Chemistry: natural resins or derivatives; peptides or proteins; – Proteins – i.e. – more than 100 amino acid residues – Blood proteins or globulins – e.g. – proteoglycans – platelet...
Reexamination Certificate
2001-05-15
2004-05-11
Helms, Larry R. (Department: 1642)
Chemistry: natural resins or derivatives; peptides or proteins;
Proteins, i.e., more than 100 amino acid residues
Blood proteins or globulins, e.g., proteoglycans, platelet...
C530S388230, C530S388850, C424S130100
Reexamination Certificate
active
06734286
ABSTRACT:
The present invention relates to a recombinant antibody molecule (RAM), and especially a humanized antibody molecule (HAM) having specificity for human interleukin-5 (hIL-5), the nucleic acids which encode the heavy and light chain variable domains of said recombinant antibody, a process for producing said antibody using recombinant DNA technology and the therapeutic use of the recombinant antibody.
In the present application, the term “recombinant antibody molecule” (RAM) is used to describe an antibody produced by a process involving the use of recombinant DNA technology. The term “humanized antibody molecule” (HAM) is used to describe a molecule being derived from a human immunoglobulin. The antigen binding site may comprise either complete variable domains fused onto constant domains or one of more complementary determining regions (CDRs) grafted onto appropriate framework regions in the variable domain. The abbreviation “MAb” is used to indicate a monoclonal antibody.
The term “recombinant antibody molecule” includes not only complete immunoglobulin molecules but also any antigen binding immunoglobulin fragments, such as Fv, Fab and F(ab′)
2
fragments, and any derivatives thereof, such as single chain Fv fragments.
Natural immunoglobulins have been used in assay, diagnosis and, to a limited extent, therapy. The use of immunoglobulins in therapy has been hindered as most antibodies of potential use as therapeutic agents are MAbs produced by fusions of a rodent spleen cells with rodent myeloma cells. These MAbs are therefore essentially rodent proteins. The use of these MAbs as therapeutic agents in human can give rise to an undesirable immune response termed the HAMA (Human Anti-mouse Antibody) response. The use of rodent MAbs as therapeutic agents in humans is inherently limited by the fact that the human subject will mount an immunological response to the MAb which would either remove it entirely or at least reduce its effectiveness.
A number of techniques to reduce the antigenic characteristics of such non-human MAbs have been developed. These techniques generally involve the use of recombinant DNA technology to manipulate DNA sequences encoding the polypeptide chains of the antibody molecule. These methods are generally termed “humanization” techniques.
Early methods for humanizing MAbs involved the production of chimeric antibodies in which an antigen binding site comprising the complete variable domains of one antibody are fused to constant domains derived from another antibody. Methods for carrying out such chimerisation procedures are described in EP 0120694 (Celltech Limited) and EP 0125023 (Genentech Inc. and City of Hope). Humanized chimeric antibodies, however, still contain a significant portion of non-human amino acid sequences, and can still elicit some HAMA response, particularly if administered over a prolonged period [Begent et al., Br. J. Cancer, 62, 487 (1990)].
An alternative approach, described in EP-A-0239400 (Winter), involves the grafting of the complementarity determining region (CDRs) of a mouse MAb on to framework regions of the variable domains of a human immunoglobulin using recombinant DNA techniques. There are three CDRs (CDR1, CDR2 and CDR3) in each of the heavy and light chain variable domains. Such CDR-grafted humanized antibodies are much less likely to give rise to a HAMA response than humanized chimeric antibodies in view of the much lower proportion of non-human amino acid sequences which they contain. In Riechmann et al. [Nature, 332 323-324 (1988)] it was found that the transfer of the CDRs alone, as defined by Kabat [Sequences or Proteins of Immunological Interest, US Department of Health and Human Services, NIH, USA (1987)], was not sufficient to provide satisfactory antigen binding activity in the CDR-grafted product. Riechmann et al. found that it was necessary to convert a number of residues outside the CDRs, in particular in the loop adjacent CDR1. However, the binding affinity of the best CDR-grafted antibodies obtained was still significantly less than that of the original MAb.
In WO 91/09967, Adair et al. described CDR-grafted antibody heavy and light chains, and determined a hierarchy of donor residues.
In WO 93/16184, Chou et al. described the design, cloning and expression of humanized monoclonal antibodies against human interleukin-5. A method for selecting human antibody sequences to be used as human frameworks for humanization of an animal antibody is suggested, comprising the steps of comparing human variable domain sequences with the variable domain sequences of the animal MAb that is to be humanized for percentage identities, sequence ambiguities and similar PIN-region spacing. PIN-region spacing is defined as the number of residues between the cysteine residues forming the intra domain disulfide bridges. The human antibody having the best combination of these features is selected. A method for determining which variable domain residues of an animal MAb which should be selected for humanization is also suggested, comprising determining potential minimum residues (residues which comprise CDR structural loops and the residues required to support and/or orientate the CDR structural loops) and maximum residues (residues which comprise Kabat CDRs, CDR structural loops, residues required to support and/or orientate the CDR structural loops and residues which fall within about 10 Å of a CDR structural loop and possess a water solvent accessible surface of about 5 Å
2
or greater) of the animal monoclonal antibody. Furthermore, computer modelling is performed on all possible recombinant antibodies, comprising the human antibody framework sequence into which minimum and maximum residues have been inserted. The minimum or maximum residues are selected based on the combination which produces a recombinant antibody having a computer-model structure closest to that of the animal monoclonal antibody. The humanized anti-IL-5 antibody obtained appears to have lost a substantial amount of its affinity for the hIL-5 molecule.
It is an aim of the present invention to provide a humanized antibody molecule having improved affinity for the hIL-5 molecule.
Accordingly the present invention provides a RAM having affinity for human IL-5 and comprising antigen binding regions derived from heavy and/or light chain variable domains of a donor antibody having affinity for human IL-5, the RAM having a binding affinity similar to that of the donor antibody.
The RAM of invention may comprise antigen binding regions from any suitable donor anti-IL-5 antibody. Typically the donor anti-IL-5 antibody is a rodent MAb. Preferably the donor antibody is MAb 39D10.
The variable domains of the heavy and light chains of MAb 39D10 are hereinafter specifically described with reference to
FIGS. 1 and 2
.
According to one preferred aspect of the invention, the RAM of the present invention is an anti-IL-5 antibody molecule having affinity for the human IL-5 antigen comprising a composite heavy chain and a complementary light chain, said composite heavy chain having a variable domain comprising predominantly acceptor antibody heavy chain framework residues and donor antibody heavy chain antigen-binding residues, said donor antibody having affinity for human IL-5, wherein said composite heavy chain comprises donor residues at least at positions 31-35, 50-65 and 95-102 (according to the Kabat numbering system) [Kabat et al., Sequences of Proteins of Immunological Interest, Vol I, Fifth Edition, 1991, US Department of Health and Human Services, National Institute of Health].
Preferably, the composite heavy chain framework additionally comprises donor residues at positions 23, 24, 27-30, 37, 49, 73 and 76-78 or 24, 27-30, 37, 49, 73, 76 and 78.
According to a second preferred aspect of the present invention, there is provided an anti-IL-5 antibody molecule having affinity for a human IL-5 antigen comprising a composite light chain and a complementary heavy chain, said composite light chain having a variable
Athwal Diljeet Singh
Bodmer Mark William
Emtage John Spencer
Celltech R&D Limited
Helms Larry R.
O'Connor P.C. Cozen
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