IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
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`In the Inter Partes Review of:
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`Trial Number: To Be Assigned
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`U.S. Patent No. 6,407,213
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`Filed: November 17, 1993
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`Issued: June 18, 2002
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`Inventor(s): Paul J. Carter, Leonard G. Presta
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`Assignee: Genentech, Inc.
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`Title: Method for making humanized antibodies Panel: To Be Assigned
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`Mail Stop Inter Partes Review
`Commissioner for Patents
`P.O. Box 1450
`Alexandria, VA 22313-1450
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`DECLARATION OF TIMOTHY BUSS
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`PFIZER EX. 1504
`Page 1
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`In the Inter Partes Review of:
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`Trial Number: To Be Assigned
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`U.S. Patent No. 6,407,213
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`Filed: November 17, 1993
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`Issued: June 18, 2002
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`Inventor(s): Paul J. Carter, Leonard G. Presta
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`Assignee: Genentech, Inc.
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`Title: Method for making humanized antibodies Panel: To Be Assigned
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`Mail Stop Inter Partes Review
`Commissioner for Patents
`P.O. Box 1450
`Alexandria, VA 22313-1450
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`DECLARATION OF TIMOTHY BUSS
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`PFIZER EX. 1504
`Page 1
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`TABLE OF CONTENTS
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`I.
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`QUALIFICATIONS AND BACKGROUND ................................................. 1
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`A.
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`B.
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`C.
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`Education and Experience ..................................................................... 1
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`Bases for Opinions and Materials Considered ...................................... 5
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`Scope of Work ....................................................................................... 5
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`II.
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`SUMMARY OF OPINIONS ........................................................................... 6
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`III. LEGAL STANDARDS ................................................................................... 9
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`IV. PERSON OF ORDINARY SKILL IN THE ART ........................................ 11
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`V.
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`THE ’213 PATENT (EX. 1501) .................................................................... 14
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`VI. STATE OF THE ART OF MONOCLONAL ANTIBODY
`THERAPIES AND CANCER ....................................................................... 14
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`Early Antibody Therapy ...................................................................... 14
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`Efforts to Reduce Immunogenicity—Chimerization and
`Humanization ...................................................................................... 18
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`Breast Cancer and HER-2 ................................................................... 24
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`Identification and Characterization of 4D5, a Potential
`Therapeutic Mouse Monoclonal Antibody to HER-2/neu .................. 30
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`Humanization of 4D5 to Enable Therapeutic Use .............................. 37
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`A.
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`B.
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`C.
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`D.
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`E.
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`i
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`PFIZER EX. 1504
`Page 2
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`1. My name is Timothy Buss I have been retained by counsel for Pfizer,
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`Inc. (“Pfizer”). I understand that Pfizer intends to file petitions for inter partes
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`review of U.S. Patent No. 6,407,213 (“the ’213 patent”) (Ex. 1501), which is
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`assigned to Genentech, Inc. I also understand that Pfizer will request that the
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`United States Patent and Trademark Office cancel certain claims of the ’213 patent
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`as unpatentable in their petitions. I submit this expert declaration in support of
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`Pfizer’s petitions.
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`I.
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`QUALIFICATIONS AND BACKGROUND
`A. Education and Experience
`2.
`I am currently an independent consultant in the antibody engineering
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`field. As a consultant, I help clients with a variety antibody discovery and
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`development issues. In particular, I advise clients on choosing the best methods to
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`immunize and screen monoclonal antibodies, humanize antibodies by CDR
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`grafting onto human frameworks and develop methods for expression and
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`purification of recombinant proteins. At the present time, I am working with two
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`nonprofit research organizations and a gene therapy company on issues relating to
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`antibody generation, engineering, affinity maturation and phage display.
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`3.
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`In all, I have more than 25 years of practical and research experience
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`specializing in antibody design, humanization, and expression. My curriculum
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`vitae is attached hereto as Exhibit A.
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`PFIZER EX. 1504
`Page 3
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`4.
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`I received my Higher National Certificate (“HNC”) in applied biology
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`from Cambridgeshire College of Arts and Technology (now part of Anglia Ruskin
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`University) in the UK where I attended from 1981–86. While attending
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`Cambridgeshire College of Arts and Technology, I worked as an Assistant
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`Scientific Officer in the Director’s Group, Agricultural and Food Research Council
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`Institute of Animal Physiology and Genetics Research (1981–87).
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`5.
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`In 1987, I became a Scientific Officer at the Medical Research
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`Council (“MRC”) Group, Department of Neuroendocrinology at the AFRC
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`Institute of Animal Physiology and Genetics Research. My work at the MRC
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`included cloning, expression, and purification of proteins for polyclonal antibody
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`production as well as associated animal work.
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`6.
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`In 1991, I became a Higher Scientific Officer at the Cambridge Centre
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`for Protein Engineering, Laboratory of Molecular Biology. There, I worked under
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`Dr. Sir Gregory Winter and focused on, among other things, expression and
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`purification of monoclonal and recombinant humanized antibodies and generation
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`of vectors for antibody phage display. In 1993, I moved to the Fred Hutchinson
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`Cancer Research Center in Seattle, WA. My work there included cloning,
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`expression, and purification of humanized antibodies as well as the development of
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`protocols for the expression and purification of recombinant proteins.
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`2
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`PFIZER EX. 1504
`Page 4
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`7.
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`In 2002, I moved to the Sidney Kimmel Cancer Center, where my
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`work involved the cloning and expression of monoclonal antibodies; the design,
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`construction, and expression of murine, chimeric, and humanized antibodies for
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`tumor targeting projects; and the generation of phage antibody libraries from
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`immunized mice to generate novel binders to targets on vascular endothelial cells.
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`8.
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`In 2008, I became a Senior Scientist at Ambrx, Inc. In that position, I
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`was responsible for antibody generation and development, including the design and
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`generation of recombinant proteins and chimeric and humanized antibodies. I also
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`supervised development from initial antigen design through preclinical testing of
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`the humanized antibody lead candidate, generated monoclonal antibodies for
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`internal projects, designed and produced bispecific and multifunctional antibodies
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`and antibody-based proteins, and made Fc modifications to alter effector functions.
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`I was also project leader on several collaborations with large pharmaceutical
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`companies. I remained at Ambrx, Inc. until 2015.
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`9.
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`In addition to my full time experience described above, I have also
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`been involved with a number of consulting projects. From August 2015 to March
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`2016, I worked as a Research Scientist and Consultant at the California Institute
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`for Biomedical Research. In this position, I worked to troubleshoot antibody
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`related projects and advise on antibody research, humanization, design, expression,
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`3
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`PFIZER EX. 1504
`Page 5
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`and purification. In addition, as discussed above in ¶ 2, I am currently an
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`independent consultant in the antibody engineering field.
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`10.
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`In connection with my research activities, I have published several
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`articles on antibody design, engineering, and use. In 1998, I published an article on
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`conformational changes in the complementarity determining regions induced by
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`engineering these segments within human framework regions. See Exhibit A at 4
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`(Publications). In 2001, I published an article on the effects of framework
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`mutations at Residues 27 and 71 on the CDRs of humanized antibodies. See id. In
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`addition, I have published articles on the use of human germline framework
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`regions for the humanization of murine antibodies and the preparation of
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`humanized antibodies with reduced immunogenicity by using human genomic V
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`gene framework sequences whose CDR’s canonical class match closest to the
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`canonical class of murine antibodies. See id. Finally, I have published on the use of
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`engineered antibodies designed to deliver therapeutic agents to specific tissues and
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`the engineering of a new antibody, J120, and expression and sequence of its
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`antigen, CD34. See id.
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`11.
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`I am also a named inventor on several patents and patent applications
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`in the antibody engineering field. See id. at 5 (“Patents”).
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`4
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`PFIZER EX. 1504
`Page 6
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`B.
`Bases for Opinions and Materials Considered
`12. Exhibit B includes a list of the materials I considered, in addition to
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`my experience, education, and training, in providing the opinions contained herein.
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`13.
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`I understand a third-party, Mylan, previously filed IPR petitions
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`challenging claims of the ’213 patent. I have reviewed and considered Mylan’s IPR
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`petitions and the declarations filed in support of Mylan’s IPR petitions. Applying
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`my independent judgement and expertise, after having independently reviewed and
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`analyzed all of the materials in Mylan expert Dr. Edward Ball’s materials
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`considered lists, and after having done the additional work of fact checking and
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`considering whether potential counterarguments may exist, I have come to the
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`same conclusions as Dr. Ball and I agree with the analysis in his declaration as set
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`forth below. Readers of this declaration may note the language and organization is
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`similar to that of Dr. Ball’s declaration because it did not seem a necessary
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`expenditure of resources to rewrite the material which I independently confirmed
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`as acceptable and correct. The opinions in this declaration should be considered
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`mine.
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`C.
`14.
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`Scope of Work
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`I have been retained by Pfizer as a technical expert in this matter to
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`provide various opinions regarding the ’213 patent. I receive $300 per hour for my
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`services. No part of my compensation is dependent upon my opinions given or the
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`5
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`PFIZER EX. 1504
`Page 7
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`outcome of this case. I do not have any other current or past affiliation as an expert
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`witness or consultant with Pfizer. I do not have any current or past affiliation with
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`Genentech, Inc., or any of the named inventors on the ’213 patent.
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`II.
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`SUMMARY OF OPINIONS
`15. To summarize, for the reasons set forth below, it is my opinion that
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`one of ordinary skill in the art would have recognized the power and potential of
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`monoclonal antibodies (MAbs or MoAbs) as therapies for a number of diseases
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`including breast cancer while acknowledging the limitation of their use due to
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`immunogenic effects upon repeated administration of mouse monoclonal
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`antibodies. Moreover, one of ordinary skill in the art would have recognized that
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`humanization of mouse monoclonal antibodies as developed by Queen et al., A
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`Humanized antibody that binds to the interleukin 2 receptor, 86 PROC. NAT’L
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`ACAD. SCI. USA 10029–33 (1989) (“Queen 1989”) (Ex. 1534) and others would
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`overcome this limitation. With respect to cancer, one skilled in the art would have
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`identified HER-2/neu as a target for breast cancer therapy based on the prevalence
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`of this gene in a significant number of human breast cancer and other types of
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`cancers as well as the overexpression of HER-2/neu to cause cell transformation
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`and tumorigenesis.
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`16. Accordingly, it is my opinion that because of the well-documented
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`pre-1991 reports of excellent specificity and potent anti-proliferative and cytotoxic
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`6
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`PFIZER EX. 1504
`Page 8
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`effects of the mouse monoclonal 4D5 antibody directed to HER-2/neu as presented
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`in Hudziak et al., p185HER2 Monoclonal Antibody Has Antiproliferative Effects In
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`Vitro and Sensitizes Human Breast Tumor Cells to Tumor Necrosis Factor, 9(3)
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`MOLECULAR CELLULAR BIOLOGY 1165 (1989) (“Hudziak 1989”) (Ex. 1521), a
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`person of ordinary skill in the art would have identified 4D5 as a promising
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`candidate for humanization, at least as early as March 1989. After singling out 4D5
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`from a panel of monoclonal antibodies, Hudziak 1989 (Ex. 1521) identified the
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`4D5 antibody as showing good specificity toward the HER-2 receptor extracellular
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`domain and did not cross-react or bind to the EGF receptor (HER-1). The 4D5
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`antibody also demonstrated growth inhibitory and anti-proliferative effects on
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`HER-2 positive SK-BR-3 breast cancer cells. As Hudziak 1989 (Ex. 1521) noted,
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`the 4D5 antibody had the best effect of the tested anti-HER-2 antibodies in
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`inhibiting the growth of these cells leading the authors to conclude that
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`“[m]aximum inhibition was obtained with monoclonal antibody 4D5 which
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`inhibited cellular proliferation by 56%.” Id. at 12. The 4D5 antibody was also
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`shown to downregulate p185HER2 by allowing the protein to be degraded more
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`quickly in the cell. Finally, the 4D5 antibody sensitized HER-2 positive breast
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`cancer cells to TNF-alpha mediated cytotoxicity.
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`17. Furthermore, Shepard et al., Monoclonal Antibody Therapy of Human
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`Cancer: Taking the HER2 Protooncogene to the Clinic, 11(3) J. CLINICAL
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`PFIZER EX. 1504
`Page 9
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`IMMUNOLOGY, 117 (1991) (Ex. 1548) reported that a human tumor xenograft
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`model was used to “support[] the application of muMAb 4D5 to human cancer
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`therapy” and “its ability to inhibit the growth of tumor cells overexpressing
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`p185HER2 in vivo.” Id. at 8. In tumor bearing athymic mice, the authors
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`administered either the 4D5 antibody, a control antibody 5B6, or PBS and
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`observed that “[o]n day 20, average tumor weights of animals receiving muMAb
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`4D5 were significantly less than those receiving the same dose of the control
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`antibody muMAb 5B6.” Id. at 9. These observations allow Shepard et al. to
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`conclude that “[t]he muMAb 4D5 also serves as a template for antibody
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`engineering efforts to construct humanized versions more suitable for chronic
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`therapy or other molecules which may be directly cytotoxic for tumor cells
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`overexpressing the HER2 protooncogene.” Id. at 12.
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`18. Thus in my opinion, one of ordinary skill in the art would have
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`acknowledged and recognized the above-described promising properties of the
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`mouse monoclonal antibody 4D5 in vitro and in vivo and have strong motivation to
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`select this antibody as a prime candidate for further development as a therapy for
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`breast cancer. It then follows, that one of ordinary skill in the art would logically
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`proceed to develop the monoclonal 4D5 antibody as a breast cancer therapeutic via
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`well-established humanization
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`techniques,
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`thereby reducing
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`the antibody’s
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`PFIZER EX. 1504
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`immunogenicity and restoring antibody-dependent cell-mediated cytotoxicity
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`(ADCC) and effector cell binding.
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`III. LEGAL STANDARDS
`19.
`In preparing and forming my opinions set forth in this declaration, I
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`have been informed regarding the relevant legal principles. I have used my
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`understanding of those principles in forming my opinions. My understanding of
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`those principles is summarized below.
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`20.
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`I understand a patent has three primary parts: the specification, the
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`drawings, and the claims. The specification consists of a written description of the
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`invention and must provide a sufficient description to enable one skilled in the art
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`to practice the invention. The drawings illustrate the invention. The claims appear
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`at the end of the specification as numbered paragraphs. I am told the claims define
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`the metes and bounds of the property right conveyed by the patent.
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`21.
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`I understand claims can be independent or dependent. Dependent
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`claims refer back to and incorporate at least one other claim. Dependent claims
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`include all the limitations of any claims incorporated by reference into the
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`dependent claim.
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`PFIZER EX. 1504
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`22.
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`I have also been told that claims should be given their broadest
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`reasonable interpretation in light of the specification from the perspective of a
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`person of ordinary skill in the art at the time of the alleged invention.1
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`23.
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`I understand prior art to the ’213 patent includes patents, printed
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`publications and products in the relevant art that predate the priority date of the
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`’213 patent.
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`24.
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`I am told a claim is invalid if it is anticipated or obvious. I understand
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`anticipation requires that every element and limitation of the claim was previously
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`described in a single prior art reference, either expressly or inherently, before the
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`date of the alleged invention.
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`25. To determine whether a claim is obvious, I understand the scope and
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`content of the prior art are to be determined, differences between the prior art and
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`the claims at issue are to be ascertained, and the level of ordinary skill in the
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`pertinent art resolved. I also understand that secondary considerations such as
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`commercial success, long felt but unsolved needs, failure of others, etc., may have
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`some relevancy to whether or not the claim is obvious or nonobvious. I understand
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`that obviousness is assessed at the time of the alleged invention.
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`1 I have been asked to assume the priority date of the ’213 patent (June 14, 1991)
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`is the date of the alleged invention.
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`Page 12
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`26.
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`I am also informed that when there is some recognized reason to solve
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`a problem, and there are a finite number of identified, predictable and known
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`solutions, a person of ordinary skill in the art has good reason to pursue the known
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`options within his or her technical grasp. If such an approach leads to expected
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`success, it is likely not the product of innovation but of ordinary skill and common
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`sense. In such a circumstance, when a patent simply arranges old elements with
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`each performing its known function and yields no more than what one would
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`expect from such an arrangement, the combination is obvious.
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`27.
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`I have been
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`told
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`that Pfizer bears
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`the burden of proving
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`unpatentability by a preponderance of the evidence. I am informed that this
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`preponderance of the evidence standard means that Pfizer must show that
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`unpatentability is more probable than not. I have taken these principles into
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`account when forming my opinions in this case.
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`IV. PERSON OF ORDINARY SKILL IN THE ART
`28.
`I have been informed by counsel that the obviousness analysis is to be
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`conducted from the perspective of a person of ordinary skill in the art (a “person of
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`ordinary skill”) at the time of the alleged invention.
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`29.
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`I have also been informed by counsel that in defining a person of
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`ordinary skill in the art the following factors may be considered: (1) the
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`PFIZER EX. 1504
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`educational level of the inventor;2 (2) the type of problems encountered in the art;
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`(3) prior art solutions to those problems; (4) rapidity with which innovations are
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`made; and (5) sophistication of the technology and educational level of active
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`workers in the field.
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`30.
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`I understand that Dr. Jefferson Foote is also submitting a declaration
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`in connection with Pfizer’s IPR petitions. I have spoken with Dr. Foote and I
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`understand that he has expressed an opinion that a person of ordinary skill in the
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`art related to the ’213 patent would be an individual that developed protein
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`therapeutics. This person would have a Ph.D. or equivalent (for example,
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`knowledge gained through 4–5 years of work experience) in molecular biology,
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`immunology, biochemistry or a closely related field, and may work as a member of
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`a team. A team member or advisor or consultant would have an M.D. with clinical
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`experience in the disease or disease area (e.g., oncology) for which the antibody
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`development is intended.
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`2 A review of To Build a Better Mousetrap, Use Human Parts, Journal of the
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`National Cancer Institute, Vol. 90, No. 1, January 7, 1998 (Ex. 1685) suggests
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`named inventors Paul Carter and Leonard Presta both held Ph.D.s and were
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`working at Genentech at the time of the alleged invention. See Ex. 1685 at 9.
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`12
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`31. For example, as a Ph.D. or equivalent the person of ordinary skill in
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`the art would have the educational background above with experience in common
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`laboratory techniques in molecular biology, such as those in the popular how-to
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`handbook, “Molecular Cloning Techniques: A Laboratory Manual”, by Sambrook
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`and Fritsch, 1989 (Ex. 1597). This experience is consistent with the types of
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`problems encountered in the art of protein engineering, which would have included
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`performing three-dimensional computer modeling of protein structures, domain
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`and sequence manipulation and swapping, construction and expression of
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`recombinant proteins, antibody binding assays (for specificity and affinity),
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`immunogenicity testing and the like. The experience may come from the person of
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`ordinary skill in the art’s own experience, or may come through research or work
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`collaborations with other
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`individual(s) with experience
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`in
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`the medical,
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`pharmaceutical or biotech industry, e.g., as members of a research team or group.
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`32. A person of ordinary skill in the art would also be well-versed in the
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`world-wide literature on antibody therapeutics that was available as of the ’213
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`patent. As mentioned above, the person of ordinary skill in the art may work as
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`part of a team or collaboration to develop a humanized monoclonal antibody for
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`therapeutic use, including consulting with others to select non-human monoclonal
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`antibodies (such as a mouse monoclonal antibody) for humanization, as well as
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`subsequent testing of the humanized antibody and its intermediates. Additionally,
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`13
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`PFIZER EX. 1504
`Page 15
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`in the prior art, computer modeling for humanization was a known methodology.
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`The field was advancing rapidly, and individuals working in the field were highly
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`sophisticated and using the most advanced scientific techniques.
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`33. Based on the factors I understand I am supposed to consider,
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`particularly factors 2–5 (¶ 29) with which I am most familiar given my experience,
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`in my opinion Dr. Foote’s definition of one of skill in the art is a sound one and I
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`adopt and apply it here.
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`V. THE ’213 PATENT (EX. 1501)
`34.
`I have read the ’213 patent entitled “Method for Making Humanized
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`Antibodies,” as well as its issued claims. I understand Pfizer is challenging claims
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`1, 2, 4, 12, 25, 29–31, 33, 42, 60, 62–67, 69 and 71–81 (“Challenged Claims”).
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`The Challenged Claims include claims that relate to a humanized antibody which
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`binds to p185HER2, i.e., claims 30, 31, 33, 42 and 60. I have been asked by Pfizer to
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`comment on antibody therapies, and in particular those that relate to p185HER2 and
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`breast cancer.
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`VI. STATE OF THE ART OF MONOCLONAL ANTIBODY THERAPIES
`AND CANCER
`A. Early Antibody Therapy
`35. Because of their specificity to an antigen, antibodies were considered
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`very early on as potential therapeutics for the treatment of diseases and conditions.
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`In particular, monoclonal antibodies created from mice, developed by Georges
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`PFIZER EX. 1504
`Page 16
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`Köhler and César Milstein in 1975, were of great interest to researchers as these
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`types of antibodies were of a single clonal population of antibodies which all
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`bound to the same antigen with the same specificity. See, e.g., Köhler et al.,
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`Continuous cultures of fused cells secreting antibody of predefined specificity,
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`256(5517) NATURE 495 (1975) (Ex. 1522). In this seminal paper, Köhler and
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`Milstein developed the hybridoma cell technique that fused a mouse myeloma cell
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`with antibody-producing mouse spleen cells from an immunized donor. It then
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`became “possible to hybridise antibody-producing cells from different origins” and
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`that “[s]uch cells [could] be grown in vitro in massive cultures to provide a specific
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`antibody.” Id. at 5. The authors, who went on to receive the 1984 Nobel Prize for
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`medicine for this work, contemplated that “[s]uch cultures could be valuable for
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`medical and industrial use.” Id. Monoclonal antibody technology thus enabled the
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`isolation and large scale production of a single specific antibody and opened the
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`door to using antibodies for therapeutic and diagnostic purposes. See, e.g.,
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`Prabakaran, The Quest for a Magic Bullet, 349(6246) SCIENCE 389 (2015) (Ex.
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`1523 at 5) (“Milstein sent samples and protocols of his newly created antibody-
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`secreting cell lines to other research institutions and even trained scientists to
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`generate their own hybridomas.…In the years that followed, there was an
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`explosion in Mab research. Some were generated to identify different types of
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`white blood cells, and several proved to be important in investigating HIV/AIDS.
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`PFIZER EX. 1504
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`The first medical application of this technology used Mabs to purify interferons,
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`signaling proteins that are released by cells in response to the presence of
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`pathogens.”); Marks, The story of Cesar Milstein and Monoclonal Antibodies: A
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`Healthcare Revolution
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`in
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`the Making, http://www.whatisbiotechnology.org/
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`exhibitions/milstein (last visited April 13, 2017) (Ex. 1524 at 56–57). (“By the
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`time the Nobel Prize was awarded to Milstein and his colleagues, monoclonal
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`antibodies had become a ubiquitous method for researchers in a multitude of
`
`disciplines. The technology not only provided the tool for those involved in basic
`
`science, but also for those looking to develop new diagnostics and therapies.”)
`
`36. Researchers thus immediately recognized the therapeutic potential of
`
`monoclonal antibodies, and began administering murine monoclonal antibodies in
`
`humans in an attempt to treat a variety of diseases, including cancer and
`
`immunological disorders. For example, the first Mab approved for human use,
`
`murine monoclonal anti-CD3 antibody, OKT3
`
`(muromonab-CD3), was
`
`investigated for its immunosuppressive activities in preventing organ graft
`
`rejection. See, e.g., Cosimi et al., Treatment of Acute Renal Allograft Rejection
`
`with OKT3 Monoclonal Antibody, 32 TRANSPLANTATION 535−39 (1981) (Ex.
`
`1525); Ortho Multicenter Transplant Study Group, A Randomized Clinical Trial of
`
`OKT3 Monoclonal Antibody for Acute Rejection of Cadveric Renal Transplants,
`
`313(6) NEW ENG. J. MED. 337 (1985) (Ex. 1526). Administration of OKT3, which
`
`
`
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`16
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`PFIZER EX. 1504
`Page 18
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`
`
`
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`binds to CD3 on human T-cells and suppresses T-cell function, in patients with
`
`kidney transplants was found to be more effective in treating and reversing kidney
`
`transplant rejections than conventional steroids. Id. at 2, Abstract. Despite OKT3’s
`
`impressive and potent immunosuppressive effects, it was also found that OKT3, as
`
`a murine monoclonal antibody, elicited a strong human antibody response against
`
`OKT3 itself (HAMA Human Anti-Mouse Antibody). Jaffers et al., Monoclonal
`
`Antibody Therapy: Anti-idiotypic and Non-anti-idiotypic Antibodies to OKT3
`
`Arising Despite Intense Immunosuppression, 41(5) TRANSPLANTATION 572 (1986)
`
`(Ex. 1527). When patients with a kidney
`
`transplant received repeated
`
`administration of OKT3 over the course of 10–20 days, it was found that 75% of
`
`the patients had already developed detectable antibodies against the administered
`
`OKT3 murine monoclonal antibody. Id. at 7, Abstract. The authors postulate that
`
`“the immune response to this and probably other monoclonal antibodie,s can block
`
`their therapeutic effectiveness and can arise despite intense immunosuppression.”
`
`Id. Thus, prolonged or repeated administration of murine monoclonal antibodies
`
`was recognized as an obstacle to their use in therapy.
`
`37. With respect to cancer, Hilary Koprowski’s group from the Wistar
`
`Institute in Philadelphia in 1982, investigated the use a murine monoclonal
`
`antibody 17-1A, which was shown to lyse and specifically inhibit growth of human
`
`colon carcinomas xenografted in athymic (nu/nu) mice. See Sears et al., Phase-I
`
`
`
`
`17
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`PFIZER EX. 1504
`Page 19
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`
`
`
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`Clinical Trial of Monoclonal Antibody in Treatment of Gastrointestinal Tumours,
`
`LANCET 762 (1982) (“Sears”) (Ex. 1528). The authors noted that while there was
`
`promise of therapeutic efficacy, three of four patients developed antibodies against
`
`the administered mouse immunoglobulin, with one patient exhibiting an adverse
`
`clinical reaction to the last injection of the antibody. Id. at 4. The investigators also
`
`postulated that the development of an immune reaction to the administered mouse
`
`immunoglobulins “may limit repeated administration of whole molecules of mouse
`
`immunoglobulins.” Id. at 5 (emphasis added); see also Sikora, Monoclonal
`
`antibodies in oncology, 35 J. CLINICAL PATHOLOGY 369–75 (1982) (Ex. 1529)
`
`(review article disclosing use of monoclonal antibodies in diagnostic and oncology
`
`treatment areas).
`
`B.
`
`to Reduce
`Efforts
`Humanization
`38. An approach to reduce the well-documented problems of immune or
`
`Immunogenicity—Chimerization
`
`and
`
`immunogenic responses observed in the therapeutic use of murine monoclonal
`
`antibodies was developed in the 1980s as researchers began producing chimeric
`
`antibodies that combined the variable (V) region binding domain of a murine
`
`antibody with human antibody constant (C) domains. Morrison et al., Chimeric
`
`human antibody molecules: Mouse antigen-binding domains with human constant
`
`region domains, 81 PROC. NAT’L ACAD. SCI. USA 6851 (1984) (Ex. 1531). Hence,
`
`a chimeric antibody would retain the binding specificity of the original murine
`
`
`
`
`18
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`PFIZER EX. 1504
`Page 20
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`
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`
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`monoclonal antibody but have the human constant domain. As a result, the
`
`chimeric antibody would contain less amino acid sequences foreign to the human
`
`immune system and therefore be less immunogenic relative to the murine
`
`monoclonal antibody. Id. at 10. Further, because of the presence of a human
`
`constant domain, chimeric antibodies can also have improved function with respect
`
`to a patient’s effector cells over its murine monoclonal counterparts. Liu et al.,
`
`Chimeric mouse-human IgG1 antibody that can mediate lysis of cancer cells, 84
`
`PROC. NAT’L ACAD. SCI. USA 3439 (1987) (Ex. 1532). In cytotoxicity studies of
`
`carcinoma cell lines with effector cells, Liu et al. reported that the chimeric L6
`
`antibody mediated antibody-dependent cellular cytotoxicity (ADCC) at 100 times
`
`lower concentration than the mouse monoclonal L6 antibody. Id. at 9, Abstract, 13,
`
`Fig. 6. Further, the chimeric L6 antibody gave higher human complement-
`
`dependent cytotoxicity (CDC) when lysing tumor cells in the presence of human
`
`complement. Id. at 12, Fig. 5.
`
`39. The properties of chimeric antibodies, which include reduced
`
`immunogenicity and improved effector function, are therefore advantageous over
`
`their murine monoclonal antibody counterparts. Unfortunately, this chimeric
`
`approach would not be applicable for OKT3 and others like it, because it was
`
`discovered that much of the strong immune response is directed against the
`
`variable region of OKT3 rather than the constant domain. Ex. 1527 at 12
`
`
`
`
`19
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`PFIZER EX. 1504
`Page 21
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`
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`
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`(“Overall, 75% of our patients who had any antibody response made anti-Id [anti-
`
`idiotype] that was able to block antigen binding.”) (emphasis added). Thus the
`
`construction of certain chimeric antibodies where their non-human variable region
`
`elicited immunogenic effects could still suffer from some of the same therapeutic
`
`issues and side effects as their murine monoclonal counterparts.
`
`40. Antibody engineering efforts sought to further minimize and reduce
`
`the immunogenicity of murine antibodies by constructing antibodies in which only
`
`the antigen binding parts of the mouse antibody, i.e., the complementarity
`
`determining regions (CDRs), were combined with human framework domains in
`
`the variable region along with the human constant regions. This technique, which
`
`sought
`
`to further ‘humanize’ or ‘reshape’ a non-human (e.g., mouse)
`
`immunoglobulin by combining its CDRs with a human framework was pioneered
`
`by Sir Gregory Winter and his colleagues at the Medical Research Council (MRC)
`
`Riechmann et al. Reshaping human antibodies for therapy. Nature 332:323-327
`
`(March 24, 1988) (“Riechmann”) (Ex. 1569). See also Verhoeyen et al., Reshaping
`
`Human Antibodies: Grafting an Antilysozyme Activity, 239 SCIENCE 1534 (1988)
`
`(Ex. 1568).
`
`41. The Winter group constructed the first humanized antibodies by
`
`combining or
`
`‘grafting’
`
`the entire CDRs
`
`from a non-human donor’s
`
`immunoglobulin onto a human acceptor framework to form a functional antibody.
`
`
`
`
`20
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`PFIZER EX. 1504
`Page 22
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`
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`This CDR grafting procedure is first demonstrated in Jones et al., Replacing the
`
`complementarity-determining regions in a human antibody with those from a
`
`mouse, 321 NATURE 522– 25 (1986) (“Jones”) (Ex. 1533).
`
`42. Concurrent to the humanization work done by Winter at the MRC, a
`
`group led by Cary Queen at Protein Design Labs (PDL) focused on humanizing the
`
`murine monoclonal antibody anti-Tac which b
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