Effect of denosumab on bone density and turnover in postmenopausal women with low bone mass after long-term continued, discontinued, and restarting of therapy: a randomized blinded phase 2 clinical trial.
BACKGROUND
Denosumab is a fully human monoclonal antibody that inhibits receptor activator of nuclear factor-kappa B ligand (RANKL), an essential mediator of osteoclast formation, function, and survival that has been shown to decrease bone turnover and increase bone mineral density (BMD) in treated patients. We assessed the long-term efficacy and safety of denosumab, and the effects of discontinuing and restarting denosumab treatment in postmenopausal women with low bone mass.


METHODS
Postmenopausal women with a lumbar spine T-score of -1.8 to -4.0 or proximal femur T-score of -1.8 to -3.5 were randomized to denosumab every 3 months (Q3M; 6, 14, or 30 mg) or every 6 months (Q6M; 14, 60, 100, or 210 mg); placebo; or open-label oral alendronate weekly. After 24 months, patients receiving denosumab either continued treatment at 60 mg Q6M for an additional 24 months, discontinued therapy, or discontinued treatment for 12 months then re-initiated denosumab (60 mg Q6M) for 12 months. The placebo cohort was maintained. Alendronate-treated patients discontinued alendronate and were followed. Changes in BMD and bone turnover markers (BTM) as well as safety outcomes were evaluated.


RESULTS
Overall, 262/412 (64%) patients completed 48 months of study. Continuous, long-term denosumab treatment increased BMD at the lumbar spine (9.4% to 11.8%) and total hip (4.0% to 6.1%). BTM were consistently suppressed over 48 months. Discontinuation of denosumab was associated with a BMD decrease of 6.6% at the lumbar spine and 5.3% at the total hip within the first 12 months of treatment discontinuation. Retreatment with denosumab increased lumbar spine BMD by 9.0% from original baseline values. Levels of BTM increased upon discontinuation and decreased with retreatment. Adverse event rates were similar among treatment groups.


CONCLUSIONS
In postmenopausal women with low BMD, long-term denosumab treatment led to gains in BMD and reduction of BTM throughout the course of the study. The effects on bone turnover were fully reversible with discontinuation and restored with subsequent retreatment.
Colorado Center for Bone Research, 3190 South Wadsworth Blvd, Ste 250, Lakewood, CO 80227, USA. Electronic address: millerccbr@aol.com.
Paul D
PD
Miller
Bethesda Health Research Center, Bethesda, MD, USA.
Michael A
MA
Bolognese
New Mexico Clinical Research and Osteoporosis Center, Albuquerque, NM, USA.
E Michael
EM
Lewiecki
Oregon Osteoporosis Center, Portland, OR, USA.
Michael R
MR
McClung
Amgen Inc., Thousand Oaks, CA, USA.
Beiying
B
Ding
Amgen Inc., Thousand Oaks, CA, USA.
Matthew
M
Austin
Amgen Inc., Thousand Oaks, CA, USA.
Yu
Y
Liu
Amgen Inc., Thousand Oaks, CA, USA.
Javier
J
San Martin
D019386:Alendronate / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000009:adverse effects / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D015415:Biomarkers / Q000378:metabolism; D015519:Bone Density / Q000187:drug effects*; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D001842:Bone and Bones / Q000187:drug effects* / Q000473:pathology*; D003710:Demography; D000069448:Denosumab; D005260:Female; D006801:Humans; D008875:Middle Aged; D009929:Organ Size / Q000187:drug effects; D017698:Postmenopause / Q000187:drug effects*; D053245:RANK Ligand / Q000009:adverse effects / Q000494:pharmacology*; D016037:Single-Blind Method; D013997:Time Factors; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D015415:Biomarkers; D050071:Bone Density Conservation Agents; D053245:RANK Ligand; D000069448:Denosumab; D019386:Alendronate