Clover’s COVID-19 vaccine candidate demonstrates superior booster responses compared to inactivated vaccine

Clover Biopharmaceuticals

— Up to 12-fold higher neutralizing antibody titers observed in participants who received SCB-2019 (CpG 1018/Alum) as heterologous third dose after two doses of inactivated vaccine compared to a third dose of it inactivated vaccine

– Superior immune responses observed for SCB-2019 vs. inactivated booster vs. parent strain and Omicron subvariants

— Positive heterologous booster responses consistent with previous observations for homologous booster and in previously infected individuals, highlighting the potential of SCB-2019 as a universal COVID-19 booster

SHANGHAI, China, Sept. 06, 2022 (GLOBE NEWSWIRE) — Clover Biopharmaceuticals, Ltd. (Clover; HKEX: 02197), a global clinical-stage biotechnology company developing novel vaccine and biologic therapeutic candidates, today announced positive data from the ongoing Phase 3 Study evaluating Clover’s SCB-2019 (CpG 1018/Alum) as universal candidate COVID-19 booster vaccine. Preliminary data showed that SCB-2019 induced superior levels of neutralizing antibodies against the original strain of SARS-CoV-2 and Omicron’s BA.1 and BA.2 subvariants when administered as a heterologous third dose to participants who had previously received two doses of inactivated vaccine compared to a third dose of the inactivated vaccine.

“Positive booster data against Omicron subvariants from this Phase 3 heterologous booster study represents a pivotal step in our efforts to develop our lead COVID-19 vaccine candidate as a universal booster.” said Dr. Nicholas Jackson, President of Global R&D of Clover. “These results further validate our confidence in SCB-2019 as a valuable COVID-19 prevention option, especially in China and other countries and regions where inactivated vaccines have played an important role in primary vaccination campaigns.”

A booster dose of SCB-2019 in participants who had previously received two doses of the inactivated vaccine elicited superior neutralizing immune responses against the parent strain and Omicron BA.1 and BA.2 compared to responses in participants who had received a third dose of the inactivated vaccine. Preliminary analyzes in subjects with low pre-boost neutralizing antibody levels (defined as baseline pre-boost neutralizing antibody titers ≤100 using validated live SARS-CoV-2 neutralization assays) showed that SCB-2019 induced a 17-fold increase in neutralizing antibodies to baseline strain, with geometric mean antibody titers (GMT) increasing from 44 at baseline (pre-booster) to 733 (14 days post-booster). This response was 12-fold higher than the response to the inactivated vaccine, which caused a 2-fold increase (GMTs: 33 [baseline]61 [post-booster]) in neutralizing antibodies against the parent strain. In the same population, SCB-2019 caused a 6-fold increase (GMTs: 33 [baseline]193 [post-booster]) in neutralizing antibodies against Omicron BA.1 and an 8-fold increase (GMTs: 51 [baseline]410 [post-booster]) in neutralizing antibodies against Omicron BA.2. This response was 5- and 6-fold higher, respectively, than the response to the inactivated vaccine, which induced a 1-fold increase (GMTs: 30 [baseline]42 [post-booster]) versus Omicron BA.1 and 1-fold increase (GMTs: 47 [baseline]67 [post-booster]) against Omicron BA.2. Additional results against Omicron BA.5 in these participants are expected in the near future.

These heterologous recall responses are consistent with previous observations of SCB-2019 (CpG 1018/Alum) as a homologous enhancer against Omicron BA.1 (LINK) and BA.2 (LINK) and in subjects with prior Omicron infection BA.5 ( LINK ) and the original strain and all other variants of concern ( LINK ).

These results are part of a Phase 3, double-blind, randomized, controlled study evaluating the safety and immunogenicity of SCB-2019 given as a booster dose in subjects who received two doses of inactivated vaccine compared with a third, homologous booster dose of the inactivated vaccine. Clover is currently enrolling a subcohort evaluating SCB-2019 as a fourth-dose booster in individuals who have previously received three doses of the inactivated vaccine compared to a fourth, homologous booster dose of the inactivated vaccine. The study has enrolled over 1,500 adult and elderly participants in the Philippines to date.

These new study data add to the growing body of evidence evaluating SCB-2019 as a potential universal candidate COVID-19 enhancer. Clover remains focused on completing regulatory submissions to the National Medical Products Administration of China, the European Medicines Agency and the World Health Organization for SCB-2019 in the second half of 2022, while preparing for its commercialization in China and globally.

About SCB-2019 (CpG 1018/Alum)
Using 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 SARS-CoV-2 virus strain. Clover created the COVID-19 vaccine candidate by combining SCB-2019 with Dynavax’s (Nasdaq: DVAX) advanced adjuvant CpG 1018 and aluminum hydroxide (alum).

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 biological therapies. Clover leveraged the Trimer-Tag™ technology platform to become a vaccine developer for COVID-19 and created SCB-2019 (CpG 1018/Alum) to address the COVID-19 pandemic caused by SARS-CoV-2.

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

Clover Forward-Looking Statements
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Clover Biopharmaceuticals:
Albert Liao
Executive Director of Corporate Communications

Naomi Eichenbaum
Vice President, Investor Relations

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