• Proportion of subjects who require a secondary intervention to promote fracture healing [ Time Frame: 48 weeks ] [ Designated as safety issue: No ]
• Impact on the subject's ability to return to normal function, general health status, work productivity, and degree of pain at fracture site compared with placebo and Standard of Care groups [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
• Time to fracture healing compared with Standard of Care [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
• Proportion of patients healed compared with placebo [ Time Frame: 16 weeks ] [ Designated as safety issue: No ]
• Time to regular callus formation compared with placebo [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]

• Time to fracture healing as assessed by the central orthopedic panel read radiographic measurements, compared with SOC;
• Time to fracture healing as assessed by the treating physician, compared with placebo;
• Proportion of patients healed at 16 weeks, compared with placebo;
• Time to regular callus formation as assessed by the central orthopedic panel read radiographic measurements, compared with placebo;
• Impact on the subject�s ability to return to normal function, general health status, work productivity, and degree of pain at fracture site compared with placebo and SOC groups;
• The proportion of subjects who require a secondary intervention to promote fracture healing within 48 weeks of the study period, including:
• Bone graft;
• Revision of intramedullary (IM) nail;
• IM nail removal and plating or external fixation;
• Nail dynamization to promote healing.

The purpose of this study is to find out the good and bad effects of an investigational drug called CP-533,536 in patients with closed fracture of the tibial shaft undergoing internal fixation using reamed inter-locked IM nailing procedure

• Drug: CP-533, 536
• Drug: Placebo
• Procedure: Standard of Care
• Drug: CP-533,536

Inclusion Criteria:

• Males or females 17 years or older with confirmed closure of the tibial epiphyses, with a closed fracture of the tibial diaphysis undergoing treatment with reamed locked IM nailing procedure and the absence of an associated compartment syndrome or vascular injury;
• Closed tibial fractures Types A, B & C (See OTA fracture classification) can be included.

Exclusion Criteria:

• Previous fractures of the same tibia that may impact nailing procedure or impaired visibility of current fracture or a history of osteomyelitis;
• Subjects with any other clinically significant injuries, which may significantly impair weight bearing of the affected limb;
• Subjects with a fracture gap of >1cm after initial surgery and prior to drug administration;
• Any other planned invasive or non invasive interventions intended to promote bone healing of the tibial fracture under study are not allowed in the first 24 weeks after treatment.