Background: HPV associated oropharyngeal cancers are increasing in prevalence worldwide. Recurrence after primary chemoradiotherapy or surgery is not uncommon, and hard to treat. Polynucleotide vaccines encoding HPV16 E6/E7 fusion proteins have demonstrated efficacy in several animal models of HPV associated cancer.
Aim: This study aimed to evaluate a polynucleotide immunotherapy targeted at HPV16 E6 and E7 proteins for immunogenicity and safety in patients with apparent cure after primary therapy for HPV associated oropharyngeal cancer.
Methods: A 1:1 mixture of 2 codon modified polynucleotide vaccines encoding HPV16 E6 and E7 with or without ubiquitin were administered at three doses (0.25mg, 1mg, 4mg) intracutaneously on 3 occasions to a total of 12 subjects with treated HPV associated oropharyngeal cancer
Results: The vaccine was overall safe and well tolerated. Only minor local adverse events attributable to the vaccine at the site of injection were observed. A cell mediated response to HPV 16 E6 and E7 was evident at baseline in all participants using ELISpot. Antibodies against HPV 16 E7 were evident at baseline in 11 of 12 participants using ELISA. Of 12 subjects, 10 demonstrated a significant immune response to one or more of the peptide pools at one or more timepoints.
Conclusion: This polynucleotide vaccine enhanced specific immunity to a virus derived tumour associated antigen in the majority of immunised subjects without significant adverse events. A further study in subjects with recurrent disease will commence in 2020.