Effects of teriparatide, alendronate, or both on bone turnover in osteoporotic men.
BACKGROUND
We have previously demonstrated that alendronate reduces the ability of teriparatide to increase bone mineral density (BMD) in osteoporotic men. The underlying basis for this observation is poorly understood.


OBJECTIVE
The primary aim of this study was to determine whether teriparatide increases osteoblast activity when the ability of teriparatide to increase osteoclast activity is suppressed by alendronate.


METHODS
This was a nonblinded, randomized, controlled trial.


METHODS
The study was conducted at the General Clinical Research Center of a teaching hospital.


METHODS
We studied 63 men, age 46-85, with low spine and/or hip BMD.


METHODS
Subjects received alendronate 10 mg daily (group 1), teriparatide 37 microg sc daily (group 2), or both (group 3) for 30 months. Teriparatide was begun at month 6.


METHODS
The primary endpoint was the change in serum N-telopeptide, osteocalcin, and amino-terminal propeptide of type 1 procollagen.


RESULTS
In men receiving teriparatide monotherapy (group 2), levels of all bone turnover markers increased markedly during the first 6 months of teriparatide administration and then declined toward baseline during the next 18 months. In men who received combination therapy (group 3), bone turnover marker levels declined in the first 6 months (while receiving alendronate alone) and then returned to baseline levels (N-telopeptide) or above (osteocalcin and amino-terminal propeptide of type 1 procollagen) after teriparatide was added. Changes in each marker were significantly different between groups 1 and 2 (all P values < 0.001), groups 1 and 3 (all P values < 0.001), and groups 2 and 3 (all P values < 0.03).


CONCLUSIONS
As with BMD, alendronate impairs the action of teriparatide to increase bone turnover in men.
Finkelstein
Joel S
JS
Endocrine Unit, Bulfinch 327, Department of Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA. jfinkelstein@partners.org
Leder
Benjamin Z
BZ
Burnett
Sherri-Ann M
SM
Wyland
Jason J
JJ
Lee
Hang
H
de la Paz
Amanda Victoria
AV
Gibson
Kate
K
Neer
Robert M
RM