When Does Xtandi Patent Expire?

The earliest patent in the Xtandi portfolio has already lapsed (2026), so generic or biosimilar competitors are legally clear to enter the market for that specific composition or method. Later patents extending to 2037 may still cover specific formulations, dosing regimens, or manufacturing processes — these "secondary" patents are commonly the subject of Paragraph IV challenges by generic drug makers.

Because Xtandi's earliest patent has already expired, generic versions are technically clear to enter the market for that specific patented composition. Whether a generic is actually available depends on FDA Orange Book listings for any later patents, ANDA approvals, and any ongoing Paragraph IV settlements. Patients and prescribers should check the FDA's Orange Book or GoodRx for current generic availability.

For the authoritative listing of patents tied to a specific drug — the patents an ANDA filer is legally required to address under 21 USC § 355(j) — consult the FDA Orange Book. Underlying utility patent data on this page is sourced from USPTO PatentsView, the federal government's free public patent API.

Xtandi is protected by 7 US patents, a mid-sized portfolio that is typical for an established branded drug in mid-lifecycle. The portfolio likely combines a primary composition-of-matter patent (the strongest form of protection) with a layer of formulation, dosing, and method-of-use patents that extend exclusivity beyond the original composition expiry — a common strategy known as "patent layering" or, less charitably, "evergreening."

Xtandi patent rights are held across 2 entities: Astellas Pharma Inc., Pfizer Inc.. Multi-assignee portfolios usually reflect co-development partnerships, licensing splits between an originator and a marketing partner, or assignments made during corporate restructurings. Multi-party ownership can complicate generic entry — a challenger may need to clear patents from each holder separately, and settlements are harder to reach.

The Xtandi portfolio scores 59/100 (Grade C, "moderate") on the PatentCliff Strength index. The strongest signal is portfolio size (84/100), and the weakest is claims breadth (14/100). The four factors are weighted by how well they predict real-world resilience to generic challenge: portfolio size 30%, claims breadth 25%, time remaining 25%, and technology diversity 20%.

Looking at the 7 dated patents in the portfolio, the largest cluster (3 patents) falls in the "5–10 years (2032–2036)" bucket. That distribution matters because generic entry is gated by the latest unexpired blocking patent, not the earliest — even one late-expiring formulation patent can delay biosimilar launch by years if it survives a Paragraph IV challenge.

The 20-year patent term in the United States runs from the earliest non-provisional filing date, not the grant date. That means a patent granted in 2015 from a 2010 filing has only 15 years of life left at grant — a feature of US patent law that creates the layered "cliff" pattern visible in most branded drug portfolios. Patent Term Extension under 35 USC § 156 can add up to 5 years for time lost to FDA review, and pediatric exclusivity can add 6 months on top.