20 July 2021 - - US-based biotechnology company Meissa Vaccines has released of preclinical data in nonhuman primates of the company's intranasal recombinant live attenuated COVID-19 vaccine (MV-014-212), the company said.

According to the company, the data demonstrate that a single adjuvant-free dose of MV-014-212 provided equivalent protection against SARS-CoV-2 challenge compared to reported efficacy in NHP models of currently authorized vaccines.

Furthermore, the data show that MV-014-212 stimulates mucosal (nasal IgA) antibodies in the upper respiratory tract, the major infection route for SARS-CoV-2, and systemic (serum neutralizing and binding IgG) antibodies.

Meissa also announced that the company has enrolled and dosed SARS-CoV-2 seronegative and seropositive adult participants in all dosage groups of a Phase 1 clinical trial of MV-014-212 (ClinicalTrials.gov identifier: NCT04798001). Interim analysis of the trial data is expected later this year.

Injected vaccines are likely to curtail but not contain transmission, whereas a live attenuated intranasal vaccine has the greatest potential to block transmission, prevent infections, and provide broad and long-lasting immunity.

The mucosal immune response is the first line of defense against respiratory viruses, providing fast-acting protection at the primary site of exposure.

In NHPs, Meissa's intranasal COVID-19 vaccine generated both mucosal and systemic antibodies and was highly protective against wild-type SARS-CoV-2 challenge.

Serum antibodies were able to neutralize wild-type SARS-CoV-2, B.1.351 (Beta, South Africa), and B.1.1.7 (Alpha, UK). Additional data from serial passaging in manufacturing cell line and virus shed from NHPs showed that MV-014-212 has a stable genotype in vitro and in vivo.

Because coronaviruses are genetically unstable, a conventional live attenuated coronavirus vaccine strategy is not recommended for SARS-CoV-2.

To overcome this challenge, MV-014-212 was built on the company's AttenuBlock platform.

This platform incorporates 10 years of research and development employing rational and precise codon deoptimization and other genetic strategies to produce a vaccine backbone that provides appropriate attenuation, genetic stability, and optimized immunity.

In addition, live attenuated vaccines are effective at lower dosages and scalable with a straightforward and economical manufacturing process.

Meissa Vaccines was founded with a mission to protect people everywhere from life threatening respiratory viruses and a commitment to develop innovative technologies capable of delivering effective vaccines at a global scale.

Meissa is advancing live attenuated vaccine candidates against respiratory syncytial virus, SARS-CoV-2 (COVID-19), and human metapneumovirus.

These vaccine candidates have been developed using the company's proprietary AttenuBlock synthetic biology platform, which includes codon deoptimization and technologies exclusively licensed from Emory University and Children's Healthcare of Atlanta.

Meissa's live attenuated vaccine candidates are formulated to be delivered as a single, intranasal, adjuvant-free, needle-free dose and are designed to generate a strong, durable immune response to prevent infection and disease. Meissa is headquartered in Redwood City, Calif.