BACKGROUNDWe investigated the safety, tolerability, and pharmacokinetics of intravenous recombinant human Neuregulin-1 (rhNRG-1), a DNA recombinant protein for the treatment of chronic heart failure, in healthy Chinese volunteers following single and multiple dose administration.METHODS AND RESULTSTo evaluate the safety and tolerance after single-dosing escalation, 28 subjects were divided into six groups (0.2, 0.4, 0.8, 1.2, 1.6, and 2.4 μg/kg) to receive an intravenous (IV) infusion of rhNRG-1 over 10 min by a randomized, open-label design. Only the 1.2 μg/kg dose group obtained pharmacokinetic parameters: Cmax was 7.645 (24.21) ng/mL, AUC0-t was 97.088 (21.41) min·ng/mL. To assess the safety and pharmacokinetics after multiple-dosing, 32 subjects were divided into four groups (0.2, 0.4, 0.8, and 1.2 μg/kg) to receive a 10-min IV infusion of rhNRG-1 for five consecutive days. After multiple dosing of 1.2 μg/kg, the Cmax value at day 5 was 8.838 (51.6) ng/mL and the AUC0-t value at day 5 was 109.890 (32.99) min·ng/mL. RhNRG-1 is rapidly cleared from the blood and has a short t1/2 of about 10 min. The adverse events related to rhNRG-1 mainly included flat or inverted T wave and gastrointestinal reactions, all of which were mild.CONCLUSIONSIt is concluded that rhNRG-1 is safe and well tolerated in healthy Chinese subjects at the dosing levels used in this study. The severity and frequency of adverse events did not increase with the prolongation of administration time.CLINICAL TRIAL REGISTRATIONChinese Clinical Trial Registry ( http://www.chictr.org.cn ) Identifier No. ChiCTR2000041107.