Judge Finds Scantibodies’ Own Tests Exonerate Immutopics

Posted on | September 23, 2008 | No Comments

2008-1522 Scantibodies v. Immunopics
CD/CA 04-8871
Judge Mariana Pfaelzer

Scantibodies appeals from the order of Judge Mariana Pfaelzer granting summary judgment of non-infringement to Immunopics.  The court did deny Immunopics’ motion with respect to best mode, enablement, on-sale and obviousness. 

Scantibodies was asserting 6,689,566 directed to methods and devices for detecting whole or non-fragmented parathyroid hormone (PTH) in a biological sample.

Claim 1 of the ’566 is reflective of the various claims asserted:

1. A substantially pure antibody or antibody fragment specific for an
initial peptide sequence of whole parathyroid hormone wherein said
initial peptide sequence consists of VAL-SER-GLU-ILE-GLN-LEU-MET (SEQ
ID NO:3), and wherein at least four amino acids in said initial peptide
sequence are part of a reactive portion with said antibody.

The court construed several terms, and in particular "specific for an
initial peptide sequence…" as meaning "exhibiting significantly greater binding affinity for the PTH(2-8) region of whole PTH than for the PTH(9-84) region."  The (2-8) and (9-84) nomenclature refers to amino acids, and this claim language is part of every claim of the ’566.

On summary judgment, Immutopics relied on previous tests performed by Scantibodies showing that the accused Immutopics’ antibody did not have an affinity for binding with the PTH(2-8) region:

In work that dates to 2004, Dr. Zan Yang, an employee of Scantibodies, conducted preliminary testing to determine whether Immutopics’ accused antibody infringed the claims. See Newboles Decl. Supp. Immutopics’ Mot. Summ. J. Non-Infringement (“Newboles Non-Infringement Decl.”), Exh. K. (excerpts from deposition of Dr. Yang, and results of his testing). Significantly, in a series of inhibition assays, Dr. Yang found that Immutopics’ accused product does not bind to the 1-8 PTH or 2-8 PTH peptides. Id., Exh. K at 25-33. Thus, he concluded that “1-8 PTH does not contain the full Immutopics epitope,” and likewise “2-8 PTH does not contain the full Immutopics epitope.” Id., Exh. K at 33. (Used in this context, an “epitope” is the region of PTH for which the antibody has the greatest binding affinity.) Dr. Yang concluded that the full epitope is either 2-10 PTH or 2-11 PTH. Id., Exh. K at 33; see also Plaintiff’s Response to Defendants’ Fifth Request for Admissions, Newboles Non-Infringement Decl., Exh. I at 6 (admitting that the epitope to which Immutopics’ accused antibodies bound “includes (2-11) PTH”).

The court found this testing dispositive:

In light of the Court’s construction, Dr. Yang’s testing establishes that Immutopics does not infringe any claim of the ‘566 Patent. An antibody does not satisfy the “specific for “claim limitation unless it exhibits “significantly greater” affinity for amino acids 2-8 than amino acids 9, 10, 11, 12, and so on. If the full Immutopics epitope is 2-10 or 2-11, then Immutopics’ antibodies bind very strongly to amino acids 9, 10, and perhaps 11, as well as binding very strongly to amino acids 1-8. Indeed, Dr. Yang’s results demonstrate that the affinity of Immutopics’ antibody for amino acids 9, 10, and 11 of PTH are so strong that the antibody will not bind at all when those amino acids are missing – Immutopics’ antibodies failed to bind to either the 1-8 PTH or 2-8 PTH peptides. Because of this difference in the epitope of 2-3 amino acids, it cannot be said that Immutopics’ antibodies exhibit significantly greater affinity for PTH 2-8 than for PTH 9-84.

The court further noted that Scantibodies did not offer any evidence or other material to show that Dr. Yang’s test results were wrong or that the accused antibody did in fact have an affinity for binding with the PTH(2-8) region.

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