[Edaily Reporter KIM SUNG-JIN ] #SK Bioscience has completed the global Phase 1 clinical trial for “GBP560,” a Japanese encephalitis vaccine candidate currently under development using messenger ribonucleic acid (mRNA) technology. Although the company has already received approval for its Investigational New Drug (IND) application covering both Phase 1 and Phase 2 trials, it plans to first review the results of the Phase 1 trial before deciding whether to proceed to Phase 2. Given that no mRNA vaccine has yet been commercialized in South Korea and that development requires substantial funding and time, the company intends to proceed cautiously by reviewing data at each stage.

Number of Trial Participants Reduced from 402 to 161… Trial Design Remains Unchanged

According to ClinicalTrials.gov, an international clinical trial registry, on the 18th, the Phase 1 trial for GBP560 was completed as of July 31. A total of 161 participants were enrolled, representing approximately 40% of the 402 participants originally planned for both Phase 1 and Phase 2 combined. The expected completion date was also changed from March 2028 to July 31, 2026, as of last December.

While the numbers alone may suggest the trial was scaled back, the design itself remained unchanged. According to the records, key design elements—such as the composition of the treatment groups and the two-stage structure—remained unchanged; only the number of enrolled participants was adjusted. It is believed that the protocol was marked as completed after conducting the trial only up to the Phase 1 scale.

This clinical trial consisted of six treatment groups, with the two candidate compounds, GBP560-A and GBP560-B, each administered at three doses: 3 μg, 15 μg, and 50 μg. Participants received intramuscular injections of 0.5 mL on two occasions—Day 1 and Day 29—and the objective of Phase 1 was to identify the optimal combination among the two candidates and the three dose levels.

Two commercially available Japanese encephalitis vaccines were selected as the control groups: Valneva’s inactivated vaccine “Ixiaxo” and Sanofi’s live vaccine “Imogep.” The Imogep group was designed to receive saline on Day 1 and Imogep on Day 29. Inactivated vaccines have the advantage of not replicating in the body, making them suitable even for immunocompromised individuals. Live vaccines, as the name suggests, involve administering a weakened form of the live virus; while they provide strong and long-lasting immunity, they may pose risks to immunocompromised individuals. The mRNA vaccine represents a third approach that falls outside these two categories; it is believed that the two vaccines were selected as controls to comparatively evaluate both safety and immunological persistence.

The mRNA vaccine currently under development by SK Bioscience is a next-generation vaccine that induces an immune response by introducing a portion of the virus’s genetic information into the body. Unlike conventional vaccines, which introduce live or inactivated pathogens into the body, mRNA vaccines work by synthesizing the genetic information for a specific viral protein into mRNA. Our body’s cells produce proteins through the process of “DNA (original blueprint) → mRNA (work instructions) → protein (final product)”; the mRNA vaccine directly introduces the mRNA—the work instructions—to synthesize specific viral proteins.

“A Phased Decision, Not a Halt”… Phase 1 Results by Year-End Will Be a Turning Point

SK Bioscience plans to release the results of this Phase 1 clinical trial by the end of this year. If the results are positive, the company plans to proceed to Phase 2 and actively explore the possibility of commercialization.

An SK Bioscience official explained, “We have not halted the clinical trial,” adding, “Although we initially applied for and received approval for both Phase 1 and Phase 2 simultaneously, our plan was to first review the Phase 1 results before deciding whether to proceed to Phase 2.” The official continued, “The Phase 1 results are expected by the end of this year; if the results are favorable, we will move to Phase 2, but if not, we may make a different decision.”

Cost and time constraints are cited as the reasons for this cautious approach. A company official said, “Since mRNA vaccine research has not yet reached a sufficiently advanced stage, development requires significant funding and time,” adding, “We are proceeding cautiously, verifying data at each stage.”

It is not uncommon in vaccine development to receive approval for Phase 1 and Phase 2 as a single plan and then decide whether to proceed to the next phase based on interim results. This approach has the advantage of shortening the development period while avoiding unnecessary resource allocation.

SK Bioscience explained that the purpose of this Japanese encephalitis mRNA vaccine research is not solely for commercialization. A company official said, “The goal of this research is not merely to create a Japanese encephalitis mRNA vaccine, but rather to build a platform,” adding, “It should be understood as a means of securing a library.”

“The Goal Is to Secure a Platform”… The Symbolic Significance of GBP560

GBP560 is the first mRNA vaccine being developed by SK Bioscience. Although mRNA technology garnered significant attention when Pfizer and Moderna released vaccines within a year during the COVID-19 pandemic, there have been no successful commercialization cases in South Korea to date. It is widely recognized that the barriers to entry for latecomers are high, as foreign companies hold most of the core technologies and intellectual property rights.

SK Bioscience’s current mRNA vaccine project is part of the “100-Day Mission” being carried out in collaboration with the Coalition for Epidemic Preparedness Innovations (CEPI). The “100-Day Mission” aims to develop a vaccine within weeks of the outbreak of an unknown infectious disease (Disease-X), produce it on a large scale, and respond to a pandemic within 100 days.

SK Bioscience launched this project after signing an agreement in 2022 with the international organization CEPI to receive $40 million in initial R&D funding. Once the project enters the late-stage development phase, CEPI plans to provide SK Bioscience with up to an additional $100 million. Along with the Japanese encephalitis vaccine, a vaccine for Lassa fever is also included in this project.

The advantage of mRNA vaccine platform technology is that it utilizes genetic sequences to establish a rapid mass production system compared to existing platforms. Unlike conventional vaccines, which must be developed anew for each pathogen, mRNA vaccines allow the platform to be reused simply by replacing the sequence, enabling a swift response.

As a result, the potential for market expansion is highly rated. According to Nova One Advisor, a global market research firm, the global mRNA pharmaceutical market is projected to grow at a compound annual growth rate (CAGR) of 17.06%, reaching $58.9 billion (approximately 84.5 trillion won) by 2033.

GBP560 is expected to hold significance for SK Bioscience that goes beyond that of a single pipeline. This is because the company can only establish its reputation as a manufacturer capable of producing mRNA vaccines by achieving success with this project. Previously, SK Bioscience successfully developed and commercialized the COVID-19 vaccine “SkyCovion” in 2022, but by that time, the COVID-19 pandemic had already largely subsided. Should another pandemic occur in the future, companies that have secured mRNA vaccine technology are likely to respond proactively. In particular, since GBP560 is the first compound being developed by SK Bioscience, it is expected to have a significant impact on both internal investment and external trust.