As COVID-19 diagnoses and hospitalizations fall, and some mask mandates are lifted around the country, it’s tempting to dream about a world without the novel coronavirus. But many biopharma companies are betting the virus is here to stay—and they’re continuing to develop vaccines and drug treatments to keep it under control.
Two of those companies, CureVac and Memo Therapeutics, released animal data over the last week that provide a glimpse into the future of their COVID-19 development efforts.
CureVac, which is preparing to file for U.S. and European authorization for its mRNA vaccine, is now working on a second-generation version of the shot with partner GlaxoSmithKline. Rats immunized with one dose of the next-gen vaccine mounted strong immune responses against the virus, CureVac scientists reported on the journal preprint site bioRxiv.
CureVac’s follow-up vaccine, dubbed CV2CoV, was designed with “a new mRNA backbone” that it and GSK hope to show will improve the immune response to emerging COVID variants, potentially at lower doses than current mRNA vaccines require, the company said in a statement. CureVac and GSK formed an alliance in February, under which GSK agreed to help manufacture the first-generation version of CureVac’s vaccine while simultaneously working to improve the product.
The scientists working on CV2CoV made changes intended to improve RNA stability in the hopes of prolonging expression of the SARS-CoV-2 S protein and improving the immune response.
In the study, the rats were vaccinated twice with CV2CoV at different doses. All of the vaccinated animals generated neutralizing antibodies against COVID at all dose levels. Serum collected from the rodents showed cross-neutralization of virus variants first reported in Denmark, the U.K. and South Africa. And all of the animals except for the rats that got the lowest dose were fully protected after just one shot, CureVac reported.
That’s significant, given that preclinical studies of the first-generation of CureVac’s shot, CVnCoV, showed two doses were necessary for full protection. CureVac is planning to apply for authorization for its shot with two doses, similar to the regimen that rolled out for the currently marketed mRNA vaccines from Moderna and Pfizer-BioNTech.
But the second-generation shot from CureVac and GSK could fill a void in the vaccine market, the researchers argued in the new study. “Its ability to induce high levels of antibodies against SARS-CoV-2 at low doses supports a scenario in which vaccination with CV2CoV allows dose sparing that might be able to contribute to reduce worldwide vaccine shortage,” they wrote.
Meanwhile, a Swiss biotech that’s working on next-gen COVID drugs said it’s seeing promising preclinical results for its antibody candidate. Memo Therapeutics reported Monday that its treatment, MTX-COVAB, which was derived from patients who recovered from COVID-19, is effective against the original strain of the virus as well as the U.K. variant.
Memo used a single-cell molecular cloning and screening system to identify MTX-COVAB in a matter of weeks. It also used the technology to discover “a very promising antibody candidate against the South African variant,” the company said in a statement.
Memo’s scientists aren’t alone in their belief that COVID antibody treatments are still needed, even as vaccinations ramp up across the world. Regeneron CEO Len Schleifer told analysts recently he was confident demand for his company’s antibody combo, Regen-Cov, would persist. And even though the FDA revoked its emergency authorization of Eli Lilly’s solo antibody drug, bamlanivimab, the company is marketing it as part of a combination treatment with another antibody, etesevimab.
As for Memo, it continues to study samples taken from recovered COVID-19 patients in the hopes of developing more antibody-based drugs to address emerging variants. And it's preparing MTX-COVAB for clinical trials.
“Vaccines will not always be effective against all variants, so the ability of our technology to rapidly identify active antibodies could form an additional strategy to combat the spread of these mutant strains,” said Christoph Esslinger, Ph.D., chief scientific officer and co-founder of Memo, said in a statement.