Nerve growth factor (NGF) is an important mediator of pain and hyperalgesia and 
has become a target of novel analgesic therapeutics. Tanezumab is a humanized 
IgG(2) antibody that binds NGF with high affinity and specificity. In a study to 
assess the toxicity and pharmacokinetic properties of tanezumab in adult, male 
and female, cynomolgus monkeys following weekly intravenous administration of 1, 
10, or 30 mg/kg for up to 26 weeks (followed by an 8-week recovery period), 
tanezumab was well tolerated with no macroscopic or microscopic effects on those 
brain, spinal cord, nerve, or ganglia sections evaluated. One fifth of 
tanezumab-treated monkeys developed an antibody response to tanezumab that 
prevented maintenance of tanezumab exposure between dosing. In the 
antibody-negative animals, accumulation of tanezumab was observed; steady state 
was achieved approximately 8 weeks after the first dose of study drug, and 
exposure to tanezumab was approximately dose proportional with no observed 
difference between male and female animals. One monkey died during the study; 
this monkey had findings suggestive of hypersensitivity reaction. The favorable 
toxicity and pharmacokinetic profile of tanezumab seen in this study supports 
its further evaluation for the treatment of pain in clinical practice.