Phase I safety and antigenicity of TA-GW: a recombinant HPV6 L2E7 vaccine for the treatment of genital warts.

A phase I double-blind, randomized, placebo-controlled study was carried out in healthy subjects to assess the safety and immunogenicity of TA-GW, a recombinant HPV6 L2E7 fusion protein vaccine for the treatment of genital warts. Forty-two healthy male volunteers were randomised to receive three intramuscular injections of either 0, 3, 30 or 300 microg of recombinant L2E7 adsorbed onto Alhydrogel. Two vaccination schedules were compared: weeks 0, 1 and 4 (accelerated schedule) and weeks 0, 4 and 8 (classical schedule). Subjects were monitored for adverse events throughout. Immunogenicity was assessed by measuring L2E7 specific in vitro T cell proliferative responses, production of IFNgamma and IL-5 and serum antibodies. Dose-dependent and long-lived T and B cell immune responses were elicited by TA-GW with both vaccination schedules. In conclusion, TA-GW is both safe, well-tolerated and immunogenic. The results allow the selection of the 300-microg vaccine formulation and accelerated vaccination schedule for phase II trials in patients with genital warts.