By Ed Susman
ORLANDO, FL -- December 13, 2006 -- A subset of patients with multiple myeloma who have elevated bone-specific alkaline phosphate levels appear to have better outcomes if they are treated with zoledronic acid (Zometa) than with pamidronate, researchers said here at the American Society of Hematology (ASH) 48th Annual Meeting and Exposition.
"These exploratory analyses suggest that, in addition to its established benefits in preventing skeletal complications, zoledronic acid may improve survival compared with pamidronate in patients with multiple myeloma who have high bone-specific alkaline phosphate levels," said James Berenson, MD, medical and scientific director, Institute for Bone Cancer Research, West Hollywood, California.
In his retrospective study, Dr. Berenson and colleagues scrutinized results of clinical trials in which patients were treated with either 4-mg infusions of the bisphosphonate zoledronic acid or with 90 mg of pamidronate. In particular the researchers were seeking to determine if there were differences in survival between the two treatment groups.
They reviewed the medical records of 353 patients with multiple myeloma. Dr. Berenson identified 212 patients with sufficient information on baseline bone-specific alkaline phosphate levels, 109 of whom were treated with zoledronic acid and 103 treated with pamidronate.
It appeared that patients on zoledronic acid who had higher levels of bone-specific alkaline phosphate levels did better than those on pamidronate.
Zoledronic acid significantly reduced the risk of death by approximately 42% compared with pamidronate (P =.03), said Dr. Berenson. The statistical difference held up whether the researchers used univariate or multivariate analyses.
Overall, patients with the highest levels of bone-specific alkaline phosphate (>146 mcg/L) fared better. Among the 89 patients with high baseline levels, the zoledronic acid group achieved an 82% survival compared with 53% for pamidronate (P =.041). Zoledronic acid significantly reduced the risk of death in this subset by approximately 56% compared with pamidronate (P <.05), Dr. Berenson said in his poster presentation December 12th.
"Prospective trials are needed to investigate the improved survival in this subset of patients," he said. The study was supported by Novartis, East Hanover, New Jersey.
[Presentation title: Zoledronic Acid May Improve Survival Compared to Pamidronate in Patients With MM and High BALP Levels: Univariate and Multivariate Models of Hazard Ratios. Poster 3589]
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