tetano
Editor, Senior Moderator
Front Immunol
. 2025 Jun 16:16:1571092.
doi: 10.3389/fimmu.2025.1571092. eCollection 2025. A novel and safe SmartCap[SUP]®[/SUP] SC101 to develop the COVID-19 mRNA vaccine STP2104 inducing potent immune responses in humans
Rachel Kim[SUP] #[/SUP][SUP] 1 [/SUP], Tae-Gi Uhm[SUP] #[/SUP][SUP] 1 [/SUP], Jisu Kim[SUP] 1 [/SUP], Dayeon Woo[SUP] 1 [/SUP], Uk-Il Kim[SUP] 1 [/SUP], Xue Meng[SUP] 1 [/SUP], Byounggu Yang[SUP] 1 [/SUP], Suhyeon Kim[SUP] 1 [/SUP], Heejene Kim[SUP] 1 [/SUP], Jonghyeon Kim[SUP] 1 [/SUP], Sunkyung Yoon[SUP] 2 [/SUP], Joo-Young Lee[SUP] 1 [/SUP], Byungkyun Kim[SUP] 1 [/SUP], Dongheon Cho[SUP] 1 [/SUP], Duckho Chang[SUP] 1 [/SUP], Young-Hwan Cho[SUP] 1 [/SUP], Kanghyun Choi[SUP] 1 [/SUP], WonSeok Gwak[SUP] 2 [/SUP], Hoon-Woo Lee[SUP] 1 [/SUP], Jieun Bang[SUP] 1 [/SUP], Elizabeth Hellström[SUP] 3 [/SUP], Byoungguk Kim[SUP] 2 [/SUP], Kyungjin Kim[SUP] #[/SUP][SUP] 1 [/SUP], Joo-Sung Yang[SUP] #[/SUP][SUP] 1 [/SUP]
Affiliations
We have developed a 5'-capping library screening (CLS) method using over 30 different novel cap analogues. The optimal 5'-cap for the coronavirus disease 2019 (COVID-19) mRNA vaccine STP2104 was selected and applied. This is the first report to describe the proven safety of the novel cap analogue, SmartCap[SUP]®[/SUP] SC101, in humans and emphasize the importance of cap selection. STP2104 demonstrates safety, tolerability, and strong immune responses in humans. After confirming its safety through a GLP toxicity study, STP2104 was administered intramuscularly as a two-dose vaccine, separated by 28 days, in COVID-19-naive, healthy adult volunteers. In this multicenter, open-label, dose-escalation, phase I study with 30 participants (18 to 55 years of age), 15 individuals each were assigned to the low-dose (25 μg) and high-dose (50 μg) cohorts. The primary endpoints were the safety and immunogenicity in all cohorts. During the reporting period of the trial, no serious adverse events were reported. A plaque reduction neutralization test demonstrated an at least 21-fold increase in NAb titers from both cohorts when comparing pre-vaccination to 4-week post-second vaccination. These safety and NAb titer interim results support the efficiency and safety of SC101 and the STP2104 mRNA vaccine, including how STP2104 effectively induces NAb titers against SARS-CoV-2.
Keywords: 5’-cap analogue; COVID-19; Capping Library Screening; SARS-CoV-2; STP2104; SmartCap®; human clinical trial study; mRNA vaccine.
. 2025 Jun 16:16:1571092.
doi: 10.3389/fimmu.2025.1571092. eCollection 2025. A novel and safe SmartCap[SUP]®[/SUP] SC101 to develop the COVID-19 mRNA vaccine STP2104 inducing potent immune responses in humans
Rachel Kim[SUP] #[/SUP][SUP] 1 [/SUP], Tae-Gi Uhm[SUP] #[/SUP][SUP] 1 [/SUP], Jisu Kim[SUP] 1 [/SUP], Dayeon Woo[SUP] 1 [/SUP], Uk-Il Kim[SUP] 1 [/SUP], Xue Meng[SUP] 1 [/SUP], Byounggu Yang[SUP] 1 [/SUP], Suhyeon Kim[SUP] 1 [/SUP], Heejene Kim[SUP] 1 [/SUP], Jonghyeon Kim[SUP] 1 [/SUP], Sunkyung Yoon[SUP] 2 [/SUP], Joo-Young Lee[SUP] 1 [/SUP], Byungkyun Kim[SUP] 1 [/SUP], Dongheon Cho[SUP] 1 [/SUP], Duckho Chang[SUP] 1 [/SUP], Young-Hwan Cho[SUP] 1 [/SUP], Kanghyun Choi[SUP] 1 [/SUP], WonSeok Gwak[SUP] 2 [/SUP], Hoon-Woo Lee[SUP] 1 [/SUP], Jieun Bang[SUP] 1 [/SUP], Elizabeth Hellström[SUP] 3 [/SUP], Byoungguk Kim[SUP] 2 [/SUP], Kyungjin Kim[SUP] #[/SUP][SUP] 1 [/SUP], Joo-Sung Yang[SUP] #[/SUP][SUP] 1 [/SUP]
Affiliations
- PMID: 40589754
- PMCID: PMC12206861
- DOI: 10.3389/fimmu.2025.1571092
We have developed a 5'-capping library screening (CLS) method using over 30 different novel cap analogues. The optimal 5'-cap for the coronavirus disease 2019 (COVID-19) mRNA vaccine STP2104 was selected and applied. This is the first report to describe the proven safety of the novel cap analogue, SmartCap[SUP]®[/SUP] SC101, in humans and emphasize the importance of cap selection. STP2104 demonstrates safety, tolerability, and strong immune responses in humans. After confirming its safety through a GLP toxicity study, STP2104 was administered intramuscularly as a two-dose vaccine, separated by 28 days, in COVID-19-naive, healthy adult volunteers. In this multicenter, open-label, dose-escalation, phase I study with 30 participants (18 to 55 years of age), 15 individuals each were assigned to the low-dose (25 μg) and high-dose (50 μg) cohorts. The primary endpoints were the safety and immunogenicity in all cohorts. During the reporting period of the trial, no serious adverse events were reported. A plaque reduction neutralization test demonstrated an at least 21-fold increase in NAb titers from both cohorts when comparing pre-vaccination to 4-week post-second vaccination. These safety and NAb titer interim results support the efficiency and safety of SC101 and the STP2104 mRNA vaccine, including how STP2104 effectively induces NAb titers against SARS-CoV-2.
Keywords: 5’-cap analogue; COVID-19; Capping Library Screening; SARS-CoV-2; STP2104; SmartCap®; human clinical trial study; mRNA vaccine.