Upon discussions with U.S. PTO examiners, we have learned that the U.S. PTO has given unofficial guidance to the examiners on restriction requirements for applications containing claims directed to diagnostic methods using more than one polymorphism, such as single nucleotide polymorphisms (SNPs). The examiners have been instructed to require the Applicant to elect only one SNP per application. The guidance also requires that this election is made as a group, not species election.
The U.S. PTO rationalizes its guidance based on at least the following points:
- If the Applicant tries to elect a group: “SNP and any marker in linkage disequilibrium with it,” no matter how tight the r-value for the linkage disequilibrium (LD) is, the U.S. PTO will consider it causing a written description and potentially also an enablement problem. This is because not all possible markers are “structurally defined” in the specification, and thus the breath of the claim has not been adequately described. Therefore, these kinds of claims are very likely to be rejected as not complying with 35 U.S.C. §112, second paragraph definiteness requirement as well as with 35 U.S.C. §112, first paragraph, written description requirement.
- If the Applicant elects “a SNP selected from the group consisting of SNP1, SNP2 and SNP3,” which is often seen in applications where the Applicant has tested several markers and all of them are in LD and/or appear to be associated with the phenotype, the U.S. PTO takes the position that these claims “cause too heavy a search burden” for the examiner and a restriction requirement is justified.
Applicants can naturally pursue diagnostic claims using all or a selection of the SNPs defined and described in the specification. This can be accomplished by first electing one SNP, and if the elected SNP is determined patentable so long as each additional claim also encompasses the originally elected SNP (and the specification provides enablement with respect to the other markers—i.e. some showing that they work in the diagnostic methods or at least that they are in tight LD with the originally elected SNP). The additional SNPs could be added as one or more dependent claims. Essentially, one could therefore obtain a claim to a method for diagnosing a condition by determining if the patient carries “the elected SNP and optionally one or more of the other SNPs.” Of course, this claim does not prevent a competitor from any and all but the one SNP Applicant have been forced to elect, particularly if diagnosis based on the other markers without the elected SNP is possible. To protect against this possibility, separate divisional applications should be pursued for each of the critical diagnostic markers.
Examiners consulted regarding this policy acknowledge that this position may not be optimal for commercial usefulness of claims to diagnostic methods as it forces these methods into a relatively narrow scope. However, we were advised that this is the U.S. PTO’s current position, and therefore, traversal of such restriction requirements is unlikely to succeed. According to the PTO, they have a large number of SNP-based diagnostic tests in the examination pipeline, and all of them should be treated using these guidelines.
Knowledge about this unofficial policy allows the Applicant to consider budgeting their resources to cover the most important associations for any given diagnostic test. In case of an early stage discovery, this may mean allocating resources to file several divisional applications to ensure coverage for use of multiple markers, one of which may, in larger clinical studies, prove to be more valuable than the others.