Intranasal delivery of a next-generation NDV-based, COVID-19 booster vaccine shows promise

The Icahn School of Medicine at Mount Sinai (Icahn Mount Sinai) in New York City is pleased to announce that CastleVax, Inc., has completed enrollment and a preliminary analysis of a phase 1 trial of its licensed Newcastle disease virus (NDV)-based COVID-19 booster vaccine.

The phase 1 study evaluated two dose levels of the live, recombinant vaccine, NDV-HXP-Spike(S), delivered intranasally, intramuscularly, or via both routes in combination, in participants previously vaccinated with an authorized intramuscular COVID-19 vaccine.

Interim results show that intranasal delivery resulted in a robust S-specific, secretory IgA response in saliva relative to pre-booster levels, which is important for conferring mucosal immunity and has the potential to prevent infection and/or transmission of COVID-19. In addition, a strong boosting of serum neutralizing-antibody response was observed, which is important for conferring systemic immunity and prevention of severe disease, hospitalization, and death (the efficacy endpoint(s) for currently authorized intramuscularly delivered vaccines). The safety profile was also acceptable, successfully clearing the Data Safety Monitoring Board reviews.

"We are thrilled with the progress led by principal investigator Sean Liu, MD, Ph.D., and our Mount Sinai colleagues, and are both excited and encouraged by these preliminary results," said Michael Egan, Ph.D., CastleVax Chief Scientific Officer and acting Chief Executive Officer. "Dr. Liu's preliminary findings complement those of our development partners in Mexico, Avimex, whose interim phase 3 results showed their live, attenuated NDV-based vaccine (Patria® (AVX/COVID-12), licensed from CastleVax, was effective as a booster against COVID-19."

"The initial observations from our phase 1 trial of NDV-HXP-S as a COVID-19 booster vaccination suggest that it is safe and well-tolerated when delivered intranasally and/or intramuscularly to healthy adults. The preliminary exploratory findings looking at mucosal and systemic antibody responses are encouraging, particularly when NDV-HXP-S is administered intranasally. There is a growing interest in developing vaccines that not only protect against the severe illnesses caused by respiratory pathogens but also limit host susceptibility and decrease person-to-person transmissions by enhancing the mucosal immune response. I am excited to watch as the NDV-vectored vaccine platform matures to address newer variants of concern in larger randomized controlled trials," said Sean Liu, MD, Ph.D., Assistant Professor of Medicine (Infectious Diseases, and Hospital Medicine) at the Icahn School of Medicine at Mount Sinai.

The NDV-vectored vaccine platform was developed by Peter Palese, Ph.D., Horace W. Goldsmith Professor and Chair of Microbiology; Adolfo García-Sastre, Ph.D., Irene and Dr. Arthur M. Fishberg Professor of Medicine and Director of the Global Health and Emerging Pathogens Institute; and Florian Krammer, Ph.D., Professor of Microbiology, and Pathology, Molecular and Cell Based Medicine, at Icahn Mount Sinai, and was licensed by Mount Sinai to CastleVax Inc. Mount Sinai has a financial interest in this technology and in CastleVax.

Provided by The Mount Sinai Hospital