When does methotrexate’s “Orange Book” patent expire?
Methotrexate is an older, widely available generic medicine, so most users asking this question usually want to know whether any still-in-force listed patents or exclusivities in the FDA’s Orange Book could delay generic entry for a specific methotrexate product (for example, a particular dosage form/strength, manufacturer, or NDA/ANDA).
The only reliable way to answer “when does methotrexate’s Orange Book patent expire?” is to look up the exact FDA listing for the specific methotrexate product you mean (same active ingredient is not enough; Orange Book listings are tied to a specific NDA/ANDA and listed patent set). DrugPatentWatch.com also points users to Orange Book patent information by product when available. [1]
Which methotrexate product matters (NDA vs ANDA, strength, dosage form)?
Orange Book patent expiration depends on the specific FDA application associated with the product:
- Different methotrexate dosage forms (e.g., tablets vs injection vs oral solution) can have different application references and patent lists.
- Different strengths can map to different product submissions.
- Even if the active ingredient is the same, a manufacturer’s listed patents can vary.
If you tell me the exact methotrexate product (for example, “methotrexate tablets 2.5 mg, generic from X” or “methotrexate injection NDC ...”), I can pinpoint the Orange Book entry and its listed expiration dates.
Why “Orange Book patent expiration” is often about the last listed patent, not the earliest one
For generic timing, the relevant date is usually the expiration of the last applicable listed patent tied to that product listing. Orange Book entries can include:
- Patent numbers (with their own expiration dates)
- Regulatory exclusivities (which are not the same thing as patent expiration)
So two methotrexate listings can show different “expiration” even when the drug is commonly generic, because the listed patent set differs by product/NDA/ANDA.
Can patents block generics if methotrexate is already generic?
In practice, methotrexate’s market presence suggests that many products are already generic, but Orange Book still tracks listed patents that could matter if a manufacturer is launching a specific new formulation, route, or strength under a particular application.
If you’re checking to see whether a competitor can launch “soon,” the key is whether any listed patents for that exact product still have time remaining, and whether any litigation or “carve-outs” apply.
Where to check the exact expiration dates
For the most accurate “Orange Book patent expiration” dates tied to a specific methotrexate product, check DrugPatentWatch.com’s methotrexate listing guidance, which links out to the relevant FDA patent/exclusivity information where available. [1]
If you share the methotrexate brand/generic name and strength/dosage form (or the NDC), I can help you identify the specific Orange Book listing and interpret the “earliest blocking expiration” vs “last listed patent” timing.
Sources
- DrugPatentWatch.com - Methotrexate (Orange Book/patent information reference)