Intradermal vaccination of HPV-16 E6 synthetic peptides conjugated to an optimized Toll-like receptor 2 ligand shows safety and potent T cell immunogenicity in patients with HPV-16 positive (pre-)malignant lesions

Frank M Speetjens, Marij J P Welters, Marije Slingerland, Mariette I E van Poelgeest, Peggy J de Vos van Steenwijk, Inge Roozen, Sanne Boekestijn, Nikki M Loof, Gijs G Zom, A Rob P M Valentijn, Willem-Jan Krebber, Nico J Meeuwenoord, Catharina A H Janssen, Cornelis J M Melief, Gijs A van der Marel, Dmitri V Filippov, Sjoerd H van der Burg, Hans Gelderblom, Ferry Ossendorp*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Web of Science)


BACKGROUND: Amplivant is a molecularly optimized Toll-like receptor 2 ligand that can be covalently conjugated to tumor peptide antigens. In preclinical models, amplivant-adjuvanted synthetic long peptides (SLPs) strongly enhanced antigen presentation by dendritic cells, T cell priming and induction of effective antitumor responses. The current study is a first-in-human trial to investigate safety and immunogenicity of amplivant conjugated to human papillomavirus (HPV) 16-SLP.

METHODS: A dose escalation phase I vaccination trial was performed in 25 patients treated for HPV16 positive (pre-)malignant lesions. Amplivant was conjugated to two SLPs derived from the two most immunodominant regions of the HPV16 E6 oncoprotein. The vaccine, containing a mix of these two conjugates in watery solution without any other formulation, was injected intradermally three times with a 3-week interval in four dose groups (1, 5, 20 or 50 µg per conjugated peptide). Safety data were collected during the study. Peptide-specific T cell immune responses were determined in blood samples taken before, during and after vaccination using complementary immunological assays.

RESULTS: Toxicity after three amplivant-conjugated HPV16-SLP vaccinations was limited to grade 1 or 2, observed as predominantly mild skin inflammation at the vaccination site and sometimes mild flu-like symptoms. Adverse events varied from none in the lowest dose group to mild/moderate vaccine-related inflammation in all patients and flu-like symptoms in three out of seven patients in the highest dose group, after at least one injection. In the lowest dose group, vaccine-induced T cell responses were observed in the blood of three out of six vaccinated persons. In the highest dose group, all patients displayed a strong HPV16-specific T cell response after vaccination. These HPV16-specific T cell responses lasted until the end of the trial.

CONCLUSIONS: Amplivant-conjugated SLPs can safely be used as an intradermal therapeutic vaccine to induce robust HPV16-specific T cell immunity in patients previously treated for HPV16 positive (pre-) malignancies. Increased vaccine dose was associated with a higher number of mild adverse events and with stronger systemic T cell immunity.

TRIAL REGISTRATION NUMBERS: NCT02821494 and 2014-000658-12.

Original languageEnglish
Article numbere005016
JournalJournal for ImmunoTherapy of Cancer
Issue number10
Publication statusPublished - Oct 2022


  • Female
  • Humans
  • T-Lymphocytes
  • Toll-Like Receptor 2
  • Ligands
  • Immunodominant Epitopes
  • Cancer Vaccines
  • Uterine Cervical Neoplasms
  • Human papillomavirus 16
  • Vaccination
  • Peptides
  • Inflammation/drug therapy

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