Peter,
Also, the invention is not limited to the CD19 and CD20 antibodies. Rather, the invention encompasses the use of antibodies which are identify antigens associated with cells of the B cell lineage to treat cancers which are clonal from such cells.
Then if we imply that "the" specifies radio-immunoconjugates, then it also specifies IgG2a-class antibodies.
I suspect what they're trying to do is block Zev and related patents. For example, they go to the trouble to mention, but not claim IgG1-based Fabs (and to suggest that they would not be novel):
Furthermore, it is expected that it is advantageous to provide Fab, Fab' or F(ab').sub.2 fragments containing the antigen-binding portion of the B1 antibody as the B cell targeting moiety. Such antibody fragments might provide better diffusion characteristics in vivo, due to their smaller size, than the whole B1 antibody, in addition to also being less likely to evoke a HAMA response. While F(ab').sub.2 fragments of B1 itself are not stable, due to the IgG2a nature of the antibody, an IgG1 constant region variant of B1 could be produced which would form stable F(ab') ).sub.2 fragments. The means for engineering of antibodies by recombinant DNA and chemical modification methods are considered well-known in the art.
We really have to stop doing all the work for IDPH and CLTR IP counsel.
biowa, neAPA (not even an Amateur Patent Attorney) |
