Data Confirms Zometa Reduces Bone Loss and Recurrence Risk

Zometa (zoledronic acid) is commonly used to combat bone loss caused by aromatase inhibitors, a type of hormonal therapy. Zometa is a bisphosphonate, which works by attaching to the surface of bone tissue and blocking natural bone breakdown, thereby promoting an increase in bone mineral density. Earlier trials have shown that Zometa may also have anti-cancer activity, which is of particular interest to researchers.

ZO-FAST, an international phase III study, looked at 1,064 postmenopausal women with early-stage breast cancer taking five years of Femara (letrozole), an aromatase inhibitor.

Atlast year’s SABCS, researchers announced one-year results from both the ZO-FAST study and the American Zometa trial, Z-FAST. Patients who began to receive Zometa at the same time as Femara had higher bone density in the spine and a lower rate of hip fractures than women who took Zometa only after bone loss was detected.

This year’s SABCS presentation showed that after three years of median follow-up, patients given Zometa upfront fared better in regard to bone mineral density, disease-free survival, and recurrence risk. When comparing the two groups, there was a 9.3percent difference in bone density of the lower spine and 5.4percent difference in hip fractures. While the risk of general overall fractures was similar in both arms, Holger Eidtmann, MD, lead investigator of the study, noted that it may be too early to see a significant difference because of the relatively young age of the patient population, which was a median age of 57 and 58 years. Recurrence rates were also lower in the group taking Zometa upfront, 22 compared with 40.

Side effects were minimal in the study groups, but did include bone pain, fever, and headache in the upfront group, mostly with the first infusion of Zometa. The delayed group recorded weight gain and back pain. One patient in the upfront Zometa group developed osteonecrosis of the jaw, a rare, but serious side effect of bisphosphonates. Researchers noted that three-year results are still early and they are continuing to examine long-term data.

For more on bone health, read “Good to the Bone” in CURE’s Winter 2007 issue.

Read more of CURE's coverage of the 31st annual San Antonio Breast Cancer Symposium at https://www.curetoday.com/conference/sabcs