NEW YORK (Reuters Health) - A group of chemotherapy experts is refuting the conclusion reached last month by an American Society of Clinical Oncology (ASCO) panel that chemotherapy sensitivity and resistance assays (CSRAs) are not yet ready for routine use.
Chemotherapy for a given malignancy is usually selected based on an algorithm, derived from years of clinical research. With CSRA testing, by contrast, different chemotherapy drugs are tested against samples of a patient’s tumor to identify the most active agent.
After reviewing 12 trials that looked at CSRA testing, the ASCO panel concluded that there is currently insufficient evidence to support the use of CSRAs, outside of clinical trials, to select chemotherapeutic agents for a particular patient (see Reuters Health report August 12, 2004).
“ASCO’s findings could potentially limit patient access to a technology that has proven capable of identifying active treatment,” Dr. Robert Nagourney, a leader of the Clinical Oncologists for Individualized Therapy (COFIT), said in a statement.
“While we agree with ASCO’s conclusion that CSRA research should be a priority, we take issue with the composition of the panel, the methods for trial selection, the analytic process and, most fundamentally, with the suggestion that the data does not support the utility of these tests,” noted Dr. Nagourney, medical and laboratory director of Rational Therapeutics, a company that makes CSRAs.
According to a COFIT press release, the ASCO panel did not include or consult with researchers who were actively working with cell death-based CSRAs. Also, COFIT claims that ASCO’s collaboration with Blue Cross/Blue Shield during the review represents a conflict of interest since the insurance group is on record against using CSRAs.
COFIT also takes issue with the methodology of ASCO’s review. First, the group notes that many of the studies included in the review focused on older cell growth CSRAs, rather than the newer, and improved, cell-death assays. Secondly, COFIT states that CSRA testing was evaluated based on patient outcome, a high standard that is seldom applied to empiric approaches to chemotherapy selection.
ASCO, however, stands by its research methods and the conclusion reached.
“It’s a very intuitive question to want to know whether there are ways of testing a cancer to see if we can treat it better,” Dr. Harold J. Burstein, a member of the ASCO working group from Dana-Farber Cancer Institute in Boston, told Reuters Health. “The ASCO panel was charged with determining if there was evidence to show that CSRA testing changed clinical management for the better. The shorter answer was no.”
“The argument that the studies were not selected appropriately is just not true -- they were exhaustively searched,” Dr. Burstein noted. “The argument that the panel membership was inadequate because we didn’t have representatives from every conceivable methodology is also not true. Our goal wasn’t to appraise these as technical or pathologic assays, but to assess them as tools for patient management.”
As a final point, Dr. Burstein contends that patient outcome is a more relevant endpoint than simply looking at the test’s ability to predict a response. “Much of the time the CSRA comes back and says ‘you have lung cancer you should get platinum’, but everybody gets platinum anyway. With CSRAs, you haven’t generated information that changes clinical management.”
A member of COFIT was unavailable for comment.
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