Monoclonal antibodies (mAbs) are defined by the epitope (the small area of the target molecule AKA antigen) that they recognize and bind to. Therefore, even two mAbs to the same target antigen may be very different even if they bind to neighboring or overlapping epitopes within it. The strength of binding and how that binding affects the function and metabolism in the body of the antigen will also vary. It may be the case that the company, Hoffman-LaRoche in this case, might test a series of mAbs to CD44 to try to find the most clinically effective one. But I doubt they'd do too many of those - clinical trials of this size (multinational and multi-institutional) are extremely expensive.
This looks like a Phase I/ II trial, which is focused determining toxicity in humans and finding initial evidence of therapeutic effect rather than a full-scale Phase III clinical trial. Very likely, the only efficacy data they have so far is in animal or laboratory studies.
Make sure your friend reads the informed consent materials very carefully and discusses it thoroughly with her physician. A second opinion is always valuable, also. However, nothing jumps out at me as being 'wrong' about this study. It had to pass ethical review boards in three countries and two US institutions. You might check on the reputations of the physicians and institutions involved if you're still concerned.
I tried the following search of PubMed:
("Antibodies, Monoclonal/therapeutic use"[mh] OR monoclonal antibody*[tw]) AND ("Antigens, CD44"[mh] OR CD44[tw]) AND clinical trial[pt]
It looks like a couple of different mAbs to CD44 are being tested in breast cancer and head & neck cancer. Those mAbs have different names; you'll have to look deeper into the articles to determine what company (if any) is involved and what similarity they might have to RO5429083. At first glance, I think they're probably different anti-CD44 mAbs, but you'd have to look in more detail.
Hope some of this helps,
Jennifer A. Lyon, MS, MLIS, AHIP
Clinical Research Librarian
Health Science Center Libraries
University of Florida
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Date: Mon, 19 Dec 2011 11:03:23 -0500
From: "Dr. Amy Price" <[log in to unmask]>
Subject: <No subject given>
I wonder if any one has experience with this class of drug
&rank=1 RO5429083 for chemotherapy?
RO5429083 is a humanized monoclonal antibody that binds to CD44, a transmembrane glycoprotein that is expressed in many cells, but what seems to have a more critical role in malignant growth. It is given as an IV infusion once every 2 weeks in patients with metastatic and/or advanced solid tumors that express CD44.
I have a friend who is short on options and is shortlisted for this on a clinical trial. I understand that 'new' drugs are developed that are about the same as the old etc and wonder if any of you would have experience or papers on efficacy?