PaTH Study: Parathyroid Hormone and Alendronate for Osteoporosis

The PaTH study is a 2-year, multicenter, double-blind, placebo-controlled trial to test the efficacy of combining hPTH (1-84) and alendronate for treating osteoporosis in postmenopausal women. 238 women were randomized between 55 and 85 years of age to receive either: (1) PTH for 1 year followed by alendronate for 1 year; (2) PTH and alendronate for 1 year followed by alendronate for 1 year; (3) alendronate for 2 years; or (4) PTH for 1 year followed by placebo for 1 year. The primary endpoints are changes in bone mineral density at several sites and changes in biochemical markers. In addition, we will assess specific biochemical markers of bone turnover (e.g., osteocalcin, deoxypridinoline, N-telopeptide, bone-specific alkaline phosphatase and bone sialoprotein) to determine if they can predict the skeletal response to combination therapy. We will also determine whether PTH positively affects ultrasound measurements in the calcaneus.