Safety of an Escherichia coli-expressed bivalent human papillomavirus (types 16 and 18) L1 virus-like particle vaccine: an open-label phase I clinical trial.

An Escherichia coli-expressed recombinant bivalent human papillomavirus (types 16 and 18) vaccine candidate has been shown to be safe and immunogenic in preclinical trials. The safety of this vaccine was analyzed in an open-label phase I clinical trial in Jiangsu province, China. Thirty-eight healthy women from 18 to 55 y of age were enrolled and vaccinated at 0, 1, and 6 mo. Adverse events that occurred within 30 d after each injection and serious adverse events that occurred throughout the study were recorded. In addition, blood parameters were tested before and after each injection. All but one woman received all 3 doses. Thirty-two (84.2%) of the participants reported adverse events, all adverse events of which were mild, of short duration and resolved spontaneously. No serious adverse events occurred during the study. Changes in blood parameters after each injection were random, mild, and not clinically significant. These preliminary results show that a new Escherichia coli-expressed recombinant HPV 16/18 bivalent vaccine is well tolerated in healthy women and support further immunogenicity and efficacy studies for this HPV vaccine candidate.