Origional article written in 2020. Uodated with recent law
changes in 2023.
The COVID-19 pandemic has highlighted the importance of
investigating the use of known medications for the treatment of new
diseases. Given the long road to clinical approval for new drugs,
the repurposing of existing drugs represents a promising avenue,
particularly in the face of fast-moving pandemics. Patents
protecting new uses of known drugs may also provide valuable
protection for innovators after expiry of the initial
composition-of-matter patent.
In this article, we consider so-called "second medical
use" patents from the perspective of European patent law.
Patenting second and subsequent medical uses
Where a substance or composition is already known for one
medical use, it may still be patentable for a second or subsequent
medical use, provided that use is novel and inventive (Art. 54(5)
EPC).
In the US and other territories, such uses may be protected by way
of method of treatment patents. However, in Europe, methods of
treatment are excluded from patentability. The new use of a known
medication must therefore be patented in a different way, as we
discuss below.
A second or subsequent medical use may relate to:
- the use of a known drug to treat a new disease ("Known drug/new disease"); or
- the use of a known drug to treat a known disease using a new therapeutic method ("Known drug/known disease/new therapeutic use")
Considering each in turn:
1. Known drug/new disease
In order to claim a second or subsequent medical use at the
European Patent Office, the following claim format should be
used:
"Product X for use in the treatment of disease Y"
While in most claims the phrase "for use" is interpreted
as "suitable for use", second medical use claims
represent an exception and are fully use-limited product
claims.
The treatment of more than one disease can be
covered by a single claim, provided that the treatment of those
diseases forms a single general inventive concept (Art. 82
EPC).
It is possible to define the condition being treated in
functional terms, for example "the treatment
of any condition susceptible of being improved or prevented by
selective occupation of receptor x". However, it is necessary
for the patent application to set out experimental tests or
testable criteria to allow the skilled person to recognise
conditions that fall within this definition, or that such tests are
common general knowledge in the art (T241/95). Furthermore, the
patent application should indicate specific examples of such
conditions, to ensure that the invention clearly relates to a
therapeutic application and not merely the discovery of a
pharmacological effect (T241/95).
In Europe, the product in a second medical use claim must be a
"substance or composition".
"Substances or compositions" are generally held to relate
to "the active agent" of a particular medical use, such
as those which act by pharmacological, immunological and/or
metabolic means. For example, a dye used for selectively staining a
component of the eye during surgery was considered a
"substance or composition" (T826/06).
In the past, formulations which achieve their therapeutic effect
through mechanical mechanisms were generally not considered to be
patentable using a second medical use claim. For example, an
injectable filler that, despite being made up of chemical molecules
such as collagen, achieves its role in surgery in view of its
macroscopic 3D form, was not considered a "substance or
composition" according to Article 54(5) EPC (T1758/15).
However, the decision in T264/17 suggests that a broader
interpretation of "substance or composition" that goes
beyond traditional chemical activity might be used. The Board of
Appeal held that the new use of a known lubricant for the
replacement of synovial fluid in diseased joints may be protected
using a second medical use claim. The lubricants are chemically
inert, but achieve their lubricating effect based on their
omniphobic properties, which are the result of their chemical
structure. The Board considered that, as the physiological effect
of the lubricant is achieved through a particular interaction (or
rather non-interaction) with biological tissue, it is secondary
whether the lubricants are deemed active agents in the traditional
sense.
Second medical use claims cannot be used to protect a new medical
use of any other type of product, for example a device (T2003/08,
T773/10). However, such claims can specify that a substance or
composition (e.g. a drug) is used in conjunction with a device, and
its use in conjunction with the device may be the sole novel and
inventive feature of this claim.
Language to avoid
Claims in the format "Use of product X in the treatment
of disease Y" or "A method of treating a subject
afflicted with/suffering from disease Y by administration of
product X" are not allowed as they relate to a method of
treatment and such methods are excluded from patentability in
Europe (Art. 53(c) EPC).
Claims in the format "Product X for use in treating a subject
afflicted with/suffering from disease Y" should be avoided as
there is a risk that the EPO may consider that such claims are not
actually limited to the treatment of disease Y.
So-called "Swiss-style claims" in the format "Use
of product X for the manufacture of a medicament for the treatment
of disease Y" are no longer valid for applications with a
priority date of 29 January 2011 or later.
2. Known drug/known disease/new therapeutic use
G2/08 clarified that a new medical use does not have to be
limited to the treatment of a new disease. It can encompass the
treatment of the same disease by a new therapeutic method, for
example a new dosage regime,
administration mode or patient
group.
Claims relating to such new therapeutic methods should take the
following form:
"Product X for use in the treatment of disease Y, wherein
product X is [new feature]."
For a new dosage regime, the above claim could
specify that, for example, the product is "administered three
times daily", or in a specific discontinuous administration
pattern (T1020/03). If the dosage regime claimed is a selection
from a broader known range, the existing case law with respect to
selection inventions applies.
For a new mode of administration, the above claim
could specify that product X is "administered topically"
or "administered subcutaneously", for example
(T51/93).
For a new patient group, the new group must be
distinguished from the known group by its physiological or
pathological status (T19/86, T233/96). Usually, the new group must
not overlap with the old group (T233/96). However, the Boards of
Appeal have held that novelty may also be established for a
subgroup of subjects that overlaps with a larger population of
previously treated subjects, if the identifying feature of the
subgroup was not previously known. The identifying feature may be,
for example, the treatment history of the patients (T1491/14) or a
biomarker predicting the responsiveness of the subjects to the
treatment (T694/16).
The new patient group must also not be arbitrary; a special
technical effect within the group claimed must have been observed
(T233/96). Examples of new patient groups include an
immunologically different population of animals e.g. sero-positive
piglets (vs sero-negative piglets, T19/86) or haemophilic patients
(vs non-haemophilic patients, T0893/90).
The new patient group can also be established by reference to a
diagnostic method in the claim. For example, reciting an active
step of determining the presence or absence of a biomarker, or
defining a population of patients having said biomarker, may render
a claim novel, even if the drug was known for the treatment of the
same disease (T734/12).
As with other inventions, these new therapeutic uses must still
fulfil the requirements of novelty, inventive step and
sufficiency.
Practice points
- It is possible to patent:
- the use of a known drug to treat a new disease; and
- the use of a known drug to treat a known disease using a new therapeutic method, e.g. a new dosage regime, administration mode or patient group.
- The correct claim format must be used:
- "Product X for use in the treatment of disease Y"; or
- "Product X for use in the treatment of disease Y, wherein product X is [new feature]."
- Method of treatment claims (e.g. "Use of product X in the treatment of disease Y" or "A method of treating a subject afflicted with/suffering from disease Y by administration of product X") are not patentable in Europe and should be reworded to one of the above formats.
- The product in a second medical use claim must be a "substance or composition" (usually the active ingredient); it is not possible to patent a new medical use of a known device.
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