GH in combination with bisphosphonate treatment in osteogenesis imperfecta

Objective: To verify the effects of bisphosphonates (Bps) in combination with recombinant human GH (rGH) in pediatric osteogenesis imperfecta (OI) patients; we focused on possible improvement of bone mineral density (BMD), projected bone areas, growth velocity, and fractures risk. Design: A randomized controlled 1-year clinical trial on 30 prepubertal children (M: F = 14:16) affected by OI (type I, IV, and III) being treated with neridronate. Methods: Following an observational period of 12 months during ongoing neridronate treatment, the patients were randomly divided into two groups: 15 were treated for 12 months with rGH and neridronate (group Bp+rGH) and 15 continued neridronate alone (group Bp). We evaluated auxological parameters, number of fractures, bone age (BA), bone metabolic parameters, and bone mass measurements (at lumbar spine and radius by dual-energy X-ray absorptiometry). Results: The mean variation in percentage of BMD (Delta%BMD)-at lumbar spine (L2-L4), at distal and ultradistal radius-and the projected area of lumbar spine increased significantly in group Bp+rGH (P<0.05). Growth velocity was significantly higher during rGH treatment in group Bp+rGH versus group Bp and versus pretreatment (P<0.05), with no difference in increase in BA or fracture risk rate. Patients with quantitative (-qt) collagen synthesis defects had a higher, although not significant, response to rGH in terms of growth velocity and BMD. Conclusions: In OI patients, the combined rGH-Bp treatment may give better results than Bp treatment alone, in terms of BMD, lumbar spine projected area and growth velocity, particularly in patients with quantitative defects.