Children RSV Vaccine Candidate Posts Positive Interim Clinical Data

A clinical-stage intranasal vaccine company developing parainfluenza virus 5 (PIV5)-vectored vaccines that harness the full breadth of the immune system to protect against serious infectious diseases today announced preliminary data from the first two cohorts of a Phase 1/2a clinical trial studying BLB201, a vaccine candidate against severe respiratory syncytial virus (RSV) disease.

On March 21, 2024, Blue Lake Biotechnology, Inc., stated the data show that BLB201 is immunogenic and well tolerated, with no significant safety events reported to date following a single intranasal dose in RSV seropositive children 18-59 months of age.

The ongoing trial is currently enrolling both RSV seropositive and RSV seronegative children as young as eight months of age.

No vaccine-related severe safety signals have been reported among the initial 10 participants ages 18-59 months who received the BLB201 study vaccine in this Phase 1/2a study (NCT05655182).

In the five participants who received the higher dose of 10⁷ PFU of BLB201, prominent increases in RSV neutralizing antibody (nAb) responses were observed at four weeks post-vaccination, with 80% having a 3.6- to 57-fold rise in nABs over baseline.

RSV-specific mucosal IgA antibody and cellular immune responses were also observed.

“Given the challenges of developing an RSV vaccine for children, it is highly encouraging that BLB201, our intranasal RSV vaccine candidate, has been well tolerated in this age group so far,” said Biao He, Ph.D., founder and CEO of Blue Lake Biotechnology, in a press release.

“It is also very exciting to see RSV-specific immune responses to our vaccine in children who have previously been exposed to RSV. We are eager to generate more data in younger children, including infants who have not had prior exposure to RSV, and to develop a highly effective and safe vaccine to protect this vulnerable population from RSV.” 

As of March 2024, approved antibody drugs and a maternal RSV vaccine can provide passive immunity against RSV in infants. However, no RSV vaccine has been approved for generating prophylactic immunity in infants and children.