Where are we now?
Currently, there are more than 20 monoclonals—including murine, chimeric, humanized, and human—that have won FDA approval, including those aimed at transplant rejection (Muromonab, the first approved MAb back in 1986 is one of these and others have followed), auto-immune disorders, leukemias, colorectal cancer, breast cancer, non-Hodgkin lymphoma, certain viral infections, and macular degeneration. The widely used breast cancer drug Herceptin is a monoclonal antibody as is Zenapax (used in kidney transplants) and Avastin (used for colon cancer.)
More than half of those have come onto the market since the beginning
of this century, and, with perhaps as many as several hundred more now making
their way to or through the approval process. It seems clear that the MAbs
are likely to become common tools in 21st century medicine, which hasn’t
stopped searching for more efficient, more accessible and more effective
ways to develop and use them.
Looking ahead, those close to the technology see both hurdles yet to be cleared and potentially limitless opportunity, both for healthcare and for the industry.
The widespread interest in MAbs and the laboratory successes they are enjoying, coupled with encouraging economic factors in an era of concern about pharmaceutical costs, have begun to pay off and biotechnology is pressing ahead to create them and get them into the marketplace. Beyond their clinical advantages and versatility, industry leaders have noted, they are far easier and far quicker to develop than traditional drugs. Where the average pharmaceutical requires an investment of five years and $20 million to make it to the testing phase, for MAbs, the figures become two years and $2 million, and antibodies are unlikely to run into regulatory problems because they have little toxicity.
Ironically, though, other economic considerations offer one of the biggest challenges to further development of the technology. Developing the plants and “bioreactors” that can produce MAbs is costly and requires huge start-up costs and lengthy timeframes for construction and regulatory approvals. An industry estimate several years ago suggested that the need by 2010 would be for 25 new plants worldwide (in addition to the ten then operating) at a cost of $5 billion, if as expected some 100 new MAbs are ready for market by then. (More on naming conventions for monoclonal antibodies.)
That picture is further complicated by what biotech companies say is a reluctance on the part of lenders to fund such projects, because the first generation MAbs of the 1980s attracted large investment and then failed to deliver—and that has meant a lingering bad taste in the mouths of many bankers. MAbs continue to find use in new places - a recent test of the human monoclonal antibody raxibacumab found it effective in protecting against anthrax infection.