An inhalable nanobody-based treatment may effectively prevent and treat SARS-CoV-2 infections when administered at ultra-low doses, according to a new study in Syrian hamsters. This novel therapy, Pittsburgh inhalable Nanobody 21 (PiN-21), could provide an affordable, needle-free alternative to monoclonal antibodies for treating early infections. Sham Nambulli and colleagues recently developed PiN-21, which uses single-domain antibody fragments that are cheaper to produce than monoclonal antibodies. However, until this study, the efficacy of PiN-21 had not been reported in living organisms. To advance the development of this treatment, Nambulli et al. administered a 0.6 milligram per kilogram dose of PiN-21 into the nasal cavities of hamsters immediately after they were infected with SARS-CoV-2 via the trachea. The treatment prevented significant weight loss in the infected hamsters and essentially eliminated the virus after 10 days. The authors also found that PiN-21 remained effective at clearing the virus from the lungs when the virus was administered through the nasal cavities, suggesting the treatment works regardless of the original route of viral entry. In another experiment, the researchers placed infected hamsters in a whole-body exposure chamber where a single 0.2 milligram per kilogram dose of PiN-21 nanobodies was aerosolized with a nebulizer, finding that the viral load in the hamsters' lung tissue diminished by six orders of magnitude. "We envision that PiN-21 aerosolization treatment could provide both a convenient and cost-effective solution to alleviate disease onset and reduce virus transmission, especially for mild COVID-19 patients who constitute major populations of infections," the authors write. They add that further preclinical trials, including safety tests in non-human primates, will be needed before PiN-21 moves to human trials.
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Journal
Science Advances