Patients treated with Zometa (zoledronic acid) lived an average of five and a half months longer than patients taking clodronic acid, an oral bone drug that is not used in the U.S.
Zometa and other drugs in the class known as bisphosphonates are also used in the treatment of breast cancer with bone involvement and other solid tumors that have spread to the bone.
The study is the first to show a survival benefit for a bisphosphonate in multiple myeloma patients, and its lead author says it should be considered the bone drug of choice in those with the disease.
But a multiple myeloma specialist who spoke to WebMD is not so sure. S. Vincent Rajkumar, MD, of the Mayo Clinic in Rochester, Minn., says the intravenous bisphosphonate Aredia (pamidronate), which is also widely use to treat the cancer in the U.S., may be just as effective.
“This study confirms the value of giving an IV bisphosphonate monthly to patients with myeloma-related bone disease, which is what oncologists in the U.S. have been doing,” he says. “We now know there is a survival benefit with Zometa. Since Aredia wasn’t studied, we don’t know if the same benefit exists with this drug.”
Prevalence of Multiple Myeloma
Around 20,000 people in the U.S. are diagnosed with multiple myeloma each year and an estimated 10, 650 people will die of the disease, according to the American Cancer Society.
Slightly less than one in three patients live for five years or more following diagnosis of the bone marrow cancer. Bone weakening and bone lesions are a common symptom of the disease, with around 70% of patients having bone lesions at diagnosis.
The newly published study included 1,960 patients in the U.K. with newly diagnosed disease treated with the standard chemotherapy at the time along with either Zometa or the oral bisphosphonate clodronic acid, which is used in Europe but not the U.S.
The study ran from May 2003 until November 2007, with funding support from Zometa manufacturer Novartis and several other pharmaceutical companies.
Patients in the Zometa group lived an average of 50 months, compared to 44.5 months for patients treated with clodronic acid.
Those who got the intravenous bone drug were 16% less likely to die of their disease during the study and follow-up.
The survival advantage was not fully explained by the drug’s impact on bone, leading the researchers to suggest that it might have an independent impact on cancer cells.
The American Society of Clinical Oncology recommends monthly intravenous treatment with either Zometa or pamidronate for patients with multiple myeloma-related bone lesions or bone weakening.
Gareth J. Morgan, MD, who led the British study, says the group should revisit these guidelines in light of the new findings.
“The question now becomes, ‘Do you continue to use pamidronate or do you go with the drug that has been shown to increase survival,’” he says.
A much smaller U.S. study, which compared Zometa and Aredia, showed no major differences between the two drugs, but it was not large enough to show a survival advantage for either.
Nevertheless, Rajkumar says the study might have offered a signal of an advantage or disadvantage if the impact on survival were significantly different.
In an editorial assessing the new research, he points out that the generic version of pamidronate is 10 times less expensive than Zometa and has a lower reported risk of a jaw bone deterioration, which is a not uncommon side effect of treatment.
Both the study and editorial are published in the Dec. 4 issue of The Lancet.
In the U.S., multiple myeloma patients without evidence of bone disease are not routinely treated with bisphosphonates.