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Clover’s Efficacy Data in Previously-Infected Individuals is Published in Lancet Infectious Disease

Clover’s Efficacy Data in Previously-Infected Individuals is Published in Lancet Infectious Disease GlobeNewswire April 20, 2022

--94% cumulative protective effect against COVID-19 in previously-infected individuals that subsequently received Clover’s COVID-19 vaccine candidate--

--First and only COVID-19 vaccine candidate to demonstrate significantly reduced risk of COVID-19 of any severity in previously-infected individuals in a randomized efficacy clinical trial--

SHANGHAI, China, April 20, 2022 (GLOBE NEWSWIRE) -- Clover Biopharmaceuticals, Ltd. (Clover; HKEX: 02197), a global clinical-stage biotechnology company developing novel vaccines and biologic therapeutic candidates, today announced additional data from SPECTRA, a global pivotal Phase 2/3 clinical trial, that shows SCB-2019 (CpG 1018/Alum) provides significant incremental protection against COVID-19 in a previously-infected participant population and has been published in the peer-reviewed journal, Lancet Infectious Disease. The paper, entitled Impact of previous exposure to SARS-CoV-2 and of S-Trimer (SCB-2019) COVID-19 vaccination on the risk of reinfection: a randomised, double-blinded, placebo-controlled, phase 2 and 3 trial, can be accessed here.

“Despite historic progress with vaccination efforts over the past two years, COVID-19 continues to pose a serious threat globally, including for those who have been previously exposed to SARS-CoV-2,” said Dr. Nicholas Jackson, President of Global Research and Development of Clover. “The newly published data underscores the importance of vaccination even after prior infection, and the potential of SCB-2019 (CpG 1018/Alum) as a universal booster with a favorable safety and tolerability profile to help address ongoing and future outbreaks in China and the rest of the world.”

This study evaluated the efficacy, safety, and reactogenicity of SCB-2019 (CpG 1018/Alum) in participants who had previously been infected with SARS-CoV-2 before vaccination. Of the 30,174 total participants enrolled in SPECTRA, 14,692 participants with evidence of exposure to SARS-CoV-2 at baseline were evaluated in the full analysis set, with 7,353 individuals randomized in the vaccine arm and 7,339 individuals randomized in the placebo arm.

Boosting individuals who previously had SARS-CoV-2 infection:
Vaccination with SCB-2019 (CpG 1018/Alum) in individuals previously infected with SARS-CoV-2 showed a cumulative protective effect of 89.7% (95% CI: 82.5 – 94.4) after one dose and 93.8% (95% CI: 88.9 – 97.0) after two doses against COVID-19 of any severity, against any strain of SARS-CoV-2, as compared to SARS-CoV-2 naïve placebo recipients. In the previously-infected population, incremental risk reduction against COVID-19 of any severity of SCB-2019 (CpG 1018/Alum) vaccination versus placebo was 49.9% after one dose and 64.2% after two doses. Further, SCB-2019 (CpG 1018/Alum) demonstrated a favorable safety profile with infrequent severe and serious adverse events (AEs) that were balanced between vaccine and placebo groups. Solicited local AEs were mostly mild and transient cases of pain at the injection site and decreased in frequency after the second dose. 

In conclusion, these data highlight that a single-dose or two-dose primary vaccination with SCB-2019 (CpG 1018/Alum) increased protection against COVID-19 following previous exposure to SARS-CoV-2. SCB-2019 (CpG 1018/Alum) remains the first and only COVID-19 vaccine candidate to demonstrate significant protection against COVID-19 of any severity in previously-infected individuals in a randomized clinical efficacy trial, and provides Clover with confidence in advancing the vaccine candidate as a universal COVID-19 booster.

About SCB-2019 (CpG 1018/Alum)
Employing the Trimer-Tag™ technology platform, Clover developed the SCB-2019 antigen, a stabilized trimeric form of the S-protein (referred to as S-Trimer™) based on the original strain of the SARS-CoV-2 virus. Clover created its COVID-19 vaccine candidate by combining SCB-2019 with Dynavax’s (Nasdaq: DVAX) CpG 1018 advanced adjuvant and aluminum hydroxide (alum).

SPECTRA (Study Evaluating Protective-Efficacy and Safety of Clover’s Trimeric Recombinant Protein-based and Adjuvanted COVID-19 Vaccine) is a 1:1 randomized, placebo-controlled, double-blinded study to evaluate the efficacy, safety and immunogenicity of SCB-2019 (CpG 1018/Alum) compared to placebo in over 30,000 participants 18 years of age and older in five countries. Participants received SCB-2019 (CpG 1018/Alum) administered in a two-dose regimen, 21 days apart, or placebo.

About Clover Biopharmaceuticals
Clover Biopharmaceuticals is a global clinical-stage biotechnology company committed to developing novel vaccines and biologic therapeutic candidates. The Trimer-Tag™ technology platform is a product development platform for the creation of novel vaccines and biologic therapies. Clover leveraged the Trimer-Tag™ technology platform to become a COVID-19 vaccine developer and created SCB-2019 (CpG 1018/Alum) to address the COVID-19 pandemic caused by SARS-CoV-2.

For more information, please visit Clover’s website: and follow the company on LinkedIn.

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Clover Biopharmaceuticals:

Cindy Min
SVP, Public Affairs

Naomi Eichenbaum
VP, Investor Relations 

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