Controversial ‘Smart Drug’ Improves Leukemia Treatment in Older Patients
Researchers say gemtuzumab ozogamicin is safe if dosed appropriately (Nov. 12)
A new study led by researchers at Cardiff University in the U.K. has found that patients with acute myeloid leukemia (AML) given a new type of “smart drug” in addition to chemotherapy were 22% less likely to relapse and about 13% less likely to die from their disease.
Of the 1,115 patients who took part in the trial, 68% relapsed on the new treatment within 3 years, compared with 76% of those who received standard therapy. Moreover, 25% of the patients given the new treatment were still alive after 3 years, compared with 20% of those on standard treatment.
The drug — gemtuzumab ozogamicin (GO) — is part of a new class of “antibody conjugate” agents. Treatment with these drugs involves attaching chemotherapy molecules to antibodies specifically designed to recognize proteins on the surface of cancer cells, thereby targeting the cancer while leaving healthy cells unharmed.
The results were published in the Journal of Clinical Oncology.
“These promising results demonstrate how targeting a protein present in more than 90% of AML patients can boost treatment without excessively increasing side effects,” said chief investigator Professor Alan Burnett.
"Although there has been some controversy around the use of GO following its withdrawal in the U.S. two years ago, these results appear extremely promising and suggest no such cause for concern if the appropriate dose is given,” Burnett added. “Crucially, this represents some of the first progress in treating AML patients of this age group for at least 20 years."
Trial participants were recruited at 149 hospitals in the U.K. and Denmark. All of the patients had been recently diagnosed with either AML or high-risk myelodysplastic syndrome, which can develop into AML. Most of the patients were more than 60 years old. Each patient was randomly assigned to receive one of two standard chemotherapy regimes, either with or without GO.
Dr. Kate Law, director of clinical research at Cancer Research U.K., observed: "In general, the outlook for leukemia patients has improved dramatically in recent decades. But when leukemia is diagnosed in older people, it’s much harder to treat, and there is a real need for effective treatments that are suitable for this age group.”
"Importantly, this new trial shows that GO may have particular benefits for patients over 60, who may be unsuitable for other more-intensive treatments,” she said. “This is good news, and we are now looking to see if these results can be replicated in younger patients."
Source: Cardiff University; November 12, 2012.