The pros and cons of using proxy measures in clinical trials.
Clinical trials for cancer drugs increasingly use disease-free survival as a surrogate measure for overall survival.
This shortcut means researchers can wind up the trial without waiting for a significant survival gap to appear in the trial cohort.
Reporting results earlier means the cancer drug might be listed on the PBS sooner so the benefits to patients are tangible.
But this method also has a drawback.
Patients taking a cancer drug can live disease free for years and then have a sudden and deadly recurrence of cancer – and pass away at exactly the same time as the placebo group on average.
This means the drug was effective in removing the shadow of cancer but not actually increasing overall lifespan for the treatment group.
The question for government then is, can they rely on DFS as a proxy measure for overall survival? And is disease-free survival a valid measure of quality of life in itself?
Italian oncologist Professor Alberto Sobrero spoke on this topic at the Australasian Gastro-Intestinal Trials Group Annual Scientific Meeting recently.
There is no question, he says, patients would rather live longer without disease even if their overall survival is the same in the end.
“Disease-free survival by itself contains an intrinsic value for patient and therefore should be used as the primary endpoint of adjuvant trials,” he says.
He joins us on the Oncology Republic podcast to discuss this topic in depth.
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