Types of pharmaceutical patent, and what each one actually blocks

One molecule, many patents

A new medicine typically arrives with one patent on the molecule and leaves the market with a dozen on everything around it. Each later patent was filed years after the first, so each expires years later. The commercial question is never “has the patent expired” but “which patents are left, what do they cover, and would our product fall inside them”.

The types

Compound (product) patent. Claims the molecule itself, or a class of molecules that includes it. It is the strongest patent: it blocks every form, dose, use and process involving the compound. It is almost always the “basic patent” for the SPC, and it is the one the dapagliflozin, apixaban and enzalutamide cases were fought over. When the compound patent and its SPC are gone, the molecule is free; what remains is a question of how you make and sell it.

Formulation patent. Claims a particular pharmaceutical form: a sustained-release tablet, a specific excipient system, a stable solution. It blocks that formulation only. A generic with a different formulation that achieves the same bioequivalence does not infringe, which is why these are often designed around, and why they are litigated when they cannot be.

Use (second medical use) patent. Claims the compound for a new therapeutic use, or a specific dosing regimen. Since the molecule is known, the patent protects only the use. A generic can be authorised with that indication carved out of its label (a “skinny label”), though whether the generic then induces infringement when prescribers use it for the patented indication has been litigated repeatedly. Bayer’s once-daily rivaroxaban patent was a dosing-regimen patent of this kind.

Process patent. Claims a way of making the compound. It blocks that route, and in Europe also products directly obtained by it, but not the compound made another way. Significant where the only practical synthesis is patented; otherwise a nuisance rather than a wall.

Polymorph and salt patents. Claims a particular crystalline form or salt. Often filed late in the compound’s life. Whether they block a generic depends on whether the generic can use a different form that is stable and bioequivalent, which is a chemistry question before it is a legal one.

Combination patent. Claims the compound together with another active substance. It blocks the combination product and may support its own SPC, though the Court of Justice has made combination SPCs harder to sustain where the combination was not the patent’s real invention.

Which patents carry SPCs

An SPC needs a “basic patent” that protects the product, and the regulation allows that patent to be a product, process or application patent. In practice SPCs sit on the compound patent, because that is the one that protects the authorised active substance most clearly. Formulation and use patents rarely support an SPC for the same product, and only one SPC per product per patent holder is allowed in each country.

Reading a product’s patent stack

For a given product in a given country, the useful order is:

1. Compound patent and SPC: when does the molecule become free?
2. Secondary patents in force after that date: list them by type and expiry.
3. For each, ask what your product does: same formulation? same indication on the label? same salt or form? same route of synthesis? If no, the patent may not matter; if yes, it is a live obstacle until it expires or falls.
4. Litigation status: has this patent been upheld or revoked anywhere, and in this country?

Secondary patents are filed under different numbers from the compound patent and are often not in the SPC register at all; a search by product or substance in the national patent register, and in the EPO’s register for pending European applications, is needed to see them.

What it means commercially

For generics and launch planners, the stack is the launch plan: the compound SPC gives the earliest possible date, the secondary patents decide whether the launch is clear, carved out, designed around or at risk.

For parallel traders, secondary patents are usually irrelevant to importing the originator’s own product, which the patentee put on the market; they matter where a generic is the product being moved.

For buyers, the stack explains why a product “off patent” since 2024 still has no generic in 2026 in one country but does in another: a formulation or use patent fell in one place and stood in the other.

MPA Search’s patents data focuses on the product and preparation patents and the SPCs that set the date for each molecule and country; the further patents affecting a specific product are what MPA’s expert support covers.