美国罕见病药物_独占性_定价和受治患者（英文版）_23页_858kb

Summary of Orphan Drugs in the United States

Core Content

This document provides an in-depth analysis of orphan drugs in the United States, focusing on market exclusivity, pricing trends, and treated patient populations. It highlights the regulatory framework, economic implications, and challenges in diagnosis and treatment for rare diseases.

Key Findings

Orphan Drug Exclusivity

• The Orphan Drug Act of 1983 grants a seven-year market exclusivity for orphan drugs, but this is often shorter than patent protection.
• Of the 503 orphan drugs approved since 1983, 217 are no longer protected by either orphan exclusivity or patents.
  • Only 116 of these face generic or biosimilar competition, while 101 do not.
• The median annual spending for these 101 drugs in 2017 was $8.6 million, indicating limited commercial opportunities for generic competitors.
• Epogen is the highest-spending orphan drug in this group, with $200 million in spending, and the first biosimilar was launched in November 2018.
• Excluding the top eight drugs, the average spending for unprotected orphan drugs was $22.1 million, and the average time since exclusivity lapse was 10.5 years.

Pricing Trends

• Orphan drug prices have grown more slowly than the total branded market over the past 25 years.
• From 1993 to 2002, orphan drug prices grew faster than the overall branded market, but this trend reversed from 2003 to 2017.
• Orphan drugs generally exhibit lower price increases after receiving their first orphan designation.
• 10 of 12 periods before orphan designation and 19 of 31 periods after had observed price increases below the market benchmark.
• Some orphan drugs, like blood factor VIII, have seen significant price fluctuations, with a peak in 1996 and a sharp decline by 2017.

Treated Patient Populations

• Orphan drugs are intended for very small patient populations, typically below 200,000 patients per year.
• Approximately 10% of patients with rare diseases receive treatment with orphan drugs.
• About 25% of orphan drug indications target populations smaller than 5,000, with treated patients averaging 13.5% of disease prevalence.
• Some rare diseases have seen increases in prevalence due to better diagnosis and evolving clinical understanding, such as rosacea, which now affects nearly 16 million Americans.
• Only 3% of orphan-designated diseases have a prevalence above 200,000, often due to low financial returns or changing epidemiology.

Main Points

• Market exclusivity is a key factor in the sustainability of orphan drugs, but patent expiration is more commonly the reason for competition entry.
• High-priced orphan drugs typically treat fewer patients, suggesting a trade-off between cost and patient volume.
• Diagnosis and treatment of rare diseases are challenging, contributing to low treatment rates.
• Epidemiological data for rare diseases is inconsistent and subject to interpretation, due to limited patient registries and research variability.
• Orphan drug exclusivity does not prevent competition in non-orphan uses, nor in orphan uses where exclusivity has expired.

Conclusion

The Orphan Drug Act has played a crucial role in encouraging development of treatments for rare diseases, but market exclusivity is not always the main barrier to competition. Pricing trends show that orphan drugs are generally less expensive than the overall branded market, and treated patient populations are often small, which can limit commercial viability and competition. The identification and diagnosis of rare diseases remain major challenges, and efforts to improve awareness and treatment guidance are essential to ensure access and sustainability of these therapies.