Vaccines give written description guidance

In a recent patent interference relating to vaccine technology, the US Court of Appeals provided some guidelines for the written description of biomedical inventions. The Court stated that examples are not required to support written description, that the written description standard is met even if the inventors have not yet reduced their invention to practice, and that there is no requirement for the recitation of a known biological structure within the written description.

The interference was between Falkner et al. (US patent 5,770,212) and Inglis et al. (US application 08/459,040) who both claim methods for producing vaccines against viruses that consist of a virus particle with an essential gene deleted that renders viral propagation dependent on the host-cell expression of the missing essential gene. The technology is an improvement over existing methods of producing attenuated vaccines because the modified viruses do not carry the risk of reverting back to wild-type in the host cell by recombination with host DNA.

Inglis was judged as the senior party (that is, given priority) based on several earlier filed applications that described the application of the above vaccine technology using herpesviruses as an example. The '040 patent also included passages of description dedicated to poxviruses — the subject of Falkner's patent. Falkner appealed against Inglis being awarded priority on three counts that mostly claimed that the Inglis patent lacked detailed written description and examples of the invention specifically applied to poxviruses.

The US Court of Appeals disagreed with Falkner's arguments, stating that because the differences between poxviruses and herpesviruses were well known and described in the literature the patent would have enabled a person of ordinary skill in the art to apply the invention, as described for herpesvirus, to poxvirus vaccine development. As such, the Court ruled that no detailed description of the structure of the poxvirus genes, their deletion or inactivation was required as part of the written description. Moreover, because the herpesvirus methodology can be readily applied to other viruses, there was no need for a specific poxvirus example in the Inglis patent. Regarding the reduction to practice claim, the Court pointed out that written description requires “a showing of possession of the invention” and that prior legislation has set a precedent that an invention can still be complete even if reduction to practice is absent.

Merck misses its mark

Merck has lost out in an infringement case against Mediplan Health Consulting in a ruling that has wider, and potentially damaging, implications for the US pharmaceutical industry. A US court held that the FDA's Orange Book, which lists patents that protect approved drugs, did not constitute 'effective public notice' under a statute that requires companies to 'mark' their relevant patents prior to filing an infringement lawsuit. The ruling means that Merck is only awarded damages from the date after which the infringement lawsuit was filed.

Mediplan had been offering generic simvastatin (Zocor) to US customers via an online Canadian pharmacy even though Merck's patents for the drug have not yet expired and Mediplan had not filed an Abbreviated New Drug Application (ANDA) in the US. When Merck sued Mediplan for infringement of its method and composition of matter patent (US4,444,784), Mediplan argued that Merck had failed to 'mark' simvastatin. Merck counter-argued that 'marking' was not required for a method of use patent, because no physical item exists to be marked.

With no previous cases to use as legal precedent, the court decided that the Orange Book serves as “merely a catalog that informs the public of the patent's existence” and does not constitute adequate 'public notice'. The result of this case leaves US drug companies lacking protection against non-US generic manufacturers who work outside US generic drug approval legislation.

Meanwhile, the FDA is to challenge the district court ruling that it must re-list two of Merck's simvastatin patents in the Orange Book and must allow Ranbaxy and Ivax 6-month exclusivity for their generic versions of the drug (see Patent Watch, June 2006). In its letter to the court, the FDA argues that the District Court's decision would decrease competition in the generics market and will lead to industry confusion over the agency's 'statutory authority' relating to drug patents. However, if the FDA moves towards removing the exclusivity provision that came into force under the Hatch–Waxman Act this could put generics firms off filing ANDAs because they would have to go through the costly and laborious process of a patent infringement suit with more competition when it finally reaches the market.

Ubiquitin–proteasome system modulation

On page 596 of this issue, Nalepa and colleagues review drug discovery in the ubiquitin–proteasome system (UPS), which is of interest for cancer, inflammation and neurodegenerative diseases. The table below details patent applications filed in the past year related to the therapeutic potential of the UPS. Data were kindly researched by Cora Sevilla at Thomson Scientific.

Table 1 Recent patent applications related to modulation of the ubiquitin–proteasome pathway
Full size table