Preclinical Development of ARV-2001, an Intradermally Administered mRNA–Lipid Nanoparticle Immunotherapeutic for the Treatment of HPV-16-Positive Cervical High-Grade Squamous Intraepithelial Lesions

Background/Objective: Persistent infection with human papillomavirus type 16 (HPV-16) is the principal cause of cervical high-grade squamous intraepithelial lesions (cHSIL) and cervical cancer, yet the established treatments remain limited to ablative or excisional procedures that carry reproductive risk and do not eliminate the underlying infection. We report the preclinical development of ARV-2001, a messenger RNA (mRNA)–lipid nanoparticle (LNP) immunotherapeutic encoding mutated, non-oncogenic HPV-16 E6 and E7 fused to a SARS-CoV-2 spike S2 subdomain enriched in human CD4 helper epitopes, formulated in a novel cholesterol-derived ionizable lipid (ARV-T1). Methods: Interactions of ARV-2001-expressed antigens with p53 and retinoblastoma (Rb) were evaluated in human cervical carcinoma cell line C33A, in lentiviral constructs in primary human keratinocytes, and in soft-agar colony-formation assays. ARV-2001 was administrated by intramuscular (IM) or intradermal (ID) injection in naive mice or in the TC-1 tumor models. Tumor size and survival were monitored over time and tumor-infiltrated lymphocytes were characterized by flow cytometry. Intracellular cytokine staining and Elispot were used to evaluate immunogenicity. Results: In vitro, the mutated E6/E7–S2 antigen lost the ability to degrade p53, to deregulate the retinoblastoma (Rb) pathway, and to support anchorage-independent growth, suggesting abrogation of oncogenic activity. The S2 domain and imiquimod administration each augmented antitumor activity and intratumoral CD8+ T-cell infiltration while reducing myeloid-derived suppressor cells in the syngeneic HPV-16 E6/E7 TC-1 tumor models. In addition, ID administration of ARV-2001 into TC-1 tumor-bearing mice was superior to IM administration in terms of both tumor growth inhibition and survival. ID vaccination with ARV-2001 in mice consistently elicited a more potent E6/E7-specific T-cell response than the same dose given IM. Dose-escalation studies showed a dose-dependent T cell response against E6/E7 in ID-injected mice. Conclusions: This study supports future human evaluation of intradermally administrated ARV-2001 for treatment of HPV-16+ cHSIL in clinical trials.