[Edaily Reporter YU JIN-HEE ] Despite a cumulative fatality rate of 18% in South Korea, there is no effective treatment for Severe Fever with Thrombocytopenia Syndrome (SFTS), which is dubbed the “dreaded infectious disease.” Now, domestic biotech companies are entering the clinical trial race in earnest to combat the disease.

#HYUNDAI BIOSCIENCE CO., LTD. has officially announced the start of a Phase 2 clinical trial in Korea for SFTS, led by its host-targeted universal antiviral drug “Zefti” (development code CP-COV03). On the 13th, HYUNDAI BIOSCIENCE CO., LTD. held the “Zefti SFTS Clinical Development Launch Ceremony” at the Korea Press Center in Jung-gu, Seoul, and unveiled a detailed development roadmap aimed at addressing unmet medical needs in Korea.

Fear

of SFTS as ‘Healthcare Workers Get Infected’… A Decisive Move Amid a Lack of Treatments

SFTS, transmitted by tick bites, is a high-risk infectious disease with a fatality rate soaring as high as 26.1% among those aged 70 and older. Last year alone, 280 cases were confirmed in South Korea, resulting in 41 deaths. The risk of secondary transmission between people is particularly serious, as evidenced by a cluster infection involving seven healthcare workers who were performing CPR in the intensive care unit of a tertiary general hospital in Cheongju, North Chungcheong Province. Although 97% of secondary infections in Korea are concentrated among healthcare workers, there are currently no approved specific treatments, leaving authorities with no choice but to rely on symptomatic treatment and emergency-imported medications.

Bae Byung-jun, President of HYUNDAI BIOSCIENCE CO., LTD., explained the background, stating, “While discussing global infectious disease response strategies, we recognized the serious treatment gap on the front lines of domestic disease control.” He added, “I felt a heavy sense of responsibility for the continued suffering of patients and medical staff in the past, when clinical trials were delayed due to limitations in specialized research infrastructure after cell experiments were completed. As a company possessing platform technology, we could not turn a blind eye to the crisis on the front lines, so we made the final decision to proceed to Phase 2.”

HYUNDAI BIOSCIENCE CO., LTD. had previously demonstrated Jefti’s efficacy in inhibiting the SFTS virus (IC50 < 0.125 µM) in the international academic journal *Microbiology Spectra* (2024). Subsequently, a paper by an external independent research team detailing SFTS lethal animal experiments (*Biomedicine & Pharmacotherapy*, 2025), which identified the “blood drug exposure level inducing 100% survival (AUC approximately 4,400 ng·h/mL),” and achieved a breakthrough by perfectly replicating this result (AUC 4,404 ng·h/mL) using its own formulation in studies on the same animal species (rats).

Furthermore, based on large-scale clinical data on COVID-19 (Nature Communications, 2025), the company confirmed that an average plasma concentration (approximately 0.28 µM) exceeding the virus-inhibiting concentration was maintained for five days following administration in humans, thereby solidifying the pharmacokinetic (PK) bridging. The S100A4 inflammation-regulating mechanism recently reported in *Nature Microbiology* (2026) also aligns with the company’s biomarker research findings, thereby completing the scientific foundation for advancing to Phase 2 clinical trials.

Jin Geun-woo, CEO of HYUNDAI BIOSCIENCE CO., LTD., emphasized, “SFTS has distinct seasonal characteristics, peaking between April and November, so a race against time is essential,” adding, “Based on our comprehensive scientific data, we will engage in close preliminary consultations with the Ministry of Food and Drug Safety to swiftly secure approval for a Phase 2 trial in patients.”

Technology Validated by Global Security Consortium… Cooperation with Vietnam Gains Momentum

The value of JEFTI’s platform is also being recognized on the global stage. HYUNDAI BIOSCIENCE CO., LTD., the first Korean company to become a full member of the U.S. Medical Chemical and Biological Defense Consortium (MCDC), recently concluded a joint technical review with approximately 40 officials and scientists from five U.S. government agencies. The company is currently engaged in in-depth discussions with U.S. authorities to develop solutions for Ebola and future respiratory pandemics.

Cooperation on disease prevention in Southeast Asia is also on a steady course. Key health officials attended the event in large numbers, including Nguyen Tu Giang, Chairman of Vietnam’s LIGHT Institute; Dinh Anh Tuan, Director of the Maternal and Child Health Department at the Vietnamese Ministry of Health; and Pham Ngoc Thach, Director of the National Hospital for Tropical Diseases (NHTD). As the ongoing clinical trial for adult dengue fever patients at the local National Hospital for Tropical Diseases is proceeding smoothly without any adverse reactions, both sides are now actively engaging in working-level discussions to expand the trial’s participant pool to include vulnerable groups—such as children and the elderly—who are at risk of death.

In June 2024, Japan’s Ministry of Health, Labor and Welfare granted conditional approval for the antiviral drug “Avigan,” citing the lack of alternative treatments, even though the Phase 3 clinical trial mortality rate (15.8%) fell short of the pre-set threshold (12.5%).

HYUNDAI BIOSCIENCE CO., LTD. plans to demonstrate clinical efficacy that surpasses Japan’s precedent, leveraging data from animal studies showing 100% survival rates under exposure conditions and the unparalleled safety proven in its COVID-19 clinical trial (zero serious adverse events among the 293 subjects in the analysis group).

President Bae stated, “During the COVID-19 crisis, South Korea demonstrated a strong foundation of cooperation, with the government, the Ministry of Food and Drug Safety, and the medical community coming together as one team to achieve the development of treatments and vaccines,” adding, “We will work closely with health authorities and clinical experts to swiftly provide a practical treatment alternative that protects domestic SFTS patients and frontline medical staff.”