Abstract on Article 084 EPC for the decision T0939/22 of 09.04.2024

In T 939/22 claim 1 of the main request was directed to "[a] vaccine comprising a recombinant nonpathogenic Marek's Disease Virus (rMDVnp) comprising a first nucleic acid (…) and wherein the rMDVnp is a recombinant herpesvirus of turkeys (rHVT)." The construction of rMDVnp was relevant for assessing novelty over D8. The definition of rMDVnp in the description (page 7, lines 19 to 20 of the patent in suit) stated that the term rMDVnp referred to a rMDVnp that included heterologous nucleotide sequences (i.e. sequences from pathogens other than MDV). In other words, the definition in the description equated the term rMDVnp to a specific recombinant vector with inserts of nucleotide sequences encoding proteins from other pathogens. According to the board, this definition could not change the common understanding of the terms of art rMDVnp and rHVT as used in claim 1 nor was this definition consistent with how a skilled person would understand the claim. Indeed, the skilled person would understand the terms rMDVnp and rHVT as used in claim 1 to refer to the genome of a viral vector stemming from a non-pathogenic strain of an MDV serotype. No further limitations were implied by the terms rMDVnp and rHVT. The skilled person would not understand the term rHVT to exclude viral vectors in which a specific region of the genome of HVT (which is MDV serotype 3, i.e. MDV3) has been replaced by the corresponding region of a different MDV serotype, as is the case for novel avian herpesvirus (NAHV). Of course, claim 1 further required that nucleotide sequences of at least two specified pathogens other than MDV, i.e. Newcastle disease virus (NDV) and infectious laryngotracheitis virus (ILTV), be inserted into the rMDVnp/rHVT vector. Hence, the claim was directed to a construct formed by the rMDVnp/rHVT vector and inserts of nucleotide sequences from other pathogens. The board held that the exclusion of viral constructs comprising nucleotide sequences from different MDV serotypes from the term MDVnp (page 7, lines 14 to 17 of the patent in suit) was in line with how the skilled person would understand the term MDVnp, as it did not include recombinant viral constructs but referred only to the naturally occurring viruses. Claim 1, however, was specifically directed to a vaccine comprising a recombinant non-pathogenic MDV (rMDVnp), specifically rHVT. Even if the definition of MDVnp in the description were intended to include rMDVnp in a way that excluded chimeric viruses, this could not change the skilled person's understanding of the terms rMDVnp and rHVT. In the board’s view, excluding chimeric viruses from the claimed subject-matter appeared contradictory for the following reasons. The term chimeric virus, as understood by the skilled person, related to a specific type of recombinant virus that contains genetic material from different viruses within a single viral genome construct. This typically implied that the resulting viral construct exhibits characteristics derived from each of the parental viruses. Accordingly, inserting nucleotide sequences of NDV and ILTV into the rHVT vector as claimed resulted in a chimeric virus. Therefore, chimeric viruses could not be excluded from the subject-matter of claim 1, let alone a (recombinant) NAHV that included nucleotide sequences from NDV and ILTV. The board also noted that, due to the comprising language, claim 1 did not exclude that the rMDVnp could be engineered to comprise additional nucleic acid inserts encoding antigens of pathogens other than NDV and ILTV. It was clear from the wording and structure of claims 3, 4, 9 and 11 that the inventors of D8 had envisaged both (i) a multivalent vaccine that was a mixture of different NAHV constructs, each encoding a separate foreign gene (claim 19), and (ii) a multivalent vaccine based on a single NAHV construct encoding a plurality of foreign genes (claim 11, to which vaccine claim 18 refers). A multivalent vaccine encoding more than one heterologous antigen was furthermore addressed in several passages of the description. D8 provided detailed instructions on how to prepare the recombinant chimeric virus and clear protocols on how to test them for their suitability as vaccines. Thus, sufficient information was provided to enable the skilled person to produce and test a composition suitable as a multivalent vaccine as defined in claim 18 of D8. In addition, it was credible that a recombinant MDV comprising more than one insert from two different heterologous viruses in the non-essential US2 site, encoding thus one additional foreign antigen to those tested in Examples 1 to 3 of D8, could be prepared and would provide protection by preventing or reducing the severity of a disease caused by at least one of the viruses whose antigens were encoded by the recombinant MDV construct.