A Pilot Phase 1/2a, Multicentre, Open Proof-of-concept Study on the Efficacy and Safety of Allogeneic Osteoblastic Cells (ALLOB®) Implantation in Non-infected Delayed-Union Fractures

Fracture healing is a complex physiological process caused by interaction of cellular elements, cytokines and signaling proteins, which results in the formation of new bone. There is for now no universally accepted approach to evaluate the progression of fracture healing. Typically, a fracture is considered as a delayed-union when the bone has not united within a period of time that would be considered adequate for bone healing. Delayed-union suggests that union is slow but will eventually occur without additional surgical or non-surgical intervention, whereas non-union is defined as the cessation of all reparative process of healing.

The incidence of impaired healing is estimated to range from 5 to 10% of all long bone fractures, depending on the fracture site, the type and degree of injury, among other factors. Currently the treatment of choice remains bone allograft or autograft. This procedure shows in general good results but requires an invasive surgery of several hours under general anesthesia, followed by a few days of hospitalization. Because of this, major complications have been reported in up to 20-30% of patients.

The present Phase 1/2a study aims at demonstrating the safety and efficacy of ALLOB®, a proprietary population of allogeneic osteoblastic cells, in the treatment of delayed-union fractures of long bones. In this study, delayed-union is defined at the time of screening as an absence of healing of minimum 3 months and maximum 7 months (+/- 2 weeks) after the onset of the fracture.