T 1535/23 - The return of the essentiality test (and the UPC)

Key points

• What is the test to determine if deleting a feature from claim 1 as filed violates Art. 123(2) ?
•  T 0085/16: "whether something is essential or not is not the same as whether subject-matter is directly and unambiguously derivable by a skilled person. ... Having ascertained this, it is of no relevance whether the sheets of the non-woven fibre type have been presented as being essential for the invention or whether they were indispensable for its function."
• T 1189/16: " Insbesondere ist der Wesentlichkeitstest kein Ersatz für die Anwendung des Goldstandards" 
• T 1462/14:  "The mere fact that the conditions defining the essentiality test, referred to in the Guidelines for examination are met, is not conclusive."
•  T 0437/17: The ‘essentially test’ was discussed by the Board. The Board concludes that it “[is] superfluous, unnecessary and misleading and shall not be applied”."
• "T 2095/12 r. 2.7: " The Board concurs with the findings in recent decisions, cf. for example T 1852/13 [], that the "essentiality test" of T 331/87 may not always be suitably applicable. This in particular holds true in case of intermediate generalisations, cf. T 2311/10. Generally, the "essentiality test" is an aid that can in certain circumstances be used to assess the allowability of amendments."
• The present Board, discussing a UPC decsion: "The UPC found that "the skilled person understood from the application as filed that the exact method of sealing did not contribute to, and was thus not relevant for, the technical teaching of the invention as disclosed in the application as filed (point 75 of the Grounds for the Order [UPC_CoA_382/2024]). The omission of the use of an elastomeric sealing member from claim 1 of the patent did therefore not extend beyond the content of the application as filed (point 80 of the Grounds for the Order)." 
• "as stated above, both the Court of Appeal and the board in this case, and the EPO in general, use the same principle in judging whether an amendment extends beyond the content of the application as filed"
• The present decision, in the headnote: "Omission of a feature from a claim in the context of added matter: same legal approach taken by the UPC Court of Appeal and the EPO Boards of Appeal"
• The Board, deciding on the patent in suit: "On the contrary, the parent application as filed discloses that the specific surface area of <= 2 m2/g is an essential feature of the invention disclosed in the parent application as filed.  ...  The parent application as filed thus comprises no teaching that the specific surface area referred to in independent claim 19 of the parent application as filed is not an essential feature of the invention disclosed which can be omitted to characterise Form A of the free base of palbociclib."
• The above finding is based inter alia on the following: "in example 7, the primary particle size, the powder X-ray diffraction and the specific surface area are inextricably linked. Therefore, example 7 of the parent application as filed does not disclose that Form A of the free base of palbociclib can be characterised without referring to the specific surface area. Consequently, it cannot be concluded that example 7 shows that the specific surface area is not an essential feature of the invention disclosed in the parent application as filed."
• As a comment, this post may not be the right place and time to comment publicly on the role of the UPC in shaping the case law of the EPO boards of appeal (yet). 
• Secondly, I'm not saying the essentiality test does not work in practice. What we need is a litmus test. It is the chemical reactivity of the dyes that makes the test informative. Precisely for that reason, I don't know of a use of gold as a (classical) chemical indicator - it's a noble metal. 
• It would have been useful if the Board had engaged with the line of EPO case law outlined above, in addition to their discussion of the UPC decision. 

EPO 

The link to the decision can be found after the jump.

https://www.epo.org/en/boards-of-appeal/decisions/t231535eu1