Federal Circuit Emphasizes Need For Reasonable Expectation Of Success

Author:Mr Melissa El Menaouar and Courtenay C. Brinckerhoff
Profession:Foley & Lardner

In Genzyme Corp. v. Dr. Reddy's Labs. Ltd., the Federal Circuit affirmed the district court decision upholding Genzyme's Orange Book listed patent for the cancer drug Mozobil® against an obviousness challenge, because the asserted prior art references failed to provide a reasonable expectation of success. While a non-precedential decision, this case illustrates the important role that unpredictability in the art and a lack of expectation of success can play in biotechnology patents.

The Patent at Issue

The patent at issue was Genzyme's U.S. Patent 7,897,590, directed to methods of promoting the flow of stem cells into blood for transfusion using a specific combination of drugs. The stem cells are used to treat non-Hodgkins lymphoma and other blood cancers. The only claim at issue was claim 19, which recites:

A method to obtain progenitor and/or stem cells from a subject which method comprises: (1) administering G-CSF to said subject in an amount effective to mobilize said progenitor and/or stem cells into the peripheral blood of said subject; (2) administering to said subject 1,1′-[1,4-phenylene-bis-(methylene)]-bis-1,4,8,11- tetraazacyclotetradecane or a pharmaceutically acceptable salt thereof; and (3) harvesting said progenitor and/or stem cells.

The compound 1,1′-[1,4-phenylene-bis-(methylene)]-bis-1,4,8,11-tetraazacyclotetradecane is commonly known as plerixafor.  Plerixafor is the active chemical ingredient in Genzyme's Mozobil® product.

The Asserted Prior Art References

The case stemmed from Dr. Reddy's Abbreviated New Drug Application (ANDA) seeking approval of a generic version of Mozobil®. Dr. Reddy argued that claim 19 was obvious over the combination of a journal article by Hendrix and U.S. Patent 5,824,304 ("Patent 1"), or alternatively over the combination of WO 00/45814 ("Application 1") and Patent 1.

As summarized in the Federal Circuit decision, Hendrix was focused on evaluating the safety and pharmacology of plerixafor for treating HIV. The article reported that after receiving plerixafor, all subjects had an increase in white blood cells ("WBC") in their peripheral blood. In a single line statement, the article hypothesized "binding of plerixafor to CXCR4 may inhibit the chemotactic effects of stromal cell-derived factor 1 (SDF-1) causing release of WBCs from the endothelium and/or stem cells from bone marrow."

Patent 1 disclosed a method of increasing the number of stem cells in peripheral blood by administering a blocking...

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