Shifting the burden of proof back to the patentee (T 1299/15)

In disputes of insufficiency before the EPO, the burden of proof is initially on the side of the party alleging that the patent or application is insufficient. An opponent arguing that an invention is insufficiently disclosed generally must provide evidence that, despite making all reasonable efforts, they were unable to put the invention into practice (see T 30/15, 1.4.1) (Article 83 EPC). However, as a recent Board of Appeal decision confirms (T 1299/15), it is possible for the burden of proof to shift back to the patentee if "serious doubts" exist regarding whether a skilled person could carry out the invention.

Legal background: Burden of proof

The established case law of the Boards of Appeal is that each party bears the burden of proof for the facts it alleges. During prosecution, the burden of proof lies initially with the Examiner. An Examiner may not, for example, simply recite common general knowledge against a claim if the common general knowledge (CGK) is disputed. The Examiner must instead provide documentary evidence of the CGK. Similarly, for an insufficiency, novelty or inventive step objection, the burden of proof is initially on the Examiner (T 578/06, r. 13). Notably, a recent Board of Appeal also removed the burden of proof from the applicant to demonstrate the novelty of purity inventions (T 1085/13IPKat post here). 

During opposition, the burden of proof very clearly rests with the opponent, at least initially. This applies to all forms of objection, from novelty to insufficiency. However, it is also possible for the burden of proof to shift back to the patentee in certain circumstances. In T 570/08, for example, the opponent and patentee had both submitted data relating to whether the objective problem had been solved. The opponent's data contradicted that of the patentee. The Board of Appeal was convinced that the opponent's data created sufficient doubt so as to place the burden of proof on to the patentee. 

Shifting the burden of proof - T 1299/15

The patent (EP 2191187) at issue in T 1299/15 related to a device and method for renewing buried pipes. The claimed device coats the inside of the pipes with resin and then cures the resin using LEDs. The granted patent claimed a pipe renewer comprising a spiral shaped carrier on which LEDs are arranged in a specified pattern. The pipe renewer also comprises an “adjusting device”, with which the circumference of the spiral-shaped carrier may be adjusted. The claim of insufficiency was directed at the design of the adjusting device. 

The opponent (Aarsleff, a Danish construction company) argued that the specification did not provide any embodiments of the “adjusting device”. The adjusting device is not shown in the Figures and is mentioned only once in the specification. Furthermore, the opponent argued that there were doubts as to the feasibility of the adjustment device. In particular, how may the adjusting device be attached to the carrier?  The specification suggested that pneumatic arms may be used but did not indicate how these arms may be designed so as to be compatible with a spiral carrier varying in width and length.

The Board of Appeal (3.2.05) considered the question of whether the patent (together with common general knowledge) sufficiently disclosed the adjusting device. A key problem faced by the skilled person, the Board reasoned, was how to design the adjusting device so that it could accommodate the complex 3D movements of the spiral windings. The skilled person would also have to design the adjusting device so that the arrangement of the LEDs was maintained.

Importantly, as well as not providing an embodiment in the specification, the patentee did not submit or prove that adjustment devices, such as the claimed device, were already known. The Board accepted that an expert may be able to find solutions for the problems associated with designing the adjustment device. However, the Board doubted whether such solutions could be found without inventive skill.

Therefore, the Board concluded that there were doubts as to whether the invention had been sufficiently disclosed. Furthermore, the Board reasoned, the burden of proof had shifted from the opponent to the patentee. This was because the patentee had failed to provide even one example of an adjustment device as claimed. The patent was therefore revoked for insufficiency.

The legal reasoning in this decision is similar to that of T 63/06, in which the opponent was able to shift the burden of proof with regards to the sufficiency to the patentee. In T 63/06 the Board found that the patentee was relying on only a weak presumption that the invention was sufficiently disclosed. The opponent was successfully able to shift the burden of proof by arguing that the skilled person would have difficult in putting the invention into practice. 

The recent case T 1299/15 is similarly a reminder that insufficiency attacks may be applicable even to the mechanical field. As is often the case with insufficiency disputes, the issue of how much work would need to be done by the skilled person (and whether inventive endeavour would be required) was a key issue. Following on from this, if the patentee has not provided an embodiment of the claimed invention, the burden of proof is shifted to the patentee if there is serious doubt that a skilled person could perform the invention without inventive skill.
Shifting the burden of proof back to the patentee (T 1299/15) Shifting the burden of proof back to the patentee (T 1299/15) Reviewed by Rose Hughes on Friday, November 22, 2019 Rating: 5


  1. I've had a case where the OD raised a sufficiency objection ex officio in the oral hearing and refused an adjournment to obtain proof of adequate disclosure. The burden of proof was thus placed on the patentee and at the same time the patentee was prevented from satisfying their burden. Hopefully the new rules of procedure will take such a situation into account when allowing new evidence.

  2. When looking at the file, the objection under Art 100 (b) was fully justified, and granting such a patent might not have been the wisest decision of the ED.

    It is right to say that prima facie, the onus of proof lies with an opponent, and is thus to him to bring in evidence, for instance experimental data, but it can happen that this is not possible. The present case is a good example of this. Another example, is when a method for measuring a crucial parameter of a claimed feature is lacking in the original disclosure.

    As far as Kant's problem is concerned, and if the case did actually occur as explained, then the division committed a substantial procedural violation. It is not forbidden to introduce new facts/evidence/argumentation or even grounds based on those new items, or to introduce new requests during OP, provided the party which is faced with this new situation has enough time to gain knowledge of the new facts/evidence/requests and to react.

    If the party was not given enough time to react, then the party can raise an objection of substantial procedural violation, and be it with the present or the future rules of procedure, the decision is set aside and the file is remitted for further prosecution. But merely requesting postponement might not be the best way to act. In such a situation the OD should start with a one hour’s brake, and if not sufficient, then a decision to postpone can appear justified.

    The new rules of procedure have thus nothing to do with Kant's situation, and any hope that the present rules of procedure will be applied in a more lenient manner will remain a hope, which might never realise!


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