Market Intelligence

The Five Brand Drugs Facing the Heaviest Paragraph IV Pressure

FDA's public Paragraph IV list names exactly which brands are under active generic challenge — and how many filings deep.

By Knitify Market Intelligence Team • Radar Desk

May 26, 2026 • 3 min read

Quick Takeaways

What is a Paragraph IV filing?

When a generic drug sponsor files an ANDA, it must certify the status of each listed patent on the brand drug. A Paragraph IV certification states that the listed patent is invalid or won't be infringed — i.e., the generic intends to launch before the patent's stated expiration. It triggers a 45-day patent litigation window with the brand.

Does row count = number of generic competitors?

Not exactly. The row count reflects distinct molecule-strength-applicant combinations on the list. A single applicant can appear multiple times for different strengths of the same brand drug. The row count is a strong proxy for litigation intensity but not a 1:1 competitor count.

Most-targeted brand drugs by Paragraph IV filings

Rank	Brand (RLD)	Para-IV rows	Therapeutic anchor
1	OxyContin	8	Opioid analgesic (CNS)
2	Absorica	6	Severe acne (dermatology)
2	Focalin XR	6	ADHD stimulant (CNS)
2	Requip XL	6	Parkinson's / RLS (CNS)
5	Dilaudid	5	Opioid analgesic (CNS)
5	Doryx	5	Antibiotic (derm / ID)
5	Imbruvica	5	BTK inhibitor (heme-onc)
5	Risperdal	5	Atypical antipsychotic (CNS)
5	Simcor	5	Lipid combo (CV)
5	Solodyn	5	Antibiotic (derm)
5	Tirosint	5	Levothyroxine (endocrine)

OxyContin tops the list — a story long predicted, now operationally visible in the FDA database. The 5-and-6-tier brands span CNS, dermatology, hematology-oncology, cardiovascular, antibiotics, and thyroid — a wide therapeutic spread.

How to read this

Reader	Read
Brand corporate strategy	Multi-filing brands = your erosion model needs aggressive generic-entry timing
Generic sponsor	Crowded Para-IV space = first-filer 180-day exclusivity is harder to capture
Pharma BD	Brands NOT on the heavy-filing list with near-term LOE = more publicly under-priced erosion
Investor	Compare Para-IV row count vs. sell-side consensus erosion timing

Verifiable at the FDA Paragraph IV Certifications List.

Editorial commentary on publicly available regulatory and public-database data. Not investment, legal, regulatory, or medical advice.

References

FDA Paragraph IV Certifications List View Source →
FDA Orange Book (exclusivity windows) View Source →
Knitify Radar — Patent Cliff board View Source →

Tags:

Pharma Patent-cliff Generic-drugs Paragraph-iv Loss-of-exclusivity Market-intelligence

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