Medical Treatment Patents UK 2026: What You Can Protect and What You Can’t

Medical treatment patents UK practice sits on a single, deceptively simple rule: you cannot patent a method of treating the human or animal body, but you can very often patent the product, formulation or purpose-limited use that delivers that treatment. For in-house counsel, R&D leads and life-sciences founders, the difference between an excluded method claim and a well-drafted product or second medical use claim is frequently the difference between a granted, enforceable monopoly and no protection at all. This guide sets out, for 2026, the statutory exclusion under the Patents Act 1977, how it interacts with the European Patent Convention, the claim formats that work in practice, and the evidence you need to support them.

The stakes are high because the exclusion is easy to trip over when translating a clinical insight into a patent claim. A dosing discovery, a new indication, or a combination therapy can each be protectable, or fatally unpatentable, depending purely on how the claim is framed. Below we map what medical treatment patents UK law permits, what it forbids, and how to draft around the boundary.

Quick primer, what is a patent and how it works in healthcare

A patent is a time-limited legal monopoly granted by the state in exchange for public disclosure of an invention. In the UK a patent can last up to 20 years from the filing date, subject to payment of renewal fees, and gives the proprietor the right to prevent others from making, using, selling or importing the protected invention without consent. In the life-sciences context, that monopoly is what underpins the commercial case for the significant cost of drug development, clinical trials and regulatory approval. (Note that supplementary protection certificates can, in defined circumstances, extend protection for certain medicinal products beyond the 20-year patent term.)

To be patentable in the UK an invention must be new, involve an inventive step, be capable of industrial application, and not fall within an excluded category. In healthcare, several things can be protected:

• Products. New chemical compounds, biologics, antibodies, vaccines, formulations and compositions.
• Uses. The first and subsequent (second) medical uses of a known substance.
• Devices and apparatus. Diagnostic instruments, delivery systems and medical devices that are not themselves methods practised on the body.

Applications in the UK are filed through the Intellectual Property Office (the operating name of the UK Intellectual Property Office, commonly the UKIPO), and the official procedural route is set out on the government’s apply for a patent pages. Many life-sciences applicants also route protection through the European Patent Office (EPO), which grants European patents that can take effect in the UK. Because EPO grant practice heavily influences UK outcomes, this guide addresses both.

The statutory exclusion, are medical treatments patentable in the UK?

The short answer is that methods of medical treatment are not patentable, but the therapies, products and specific uses behind them frequently are. The exclusion is deliberately narrow in its target: it removes clinical acts performed on the body from the patent system so that doctors and surgeons are not restrained by monopolies when treating patients. It does not remove the underlying medicine from protection.

Statutory text and plain-English translation

The exclusion is contained in section 4A of the Patents Act 1977, which provides that a patent shall not be granted for the invention of a method of treatment of the human or animal body by surgery or therapy, or a method of diagnosis practised on the human or animal body. Crucially, the same provision confirms that this does not prevent a product, in particular a substance or composition, from being patentable for use in such a method, including for a specified new use.

In plain terms: the act of treating a patient (the surgical or therapeutic steps performed on the body) is off-limits, but the substance or composition used in that treatment is not. That single distinction drives almost every drafting decision in this field.

What the exclusion does and does not stop

The exclusion stops you claiming, for example, “a method of treating disease X by administering compound Y to a patient.” It does not stop you claiming compound Y itself, a formulation containing it, or compound Y “for use in treating disease X.” Understanding the boundary avoids a common and costly error, filing a method claim that will never be granted, when a product or use claim protecting the same commercial activity was available.

• Excluded: surgical, therapeutic and diagnostic methods practised on the human or animal body.
• Not excluded: the compound, biologic or composition; the formulation; the first medical use of a known substance; and further (second) medical uses.
• Not excluded: diagnostic methods carried out on samples ex vivo, provided they do not include a step practised on the body.

The practical consequence is that medical treatment patents UK strategy is rarely about whether an invention can be protected at all, it is almost always about selecting the correct claim format to capture the commercial value without falling into the excluded category.

Interaction with EPC Article 53(c)

UK law is closely aligned with the European Patent Convention. Article 53(c) EPC excludes from patentability “methods for treatment of the human or animal body by surgery or therapy and diagnostic methods practised on the human or animal body,” while expressly preserving patentability for “products, in particular substances or compositions, for use in any of these methods.” Section 4A of the Patents Act 1977 mirrors this language closely, which is deliberate, the UK provision was introduced to bring domestic law into line with the EPC.

This alignment matters for two reasons. First, because European patents granted by the EPO can take effect in the UK, EPO examination practice and the decisions of its Boards of Appeal influence what can be obtained. Second, when a UK court later assesses validity or infringement, it interprets the exclusion consistently with the EPC. For applicants, the practical takeaway is that drafting to satisfy EPO practice on medical use claims will, in the great majority of cases, also satisfy UK requirements. Where the exclusion is concerned, the two systems speak substantially the same language.

Allowed claim strategies, what you can patent in practice

Once the exclusion is understood, the field opens up. There is a well-established toolkit of claim formats that capture therapeutic value while staying clear of the method prohibition. Selecting between them is the core skill in medical treatment patents UK drafting.

Product and composition claims

The strongest and broadest form of protection is a product claim to a novel compound, biologic or composition. If the active substance itself is new, a claim to the compound (or antibody, or vaccine construct) can cover uses of it across indications. This is the gold standard because it is not limited to a particular therapeutic purpose and is generally more straightforward to enforce against anyone making, importing or selling the substance.

A representative product claim reads:

“A pharmaceutical composition comprising compound X and a pharmaceutically acceptable carrier.”

Where the active ingredient is already known, a bare product claim will lack novelty. That is where the medical use formats become essential, they allow protection to attach to a new use of an old substance.

Second medical use: formats and examples

Second medical use claims are the workhorse of pharmaceutical patenting. They protect the discovery that a known substance is effective in a new therapeutic indication. Under current EPO and UK practice, the accepted format is the purpose-limited product claim, taking the form:

“Compound X for use in the treatment of disease Y.”

This format is permitted under section 4A of the Patents Act 1977 and the corresponding EPC provisions (Article 54(5) EPC). It confers a monopoly limited to the substance when intended for the specified new indication, not over every use of the compound.

Historically, applicants used the “Swiss-type” format (“use of compound X in the manufacture of a medicament for treating disease Y”). Swiss-type claims arose to circumvent the method exclusion before the purpose-limited product format was formally sanctioned. They remain valid in many granted patents and continue to be enforced, but the EPO no longer permits new Swiss-type claims for later-filed applications; the purpose-limited product claim is now the standard. When advising on a legacy portfolio, it is important to know which format applies, because the scope and enforcement characteristics of the two differ.

Devices and diagnostics

Medical device patents in the UK are treated quite differently from in-vivo methods. A device, a catheter, an implant, a delivery pen, a diagnostic analyser, is an article of manufacture and is patentable on ordinary criteria of novelty and inventive step. The method exclusion does not bite on the apparatus itself.

Diagnostics require more care. A diagnostic method practised on the body, one that includes the technical steps of examining or measuring the living body and, together with the intellectual step of attributing the results to a clinical picture, arrives at a diagnosis, can fall within the exclusion. But diagnostic techniques carried out on samples already removed from the body (blood, tissue, biopsy material) are generally patentable, as is the diagnostic device used to perform the test. The key question is whether the claimed method includes an essential step practised on the living human or animal body.

Second medical use and plausibility, prosecution and evidence for medical treatment patents UK

Obtaining a second medical use claim depends heavily on the evidence supporting the new therapeutic effect. Both the EPO and the UK apply a threshold commonly described in terms of plausibility: the application should make it credible, at the filing date, that the claimed substance achieves the asserted therapeutic effect. The precise formulation of this test has been the subject of important case law, including EPO Enlarged Board of Appeal decision G 2/21 on the reliance placed on post-published evidence.

How much data is enough?

There is no fixed quantum of data. The EPO Guidelines for Examination and the case law of the Boards of Appeal require that the specification, read with the common general knowledge, supports the asserted therapeutic effect. In practice this can be satisfied by in-vitro data, an established mechanism of action, a relevant animal model, or early clinical signals, the assessment is qualitative rather than a bright-line clinical-trial threshold.

• File as much supporting data as you can at the priority or filing date. Effects asserted with no credible basis in the application risk rejection.
• Post-filing data can support, subject to limits. Later evidence may confirm an effect, but reliance on it is constrained by the case law (including G 2/21); it generally cannot substitute for a technical effect that was not derivable from the application as filed.
• Explain the mechanism. A credible mechanistic rationale strengthens the case and helps to defend inventive step.

Claims for new indications versus known drugs

Where the compound is new, protection is broad and plausibility is less contentious because a product claim is available. Where the drug is already known, the whole value lies in the new indication, and the support for that indication is where the examiner, and later any challenger, will focus. Combination therapies raise the same issue: the inventive contribution is usually the therapeutic effect of the specific combination, so the data must support that combined effect, not merely restate the known effects of each component.

Common rejections and responses

• Lack of novelty. The prior art already discloses the substance for the same use. Response: narrow to the genuinely novel indication, patient sub-population or specific therapeutic purpose supported by the specification.
• Insufficiency. The examiner considers the therapeutic effect not credibly disclosed. Response: point to in-vitro/animal data and mechanistic reasoning already in the application; post-filing data may corroborate within the limits of the case law.
• Obviousness. The new use is said to follow from the prior art. Response: demonstrate an unexpected technical effect, a prejudice in the art, or a surprising result supported by the filed data.

Dosage regimens, treatment schedules and method claims, can you patent a dose?

Dosage regimen patents are among the most nuanced questions in medical treatment patents UK practice. The instinctive draft, “a method of treating disease Y by administering compound X at dose Z”, is an excluded method of treatment and will not be granted. Yet the discovery that a particular dose or dosing schedule delivers a surprising therapeutic benefit can be genuinely inventive and commercially critical.

Drafting dosage claims

The route through the exclusion is to cast the dosing feature as a purpose-limited product claim, following the second medical use approach. The established position, confirmed in EPO Enlarged Board of Appeal decision G 2/08, is that a new and inventive dosage regimen for a known substance can, in principle, be protected in the form:

“Compound X for use in the treatment of disease Y, wherein compound X is administered at dose Z according to schedule S.”

Here the dosing parameters are expressed as features of a purpose-limited product claim rather than as steps of a treatment method. The claim is directed to the substance for a defined therapeutic use, not to the clinical act of administering it. Formulation claims, where the dose or release profile is embodied in the physical composition itself, offer a further, often robust, alternative.

Evidence for inventive step

A dosage claim stands or falls on demonstrating a genuine, unexpected technical effect flowing from the specific regimen. Selecting a dose that a skilled clinician would arrive at through routine optimisation is unlikely to be inventive. The application should present data showing that the claimed regimen produces a result, improved efficacy, reduced toxicity, a distinct pharmacokinetic profile, that could not have been predicted, and for which the effect is credibly supported at filing.

Enforcement considerations

Because a dosage claim is drafted as a purpose-limited product claim, it is enforced against the product, for example a competitor’s medicine marketed, labelled or intended for the protected dose and indication, rather than against a clinician’s prescribing act. This makes the claim commercially usable while respecting the boundary that keeps clinical practice free of monopolies.

Enforcement and remedies in the UK, what to expect if your claim is infringed

The claim format you select does not only determine grantability, it determines how, and against whom, you can enforce.

When the method exclusion affects enforcement

Because true method-of-treatment claims cannot be granted, there is no direct patent route to sue a doctor or surgeon for performing a treatment. This is by design. For a proprietor, the practical implication is that enforcement is directed at commercial actors in the supply chain, manufacturers, importers and sellers of the infringing product, rather than at the point of clinical use. Product and purpose-limited product claims are therefore the enforceable currency of the field.

Second medical use claims raise their own enforcement subtleties. Where a competitor markets a known drug for a non-patented indication, but that same drug is prescribed off-label for the patented indication, questions arise about whether and how the second medical use claim is infringed. UK courts have considered factors such as the competitor’s packaging, labelling, and the foreseeability that the product will be used for the protected indication (see, for example, the litigation concerning pregabalin). These “skinny label” scenarios are among the most litigated issues in pharmaceutical patent enforcement, and the outcome is highly fact-sensitive.

Licensing and carve-outs in clinical use

Remedies for infringement in the UK can include injunctions, damages or an account of profits, delivery up or destruction, and declarations. Because the exclusion keeps clinical practice outside the patent monopoly, licensing strategies typically focus on the manufacturing and supply layer. Sophisticated licences may carve out particular indications, formulations or dose ranges, mapping onto the purpose-limited claim structure, to allow controlled commercialisation while preserving the proprietor’s position in the protected space. Where a European patent takes effect in the UK, enforcement proceeds under UK national law before the UK courts; note that the Unified Patent Court does not have jurisdiction over the UK, though applicants with wider European patent portfolios must still consider the UPC for participating states.

Practical checklist for drafting medical-treatment patent applications in the UK

• Lead with a product claim where the compound is new. It is the broadest and most enforceable protection.
• Use purpose-limited product claims for new uses of known substances. Draft in the “compound X for use in treating Y” format.
• Never rely on a bare method-of-treatment claim. Reframe every therapeutic method as a product or use claim.
• Cast dosing and scheduling as features of a purpose-limited product claim or embody them in a formulation claim.
• Front-load your data. File in-vitro, mechanistic, animal or clinical evidence sufficient to support each therapeutic effect at the filing date.
• Include fallback positions. Draft dependent claims to narrower indications, sub-populations, doses and formulations to survive prior-art challenges.
• Keep diagnostic steps off the body where possible. Direct claims to ex-vivo methods and to the diagnostic device.
• Plan the filing route. Decide between UKIPO, EPO and international (PCT) filing, and set priority strategy early.
• Align UK and EPO drafting. Because UK law is closely aligned with the EPC, a claim set that satisfies EPO practice will usually satisfy UK requirements.
• Consider enforcement at the drafting stage. Anticipate skinny-label and off-label scenarios and draft claims that are meaningful against supply-chain actors.

Comparison table, what you can protect vs what you can’t

Next steps, taking your medical treatment patents UK strategy forward

The rules on medical treatment patents UK applicants must navigate reward precise drafting and penalise the wrong claim format harshly: a discovery that is commercially decisive can be lost entirely if filed as an excluded method rather than a product or purpose-limited use. The most reliable protection combines robust product claims where the compound is new, well-supported second medical use and dosage claims where it is not, and an evidence package that supports the asserted effect at the filing date. Because UK law is closely aligned with the EPC, aligning your drafting with EPO practice serves both systems at once.

This guide is general information, not legal advice. Every therapeutic invention turns on its specific facts, data and prior art, and the boundary between an excluded method and a protectable use must be assessed case by case. Before filing, and certainly before any enforcement or licensing decision, obtain tailored advice from a qualified UK patent attorney or specialist solicitor who can review your data, draft to maximise scope, and align your UK and European filing strategy.

Sources

1. Patents Act 1977
2. gov.uk, Apply for a patent (UKIPO guidance)
3. European Patent Convention (EPO)
4. EPO, What are patents and what do they protect?
5. EPO Guidelines for Examination
6. WIPO, Patents overview