An issue discussed at length by Kane J in valganciclovir was whether the ‘721 patent is a selection patent -. Kane J acknowledged that “A selection patent is like all other patents; the same principles will apply” , but it is not clear that this was true in her analysis. She stated that “Although it is not essential that I make a finding that the ‘721 is or is not a selection patent, as there is no attack on utility, the characterisation as a selection patent will inform the analysis, particularly with respect to anticipation and obviousness” . This implies that it would be essential to decide whether the ‘721 patent was a selection patent if utility were in issue. Moreover, while she concluded that the ‘721 patent was not a selection patent, and she stated she would have come to the same results with respect to anticipation and obviousness even if it had held that it was a selection patent, her analysis of those issues was substantively affected by her characterization, which, as she put it would “inform the analysis” , .
In particular, Kane J appears to have been of the view that if the ‘721 patent was a selection patent, then anticipation would be assessed over the prior art disclosing the genus, while if it was not, it would be assessed over the inventive concept as disclosed in the specification:
 If the ‘721 were a selection patent from the genus, EP 329, and if the advantages over EP 329 had been noted in the ‘721, the anticipation argument would likely follow Sanofi and Eli Lilly. However, in this case, the invention of the ‘721 was the improved bioavailability over ganciclovir. If it were a selection patent, it would have been anticipated by EP 329 which disclosed the compounds and those same advantages.
With respect, neither of these alternative is correct. Section 28.2 provides that anticipation is assessed over the prior art. On the facts, this includes both EP 329 and ganciclovir. By statute, the basis for assessing anticipation cannot depend on whether the patent is a selection patent or not.
In my view the case law on selection patents does not imply that anticipation and obviousness in respect of a selection patent is to be assessed over the genus patent from which it is a selection, rather than over the prior art (or state of the art) as a whole. But there is a broader issue here regarding the usefulness of the whole concept of selection patents.
In Sanofi 2008 SCC 61 the SCC accepted the three part test set out by Maugham J in IG Farbenindustrie, (1930), 47 RPC 289 (Ch D), the “locus classicus describing selection patents,” as a “useful starting point for the analysis” , . At the same time, the Supreme Court, like Maugham J himself, recognized that “a selection patent ‘does not in its nature differ from any other patent’” , and see also . In Eli Lilly / olanzapine 2010 FCA 197, the FCA noted that there is no reference to selection patents in the Act,  and also that the Supreme Court in Sanofi had not applied the IGF conditions independently , and it emphatically affirmed that the IG Farbenindustrie conditions for a valid selection patent do not constitute an independent basis upon which to attack the validity of a patent , , . The FCA concluded that a selection patent, like any other patent, is therefore vulnerable to any attack set out in the Act, but no other . Moreover, in Sanofi the Court remarked that “Maugham J.'s analysis is consistently referred to and is well accepted,” , but barely a year later, the EWCA in Dr Reddy’s Laboratories v Eli Lilly  EWCA Civ 1362 rejected reliance on IG Farbenindustrie, both on the basis that these rule were no longer part of the law under the UK Patents Act, 1977 , and on the basis that the rules were not sound in principle . The EWCA remarked that the IG Farbenindustrie “were actually formulated under the common law,” and had been judically carried over after codification as “almost a special sub-branch of patentability." Neither the EPO nor US law has ever had any special rules for selection patents. The valganciclovir decision illustrates that a specialized doctrine of selection patents can cause considerable confusion. It clearly is not mandatory; as the FCA pointed out, even the SCC in Sanofi did not actually apply the IG Farbenindustrie approach. While the FCA in olanzapine could not reject the IG Farbenindustrie rules, in light of their endorsement by the SCC, to my mind, the FCA provided a strong hint that it may be time to join the US, the UK and the EPO, and abandon the doctrine entirely. The confusion engendered by the doctrine in valganciclovir illustrates the wisdom of that suggestion.