A Study of INFUSE Bone Graft (BMP-2) in the Treatment of Tibial Pseudarthrosis in Neurofibromatosis Type 1 (NF1)

The current study proposes adding BMP-2 (INFUSE), an anabolic agent, at the surgical site of TPA (tibial pseudarthrosis) repair in children with NF1, compared to a control group of patients treated surgically without BMP-2. The following Specific Aims will be addressed: 1) to determine if use of an osteogenic agent (BMP-2) at the time of surgical repair of TPA in NF1 patients will result in improved bone healing; 2) to document safety of BMP-2 in a pediatric NF1 population; and 3) to collect, process, and preserve biologic specimens at the time of surgery for future studies.

A randomized study will be performed by a multi-center group of the NF Consortium. A total of 54 patients will be randomized for treatment with or without INFUSE Bone Graft at the time of surgical repair. For all patients, a standard surgical procedure will be used, including: resection of pseudarthrosis tissue; placement of a rigid intramedullary rod; and placement of autogenous bone graft from iliac crest. For patients in the BMP group, the INFUSE device containing BMP-2 will in addition be applied intraoperatively to the osteotomy site. Fracture union will be determined by scoring of radiographs (RUST score) for cortical bone fusion and callus formation at the osteotomy site. RUST score at 12 months post-surgery will be the primary outcome measure to determine efficacy. Secondary measures will include determination of time to healing (months); quality of life measures; functional walking measures; and incidence of refracture after surgery. This study, once successfully completed, will determine if use of INFUSE Bone Graft improves healing of tibial pseudarthrosis in NF1 and will document safety issues. Regardless of results, the better performing of the two groups (control or BMP) will be able to serve as a much-needed control arm for future studies of additional targeted therapeutic agents for NF1-related bone disease. An international working group of orthopaedic surgeons and NF specialists has been formed and is committed to successful completion of this trial.