DetailsBoehringer Ingelheim filed three petitions attacking patents generally drawn to methods of treating RA patients with rituximab.  The decisions on two of those petitions, i.e., IPR2015-00415 and IPR2015-00417, have been addressed elsewhere.  In IPR2015-00418, the PTAB declined to institute an IPR on the petition’s challenges to the lone claim of U.S. Patent No. 8,329,172, drawn to a method of treating low-grade non-Hodgkins lymphoma (LG-NHL) with CVP tri-chemical chemotherapy and rituximab maintenance therapy.  The petition contained a single anticipation ground and 9 obviousness grounds.  For various reasons, including a failure to show that references were available as prior art, a failure to explain the reasoning underlying an assertion of obviousness, and a failure to establish that one of skill in the art would substitute one combination of chemotherapeutics for another, the PTAB declined to institute an IPR.

The single ground based on anticipation of claim 1 relied on ECOG 1496, an Eastern Cooperative Oncology Group protocol of a clinical trial for a cancer treatment.  Although Petitioner asserts that ECOG 1496 was distributed to all members of the Group without restriction on further dissemination, the PTAB found that Petitioner did not support the assertion with evidence sufficient to show that one of skill in the art could find ECOG 1496 using reasonable diligence.  The PTAB concluded that Petitioner failed to establish that ECOG 1496 was a printed publication and, for that reason, declined the anticipation ground.  The same reasoning was applied to ECOG 4494, leading the PTAB to decline to proceed with the three obviousness grounds based, in whole or part, on that protocol.

[P]ublic accessibility’ is ‘the touchstone’ [of] a printed publication. . . .  ‘[P]ublicly accessible’ [means] disseminated or otherwise made available to the extent that persons interested and ordinarily skilled in the subject matter or art exercising reasonable diligence, can locate it.

An additional six obviousness grounds relied on the McNeil reference alone or in combination with other references.  The PTAB found that claim 1 of the ‘172 patent differed from McNeil in three respects: (1) McNeil treated intermediate-grade NHL (IG-NHL), not LG-NHL; (2) McNeil taught CHOP therapy, which includes doxorubicin administration, not COP or CVP therapy; and (3) McNeil did not disclose the dosing regimen of the rituximab maintenance therapy.  The PTAB noted that the obviousness ground based on McNeil alone actually relied on eight additional references, and therefore failed to comply with the requirement of 37 C.F.R. § 42.104(b)(2) to identify all patents or printed publications relied upon for each ground.

The PTAB went on to explain that the grounds in which McNeil was expressly combined with additional references were unavailing because the additional references did not cure all of the defects in the McNeil reference.  The Rituxan® label was characterized as, at best, addressing the dosing deficiency of McNeil, but not the treatment of different patient populations (IG-NHL versus LG-NHL) or different chemotherapeutic regimens (CHOP versus CVP).  Adding Unterhalt to the mix of references addressed the CHOP versus CVP distinction, but Unterhalt also taught interferon maintenance therapy.  The PTAB found that interferon maintenance therapy relied on an immune response, but rituximab maintenance therapy depleted B cells, thereby inhibiting an immune response.  The PTAB found that Petitioner provided no explanation for how one would reasonably substitute rituximab maintenance therapy for interferon maintenance therapy.  Substituting the FDA transcript for Unterhalt led the PTAB to observe that the FDA transcript addressed therapies for relapsed patients and no explanation of how results in relapsed patients would prompt one of ordinary skill to adapt the methodology to non-relapsed patients was provided.  In general terms, the PTAB concluded that Petitioner failed to explain how one of ordinary skill would modify McNeil’s method to arrive at the claimed method.

Beyond obviousness grounds citing McNeil as primary reference, Petitioner provided an obviousness ground based on McLaughlin.  The PTAB distinguished McLaughlin as also disclosing the treatment of relapsed, not non-relapsed, LG-NHL patients, of failing to describe rituximab maintenance therapy following CVP induction therapy, and of not describing the dosing regimen for rituximab maintenance therapy.  Finally, Petitioner relied on McLaughlin and McNeil, but failed to explain with particularity how one of ordinary skill would have modified McLaughlin’s process with McNeil’s teachings to arrive at claim 1.

For the foregoing reasons, the PTAB denied the petition.  The lesson here appears to be that a Petitioner would be well-served to concentrate on promising grounds for challenging U.S. patent claims and ensure that the grounds identify all references upon which reliance is placed and provide thorough explanations of how one of ordinary skill would modify the prior art technologies to arrive at the claimed subject matter.  Although not at issue here, in its related petitions (see IPR2015-00415 and IPR2015-00417), the Petitioner ran into trouble by including comprehensive grounds that allowed the PTAB to select non-redundant grounds and deny all other grounds in an unappealable institution decision.