The potential of the current licensed preventive virus-like particle human papillomavirus (HPV) vaccines to have a major public health impact is leading to additional clinical trials.

The International Agency for Research on Cancer (IARC)/United States National Cancer Institute (NCI) Expert Meeting of September 2013 brought together a Working Group composed of experts from the non-profit public and academic sectors who possessed a wide range of expertise relevant to HPV vaccines. The Working Group reviewed the scientific evidence as to whether it might be appropriate to use a virological end-point, rather than a disease end-point such as cervical intraepithelial neoplasia of grade 2 or worse (CIN2+), as the primary end-point for some future clinical efficacy trials, and the circumstances under which immunobridging trials might be sufficient for licensure. Virological end-points could accelerate vaccine evaluation and licensure.

The Working Group developed recommendations for clinical trial primary end-points that could also include post-trial follow-up recommendations.