The Boards of Appeal (BoA) at the European Patent Office (EPO) finally seem to believe novelty in purity questions should be addressed by the golden standard for addressing novelty in other cases, thereby overthrowing the long outstanding special status of purity when facing prior art. In summary, in the decision T1085/13 and now with T0043/18 referring to T1085/13, the BoA seem to accept a new paradigm for assessing novelty in questions of purity, which aligns with the golden standard set out by G2/88 and G2/10. The question that remains is, when the Guidelines for Examination will be aligned with the view of the Boards of Appeal?

The golden standard for assessing novelty of a claimed invention has for long relied on implicit disclosure of claimed subject-matter in the prior art (G 2/88, G 2/10), where the burden of proof is in general placed on the patent office (or opposing third party).

Nevertheless, the odd-one-out, with regards to novelty, has for long been the special case of purity, where novelty has previously been addressed with a special criterion, where the burden of proof is shifted to the applicant, leaving the applicant to show that the purity of the claimed invention could not simply arise from known conventional processes, but was in fact unobtainable by previously known processes (T 990/96 of 1998).

This matter is also clearly set out by the EPO in the Guidelines for Examination (G-IV,7)  which says “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)”.

Accordingly, it is on the applicant to show that a novel degree of purity, cannot be obtained by conventional means, with the uncertainty as to what “conventional means” entails in each individual case.

The decision T1085/13 of 2018 from the BoA cast the first stone, to shatter the view on novelty of a degree of purity, set out in T 990/96. Now with T0043/18, the BoA seem to accept this as the new standard for assessing novelty of a degree of purity.

In T1085/13 the BoA found that treating purity as a special case, was in contradiction to the general principle that novelty is destroyed only by a clear and unambiguous disclosure in the prior art, thereby deviating from established practice, and the current Guidelines for Examination.

Accordingly, until T0043/18, the BoA had presented two contradictory viewpoints on novelty of a degree of purity of a known compound.

Accordingly, the aim of T0043/18 was to clarify if the BoA intend to uphold the former standard set by T 360/07 as is implemented in the Guidelines for Examination, or if they wished to adopt a new standard as set out by T 1085/13.

In T0043/18 of 2022, the BoA followed the direction set by T1085/13, by stating that a piece of prior art could only be considered against novelty of a claim to a compound of a certain purity, if the prior art discloses the claimed purity, at least implicitly e.g., by providing a method which would inevitably result in the purity as claimed.

If the prior art cited against the claim needs to be supplemented e.g., by adding an additional step to a method for producing the compound, for the skilled person to arrive at the claimed purity, then it is no longer a matter of novelty, but a matter concerning inventive step.

Accordingly, in matters of purity of compounds, the BoA continue to lean towards alignment with the otherwise golden standard for assessing novelty (G 2/88, G 2/10), thereby harmonizing the EPO’s view on novelty of compounds of previously undisclosed purity, with the novelty criteria set out in other areas.

We will continue to monitor the developments in the area, including related updates of the Guidelines for Examination at the EPO.