30 November 2022

EPO Guidelines: To follow or not to follow?

Most will be familiar with the Guidelines for Examination in the European Patent Office (Guidelines) and will be used to seeing European patent attorneys quote them both during examination and opposition proceedings before the EPO. The Guidelines are a useful resource published by the EPO setting out, from the EPO’s perspective, the approach that should be adopted before the EPO. However, recent Board of Appeal decisions have highlighted that the Guidelines are guidance and not legally binding, for example, on the Boards of Appeal.

As the name suggests, the Guidelines serve to “give instructions on the practice and procedure to be followed in the various aspects of the examination of European applications and patents in accordance with the European Patent Convention and its Implementing Regulations.” While generally useful in practice, it is prudent to remember that the Guidelines merely provide guidance and aim to serve as a basis for illustrating the law and practice before the EPO. A careful approach should therefore be taken on the over reliance and influence of the Guidelines, at the expense of case law and the European Patent Convention (EPC) itself.

Precedence at the EPO is a nuanced concept. While not legally binding in the strict sense, the Guidelines do carry influence and legal force. The Guidelines themselves state:

This raises a number of questions. Does the term “general rule” elevate the persuasive nature of the Guidelines, and suggest that they can reasonably be expected to be relied upon until some notional point in the future when they may (or may not) be amended? How much certainty can be placed on the Guidelines in their current form? If a case hinges on a point that is in conflict with the Guidelines, is the applicant facing a steep uphill battle from the outset or is there some scope for manoeuvre? In essence, it seems that the Guidelines are more or less binding on first instance Examiners and oppositions yet are only taken into account by Boards of Appeal to the extent that if their decisions diverge from the Guidelines they should explain their reasoning.

In caveating their scope and interpretation, the Guidelines explicitly state that:

“The Guidelines cannot cover all possible occurrences and exceptions in every detail, but must be regarded as general instructions that may need to be adapted to the individual case.”


“It should be noted also that the Guidelines do not constitute legal provisions.”

This reflects the fact that the Guidelines, as instructions, are non-binding in respect of decisions of the Boards of Appeal, as highlighted in Article 23(3) EPC.

“In their decisions the members of the Boards shall not be bound by any instructions and shall comply only with the provisions of this Convention.”

This echoes the overriding principle that for the ultimate authority on practice in the EPO, it is necessary to refer to the EPC itself.

So, when should one follow the interpretation and “general instructions” of the Guidelines and what degree of certainty can be placed on those instructions? What guidance do they offer when they may need to be “adapted to the individual case”? As evidenced by recent case law, the Guidelines can remain out of step with Board of Appeal decisions.

The evolving case law on selection inventions

Selection inventions have historically been a fruitful source of case law for the EPO. While the Guidelines do provide valuable guidance regarding selection inventions, updates to the Guidelines can lag behind changes to established case law of the Boards of Appeal.

Recent decisions regarding the novelty of purity inventions highlight one such inconsistency.

T 990/96 – increasing purity is conventional

Increased purity of a chemical compound falls under the concept of a selection invention before the EPO. Historically, novelty of purity inventions was regarded as a special case, and novelty was destroyed if the prior art disclosed the chemical compound and its method of manufacture, regardless of whether the claimed degree of chemical purity was disclosed in the prior art or not.

This was the view taken by the Board of Appeal in decision T 990/96 (dated 12 February 1998) that reasoned that “since conventional methods for the purification of low molecular weight organic compounds are generally part of his common knowledge….a [prior art] disclosure makes normally available this compound to the public in the sense of Article 54 EPC in all desired grades of purity.”

While in T 990/96, the Board of Appeal recognised that exceptional situations may arise and justify a different conclusion, i.e. that, for example, all previous attempts to achieve a certain degree of purity by means of conventional purification processes have failed, the burden of proof lay on the applicant in such circumstances. The fact that the prior art failed to explicitly disclose the claimed purity does not, in itself, constitute proof that the claimed purity could not be achieved using conventional methods.

Seeking guidance and referring to the Guidelines on this point, one might consider that this was the end of the story regarding the novelty of purity inventions as GL, Part G, Chapter VI, 7 states:

“A known compound is not rendered novel merely because it is available with a different degree of purity if the purity can be achieved by conventional means (see T 360/07).”

However, this appears not to be as cut and dried as it seems with two recent Board of Appeal decisions, T 1085/13 and T 0043/18, apparently conflicting with this statement.

T 1085/13 and T 0043/18 – supplementation of the prior art

In decision T 1085/13, dated 9 February 2018, the Board of Appeal found that the decision reached in T 990/96 was not compatible with well-established principles of novelty developed by the Enlarged Board of Appeal in decisions G2/88 and G2/10. Decision T 0043/18, dated 1 June 2022, closely aligns and follows the reasoning of T 1085/13 to reach the same conclusion.

Briefly, in T 1085/13, claim 1 was directed towards amorphous lercanidipine hydrochloride having a purity of at least 99.5%. In its objection of lack of novelty, the Examining Division relied on the reasoning of T 990/96 and held that because the applicant had not shown that all prior attempts to achieve the claimed level of purity had failed, the prior art anticipated the claimed purity level. Thus, the claim was not novel.

In contrast, the Board of Appeal in T 1085/13 considered the rationale of T 990/96 to not be in line with the case law developed by the Enlarged Board of Appeal, in particular decisions G 2/88 and G 2/10. Both G 2/10 and G 2/88 required at least an implicit disclosure of all features of a claim in a prior art disclosure for said prior art disclosure to be novelty destroying.

Applying this reasoning, the Board of Appeal found that “a claim defining a compound as having a certain purity therefore lacks novelty over a prior-art disclosure describing the same compound only if the prior art discloses the claimed purity at least implicitly, for example by way of a method for preparing said compound, the method inevitably resulting in the purity as claimed.”

The Board of Appeal further stated that the claim does not lack novelty if the disclosure of the prior art needs to be supplemented, for example by suitable further purification methods, to allow the skilled person to arrive at the claimed purity. Interestingly, the Board of Appeal went on to reason that whether such further purification methods are within the common general knowledge of the skilled person is irrelevant to the question of novelty and is instead to be considered in the assessment of inventive step.

An analogous situation can be found in T 0043/18. The claim in dispute was directed towards a purer dosage form of oxycodone hydrochloride and was rejected by the Opposition Division for lack of novelty based on the reasoning outlined in T 996/90. Decision T 1085/13 was only published after the Opposition Division’s decision and was subsequently cited by the patentee on appeal. Interestingly, it appears that the same Technical Board of Appeal (3.3.02) presided over both cases.

Ultimately (and perhaps unsurprisingly), the Board of Appeal in T 0043/18 followed the reasoning and conclusions set forth in T 1085/13 in relation to the assessment of novelty, in particular that the prior art would need to be supplemented with suitable further purification methods in order to (potentially) arrive at the claimed purity. Claim 1 was thus held novel over the prior art.

The Board of Appeal’s conclusion that the question of whether such further purification methods are within the remit of the common general knowledge of the skilled person is not relevant to novelty is an interesting one. The shift to evaluating this in relation to the assessment of inventive step parallels the shift seen in the “purposive selection” test when assessing the patentability of a sub-range selected from a broader numerical range of the prior art. It is no longer a requirement of novelty for the selection from the sub-range to be a “purposive one.” Instead this is now a question of inventive step, as outlined in the Guidelines:

“Decision T 261/15 confirmed that the requirement for a sub-range to represent a purposive selection is a matter of inventive step and not necessary for establishing novelty (see also G‑VI, 8).”

It is curious to note that the Guidelines have been updated to reflect this case law on the “purposive selection” test, yet they remain strangely out of sync for purity inventions, with decision T 1085/13 published over four years ago. The current Guidelines are on an annual revision cycle, with an updated version now published each March. Time will tell if future iterations of the Guidelines apply the new reasoning and provide further clarity and certainty to applicants regarding the assessment of purity inventions before the EPO.

Description amendments – an ongoing saga

Turning away from selection inventions, further points of contention between the Guidelines and the case law of the Boards of Appeal can be found in the requirements for description amendments at the EPO.

In March 2021, the updated Guidelines introduced significant and stringent changes to the requirements for amendments to the description before a European patent application could be granted. While the 2022 update has softened somewhat in this respect, there remains a heavy burden placed on applicants to amend a patent application’s description to ensure that the description is consistent with the claims.

However, the case law in this area tells a slightly different story and is far from settled. On the one hand, decision T 1989/18, dated 16 December 2021, concluded that there is no legal basis in the EPC to require that the description must be brought into line with the claims. Notably, this decision contradicted earlier decisions, such as T 1808/06, on which the wording of the Guidelines appears to have been largely based, where it was held that the description must be adapted so that the claims are supported by the description, citing Article 84 EPC.

Naturally, T 1989/18 was a welcome decision for applicants, particularly in light of the strict and somewhat onerous requirements stated in the Guidelines, and offered a glimmer of hope that Examiners may not adhere so strictly to the Guidelines. However, it is notable that the subsequent update of the Guidelines in March 2022 did not substantially change following T 1989/18, perhaps reflecting the fact that this remains an isolated decision. Thus, the description amendment requirements (if following the Guidelines) remain burdensome.

Furthermore, recent decisions such as T 1024/18 and T 0120/20 (among others) contrast with the finding in T 1989/18 and seem to affirm the instructions of the Guidelines, with the Board of Appeal in T 0120/20 specifically stating that they did not follow decision T 1989/18.

The requirement for description amendments is an ongoing point of contention and the case law is far from settled on this subject. Further referrals to the Boards of Appeal are likely and perhaps even a referral to the Enlarged Board is on the horizon.


The Guidelines are a useful and familiar resource to applicants and proprietors of European patents and applications. However, as evidenced by recent decisions, in some circumstances a cautious approach should be taken when relying on them.

When an application is important, it is worth taking a moment to consider if the conventional approach suggested by the Guidelines could be challenged in any way, even if the guidance is based on so-called “well-established EPO case law.” As we have seen from the decisions described above, the established approach can be challenged at appeal level and ultimately the case law changed.

If you would like assistance assessing if any particular case could benefit from such an approach, please contact your usual Venner Shipley attorney who would be happy to help, if necessary, along with our EPO Board of Appeal experts.