PTAB Institutes IPR of Alethia Biotherapeutics Patent Claiming Use of mAb to Treat Bone Disease

On June 15, 2015, the Patent Trial and Appeal Board (PTAB) instituted inter partes review (IPR) with respect to claims 1-6, 8-11, and 15-23 of US Patent Number 8,168,181 (Case IPR2015-00291).   The ’181 patent discloses "methods of modulating osteoclast differentiation, which may be useful in the treatment of bone loss or bone resorption in patients suffering or susceptible of suffering from a certain conditions such as osteoporosis."

Claim 1 is representative.

1. A method of impairing osteoclast differentiation in a mammal in need thereof, the method comprising administering an antibody or antigen binding fragment which specifically binds to human Siglec-15 (SEQ ID NO.:2) or murine Siglec-15 (SEQ ID NO.:108) to said mammal.

The patent owner is Alethia Biotherapeutics, a Montreal-based biotechnology company “[e]ngaged in the discovery and development of therapeutic mAbs against highly-disease tissue specific novel clinically-relevant targets.” The petitioner is Daichi Sankyo, a Japanese pharmaceutical company. According to Alethia Biotherapeutics, the two companies are developing competing products for treating bone disease based on anti-Siglec-15 antibodies that inhibit osteoclast differentiation.

The PTAB determined that there is a reasonable likelihood that Petitioner would prevail in demonstrating the unpatentability of the challenged claims as anticipated by a published PCT application, Yoshiharu Hiruma et al., WO 2009/048072.  The Hiruma reference is Daichi Sankyo's own PCT application, and the two companies appear to be attempting to patent similar same subject matter.

A critical issue in the case is whether the challenged claims are able to benefit from the filing date of a parent application.  The filing date of the ‘181 patent is October 16, 2009, but it claims priority to a continuation-in-part filed January 13, 2009, and a PCT application filed February 13, 2007. The prior art, Hiruma, published on April 16, 2009. Thus, If Alethia is able to claim priority to the earlier filed applications, then Hiruma is not prior art. But Daichi Sankyo argues that the earlier filed applications do not satisfy the written description and enablement requirements of Section 112 with respect to the challenged claims, and thus that the claims are entitled to a priority date “no earlier than April 16, 2009.”

In granting the petition, the PTAB found that “Petitioner has presented sufficient evidence, on the present record, to persuade us that the challenged claims of the ’181 patent are entitled to a priority date no earlier than April 16, 2009, on the basis of lack of adequate written description support and/or enablement of the claim subject matter in the Parent Application.

In its Preliminary Response, the Patent Owner argued that the petition should be denied because in related proceedings the PTO and PTAB have already addressed, or are currently addressing, petitioner’s arguments concerning the alleged lack of 112 support for the parent applications.  The Patent Owner also argued that Petitioner should be precluded from making arguments based on 112, i.e., lack of enablement and written description, because by statute IPR is limited to challenges based on 102 and 103, i.e., lack of novelty and obviousness. The PTAB rejected these arguments, at least for the purpose of deciding the question of whether the review should be instituted.

The PTAB decision points out that “Patent Owner does not dispute at this time that Hiruma discloses the limitations recited in the challenged claims.”  For strategic reasons, it is not uncommon for patent owners to hold back some of their best arguments at the Preliminary Response stage, saving them to use in their full Response, which is only necessary in the event IPR is instituted.  This could be what is going on here.