MONDAY, JUNE 18, 2018

Mucosis publishes preclinical data on RSV vaccines

Mucosis B.V., a clinical-stage Dutch biotechnology company, announced the publication on Monday of preclinical data demonstrating that its SynGEM intranasal respiratory syncytial virus vaccine is safe and protective in animal models.

The report, which was published in PLoS ONE, showed that SynGEM induced locally secreted immunoglobulin A antibodies in the mucosal layers and robust levels of systemic virus neutralizing antibodies in mice and cotton rats. SynGEM is a vaccine based on Mucosis' Mimopath vaccine technology which enables the presentation of a stable prefusion-like trimeric F protein. The trimeric F protein is considered important for the induction of functional immunity.

The preclinical results follow recent RSV vaccine research developments revealing a newly identified vulnerable site that is only exposed in the prefusion F protein, called antigenic site phi. The antigenic site is an essential epitope needed to effectively induce highly potent neutralizing antibodies in humans.

"We have succeeded in producing stable prefusion-like F antigen and formulating a vaccine candidate, SynGEM that presents the prefusion F epitopes of antigenic site (phi) in a safe way to the immune system," Kees Leenhouts, the chief scientific officer of Mucosis, said. "In addition, our vaccine presents the protective epitope recognized by palivizumab (an antibody used to prevent RSV). The intranasal application potentially results in an extra line of defense at the port of entry of the virus, which may also reduce virus shedding and hence may increase 'herd' immunity."

Leenhouts said the vaccine candidate could fill the gap of substantial unmet medical need by preventing RSV infections in people of all ages. In the 1960s, scientists attempted to develop a formalin-inactivated RSV vaccine, but the trials failed when the vaccine caused enhanced disease symptoms.

RSV affects more than 60 million people worldwide and causes more than one million annual hospitalizations. There is no currently available RSV vaccine.

"These positive animal data showing safe and effective protection against RSV provide further confirmation that the Mimopath vaccine platform will play a key role in meeting significant unmet medical need around the globe," Thomas Johnston, the CEO of Mucosis, said. "We remain focused on advancing the SynGEM program into human trials, as we believe its unique prefusion-like structure offers the most complete approach to generating a meaningful immune response and thereby conferring protection in those that need it the most."