Intranasal RSV Vaccine Candidate Generated Durable Immune Response

An intranasal subunit vaccine (SynGEM) that introduces the respiratory syncytial virus (RSV), has demonstrated efficacy in actuating lasting immune responses in humans, according to the results from a small, phase 1 study. 

These researchers concluded ‘that SynGEM is thus the first non-replicating intranasal RSV subunit vaccine to induce persistent antibody responses in human volunteers.” 

This is good news since there is no effective vaccine against RSV. 

RSV can cause pneumonia and bronchiolitis among people with weakened immune systems. 

This double-blind, phase 1 randomized placebo-controlled clinical trial NCT02958540 included 48 healthy participants between the ages of 18 and 49 years, was published in the American Journal of Respiratory and Critical Care Medicine. 

Seropositive participants given SynGEM experienced persistent plasmablast responses and gains in antibodies specific to RSV. 

High-dose SynGEM was associated with a 1.5-fold plateau response upon the first vaccination that persisted throughout the follow-up period without additional boosting. 

The low-dose SynGEM achieved plateau responses with a boost at day 28, but the maximum change was 2.4-fold. 

Those with lower levels of antibodies at baseline showed the strongest response to vaccination. 

And, there was heterogeneity in nasal immunoglobulin A responses, although there were no detectable levels of F protein site antibodies at site zero. 

Antibodies competing with palivizumab showed significant increments after prime/boost (prevaccination to day 56, low-dose geometric mean titer, 12.7-13.3; P <.0001; high-dose geometric mean titer, 12.7-13.6; P <.0001). 

In the US alone, the Centers for Disease Control and Prevention (CDC) estimates that RSV yearly causes more than 57,000 hospitalizations in under 5 years old and more than 177,000 hospitalizations in over 65 years old. 

Globally, RSV infections are estimated to cause more than 250,000 deaths each year. 

Recent RSV news:

• ResVax Misses Phase 3 Study Endpoint
• Skin Vaccination Using Microneedle Patch May Protect Against Respiratory Syncytial Virus
• When Are Infants Most Vulnerable to Asthma?

Limitations to this new SynGEN study included a limited size of antibody responses and a lack of explanation for low serum virus neutralization boosting with the presence of F protein-binding antibodies. This study received support from a Wellcome Trust Translation Award.

In June 2017 the biotech vaccine company Mucosis filed for bankruptcy. Mucosis had developed vaccines for over 10 years against various diseases such as RSV.

These technologies are now made available by Virtuvax on behalf of the Trustee, including full IP rights.