The purpose of this study is to determine whether bone mineral density has increased in a subgroup of postmenopausal osteoporotic women from study CR9108963, between 6 and 12 months following cessation of ronacaleret therapy.

CR9112792 is a follow-up study of CR9108963, the 12 month dose ranging study of ronacaleret (SB-751689), a calcium sensing receptor antagonist, in postmenopausal women with osteoporosis. CR9108963 evaluated the effects of ronacaleret (100mg, 200mg, 300mg, 400mg) on bone mineral density (BMD), safety and tolerability in comparison with placebo and 2 active comparators, alendronate and teriparatide. CR9108963 was terminated earlier than planned due to an observed lack of efficacy in lumbar spine and hip BMD. In this study we will follow-up subjects between 6 and 12 months after they discontinued treatment with ronacaleret to evaluate the potential for mineralization of bone following cessation of ronacaleret therapy. Subjects at pre-specified sites from the CR9108963 placebo, 200mg, 300mg and 400mg dose groups will be included in this study.

Inclusion Criteria:

• Informed consent: Subject is willing and able to provide written informed consent.
• Subjects: Subjects must have completed through the Month 12 visit of study CR9108963, or have had an early withdrawal visit on or after their Month 10 visit.
• DXA: Subjects must have either a final evaluable spine or hip DXA scan in CR9108963 as confirmed by Synarc, taken within 4 weeks of the last dose of study medication.
• Study medication: Subjects must have been on placebo or ronacaleret 200mg, 300mg or 400mg for ≥299 days in study CR9108963.

Exclusion Criteria:

• Any treatment with a PTH-based therapy or strontium ranelate after discontinuation of treatment in study CR9108963.
• Chronic systemic corticosteroid [e.g., glucocorticoid, mineralocorticoid] treatment of more than 2 intra-articular injections within the past year or use of oral, parenteral, or long-term, high-dose inhaled corticosteroids. Treatment with any topical corticosteroid will not exclude the subject from participating.
• Treatment with any topical corticosteroid will not exclude the subject from participation.
• Treatment with fluoride (dose greater than 10mg/day) for osteoporosis after discontinuation of treatment in study CR9108963.
• Administration of any investigational drug after discontinuation of treatment in study CR9108963.
• Subject who, in the opinion of the investigator, is unfit for this study or unable to comply with the requirements of the protocol.

The study population for CR9112792 will include approximately 145 postmenopausal women of those enrolled in study CR9108963, identified from subjects willing to participate and meeting eligibility criteria at pre-specified sites.