The Lancet is challenging an editorial published last month in the New England Journal of Medicine that called the results of several studies of Genentech's Herceptin cancer treatment "revolutionary." The October 20 issue of the NEJM published three studies that found patients with early stage metastatic HER2-positive breast cancers who received Herceptin along with standard chemotherapy were half as likely to experience recurrence of tumors as patients with similar cancers who received chemotherapy alone. In an editorial accompanying the studies, Gabriel Hortobagyi of the M.D. Anderson Cancer Center called the results "simply stunning" and "revolutionary" and even said that Herceptin was "maybe even a cure" for breast cancer. The Lancet says "The excitement is premature. ... It is profoundly misleading to suggest, even rhetorically, that the published data may be indicative of a cure for breast cancer."
Posted by schwitz at November 14, 2005 08:42 AM | TrackBackThere are a number of other issues on the subject of Herceptin. Take notice that these kind of individual, targeted oral drugs are "added" to the repertoire of chemotherapy mixtures a cancer patient is already taking, "instead of" taking them alone? Adding thousands of dollars to treatment.
The Dr. Katharina Pachmann, et al study in the May 2005 issue of Oncology News International reports about neoadjuvant Taxol chemotherapy causing the release of cancer cells into the blood, I'm not so sure that Herceptin is taking care of what Taxol never accomplished in the first place. It has been shown that Herceptin treatment was to reduce circulating tumor cells in patients. However, does it?
A study from Dana Farber Cancer Institute identified as many as 34% central nervous system metastases in women who receive Herceptin therapy for metastatic breast carcinoma. Patients receiving Herceptin as first-line therapy frequently develop brain metastases while responding to or stable on Herceptin.
Herceptin though, is only for the estimated 20% of breast cancer women at risk for recurrence. However, gene expression assays are panels of markers that can predict the likelihood of cancer recurrence in various populations. By testing the gene expression markers of a patient, oncologists can identify those patients unlikely to benefit from chemotherapy from those that would, saving the other 80% of cancer patients the added expense, suffering and even death from having to take chemotherapy.
Whether a patient would benefit from adjuvant therapy depends on two things: (1) whether the tumor is "destined" to come back in the first place and (2) whether the tumor is sensitive to drugs which might be used to keep it from coming back.
What a cancer patient would like ideally, is to know whether they would benefit from chemotherapy (gene expression assays). If so, which active drugs have the highest probability of working (cell culture assays), and are relatively non-toxic in a given patient (pharmacogenomic testing).
Sources:
Human Genome Project Information
Human Tumor Assay Journal
ACGT, Inc.