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Journal of Clinical Oncology, 2004 ASCO Annual Meeting Proceedings (Post-Meeting Edition).
Vol 22, No 14S (July 15 Supplement), 2004: 518
© 2004 American Society of Clinical Oncology
Effect of exemestane on bone: A randomized placebo controlled study in postmenopausal women with early breast cancer at low risk
P. E. Lonning,
J. Geisler,
L. E. Krag,
L. Ottestad,
Y. Bremnes,
A. I. Hagen,
E. Schlichting,
A. Polli,
J. Paolini and
G. Massimini
Haukeland Sykehus, Bergen, Norway; Sentralsjukehuset i Rogaland, Stavanger, Norway; Det Norske Radiumhospital, Oslo, Norway; Universitetssykehuset i Nord-Norge, Tromso, Norway; St. Olavs Hospital, Trondheim, Norway; Ulleval Universitetssykehus, Oslo, Norway; Pharmacia Italia S.p.A., Pfizer Group, Nerviano, Italy
518
Background: Studies with non-steroidal aromatase inhibitors indicated an increased bone loss risk in postmenopausal early breast cancer (EBC) patients (pts). Exemestane (E, Aromasin), a steroidal aromatase inactivator, might have no bone detrimental effect due to its 17-hydro-metabolite. Methods: We conducted a randomized, double-blind study evaluating the effect of E or placebo (P) on bone metabolism, endocrinological and metabolic parameters in postmenopausal pts with pT1N0 or T2N0 and no other risk factors or ductal carcinoma in situ (DCIS), with bone mineral density (BMD) within 2 standard deviations of the mean level for women of 65 years (yrs). Pts were randomized to receive either E 25 mg or P p.o. daily for 2 yrs, with a 1-yr follow-up. Primary objective was to demonstrate non-inferiority on BMD, determined at 6, 12 and 24 months on treatment. Planned sample size was 128 evaluable pts, assuming a yearly BMD loss of 1% on P and 2.1% on E. Results: 147 pts have been enrolled, 73 E and 74 P. Median age: 61 yrs (E) and 60 yrs (P). Performance status (PS) 0: 51 on E, 53 on P; PS 1: 22 on E, 21 on P. Median time from menopause: 9.7 yrs E and 8.0 yrs P. ER and/or PgR: +ve 130 pts, unknown 17 (15 of them DCIS). E was well tolerated, 70% of pts had drug-related events on E and 73% on P. Twelve pts withdrew for adverse events, 9 on E and 3 on P; 5 withdrew consent, 3 on E and 2 on P. Six pts relapsed, 1 on E and 5 on P. Results on BMD evaluable pts, 62 on E and 66 on P, are in Table.
Baseline (BS) osteoporosis (BMD  2.5 SD of the young adult mean) of the spine was detected in 7 pts on E and 5 pts on P, of the femoral neck in 17 pts on E and 5 on P. No normal BMD pt became osteoporotic, 6 pts on E and 5 on P with osteopenia at BS became osteoporotic on L1-L4 and 3 on E and 5 on P on femoral neck. Nine pts had fractures, 4 on E and 5 on P. Conclusions: There is no E effect on spine, and a small effect on the femoral neck. Bone loss was higher than expected in the P arm.
Author Disclosure
| Employment or Leadership |
Consultant or Advisory |
Stock Ownership |
Honoraria |
Research Funding |
Expert Testimony |
Other Remuneration |
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| Pfizer Italia S.p.A. |
Pfizer Co. |
Pfizer Co. |
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Abstract presentation from the 2004 ASCO Annual Meeting
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