Patients volunteering for early trials of experimental cancer drugs may be far safer today than their counterparts were a decade ago.
The number of patients who died from these unproven medications fell by more than 90% from 1991 to 2002, according to a study in today's Journal of the American Medical Association.
This type of early trial is among the smallest and most closely supervised. Patients, who face a slim chance of getting better and the possibility of toxic side effects, may enroll only if they have no other treatment options left.
But thanks to more ''targeted'' therapies and greater efforts to protect patient safety, the risks might not be as great.
Researchers reviewed 213 cancer studies involving nearly 6,500 patients. In trials from the first four years of the study, 1.1% of patients died because of problems caused by the drugs being investigated. In the final four years, only one patient in 1,817 -- or 0.06% -- died because of the drugs. The study did not say whether patients lived longer or if drugs worked better, although the authors noted that deaths from all causes -- from cancer to car accidents -- also declined.
Researchers focused on Phase 1 trials, the most preliminary type of study, in which scientists seek to discover a safe dose of medication. Scientists and universities are doing a better job of designing cancer trials and monitoring patient safety, says Thomas Roberts, a cancer specialist at Massachusetts General Hospital and lead author of the research paper.
New ''targeted'' cancer therapies cause fewer serious side effects than traditional chemotherapy, Roberts says. Newer drugs work by shutting down specific steps in the ways that cancer cells multiply, generally leaving healthy cells alone. In the JAMA study, traditional chemotherapy drugs were four times more likely to kill patients than targeted therapies.
Yet while some targeted therapies have been shown to prolong life and keep cancers under control, they may not make tumors smaller, says Ezekiel Emanuel, chairman of the clinical bioethics department at the National Institutes of Health, who was not involved in this study. That may explain why only 2.5% of patients studied in 1999-2002 saw their tumors shrink in half, a traditional measure of whether therapy is working. That's a decline of more than 50% since 1991-94.
Experts say the study may have underestimated the number of treatment-related deaths because researchers may not have published the results of papers with unflattering results.
Still, doctors say the study may help cancer patients decide whether to join clinical trials. Only about 3% of adult cancer patients join such studies, Roberts says.
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