IMUNON, Inc. and Acuitas Therapeutics announced the signing of an agreement to evaluate the combination of IMUNON's PLACCINE nucleic acid vaccine constructs formulated with Acuitas' proprietary lipid delivery technology. Under the agreement, IMUNON will evaluate administration of its vector constructs formulated in various Acuitas LNP formulations for gene expression and immunogenicity in murine models. IMUNON has demonstrated initial proof-of-concept of its PLACCINE nucleic acid vaccine platform in rodent and non-human primate models through intramuscular (IM) administration of PLACCINE plasmid DNA constructs expressing single or multiple SARS-CoV-2 antigens in combination with the PLACCINE delivery system.

In October 2022, IMUNON reported partial results from an ongoing non-human primate study that examined a single plasmid DNA vector containing the SARS-CoV-2 Alpha variant spike antigen formulated with a synthetic DNA delivery system. In the study, Cynomolgus monkeys were vaccinated with the PLACCINE vaccine or a commercial mRNA vaccine on Day 1, 28 and 84. Analysis of blood samples for IgG and neutralizing antibodies showed evidence of immunogenicity in both PLACCINE- and mRNA-vaccinated subjects.

PCR analysis of bronchoalveolar lavage showed viral clearance by >90% of the non-vaccinated controls. In a majority of vaccinated animals, viral clearance from nasal swab followed a similar pattern and a similar clearance profile was observed when viral load was analyzed by the tissue culture infectious dose method. In an ongoing stability study, the physio-chemical properties and immunogenicity of PLACCINE vaccine did not change during storage at 4° C for up to six months.

PLACCINE, part of IMUNON's proprietary nucleic acid technology with synthetic delivery systems platform, is the subject of multiple patent applications that cover a broad range of next-generation nucleic acid vaccines. An adaptation of the company's TheraPlas technology for therapeutic proteins, PLACCINE is a modality for prophylactic vaccines characterized by a single nucleic acid vector with multiple coding regions. The vaccine vector is designed to express multiple pathogen antigens along with the option to include a potent immune modifier.

PLACCINE has potential to be easily modified to create vaccines against a multitude of infectious diseases, with benefits including: Durability of protection – Durable antigen expression induces robust immunological response. Breadth of protection – Multi-cistronic vectors increase the breadth of immune response and allows for combination vaccines. Transmission advantage – Option for co-expression of potent immune modifiers increases the immune response and lowers the risk of viral shedding.

Safe and convenient – Synthetic delivery systems present no risk of genotoxicity (i.e., no virus or cytotoxicity) and require no device; it also allows for convenient handling for pandemic control. Flexible manufacturing – Versatile platform enables rapid response to changing pathogens; stability at normal refrigerator temperatures simplifies handling and distribution.