Prevention of HPV cancer related through HPV-9: state of the art, potential benefits and open issues

HPV vaccines currently marketed in Italy (bivalent and quadrivalent against HPV 16-18 and HPV and 6,11,16,18 respectively) are an extraordinary tool for the primary prevention of HPV related diseases, particularly of the cervical cancer. Although the implementation of the organized vaccination programs has already translated (for some endpoint) in confirmation of clinical efficacy, remains excluded a significant proportion of the diseases linked to non-vaccine HPV types. The new nonavalent vaccine (HPV9), of impending commercialization, represents an evolution of the quadrivalent, the composition of which are added five high-risk HPV types (HPV 31,33,45,52,58). The high clinical-immunological efficacy in experimental trials against the new genotypes (> 96% for CIN2 +), and the equivalence immunogenic to the four already present in the previous vaccine, will render the use of HPV9 a tool able to control in an even more effective HPV disease. The potential of the new vaccine is linked to the reduction of the HPV cancer burden by 2-20% according to anatomical site, with major benefits for cervical cancer, vulvo-vaginal, penile and more limited benefits for anal tumours. Moreover, the potential benefits could be also linked to the reduction of incidence of pre-neoplastic lesions arising in the lower-genital tract, especially in the cervix (CIN2-3), so often cause lengthy and expensive diagnostic and therapeutic procedures. In the face of this broad provision of benefit from HPV9 vaccine, we have also to consider all the variables related to its introduction in the vaccination calendars: the market price, the schedule of administration (currently in three doses) and data regarding the costeffectiveness. The authors recognize the new vaccine (currently registered only in the US) a lot of potential in the prevention of HPV-related diseases.