Moderna COVID-19 Vaccine Retains Neutralizing Activity Against Variants but Six-Fold Reduction Against South Africa: What About Brazil?

Moderna COVID-19 Vaccine Retains Neutralizing Activity Against Variants but Six-Fold Reduction Against South Africa What About Brazil TrialsiteN

Moderna announced the results from in vitro neutralization studies of sera from individuals vaccinated with Moderna COVID-19 Vaccine showing activity against emerging strains of SARS-CoV-2. Vaccination with the Moderna COVID-19 Vaccine produced neutralizing titers against all key emerging variants tested, including B.1.1.7 and B.1.351, first identified in the UK and Republic of South Africa (SA), respectively. The study showed no significant impact on neutralizing titers against the B.1.1.7 variant relative to prior variants. A six-fold reduction in neutralizing titers was observed with the B.1.351 variant relative to prior variants. Despite this reduction, neutralizing titer levels with B.1.351 (SA) remain above levels that are expected to be protective. This study was conducted in collaboration with the Vaccine Research Center (VRC) at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH). The manuscript has been submitted as a preprint to bioRxiv and will be submitted for peer-reviewed publication.  Given the major reduction in neutralizing activity, Moderna should provide more data as to why this reduction still meets “protective levels.”  TrialSite suggests that Moderna’s announcement to develop a booster vaccine based on the variant mRNA is an absolute necessity rather than out of mere “abundance of caution.”  Additionally TrialSite raises a few issues not addressed in the Moderna press release that included below. 

What doesn’t the Moderna press release also not address?

Brazilian Variant Precluded

First the company didn’t test against the P1 Brazilian variant: note that this variant includes all the key mutations of both the UK and SA variants as well as moreover this variant has been shown to escape convalescent sera, and monoclonal antibodies to much higher degree than the SA variant.  

Regulatory Complexities

Second, although the mRNA vaccine platform is perfectly suited for such an agile adaptation to variants, the wrench in the spokes is the regulatory/approval process necessary.  The key here is that Moderna refers to the change as a “booster” for the newly developed mRNA-based vaccine addressing the new variant.  This signals to the regulatory bodies to treat this modified product as the same vaccine product and hence preclude the need for more clinical trials. Hence the booster’s name mRNA-1273.351.  Is this just accepted by regulatory bodies such as the FDA, EMA and other authorities.   The vaccines must be updated regularly to offer continued protection against these newly circulating variants.   Moreover the U.S. should probably align with a number of other regulatory bodies to harmonize on sequencing samples to avoid flying blind as to what variants are circulating.  At present the U.S. performs about 2% as much sequencing as the UK. 

Transparency for Valuation

We applaud Moderna’s getting on top of this information however by not addressing the Brazilian variant could cause a real challenge to valuation in the future.

Moderna Updates

Moderna went on to describe that the two-dose regimen of the Moderna COVID-19 Vaccine at the 100 µg dose is expected to be protective against emerging strains detected to date. Nonetheless, Moderna today announced its clinical strategy to proactively address the pandemic as the virus continues to evolve. First, the Company will test an additional booster dose of its COVID-19 Vaccine (mRNA-1273) to study the ability to further increase neutralizing titers against emerging strains beyond the existing primary vaccination series. Second, the Company is advancing an emerging variant booster candidate (mRNA-1273.351) against the B.1.351 variant first identified in the Republic of South Africa. The Company is advancing mRNA-1273.351 into preclinical studies and a Phase 1 study in the U.S. to evaluate the immunological benefit of boosting with strain-specific spike proteins. Moderna expects that its mRNA-based booster vaccine (whether mRNA-1273 or mRNA-1273.351) will be able to further boost neutralizing titers in combination with all of the leading vaccine candidates.

“As we seek to defeat the COVID-19 virus, which has created a worldwide pandemic, we believe it is imperative to be proactive as the virus evolves. We are encouraged by these new data, which reinforce our confidence that the Moderna COVID-19 Vaccine should be protective against these newly detected variants,” said Stéphane Bancel, Chief Executive Officer of Moderna. “Out of an abundance of caution and leveraging the flexibility of our mRNA platform, we are advancing an emerging variant booster candidate against the variant first identified in the Republic of South Africa into the clinic to determine if it will be more effective to boost titers against this and potentially future variants.”

Background

First detected in September 2020 in the United Kingdom, the SARS-CoV-2 B.1.1.7 variant has seventeen mutations in the viral genome with eight mutations located in the spike (S) protein. The B.1.351 variant, first detected in South Africa, has ten mutations located in the spike (S) protein. Both variants have spread at a rapid rate and are associated with increased transmission and a higher viral burden after infection.

Description

The in vitro study assessed the ability of mRNA-1273 to elicit potently neutralizing antibodies against the new SARS-CoV-2 variants, using sera from eight Phase 1 clinical trial participants (aged 18-55 years) who received two 100 µg doses of mRNA-1273, and separately using sera from non-human primates (NHPs) immunized with two doses of 30 µg or 100 µg of mRNA-1273.

For the B.1.1.7 variant, neutralizing antibody titers remained high and were generally consistent with neutralizing titers relative to prior variants. No significant impact on neutralization was observed from either the full set of mutations found in the B.1.1.7 variant or from specific key mutations of concern. Although these mutations have been reported to lessen neutralization from convalescent sera and to increase infectivity, sera from the Phase 1 participants and NHPs immunized with mRNA-1273 were able to neutralize the B.1.1.7 variant to the same level as prior variants.

For the B.1.351 variant, vaccination with the Moderna COVID-19 Vaccine produces neutralizing antibody titers that remain above the neutralizing titers that were shown to protect NHPs against wildtype viral challenge. While the Company expects these levels of neutralizing antibodies to be protective, pseudovirus neutralizing antibody titers were approximately 6-fold lower relative to prior variants. These lower titers may suggest a potential risk of earlier waning of immunity to the new B.1.351 strains.

The Vaccine

The Moderna COVID-19 Vaccine (also referred to as mRNA-1273) is an mRNA vaccine against COVID-19 encoding for a prefusion stabilized form of the Spike (S) protein, which was co-developed by Moderna and investigators from NIAID’s Vaccine Research Center. The first clinical batch, which was funded by the Coalition for Epidemic Preparedness Innovations, was completed on February 7, 2020 and underwent analytical testing; it was shipped to the NIH on February 24, 2020, 42 days from sequence selection. The first participant in the NIAID-led Phase 1 study of the vaccine was dosed on March 16, 63 days from sequence selection to Phase 1 study dosing. On May 12, the FDA granted the Moderna COVID-19 Vaccine Fast Track designation. On May 29, the first participants in each age cohort: adults ages 18-55 years (n=300) and older adults ages 55 years and above (n=300) were dosed in the Phase 2 study of mRNA-1273. On July 8, the Phase 2 study completed enrollment.

On July 14, an interim analysis of the original cohorts in the NIH-led Phase 1 study of the vaccine was published in The New England Journal of Medicine. On July 28, results from a non-human primate preclinical viral challenge study evaluating the vaccine were published in The New England Journal of Medicine. Results from the second interim analysis of the NIH-led Phase 1 study of the Moderna COVID-19 Vaccine in the 56-70 and 71+ age groups were published on September 29 in The New England Journal of Medicine. On November 30, Moderna announced the primary efficacy analysis of the Phase 3 study of the vaccine conducted on 196 cases. On November 30, the Company also announced that it filed for Emergency Use Authorization with the U.S. FDA and a Conditional Marketing Authorization (CMA) with the European Medicines Agency. On November 30, the Company announced new data showing that mRNA-1273, its COVID-19 vaccine candidate, remains stable at 2° to 8°C (36° to 46°F), the temperature of a standard home or medical refrigerator, for 30 days. On December 3, a letter to the editor was published in The New England Journal of Medicine reporting that participants in the Phase 1 study of the Moderna COVID-19 Vaccine retained high levels of neutralizing antibodies through 119 days following first vaccination (90 days following second vaccination). On December 18, 2020, the FDA authorized the emergency use of the Moderna COVID-19 Vaccine in individuals 18 years of age or older.

The Biomedical Advanced Research and Development Authority (BARDA), part of the Office of the Assistant Secretary for Preparedness and Response (ASPR) within the U.S. Department of Health and Human Services (HHS) is supporting the continued research and development of the Moderna COVID-19 Vaccine with $955 million in federal funding under contract no. 75A50120C00034. BARDA is reimbursing Moderna for 100 percent of the allowable costs incurred by the Company for conducting the program described in the BARDA contract. The U.S. government has agreed to purchase supply of the Moderna COVID-19 Vaccine under U.S. Department of Defense contract no. W911QY-20-C-0100.

Moderna has also received authorization for its COVID-19 vaccine from regulatory authorities in the United States, Canada, Israel, the European Union, the United Kingdom and Switzerland. Additional authorizations are currently under review in other countries and by the World Health Organization. A summary of the Company’s work to date on COVID-19 can be found here.