Plausibility - A Review of the English and EPO cases

G2/21 and the English
Approach to Plausibility
24 Oct 2023 09:00 - 10:00
Jane Lambert
4-5 Grayʼs Inn Square
London, WC1R 6AH
The Media Centre
9 Northumberland Street
Huddersfield, HD1 1R:
www.nipclaw.com

Background
There is nothing in either art 52 (1) EPC or s.1 (1) of the Patents Act 1977 that expressly
requires an invention to be plausible.
But maybe such a requirement is implied by the conditions that an invention must
involve an inventive step and be capable of industrial application.
It may also be implied by art 83 EPC and s.14 (3) of the Patents Act which obliges
applicants to disclose their inventions in a manner suﬀiciently clear and complete for
them to be carried out by a person skilled in the art.

The Technical Board of Appeal rejected an appeal from the Examining Division to refuse
a patent for an “Element and energy production device” on the ground that the
application did not disclose the invention in a manner suﬀiciently clear and complete
for it to be carried out by a person skilled in the art. The invention was a type of cold
fusion. The Board upheld the finding of insuﬀiciency and added “an invention or an
application for a patent for an alleged invention which would not comply with the
generally accepted laws of physics would be incompatible with the requirements of
Articles 57 and 83. because it cannot be used and therefore lacks industrial
application.”
T0541/96 Zachariah’s Application

T 1063/06 Reach-through claim/Bayer Schering
A formulation of a claim whereby functionally defined chemical compounds are to be
found by means of a new kind of research tool using a screening method set out in the
description constitutes a reach-through claim which is also directed to future inventions
based on the one now being disclosed. As the applicant is entitled to claim patent
protection only for his actual contribution to the art, it is therefore both reasonable and
imperative to limit the claim's subject-matter accordingly. Patent protection under the
EPC is not designed for the purpose of reserving an unexplored field of research for a
particular applicant, as reach-through claims do, but to protect factual results of
successful research as a reward for making concrete technical results available to the
public. Appeal dismissed.

T 0609/02The Salk Institute v Karo Bios
The Salk Institute was granted a patent for “Methods mediated by the proto-oncogenic
protein complex AP-1”,
Karo Bio AB and Astra AB brought opposition proceedings. Opposition Division
disallowed several claims.
The Institute appealed.
The Board dismissed the appeal because the Institute did not justify the assertion that
the invention had the alleged therapeutic eﬀect.

The principle of "free evaluation of evidence”
According to para 4.1 of Part G of the Rules Common to all Proceedings before the
EPOThe principle of "free evaluation of evidence" is that there are no rules as to the
types of evidence that are, or are not, admissible.
The application of the “free evaluation of evidence” principle was the reason for the
referral to the Enlarged Board of Appeal in G2/21 Syngenta Ltd, v Sumitomo Chemical Co.
Ltd.

G 2/21 Syngenta Ltd v Sumitomo Chemical Co Ltd
Sumitomo obtained a patent for a mixture of insecticides which was more potent than
any of them in isolation
Syngenta brought opposition proceedings which were dismissed.
Syngenta appealed to the Technical Board of Appeal under art 100 (a) and (b)
In T 0116/18 the Board held that there had been suﬀicient disclosure of the invention
but the application might be bad for want of an inventive step if evidence of plausibility
that had been produced after filing could not be considered.

The Technical Board submitted the following questions to the Enlarged Board:
"If for acknowledgement of inventive step the patent proprietor relies on a technical
effect and has submitted evidence, such as experimental data, to prove such an effect,
this evidence not having been public before the filing date of the patent in suit and
having been filed after that date (post-published evidence):
1. Should an exception to the principle of free evaluation of evidence (see e.g. G 3/97,
Reasons 5, and G 1/12, Reasons 31) be accepted in that post-published evidence must
be disregarded on the ground that the proof of the effect rests exclusively on the
post-published evidence?”

“2. If the answer is yes (the post-published evidence must be disregarded if the proof of
the effect rests exclusively on this evidence), can the post-published evidence be taken
into consideration if, based on the information in the patent application in suit or the
common general knowledge, the skilled person at the filing date of the patent
application in suit would have considered the effect plausible (ab initio plausibility)?
3. If the answer to the first question is yes (the post-published evidence must be
disregarded if the proof of the effect rests exclusively on this evidence), can the
post-published evidence be taken into consideration if, based on the information in the
patent application in suit or the common general knowledge, the skilled person at the
filing date of the patent application in suit would have seen no reason to consider the
effect implausible (ab initio implausibility)?"

The Board answered question 1 in the negative:
"evidence submitted by a patent applicant or proprietor to prove a technical eﬀect relied
upon for acknowledgement of the inventive step of the claimed subject matter may not
be disregarded solely on the ground that such evidence, on which the eﬀect rests, had
not been public before the filing date of the patent in suit and was filed after that date."
That meant that the Board did not have to answer questions 2 and 3 but it did give
some guidance on those issues.

The Board said at para [25]:
"An effect could not be validly used in the formulation of the technical problem if the
effect required additional information not at the disposal of the skilled person even
after taking into account the content of the application in question...."
But
"A patent applicant or proprietor may rely upon a technical effect for inventive step if
the skilled person, having the common general knowledge in mind, and based on the
application as originally filed, would derive said effect as being encompassed by the
technical teaching and embodied by the same originally disclosed invention."

English Approach to Plausibility
The issue has arisen in the following cases:
● Warner-Lambert Company LLC v Generics (UK) Ltd [2018] UKSC 56
● Akebia Therapeutics Inc v FibroGen, Inc [2020] EWHC 866 (Pat) (20 April 2020)
● FibroGen Inc v Akebia Therapeutics Inc [2021] EWCA Civ 1279 (24 Aug 2021)
● Sandoz Ltd and another v Bristol-Myers Squibb Holdings Ireland (Unlimited)
Company [2022] EWHC 822 (Pat) (7 April 2022).
● Sandoz Ltd v Bristol-Myers Squibb Holdings Ireland Unlimited Company [2023]
EWCA Civ 472 (4 May 2023)
● Gilead Sciences Inc and another v NuCana PLC [2023] EWHC 611 (Pat) (21 March
2023)

Warner-Lambert Company LLC v Generics (UK) Ltd
One of Warner-Lambert;s most successful products is pregabalin which it markets in the
UK under the trade mark "Lyrica".
It was originally used for treatment of epilepsy for which EP0641330 was granted,
Just before the patent was about to expire, Warner-Lambert found that pregabalin
could be used to treat pain and obtained a new patent EP0934061 for new use.
Generics manufacturers like Mylan and Actavis could now make and sell pregabalin but
not for pain relief,
Doctors and NHS trusts prescribe pregabalin for pain relief and not just epilepsy.

Warner-Lambert Company LLC v Generics (UK) Ltd
Mylan and Actavis sued Warner Lambert for revocation of patent for use of Pregabalin
for pain relief on grounds of insuﬀiciency and obviousness.
Arnold J dismissed the claim for obviousness but revoked the patent for insuﬀiciency.
Warner-Lambert appealed against the revocation first to the CA and then to the
Supreme Court which upheld the decisions of the courts below.
Lord Sumption explained the need for plausibility in second medical use inventions at
paras [19] and [20] and a 7 point plausibility test.

Akebia Therapeutics Inc v FibroGen, Inc
A claim by Akebia Therapeutics Inc. and another to revoke 6 patents held by FibroGen
Inc. on grounds of obviousness and insuﬀiciency.
The patent claims were very broad.
Arnold LJ revoked patents on grounds of insuﬀiciency because there appeared to ne
10138
combinations which could not possibly all be right.
On appeal to CA, Borss LJ proposed the following 3-point test:
● Identify what falls into claimed class
● Determine how the invention works
● Is it possible to make a reasonable prediction that everything will work

Sandoz Ltd and another v Bristol-Myers Squibb
Sandoz and Teva sued Bristol-Myers Squibb for revocation of EP 1 427 415 B1 on
grounds of obviousness and insufficiency
Meade J said: “Lack of plausibility is not a ground for revocation in itself and it was run
both as Agrevo obviousness and insufficiency, Neither side said it made a difference
which head applies, and I agree in the light of the case law to which I refer below, in
particular Warner-Lambert and Fibrogen."
He referred to para [37] of Lord Sumptionʼs judgment and Birss LJʼs 3-point plan from
FibroGen.
He revoked the patent and was upheld on appeal..

Sandoz Ltd and another v Bristol-Myers Squibb
Arnold LJ reviewed Case G 2/21 and Warner-Lambert Company LLC v Generics (UK) Ltd
(t/a Mylan) and another.
The majority judgment in Warner-Lambert was binding on the Court at least in second
medical use cases,
He reaﬀirmed at [92] "The fundamental principle is that the scope of the patent
monopoly must be justified by the patentee's technical contribution to the art. ….. If it
is not plausible that the invention solves any technical problem then the patentee has
made no technical contribution and the invention does not involve an inventive
step…..”

Gilead Sciences Inc and another v NuCana PLC
This was an action by Gilead Sciences Inc. for revocation of EP 2955 190 B1 and EP 3
904 365 B1 for added matter, implausibility and lack of industrial applicability.
The invention related to nucleotide derivatives and the treatment of cancer.
The action came on before Meade J.
Much of the judgment concerned added matter and other causes of action.
In the discussion on plausibility Meade J applied Birss LJʼs three-point test.

Conclusion
The English courts may not have pioneered the concept of plausibility but they have
developed it.
Lord Sumptionʼs observations at para [37] of his judgment in Warner-Lambert and Birss
LJʼs three point test are useful tools for resolving plausibility issues.
G2/21 is primarily about evidence and EPO practice and is unlikely to change much in
England.
Despite the absence of a “free evaluation of evidence” principle in this country, the
English courts are not too far apart from the EPO.

Any Questions
2 Snow Hill
Birmingham
B4 6GA
0121 231 7430
07966 373922
www.4-5.c0.uk
www.nipclaw.com
jane.lambert@nipclaw.com

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