Issue 57 | March 7, 2003
COX-2 Inhibitor Reach-Through Claim Patent Held Invalid
 Claims fail to satisfy the enablement and written description requirement of 35 U.S.C. ยง 112

In a decision involving the validity of so-called "reach-through" claims, the District Court for the Western District of New York rendered a summary judgment of invalidity of the University of Rochester's U.S. Patent No. 6,048,850, directed to methods of treatment employing COX-2 inhibitors. University of Rochester v. G.D. Searle, Inc., 00-CV-6161L (W.D. New York, March 5, 2003). These pain-relieving compounds had more than $5 billion in sales last year in the U.S. alone.

Reach-through claims seek to patent downstream research products (e.g., drug compounds) discovered or developed using a biological research tool before the particular product has been identified. Thus, the discoverer of a gene encoding a biologically important enzyme may seek to claim not only the gene and enzyme but also yet-to-be-discovered small molecule inhibitors of the enzyme and methods of treatment employing the small molecule inhibitors.

This was the exact situation underlying the University of Rochester v. G.D. Searle case. The inventors of the '850 patent had discovered the gene encoding the mammalian prostaglandin H synthase-2 (PGHS-2) and its expression product. PGHS-2 was discovered to be responsible for increased prostaglandin synthesis associated with inflammation. The claims of the '850 patent were directed to methods of inhibiting PGHS-2. Claim 1 is representative:
  1. A method for selectively inhibiting PGHS-2 activity in a human host, comprising administering a non-steroidal compound that selectively inhibits activity of the PGHS-2 gene product to a human host in need of such treatment.
This is a classic reach-through claim in that it encompasses methods of treatment employing any PGHS-2 inhibitor. The patent taught methods of assaying for PGHS-2 inhibitors and disclosed tests of a few compounds, all well known, (e.g., aspirin, ibuprofen, and naproxen). However, the patent did not identify any other particular inhibitors in structural terms or in any manner that would permit one of ordinary skill in the art to envision the inhibitor without first testing it for inhibitory activity.

Relying primarily on the written description triumvirate of Fiers v. Revel, 984 F.2d 1164, 1171 (Fed. Cir.1993), Regents of the University of California v. Eli Lilly & Co., 119 F.3d 1559, 1568 (Fed. Cir. 1997), cert. denied, 523 U.S. 1089 (1998), and Enzo Biochem, Inc. v. Gen-Probe Inc., 296 F.3d 1316 (Fed. Cir. 2002), the court held:
The patent does no more than describe the desired function of the compound called for, and it contains no information by which a person of ordinary skill in the art would understand that the inventors possessed the claimed invention. At best, it simply indicates that one should run tests on a wide spectrum of compounds in the hope that at least one of them will work.
The court further noted that nowhere did the patent specify which compounds were selective inhibitors of PGHS-2; only a method of finding the compounds was disclosed. The court poignantly noted:
I recognize that the inventors and the research teams of which they were a part did apparently make some significant discoveries in this field. They realized, in light of the discovery of PGHS-2, that it would be quite beneficial if one could find a compound that would specifically target the activity of PGHS-2, but not that of PGHS-1.

What the inventors did not do, however, is succeed in taking the last, critical step of actually isolating such a compound, or at least of developing a process through which one skilled in the art would be directly led to such a compound. Absent that step, their discoveries, valuable though they might have been, did not blossom into a full-fledged, complete invention. Scientific discoveries, and theories based on those discoveries, frequently lay the groundwork for later inventions, but that does not make the discoverer the inventor as well.
The court rejected the patentee's assertion that Fiers, Eli Lilly, and Enzo were limited to DNA or nucleic acids. Based on the foregoing, the court held the claims of the '850 patent were invalid for failing to satisfy the written description requirement.

The court relied on similar reasoning in dealing with the enablement issue, holding that whereas the patent disclosed an assay for identifying a compound as a PGHS-2 inhibitor, it merely identified broad categories of compounds that might work. Without more, the court stated, this merely amounted to providing a starting point for further research, enabling a person of ordinary skill in the art to attempt to discover how to practice the claimed invention. That, the court concluded, was not enough.

Michael S. Greenfield is a partner at the law firm of McDonnell Boehnen Hulbert & Berghoff. The information contained in this email is provided for informational purposes only and does not represent legal advice. Neither the APLF nor the author intends to create an attorney client relationship by providing this information to you through this message.