoly prices for longer durations, limiting price competition that would otherwise benefit the broader healthcare system and reduce unnecessary spending.
The financial implications of these practices are evident in national spending trends. According to analysis by the Peterson-KFF, inflation-adjusted per capita spending on prescription drugs in the United States increased from $291 in 1990 to $1,084 in 2019. More recent data from the Commonwealth Fund suggests that Americans currently spend nearly twice as much on prescription medications as residents of other high-income nations. While various factors contribute to these disparities, the exploitation of patent law mechanisms stands out as a structural driver of elevated costs.
It is important to note that the study’s findings likely represent a conservative estimate of current conditions. The researchers focused on drugs approved up to 2019 and included only a five-year follow-up period for patent activity. However, they observed that patent filings are now extending up to nine years after initial FDA approval. This suggests that the gap between brand-name exclusivity and generic availability may be widening further in recent years, exacerbating the financial burden on consumers.
Drug manufacturers often argue that additional patents do not inherently delay generic competition, citing examples from earlier decades when patent thickets were less prevalent. However, the study authors point out that these historical comparisons are misleading because the scale and complexity of secondary patenting have grown significantly since 2010. The current environment is characterized by a strategic use of intellectual property to maintain market control rather than to protect genuine therapeutic innovation.
The researchers did not directly measure the specific delays in generic drug availability, acknowledging this as a limitation of their methodology. Nevertheless, the correlation between the rise in nonprimary patents and extended exclusivity periods is clear. The authors emphasize that without intervention, these practices will likely continue to entrench long periods of market dominance that are disconnected from meaningful medical advancements.
To address these issues, Tu and colleagues propose several regulatory reforms. They recommend increased scrutiny by the United States Patent and Trademark Office to prevent the approval of trivial or incremental patents. Additionally, they suggest legislative measures to limit minor add-on patents and empower courts to order disgorgement of profits from companies found to have abused patent systems. These changes aim to restore balance between innovation incentives and public access to affordable medication.
The findings underscore a growing tension between intellectual property rights and healthcare affordability. As patent thickets become more complex, the barrier to generic entry rises, keeping prices artificially high. Policymakers face the challenge of designing regulations that protect legitimate research investments while preventing the strategic manipulation of patent law to delay competition. The study serves as a call for systemic review of how patent practices impact drug pricing and patient access.
Future research will need to examine the direct impact of these patent strategies on specific drug classes and market outcomes. Understanding the precise mechanisms by which secondary patents delay generic entry will be crucial for developing effective policy solutions. Until then, the trend toward extended exclusivity through patent accumulation remains a significant factor in the ongoing debate over prescription drug costs in the United States.
Sources behind this briefing
Go to the original reporting
- Ars Technica↗To keep drug prices high, pharma has been piling up the patents
