How many drugs are losing patent protection in 2021?

Drug Landscape tracks 1 marketed drugs with at least one patent expiring in 2021, sourced from FDA Orange Book + USPTO Patent Public Search.

What is a patent cliff?

A patent cliff is the year a major branded drug loses primary patent protection, opening the market to generic or biosimilar entry. Originator revenue typically drops 30–80% within 24 months, depending on the drug class and the strength of secondary patents.

Are these forecasts accurate?

Patent expiry dates are deterministic — they're the listed expiry from the Orange Book or USPTO record. Generic / biosimilar entry timing depends on litigation outcomes, paragraph IV challenges, settlements, and exclusivity periods which can shift the practical "cliff" by months to years.

Last reviewed 2026-05-14 · How we verify

2021 Pharmaceutical Patent Cliff

1 marketed drugs with patents expiring in 2021, joined to sponsor + therapeutic area + drug class. Historical archive. Sourced from FDA Orange Book + USPTO Patent Public Search.

1 drugs 1 patents 1 therapeutic areas Historical

Sponsors most affected (1)

AstraZeneca · 1 drug

By therapeutic area

Neuroscience (1)

2021-06-01 — Quetiapine 600mg · AstraZeneca · atypical antipsychotic

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2021 patent expiries dataset (CSV / JSON)

2021 Pharmaceutical Patent Cliff

Sponsors most affected (1)

By therapeutic area

Neuroscience (1)

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