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An Open-Label Phase 2/3 Study of S-268019 (COVID-19)

A Phase 2/3 Study of S-268019 (COVID-19)

3284

This study consisted of 2 part: Main Part for the primary vaccination and Subpart for the booster vaccination. In the Immunogenicity Subset for Main Part, the proportion of the male participants was 42.8% in Naive, 47.4% in Vaccination History, 67.6% in Infection History, and 60.9% in Elderly Naive (hereinafter the same order). The median age (min-max) of the participants was 47.0 (20-63) years, 42.5 (24-62) years, 39.0 (21-64) years, and 69.0 (65-82) years, respectively. The mean BMI (SD) was 23.32 (3.95), 23.50 (3.88), 24.03 (4.44), and 23.52 (3.82), respectively. In the Immunogenicity Subset for Subpart, the proportion of the male participants was 47.3%, 48.1%, 68.0%, and 60.3%. The median age (min-max) of the participants was 48.0 (20-63) years, 43.5 (25-62) years, 42.5 (21-64) years, and 69.0 (65-82) years, respectively. The mean BMI (SD) was 23.13 (3.96), 23.83 (4.04), 24.55 (4.32), and 23.63 (4.05), respectively.

Of the 3284 registered participants, 2939 (2755 in Naive, 69 in Vaccination History, 60 in Infection History and 109 in in Elderly Naive)(hereinafter the same order) completed the study. A total of 563 participants (304, 76 , 68, and 115) were included in the Immunogenicity Subset for Main Part. A total of 389 participants (207, 54, 50, and 78) were included in the Immunogenicity Subset for Subpart.

No treatment-related deaths or SAEs were reported. In the Safety Analysis population for Main Part, solicited systemic AEs were reported in 2389 of 2951 participants [81.0%] in Naive, 61 of 76 participants [80.3%] in Vaccination History, 61 of 68 participants [89.7%] in Infection History and 64 of 118 participants (54.2%) in Elderly Naive (hereinafter the same order). The most common solicited systemic AE was fatigue. Solicited local AEs were reported in 2817 of 2951 participants [95.5%], 75 of 76 participants [98.7%], 66 of 68 participants [97.1%] and 98 of 118 participants (83.1%). The most common solicited local AE was pain. In the Safety Analysis population for Subpart, solicited systemic AEs were reported in 1804 of 2137 participants [84.4%], 39 of 55 participants [70.9%], 40 of 51 participants [78.4%] and 49 of 88 participants (55.7%). The most common solicited systemic AE was fatigue. Solicited local AEs were reported in 1940 of 2137 participants [90.8%] , 51 of 55 participants [92.7%], 48 of 51 participants [94.1%] and 73 of 88 participants (83.0%). The most common solicited local AE was pain.

As for Main part, the GMTs of SARS-CoV-2 neutralizing antibody increased from baseline after the primary vaccination in all groups. In Vaccination History and Infection History, the GMTs increased to a higher level than that of Naive. The GMTs (95% CI) in Naive, Vaccination History, Infection History, and Elderly Naive (hereinafter the same order) were 2.52 (2.50 to 2.54), 5.33 (4.51 to 6.30), 6.01 (4.72 to 7.64), and 2.53 (2.47 to 2.59) at baseline, respectively and 30.72 (27.97 to 33.73), 108.09 (92.10 to 126.87), 117.99 (98.84 to 140.86), and 20.38 (16.89 to 24.60) on Day 57, respectively. The seroconversion rates (95% CI) on Day 57 were 95.9% (93.0% to 97.9%), 100.0% (95.3% to 100.0%), 97.0% (89.5% to 99.6%), and 85.5% (77.5% to 91.5%), respectively. As for Subpart, the GMTs (95% CI) of Day 239 were 154.16 (138.40 to 171.71) in Naive and 113.14 (95.24 to 134.40) in Elderly Naive (hereinafter the same order). The GMT ratios (Day 239/Day 57)(95% CI) were 5.37 (4.74 to 6.08) and 5.91 (4.82 to 7.25), respectively, and the lower limits of the CIs for the GMT ratios were greater than the prespecified noninferiority margin of 0.67 in both groups, demonstrating noninferiority for the GMTs on Day 239 compared to Day 57. The seroresponse rates (95% CI) on Day 239 were 96.5% (93.0% to 98.6%) and 97.4% (90.9% to 99.7%). The differences in seroresponse rate (Day 239-Day 57) (95% CI) were 2.0% (-2.1% to 6.4%) and 11.7% (2.9% to 21.7%), and the lower limits of the CI for the differences were greater than the prespecified noninferiority margin of -10% in both groups, demonstrating noninferiority for the seroresponse rate on Day 239 compared to seroconversion rate on Day 57.

No significant safety concerns were identified and the safety of S-268019-b was considered generally acceptable. The GMTs of SARS-CoV-2 neutralizing antibody increased from Baseline after the second vaccination in all groups. Both the GMTs and the seroresponse rates of 28 days after the boostere vaccination were confirmed to be noninferior to those of 28 days after the second vaccination in both Naive and Elderly Naive.

June. 24, 2025

No

https://jrct.mhlw.go.jp/latest-detail/jRCT2031210383

Nagata Tsutae

Shionogi & Co., Ltd.

1-8, Doshomachi 3-chome, Chuo-ku, Osaka, Osaka

shionogiclintrials-admin@shionogi.co.jp

- Corporate Communications Department

Shionogi & Co., Ltd.

1-8, Doshomachi 3-chome, Chuo-ku, Osaka, Osaka

+81-6-6209-7885

shionogiclintrials-admin@shionogi.co.jp

Complete

Oct. 20, 2021

Interventional

single arm study

open(masking not used)

uncontrolled control

single assignment

prevention purpose

Participant must be >= 20 years of age inclusive, at the time of signing the informed consent.
Male and female
Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the ICF and in this protocol.

Positive SARS-CoV-2 antigen test result at Screening.
Presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrinological, hematological, or neurological disorders that, in the opinion of the investigator/subinvestigator, will lead to a safety issue or interfere with the assessment of efficacy
Immunosuppressed state [immunocompromised, with acquired immunodeficiency syndrome (AIDS), receiving systemic steroid or immunosuppressive drugs within 6 months prior to the first dose of study intervention, being treated for malignancy or receiving other immunosuppressive therapy].
Hypersensitivity to any of the study drugs, or components thereof, or drug or other allergy that, in the opinion of the investigator/subinvestigator, contraindicates participation in the study (except pollinosis and atopic dermatitis).
Participant has a contraindication to IM injections or blood draws. et, al.

Both

Prevention of COVID-19

S-268019 0.5 mL, intramuscular injection in the upper arm for a total of two doses.
S-268019 0.5 mL is injected intramuscularly once to the participants who wish to receive the third vaccination.

The incidence of adverse events/adverse reactions/serious adverse events/solicited adverse events/medically attended adverse events/adverse event of special interest.
SARS-CoV-2 neutralizing antibody titer on Day 239

+81-3-3881-6116

Oct. 14, 2021

none