First-in-Human Study: Amplivant® Adjuvant Boosts Immune Response of Synthetic Long Peptide Immunotherapy

• First-in-human study investigating the safety and immunogenicity of ISA’s proprietary Amplivant adjuvant conjugated to human papillomavirus type 16 (HPV16) Synthetic Long Peptides (SLPs).
• SLPs conjugated to Amplivant elicit a significant, strong immune response and dose related systemic T cell immunity when injected intradermally.
• Study demonstrates that SLPs conjugated to Amplivant have highly favourable tolerability and safety when used as an intradermal therapeutic vaccine.

Oegstgeest, The Netherlands, 08 November 2022 – ISA Pharmaceuticals B.V., a clinical stage biotech company developing immunotherapies to treat cancers and infectious diseases, is delighted to announce publication by Leiden University Medical Center (LUMC) of a phase 1 clinical study using ISA’s proprietary Amplivant® adjuvant and Synthetic Long Peptide (SLP®) therapeutic vaccine technology. The study was recently published in the Journal for ImmunoTherapy of Cancer. This open access paper is entitled ‘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 HPV16 positive (pre-)malignant lesions’ and can be found at: https://doi.org/10.1136/jitc-2022-005016.

Amplivant is a molecularly optimized Toll-like receptor 1/2 ligand that can be covalently conjugated to tumour peptide antigens. In preclinical models Amplivant-adjuvanted SLPs strongly enhance antigen presentation by dendritic cells, T cell priming, and induce effective antitumor responses.

This first-in-human clinical study demonstrated a favourable safety profile without serious adverse events and a strong immune response generated with only two Amplivant-conjugated HPV16 SLPs. The study concludes that Amplivant-conjugated SLPs can be safely used as an intradermal therapeutic vaccine to induce HPV16-specific T cell immunity in previously treated patients with HPV16-positive (pre-)malignancies. Vaccine dose escalation in 25 patients caused a corresponding increase in systemic T cell immunity.

Amplivant was conjugated to two SLPs derived from the two most immunodominant regions of the HPV16 E6 oncoprotein. Patients received 3 doses intradermally, three times a week, and with a 3-week interval in four dose groups (1, 5, 20 or 50 µg per conjugated peptide). Peptide-specific T cell immune responses were determined in PBMC’s from blood samples taken before, during and after vaccination.

Details of the study can be found on clinicaltrials.gov under the identifier NCT02821494.