Clover Biologics Announces Positive Preliminary Data from the Phase I Clinical Trial of its Bivalent RSV Vaccine Candidate SCB-1019 in a Young Adult Cohort

-- Bivalent RSV vaccine candidate SCB-1019 induces a significant increase in neutralizing titers for RSV-A and RSV-B, reaching approximately 6,600 IU/mL (6.4-fold increase) and approximately 46,000 IU/mL (12-fold improvement), respectively--

-- Preliminary data from Phase I clinical trial in targeted older population to be released in the second half of 2024 --

SHANGHAI, April 8, 2024 /PRNewswire/ -- Clover Biopharmaceuticals Limited ("Clover", SEHK: 02197), a commercial-stage global biopharmaceutical company dedicated to delivering innovative vaccines to save lives and improve global health, today announced that it has evaluated the bivalent RSV developed by Clover based on Clover's proprietary Trimer-Tag (protein trimerization) vaccine technology platform In the Phase I clinical trial of SCB-1019, a preF-trimer subunit vaccine candidate, the first cohort of young adults received positive preliminary immunogenicity and safety data.

"We are encouraged by the clinical progress of our bivalent RSV PreF vaccine candidate, which has been developed using our validated Trimer-Tag vaccine technology platform, and has obtained preliminary results from a positive Phase I clinical trial that shows a broad spectrum of neutralizing antibody responses against both viral subtypes RSV-A and RSV-B. "

Mr. Liang Guo, Chief Executive Officer and Executive Director of Clover, said

"SCB-1019 is China's first RSV PreF (pre-fusion conformation-based F protein) vaccine candidate that has advanced to clinical trials, and now we are the first to publish preliminary data from a positive clinical trial as planned, and we look forward to more positive Phase I clinical trial data in the first targeted elderly population in the second half of 2024." "

In the Phase I clinical trial, preliminary results of geometric mean titers (GMTs) and geometric fold increases (GMFRs) of neutralizing antibodies on day 0 (pre-vaccination) and day 28 (post-vaccination) of neutralizing antibodies in the first cohorts of young adults (aged 18-59 years) were given either SCB-1019 or saline placebo on day 0 (pre-vaccination) and day 28 (post-vaccination) showed the following:

RSV A Neutralizing antibodies	RSV B Neutralizing antibodies
SCB-1019 (n=8)	: 1,032 IU/mL : 6,648 IU/mL : 6.4 times better	: 3,950 IU/mL : 46,674 IU/mL : 11.8 times better
placebo Sanitary water (n=4)	: 415 IU/mL : 415 IU/mL : No significant change	: 3,783 IU/mL : 4,498 IU/mL : No significant change

The RSV-A and RSV-B neutralization tests in this study were performed in a third-party testing laboratory using a validated clinical assay and NIBSC 16/284 reference standard serum, expressed in international units per milliliter (IU/mL).

Clover's in-house RSV vaccine candidate, SCB-1019, has comparable or potentially superior preliminary immunogenicity data against neutralizing antibodies to RSV-A and RSV-B compared to other protein subunit RSV PreF vaccines[1, 2, 3], and these positive immunogenicity data further support Clover's selective development of bivalent RSV-A/B PreF vaccine strategy, as there have been data to demonstrate low immune response and/or protective efficacy against RSV-B subtypes with other monovalent vaccines targeting the RSV-A subtype only [1, 4, 5]. The clinical results also confirmed that Clover's SCB-1019 PreF antigen maintained a stable pre-fusion and trimer structure, and that exploratory immunogenicity results showed a significant increase in competitive antibody titers at the neutralization site. In addition, the planned Phase I clinical trial of geriatric cohort has progressed as scheduled, following the observation of no significant safety or reactogenicity issues in the first cohort of young adults.

The Phase I clinical trial conducted in Australia is a randomized, placebo-controlled study to evaluate the safety, reactogenicity, and immunogenicity of SCB-1019 at different dosage forms at different dose levels in young adults and older adults. Safety and immunogenicity results for the elderly population are expected in the second half of 2024.

[1] Icosavax Company Presentations (28-JUN-2022 & 22-MAY-2023) and Press Release (12-DEC-2023)

[2] NIH DS-Cav1 (DOI: 10.1016/S2213-2600(21)00098-9)

[3] Pfizer (DOI: 10.1093/infdis/jiab612)

[4] GSK ACIP Presentation (21-JUN-2023)

[5] Moderna ACIP Presentation (29-FEB-2024)

About Clover Bio

Clover is a commercial-stage global biopharmaceutical company committed to saving lives and improving global health through innovative vaccines. With our combined R&D, manufacturing and commercialization capabilities, and strong partnerships with globally distributed institutions, we have developed a diverse pipeline of vaccine candidates that enable our vaccines to prevent more diseases and help reduce the burden on public health.

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