by Dennis Crouch
My former bosses Paul Berghoff and Alison Baldwin (at MBHB) won an interesting case today on behalf of Genzyme and its corporate parent Sanofi-Aventis.
Genzyme’s patent No. 7,897,590 is an important part of modern stem-cell practice in the treatment of non-Hodgkin’s lymphoma and multiple myeloma. The patented process stimulates mobilization of a donor’s bone marrow by administering both a “granulocyte-colony stimulating factor” and also plerixafor (See Claim 19). The plerixafor drug (sold under the brand name Mozobil) is no longer patented, but the treatment protocol is patented.
In the ANDA lawsuit, the generic defendants argued that the asserted claim was obvious. Following a bench trial (no right to jury trial in ANDA cases), the district court sided with the patentee — finding insufficient evidence of obviousness. On appeal, the Federal Circuit has also affirmed.
For obviousness analysis, the first consideration is typically the scope-and-content of the prior art. Any reference used must qualify as prior art under Section 102 and must also be considered analogous or pertinent. The key prior art reference – Hendrix discussed the pharmacokinetics and use of plerixafor – but was focused on use of the drug in HIV treatment. The district court excluded Hendrix – finding that it was not analogous art since one of skill in the art would not have been looking for this type of drug in researching stem cell mobilization. On appeal, the Federal Circuit did not review that particular holding – instead finding that even if considered pertinent to an obviousness analysis, it still would not be sufficient to render the claim invalid.
For the Federal Circuit, the basic dispute comes down to whether a person of skill would have a “reasonable expectation of success” – i.e., a reasonable expectation that combining Hendrix with the other references would lead to a treatment that mobilizes stem cells as claimed.
Here, the district court found that a skilled artisan would not have had a reasonable expectation of success that plerixafor would mobilize stem cells. DRL has not shown that this determination was clearly erroneous.
The basic difficulty is that the prior art stem-cell mobilization research focused on a “completely different family of receptors” than those triggered by plerixafor; and that stem cells exhibit “around one hundred different types of receptors.” Thus, according to the court, it would have been a major leap to use plexifora as described in Hendrix for stem cell mobilization.
The one difficulty with the Federal Circuit and District Court analysis is that this key prior art reference “Hendrix” actually states that the drug may cause stem-cell mobilization.
These combined observations suggest that binding of [plexifora] to CXCR4 may inhibit the chemotactic effects of SDF-1α, causing release of WBCs from the endothelium and/or stem cells from bone marrow.
Hendrix. The Federal Circuit recognizes what’s happening here and does an interesting word dance – attempting to explain-away the statement:
Although Hendrix hypothesized in an isolated sentence, without explanation, that plerixafor may cause stem cell mobilization, the rest of the seven-page article focused on the elevation of WBC counts. . . . A skilled artisan would have recognized that Hendrix never tested for the presence of stem cells. The primary speculation in Hendrix for the phenomenon associated with elevated WBC counts was “demargination,” which refers to the release of WBCs from the endothelium. This emphasis on demargination is consistent with how an independent group of contemporary researchers perceived Hendrix.
The district court’s finding that stem cell mobilization was highly unpredictable at the time of the invention also runs counter to an expectation of success. In particular, there was great uncertainty about the role of SDF-1 or CXCR-4, if any, in the process of stem cell mobilization. …
Holding of non-obviousness affirmed since there was no reasonable expectation of success.
Note here – Although MBHB does not exert any editorial control over Patently-O, they are the primary advertiser for the site, and my former employer. DC.