Randomized Teriparatide [human parathyroid hormone (PTH) 1-34] Once-Weekly Efficacy Research (TOWER) trial for examining the reduction in new vertebral fractures in subjects with primary osteoporosis and high fracture risk.
BACKGROUND
Weekly teriparatide injection at a dose of 56.5 μg has been shown to increase bone mineral density.


OBJECTIVE
A phase 3 study was conducted to determine the efficacy of once-weekly teriparatide injection for reducing the incidence of vertebral fractures in patients with osteoporosis.


METHODS
In this randomized, multicenter, double-blind, placebo-controlled trial conducted in Japan, the incidence of morphological vertebral fractures by radiographs was assessed.


METHODS
Subjects were 578 Japanese patients between the ages of 65 and 95 yr who had prevalent vertebral fracture.


METHODS
Subjects were randomly assigned to receive once-weekly s.c. injections of teriparatide (56.5 μg) or placebo for 72 wk.


METHODS
The primary endpoint was the incidence of new vertebral fracture.


RESULTS
Once-weekly injections of teriparatide reduced the risk of new vertebral fracture with a cumulative incidence of 3.1% in the teriparatide group, compared with 14.5% in the placebo group (P < 0.01), and a relative risk of 0.20 (95% confidence interval, 0.09 to 0.45). At 72 wk, teriparatide administration increased bone mineral density by 6.4, 3.0, and 2.3% at the lumbar spine, the total hip, and the femoral neck, respectively, compared with the placebo (P < 0.01). Adverse events (AE) and the dropout rates by AE were more frequently experienced in the teriparatide group, but AE were generally mild and tolerable.


CONCLUSIONS
Weekly s.c. administration of teriparatide at a dose of 56.5 μg may provide another option of anabolic treatments in patients with osteoporosis at higher fracture risk.
Department of Orthopedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan. toshinak@med.uoeh-u.ac.jp
Toshitaka
T
Nakamura
Toshitsugu
T
Sugimoto
Tetsuo
T
Nakano
Hideaki
H
Kishimoto
Masako
M
Ito
Masao
M
Fukunaga
Hiroshi
H
Hagino
Teruki
T
Sone
Hideki
H
Yoshikawa
Yoshiki
Y
Nishizawa
Takuo
T
Fujita
Masataka
M
Shiraki
D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D007279:Injections, Subcutaneous; D007564:Japan; D053208:Kaplan-Meier Estimate; D008297:Male; D010024:Osteoporosis / Q000150:complications / Q000000981:diagnostic imaging / Q000517:prevention & control*; D011859:Radiography; D040242:Risk Reduction Behavior; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D013131:Spine / Q000000981:diagnostic imaging; D016019:Survival Analysis; D019379:Teriparatide / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*
D050071:Bone Density Conservation Agents; D019379:Teriparatide