Purpose: Cervical cancer, the second most common malignancy in women worldwide, is almost invariably associated with infection by human papillomavirus (HPV). HPV-16 or -18 is commonly present in 70% of cervical cancers. HPV-positive tumor cells present antigens of the viral protein in the context of human leukocyte antigen (HLA) class I that can be recognized by CTLs. We have conducted a study in patients with early-stage cervical cancer to assess the safety and immunological effects of vaccination with TA-HPV, a live recombinant vaccinia virus expressing modified forms of the HPV-16 and -18 E6 and E7 proteins.
Experimental design: Twenty-nine patients with clinical International Federation of Gynecologists and Obstetricians (FIGO) stage Ib or IIa cervical cancer were given two vaccinations with TA-HPV at least 4 weeks apart, starting 2 weeks before radical hysterectomy. Patients were monitored closely for side effects of the vaccination. Serial blood samples were examined for HPV-specific CTLs or changes in levels of antibodies to HPV-16 or -18 E6 and E7 proteins and to vaccinia virus.
Results: Vaccination with recombinant vaccinia was well tolerated in all patients with only mild to moderate local toxicity, and no serious adverse events were attributable to the vaccine. After a single vaccination, HPV-specific CTLs were found in four patients (HLA A1, A3, three patients; HLA A1, A24, one patient). Eight patients developed HPV-specific serological responses.
Conclusions: This study confirmed the safety and immunogenicity of the vaccine in a proportion of those patients vaccinated. Additional clinical studies using TA-HPV in combination with an additional experimental vaccine for HPV-16 are currently under way.