Radius Health, Inc (CAMBRIDGE, Massachusetts), focused on the discovery and development of drug therapies for osteoporosis and women’s health, announced the completion of patient enrollment in its phase II clinical trial of BA058, an analog of hPTHrP (human parathyroid hormone-related protein). Radius also announced the receipt of a second-tranche financing of $28.3 million based on achieving this milestone, for a total second institutional investment of $67.5 million. Six existing venture investors (MPM Capital, The Wellcome Trust, HealthCare Ventures, Oxford Bioscience Partners, BB Biotech Ventures, and Scottish Widows Investment Partnership) participated in the latest closing. Radius will use the funds to support development of its 4 major drug candidates. Radius has raised $91.5 million in private equity financing since its establishment in 2003.

The randomized, double-blind, placebo- and active comparator-controlled study is evaluating BA058 in 244 otherwise healthy postmenopausal women with osteoporosis at 35 centers in the US, UK, Argentina, and India. Other measures include the safety of BA058 across a range of doses (20, 40, or 80 μg subcutaneous daily for 6 months) as well as its ability to induce bone formation without inducing resorption. The active comparator drug arm is PTH 20 μg subcutaneous daily for 6 months. Radius expects to report results by the end of 2008.

PTHrP is a critical peptide for promoting new bone formation, with a role distinct from PTH, which regulates calcium homeostasis and bone resorption. In preclinical testing, BA058 demonstrated the potential to widen the anabolic window for bone therapeutics, that is, stimulating bone formation with a limited effect on bone resorption. In phase I studies, the compound generally was well tolerated and did not induce hypercalcemia in doses up to 80 μg. In a phase Ib clinical trial, healthy postmenopausal women ages 50 to 80 were randomized to 5, 20, 40, or 80 μg of BA058 or to placebo administered subcutaneously once-daily for 7 days. BA058 was well tolerated at all doses studied and did not induce dose-dependent hypercalcemia or bone resorption. In addition, the study demonstrated early evidence of an increase in bone formation markers over 7 days of exposure to the compound.

Radius has granted Novartis Pharmaceuticals AG an option to obtain an exclusive worldwide license (except Japan), following phase II evaluation, and to develop and commercialize all formulations of BA058. Should Novartis exercise that option, it would assume the global clinical development, manufacturing, and marketing of the compound as well as all associated costs. Radius would receive payments on the option exercise and on successful completion of certain development, regulatory, and commercial milestones. These payments could total >$500 million, part of which will be paid to Ipsen (a publicly-traded European pharmaceutical group), from which Radius exclusively licensed BA058 and its analogs in 2005. In addition, Radius would be eligible to receive sales royalties and has retained the option to co-commercialize the compound in the US.