According to Blue Lake Biotechnology, the FDA has agreed to lift a partial clinical hold on a Phase 1/2a clinical trial of BLB201 intranasal RSV vaccine in children aged 8 months to 59 months with or without prior RSV infection. During the clinical hold, the FDA allowed the trial to continue to enroll children who were more than 2 years old and who were RSV-positive.
In December 2024, the agency said that it had placed the clinical hold on all pediatric RSV vaccine trials, halting dosing of children under 2 years old and those aged 2-5 years who are RSV-negative. That hold was placed due to reports of vaccine-associated enhanced respiratory disease (VAERD) in a trial of a different company’s vaccine.
Blue Lake had announced preliminary data from the study in March 2024 demonstrating that BLB201 produced an immune response and was well tolerated, with no significant safety events observed. The company says that a December 2024 analysis of partially unblinded data from the 63 children who had been dosed prior to the hold demonstrated an 80% reduction in symptomatic RSV infections for those who received BLB201 compared to those who received a placebo.
BLB201 is PIV5 vector-based and encodes the RSV F protein. In 2022, the FDA granted Fast Track designation to BLB-201 for the prevention of RSV in children under 2 and adults over 60. That same year, the company announced results from a Phase 1 trial BLB201 in adults aged 18-59 and 60-75.
Blue Lake Biotechnology CEO Biao He commented, “FDA’s lifting of the partial clinical hold on our trial is an important step that clears a path for Blue Lake to continue to develop an RSV vaccine for toddlers. In our interactions with the FDA, the agency also recognized that there has been no evidence suggesting that BLB201 causes VAERD.”
Blue Lake Chief Medical Officer Henry Radziewicz said, “The enrollment of additional seronegative and younger toddlers will enable us to further evaluate the safety of BLB201 in children who have not been exposed to RSV and who have the greatest potential to benefit from a pediatric RSV vaccine. We also hope to expand our analysis of the clinical benefits of BLB201 in protecting children from symptomatic RSV infection as well as severe RSV infection. These safety and efficacy data will be the foundation for the development of the first RSV vaccine for toddlers. In light of recent setbacks in trials sponsored by other RSV vaccine developers, BLB201 now represents the most advanced pediatric RSV vaccine for young children in clinical development.”
Read the Blue Lake Biotechnology press release
