As the delta variant of COVID-19 continues to spread, efforts to develop antibody treatments for the virus have picked up steam. Several of those projects are inspired by llamas, which harbor tiny antibodies called nanobodies. Researchers at the Rosalind Franklin Institute in the U.K. are the latest to join the llama party with preclinical study results they hope will lead to human trials in about 18 months.
The researchers developed llama-inspired nanobodies and reported they were effective against COVID-19 in hamster models. Three of the nanobody chains neutralized the original SARS-CoV-2 virus and the alpha variant, and a fourth chain was effective at neutralizing the beta variant, the researchers reported in the journal Nature Communications. Rosalind Franklin is partnering with the University of Liverpool, the University of Oxford and Public Health England to develop the treatment.
While the work is ongoing, researcher Ray Owens, Ph.D., professor and head of protein production at Rosalind Franklin, expressed confidence about the nanobodies' potential against newer variants. "As far as we know, all the variants of concern would be covered by our suite of nanobodies," Owens told reporters during a media briefing.
The scientists injected a portion of the SARS-CoV-2 spike protein into a llama named Fifi at the University of Reading. The injections were designed to trigger her immune system to generate nanobodies that act against the virus. The researchers then took a blood sample from Fifi and purified nanobodies that could bind to the viral protein in hamster models.
The nanobody treatment can be injected like Regeneron's human antibody treatment REGEN-COV, but can also be delivered via a nasal spray, which would make it easier and cheaper to administer, the researchers said. If delivered through human airways, the spray could potentially be given at an earlier stage of infection to reduce the virus' viral load, Owens told reporters.
"You can't do microbiology tricks with human antibodies that you can do with nanobodies," Professor James Naismith, Ph.D., director of Rosalind Franklin, told reporters during the briefing.
Getting the therapy to patients will likely take many more months, however, or possibly years. The researchers need more funding to scale manufacturing and conduct further research on the treatment's safety profile, Owens told reporters. The team has discussed with regulatory bodies what will be required to design a phase 1 trial that proves safety and determines the proper dosing, Owens said.
Administering a COVID-19 therapy as a single, nebulized dose is "the dream of that therapy," Naismith said.
Rosalind Franklin researchers have plenty of rivals in the race to bring nanobody treatments to market for COVID-19. A nanobody treatment from the University of Pittsburgh was "remarkably active" against the delta variant in hamsters, researchers reported last month, also in Nature Communications. Ohio State University scientists identified two nanobodies that neutralized the alpha, beta and gamma variants in a June report.
The University of Texas at Austin, ExeVir and Twist Bioscience are also attempting to bring nanobody treatments to COVID-19 patients. ExeVir treated the first patient in a phase 1 clinical trial of its llama-inspired treatment XVR011 last month. And DiosCURE Therapeutics licensed nanobodies from the University of Bonn and Scripps Research in July that had shown promise in preclinical research reported in January. The lead candidate is still in late preclinical studies.
If any of these nanobody candidates make it to market, the technology could prove applicable well beyond COVID-19. The Rosalind Franklin researchers plan to use their platform to develop therapies for other respiratory illnesses, Naismith said.