Thank you for your inquiry.
Unfortunately there is no evidence-based answer to your question. This issue has not been looked at experimentally, and I am not aware of nor could I find any reference to the simultaneous administration of these drugs in the literature (with the exception of an interesting patent application which discusses the use of omalizumab with other immunomodulators) - here is a link to this patent.
Synergistic combination of xolair/omalizumab/e25 with immunosuppressive agent
However, this patent discussion has very little application clinically. Thus the only answer that I can give you is that I see no theoretical objection to the simultaneous administration of these two drugs, but cannot support this opinion with any data.
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.