Efficacy and safety of risedronate 150 mg once a month in the treatment of postmenopausal osteoporosis.
BACKGROUND
Risedronate has been shown to be effective in the treatment of postmenopausal osteoporosis when given orally in daily or weekly doses or on 2 consecutive days per month. This randomized, double-blind, multi-center study was designed to assess the efficacy and safety of a single 150 mg risedronate once-a-month oral dose compared with the 5 mg daily regimen.


METHODS
Women with postmenopausal osteoporosis were randomly assigned to receive risedronate 5 mg daily (n=642) or 150 mg once a month (followed by daily placebo) (n=650) in a double-blind fashion for 2 years. Study drug was taken on an empty stomach at least 30 min before breakfast. Bone mineral density, bone turnover markers, fractures, and adverse events were evaluated. The primary efficacy endpoint was the mean percent change from baseline in lumbar spine bone mineral density after 1 year.


RESULTS
538 patients in the daily group (83.8%) and 556 patients in the once-a-month group (85.5%) completed 1 year. The mean percent change in lumbar spine bone mineral density was 3.4% (95% confidence interval, 3.03% to 3.82%) in the daily group and 3.5% (95% confidence interval, 3.15% to 3.93%) in the once-a-month group. The difference between groups was -0.1% (95% confidence interval, -0.51% to 0.27%). The once-a-month regimen was determined to be non-inferior to the daily regimen based on prospectively defined criteria. The mean percent changes in bone mineral density at sites in the hip (total proximal femur, femoral neck, femoral trochanter) were also similar in both dose groups, as were the changes in biochemical markers of bone turnover. The incidence of adverse events, adverse events leading to withdrawal, and upper gastrointestinal tract adverse events were similar in the 2 treatment groups. Both regimens were well tolerated; the percent of patients who withdrew from treatment as a result of an adverse event was 9.5% in the daily group and 8.6% in the once-a-month group.


CONCLUSIONS
Risedronate 150 mg once a month is similar in efficacy and safety to daily dosing and may provide an alternative for patients who prefer once-a-month oral dosing.
Delmas
Pierre D
PD
INSERM Research Unit 831 and University of Lyon, Lyon, France. delmas@lyon.inserm.fr
McClung
Michael R
MR
Zanchetta
José R
JR
Racewicz
Artur
A
Roux
Christian
C
Benhamou
Claude-Laurent
CL
Man
Zulema
Z
Eusebio
Rachelle A
RA
Beary
John F
JF
Burgio
David E
DE
Matzkin
Ellen
E
Boonen
Steven
S
D015519:Bone Density / Q000187:drug effects; D064420:Drug-Related Side Effects and Adverse Reactions; D012968:Etidronic Acid / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy*; D000068296:Risedronic Acid; D013997:Time Factors
D000068296:Risedronic Acid; D012968:Etidronic Acid