Task: Question Answering
Input (English): Context: To investigate the use of tanezumab, a humanized monoclonal antibody that inhibits nerve growth factor, for the treatment of moderate to severe osteoarthritis in Japanese patients. Patients received tanezumab 10, 25, 50, 100, 200g/kg, or placebo and were followed for 92 or 120 days. Endpoints included the incidence of adverse events (AEs) and the change from baseline to week 8 in pain intensity and the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) subscales. Patients (n=83) were 69% female, age 44-73 years, with a Kellgren-Lawrence X-ray grade of 2-4. At week 8, compared with placebo, tanezumab 25, 100, and 200g/kg improved index knee pain during walking (-18.5,-14.3, and-27.6, respectively), index knee pain in the past 24h (-19.1,-14.6, and-24.2, respectively), current index knee pain (-16.5,-10.9, and-22.8, respectively), and the WOMAC pain (-11.5,-9.6, and-18.8, respectively), physical function (-8.7,-9.5, and-17.6, respectively), and stiffness (-20.4,-11.2, and-10.2, respectively) subscales. Overall, seven patients reported AEs of abnormal peripheral sensation: allodynia (two in the tanezumab 200g/kg group); paresthesia (two in the tanezumab 200g/kg group), dysesthesia (one in the tanezumab 200g/kg group); thermohypoesthesia (one in the tanezumab 100g/kg group), and decreased vibratory sense (one in the placebo group). All of these AEs were mild to moderate in severity and transient in nature. Tanezumab was safe and generally well tolerated and may improve pain symptoms in Japanese patients with moderate to severe osteoarthritis of the knee. CLINICALTRIALS.GOV IDENTIFIER: NCT00669409. 
 Question: What is the target of tanezumab?
Output (English): nerve growth factor