Recombinant human nerve growth factor (rhNGF) is the first neurotrophin to be investigated in clinical trials of diabetic peripheral neuropathy (DPN). To date, the drug has been administered to 60 healthy volunteers and 209 patients with DPN in phase I and II studies. Results from phase I have demonstrated rhNGF to be safe and generally well tolerated in doses up to 1.0 µg/kg given intravenously or subcutaneously for up to 12 doses. Doses investigated in phase II were 0.1 or 0.3 µg/kg s.c. 3 days a week for 6 months. Preliminary results from this trial suggest that rhNGF specifically improves the function of small-fibre sensory peripheral neurons, which is consistent with its postulated mode of action. Two pivotal 12-month phase III trials are underway in diabetic patients with symptomatic peripheral neuropathy to confirm the therapeutic effects of rhNGF. Results from these trials are expected in 2000.