Clover Biopharmaceuticals said its COVID-19 vaccine SCB-2019 (CpG 1018/Alum) elicited superior levels of neutralizing antibodies against the original strain and Omicron subvariants BA.1 and BA.2 when given as a heterologous third dose in people who previously received two doses of an inactivated vaccine compared to a third dose of the inactivated vaccine in a phase 3 trial.
Preliminary data showed that SCB-2019 elicited a 17-fold increase in neutralizing antibodies against the original strain, with geometric mean titers (GMT) of antibodies increasing from 44 at baseline (pre-booster) to 733 (14 days post-booster). The response was 12 times higher than the response to the inactivated vaccine, which elicited a 2x increase (GMTs: from 33 to 61 post-booster) in neutralizing antibodies against the original strain, the company said in a Sept. 6 press release.
In the same population, SCB-2019 elicited a 6-fold increase (GMTs: from 33 to 193) in neutralizing antibodies against Omicron BA.1 and an 8x increase (GMTs: from 51 to, 410) in neutralizing antibodies against Omicron BA.2.
The response was 5x and 6x higher, respectively, than the response to the inactivated vaccine, which elicited a 1-fold increase (GMTs: from 30 to 42) against Omicron BA.1 and a 1-fold increase (GMTs: from 47 to 67) against Omicron BA.2, the company added.
Clover noted that the the heterologous booster responses are consistent with prior results for SCB-2019 as a homologous booster against Omicron BA.1, and BA.2, and in people with prior infection .
Clover said it is currently enrolling in a sub-group in which SCB-2019 is being evaluated as a fourth dose booster in individuals previously receiving three doses of the inactivated vaccine compared to a fourth, homologous booster dose of the inactivated vaccine.
Clover created the COVID vaccine by combining SCB-2019 with Dynavax's ( NASDAQ: DVAX ) CpG 1018 advanced adjuvant and aluminum hydroxide (alum).
Clover said it was focused on completing regulatory submissions in China, EU and to the World Health Organization for SCB-2019 in H2 2022, while preparing for its commercialization.
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Clover, Dynavax COVID vaccine booster shot shows better response vs inactivated vaccine