A comparative study illustrates the ILPTO stringent homology requirements for biological sequences
A comparative review recently conducted by the ILPTO illustrates its stringent policy on permitted homology (sequence identity) thresholds for core biological sequences.
In order to evaluate how it stands compared to the EPO and the USPTO, the ILPTO sampled applications examined since 2022 and compared homology percentages across corresponding ILPTO, EPO, and USPTO applications for three categories of biological molecules – antibodies, (other) proteins, and gRNA. The analysis revealed significant differences in accepted homology percentages with ILPTO homology averages of 99% (antibodies), 95% (proteins) and 100% (gRNA), notably higher than EPO and USPTO averages. These data confirmed that the ILPTO has an overall stricter approach to homology claims than both the EPO and the USPTO, with such “homology gap” particularly pronounced compared to the EPO.
In evaluating the results, the ILPTO noted that small variations in biological sequences can lead to substantial functional diversity and that even when using current computational tools, it still remains a considerable challenge to distinguish between nonfunctional and viable sequences. While recognizing the inventors’ legitimate interest not to confine the claims to specific exemplified sequences, the ILPTO is also aware of the lack of support, enablement and freedom-to-operate issues that may arise as a result of claims with broad “clouds of homology”.
Following the study, the ILPTO will likely review its Examination Guidelines. Based on the comments in the study, we anticipate the ILPTO will adopt a combined structural-functional approach. This would limit homologous sequences to those fulfilling the claimed function, while defining core structures – such as CDRs in antibodies – that must be preserved. Less-than-100% homology may be permitted when the description or the general knowledge reasonably supports that the claimed rate of variation is expected to maintain the claimed function. This is unlikely to affect current practice and we will circulate appropriate updates in due course.
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