Zoledronic acid may slow cancer treatment-induced bone loss in premenopausal women
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Premenopausal women with hormone receptor-positive early-stage breast cancer randomly assigned zoledronic acid during chemotherapy experienced an increase in bone mineral density over 2 years vs. women assigned placebo, according to findings published in Bone.
“A 2-year treatment with zoledronic acid prevented cancer treatment-induced bone loss in premenopausal women with breast cancer and maintained the bone mass density up to 3 years posttreatment,” Ioannis Kyvernitakis, MD, PhD, of the department of obstetrics and gynecology at Buergerhospital in Frankfurt, Germany, told Endocrine Today. “The placebo group presented with a continuous decrease of BMD at all sites over the entire 5-year observation period.”
Kyvernitakis and colleagues analyzed data from 70 premenopausal women with hormone receptor-positive early-stage breast cancer (histologically confirmed invasive breast cancer, no evidence of metastases) receiving neoadjuvant or adjuvant chemotherapy and/or endocrine treatment (gonadotropin-releasing hormone therapy analogues or selective estrogen receptor modulators) as well as a T-score at study entry of at least –2.5, recruited from ProBONE II, a double-blind, randomized, placebo-controlled, single-center trial conducted at the Philipps University of Marburg. Between October 2005 and June 2009, all women received 4 mg zoledronic acid (n = 34; mean age, 43 years; all white) or placebo (n = 36; mean age, 43 years; 97.2% white) within the first two cycles of adjuvant anticancer therapy and administered every 3 months for 2 years, for a total of eight infusions (calcium and vitamin D therapy were also permitted). Follow-up occurred at 12, 24, 36 and 48 and 60 months, with BMD assessed via DXA at each visit. Primary endpoint was change in BMD at the lumbar spine between baseline and 24 months; secondary endpoints included changes in femoral neck and total hip from baseline to 24 months, as well as changes in BMD at the lumbar spine, femoral neck and total hip from baseline to 60 months.
Within the cohort, 31 women in the zoledronic acid arm and 34 women in the placebo arm were followed up to the 5-year visit.
At 24 months, women in the zoledronic acid arm experienced a mean 2.9% increase in lumbar spine BMD, whereas women in the placebo arm experienced a 7.1% decrease in lumbar spine BMD (P < .001 for group differences). Between baseline and 60 months, women in the zoledronic acid group experienced mean BMD changes of –2.2%, –1% and 1.4% at the lumbar spine, femoral neck and total hip, respectively, whereas women in the placebo arm experienced mean BMD changes of –7.3%, –5.9% and –4.5% at the same sites, respectively (P < .05 for group differences).
In the zoledronic acid arm, T-score at the lumbar spine reached the highest levels at 2 years (P < .001 for between-group differences), whereas T-score at the hip reached its peak at 4 years (P < .01 for between-group differences).
“In contract, the BMD values in the placebo arm at all sites showed a continuous decrease over the entire study period (P < .001),” the researchers wrote.
The researchers noted zoledronic acid was well-tolerated, with adverse events that were consistent with the drug’s safety profile.
“These results are in accordance with the growing body of evidence supporting the potential role of [zoledronic acid] in preventing [cancer treatment-induced bone loss] in premenopausal women being treated for early [breast cancer],” the researchers wrote. “Our results for the first time in this regard indicate the prevention of [cancer treatment-induced bone loss] not only during the treatment phase with [zoledronic acid], but also after treatment cessation up to 3 years posttreatment at the femoral neck and total hip.”
The researchers added that the findings showed a decrease of BMD in the zoledronic acid arm at the end of the third-year follow-up, and studies investigating long-term fracture risk in a similar cohort are needed. – by Regina Schaffer
For more information:
Ioannis Kyvernitakis, MD, PhD, can be reached at the Department of Obstetrics and Gynecology, Buergerhospital and Clementine Kinderhospital, Frankfurt, Nibelungenallee 37-41, 60318 Frankfurt am Main, Germany; email: janniskyvernitakis@gmail.com.
Disclosures: Novartis provided grant support for this research. Kyvernitakis reports no relevant financial disclosures. Please see the study for the other authors’ relevant financial disclosures.