Conditions: Osteoporosis Postmenopausal
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 287
Healthy volunteers: no

Brief summary:
The purpose of this study is to assess the dose-response on the percent change from baseline in lumbar spine bone mineral density (BMD) at lumbar vertebrae 1 to 4 (L1- L4) when odanacatib (MK-0822) 10 mg, 25 mg, 50 mg or placebo is orally administered once weekly for 52 weeks to Japanese involutional osteoporosis participants. The study will also assess safety and tolerability of odanacatib (10, 25, and 50 mg) in these participants.

The study will enroll approximately 280 participants and randomly assign them to 3 different doses of odanacatib or placebo for 52 weeks, along with supplemental vitamin D3 and calcium carbonate. The primary efficacy hypothesis is that a dose-response relationship on the percent change from baseline in lumbar spine BMD (L1- L4) is seen when odanacatib 10, 25, 50 mg or placebo is orally administered once weekly for 52 weeks to involutional osteoporosis participants. The primary safety hypothesis is that odanacatib will be safe and well tolerated over 52 weeks to involutional osteoporosis participants.

Detailed description:

Arms:
arm 1: After an observation period of \~5 weeks, participants receive dose-matched placebo to odanacatib once weekly for 52 weeks. Participants also receive weekly supplementation with open-label 5600 International Units (IU) vitamin D3 and 500 mg of open-label daily calcium supplement (if calcium \<1000 mg per day from dietary and other sources) throughout the observation and treatment periods. arm 2: After an observation period of \~5 weeks, participants receive 10 mg odanacatib once weekly for 52 weeks. Participants also receive weekly supplementation with open-label 5600 IU vitamin D3 and 500 mg of open-label daily calcium supplement (if calcium \<1000 mg per day from dietary and other sources) throughout the observation and treatment periods. arm 3: After an observation period of \~5 weeks, participants receive 25 mg odanacatib once weekly for 52 weeks. Participants also receive weekly supplementation with open-label 5600 IU vitamin D3 and 500 mg of open-label daily calcium supplement (if calcium \<1000 mg per day from dietary and other sources) throughout the observation and treatment periods. arm 4: After an observation period of \~5 weeks, participants receive 50 mg odanacatib once weekly for 52 weeks. Participants also receive weekly supplementation with open-label 5600 IU vitamin D3 and 500 mg of open-label daily calcium supplement (if calcium \<1000 mg per day from dietary and other sources) throughout the observation and treatment periods.

Interventions: intervention 1: Odanacatib intervention 2: Vitamin D3 intervention 3: Calcium carbonate intervention 4: Placebo
Intervention descriptions: intervention 1: Odanacatib tablets 10 mg, 25 mg, or 50 mg (depending upon randomization), taken orally once weekly for 52 weeks. intervention 2: Two Vitamin D3 tablets (5600 IU total) taken orally once weekly for 52 weeks. intervention 3: Calcium carbonate 500 mg tablet taken orally every day for 52 weeks. intervention 4: Dose-matched placebo tablets to odanacatib, taken orally once weekly for 52 weeks.

Protocol document: