IPRs are an attractive option for biosimilar applicants to clear the patent landscape before delving into litigation under the Biologics Price Competition and Innovation Act of 2009 (BPCIA), which is still in its infancy. Roche’s Herceptin® (trastuzumab) is a prime target for biosimilar makers, accounting for sales of over $6.5 billion in 2015. Mylan, Celltrion, and Pfizer, all with competing biosimilar candidates, have filed IPR petitions challenging patents reportedly covering trastuzumab. Recently, the PTAB granted a petition filed by Hospira (subsidiary of Pfizer) to institute IPR of U.S. Patent No 7,807,799 (“the ’799 patent”), directed to protein A affinity chromatography. Hospira, Inc. v. Genentech, Inc., IPR2016-01837, Paper No. 19 (April 7, 2017).

The ’799 patent claims a method of purifying a protein which comprises a CH2/CH3 region, which is common to IgG antibodies, by subjecting a composition containing the protein to protein A affinity chromatography at a temperature in a range from about 10oC to about 18oC (claim 1). In one embodiment, the protein is trastuzumab (claim 8).

The Petitioner offered eight different grounds for institution under 35 U.S.C. §102(b) or §103(a) in its petition. All of the grounds relied upon the teachings of one of two primary references. Both primary references were before the Examiner during prosecution of the ‘799 patent, but were not the basis of any rejections and were not characterized on the record. The Patent Owner did not file an optional preliminary response to the petition. The PTAB declined to exercise its discretion to deny institution under 35 U.S.C. § 325(d), and instituted trial on all eight grounds.

During prosecution, the Examiner referenced various prior art and acknowledged that the temperature range recited in claim 1 was different than that disclosed in the references. One of the primary references the petition cites allegedly teaches conducting protein A affinity chromatography at 18oC to 25oC, a range overlapping the claimed range by one degree. According to the PTAB, in the absence of evidence establishing that the claimed range is critical to the operability of the claimed invention, such a disclosure anticipates the claimed method. The second primary reference allegedly discloses protein A affinity chromatography performed at 20oC to 25oC. While this range is not within the range explicitly recited in the claims (i.e., about 10oC to about 18oC), the Petitioner successfully argued that “about 18oC” should be construed to include ± 3oC, effectively broadening the upper limit of the claimed range to 21oC. Under this construction, the temperature disclosed in the reference overlaps the claimed range. The PTAB repeatedly noted in the institution decision that the Petitioner’s arguments were unopposed; one would expect the Patent Owner to address the criticality issue and construction of “about 10oC to about 18oC” at trial.

The PTAB recently terminated two IPR proceedings relating to trastuzumab and requested by Mylan, presumably in connection with the global settlement and license agreement with Genentech and Roche that Mylan reported in March 2017. While the PTAB granted Hospira’s petition, pending still are its decisions regarding several other petitions Hospira and Celltrion separately filed and relating to trastuzumab. Stay tuned to PTABWatch for updates on these proceedings.