• Demonstrates effectiveness comparable to the global standard Oka strain vaccine

YONGIN, South Korea, March 11, 2026 -- GC Biopharma(006280.KS), a leading provider of biopharmaceutical products in South Korea, announced today that a review paper comprehensively analyzing the safety and immunogenicity of its independently developed varicella vaccine strain, 'MAV/06', has been published in the 'Human Vaccines & Therapeutics', a prestigious SCIE-indexed journal.

GC Biopharma and researchers from Ajou University, and Sungkyunkwan University jointly participated in the publication of this paper. The research team systematically analyzed more than 40 studies, including clinical trial results of the MAV/06 vaccine published between 1991 and 2023, post-marketing safety reports, real-world vaccination data, and genomic analysis data.

According to the paper, the MAV/06 strain belongs genetically to the same clade (Clade 2) as the Oka-derived vaccines well-known as the global standard, yet it shows distinguished feature from the wild-type virus, thereby proving its safety as a vaccine.

In addition, MAV/06 was confirmed to induce a broad immune response not only against Clade 2 but also against Clades 1, 3, 5, and wild-type Clade 2 viruses. This signifies that GC Biopharma's varicella vaccine can provide extensive protection against various varicella virus mutations appearing worldwide.

Furthermore, results from numerous clinical trials, including infants and immunocompromised patients, showed that the rate of neutralizing antibodies generated in the body after vaccination with the MAV/06-based varicella vaccine reached 99-100%, with antibody persistence similar to that of the Oka strain vaccine.

The analysis of real-world data accumulated over 30 years showed that the incidence of adverse events for the MAV/06-based varicella vaccine was at a level of 0.41 to 0.57 cases per 100,000 doses, which is lower than that of major global vaccines.

Notably, 'BARYCELA Inj.', GC Biopharma's second varicella vaccine, is the world's first varicella vaccine to use no antibiotics in its manufacturing process, fundamentally eliminating the possibility of adverse reactions derived from antibiotics such as Kanamycin, Neomycin, and Erythromycin.

MAV/06-based varicella vaccines have been supplied to over 20 countries more than 30 million doses to date. Also, BARYCELA Inj. obtained World Health Organization (WHO) Pre-Qualification (PQ) certification in 2023, securing competitiveness in the global public procurement market. Recently, the scope of its utilization in the global market is expected to expand with the WHO officially recognizing interchangeability with Oka strain vaccines.

"This review paper is significant in that it academically compiles the safety and effectiveness that the Korean varicella vaccine has proven in the global market over the past 30 years," said Bong-kyoo Choi, Head of the AI&Data Science Center at GC Biopharma. "We will continue to contribute to promoting the health of children worldwide, including in countries with low vaccine accessibility."

About GC Biopharma

GC Biopharma (formerly known as Green Cross Corporation) is a biopharmaceutical company headquartered in Yong-in, South Korea. The company has over half a century of experience in the development and manufacturing of plasma derivatives and vaccines, and is expanding its global presence with successful US market entry of Alyglo^®(intravenous immunoglobulin G) in 2024. In line with its mission to meet the demands of future healthcare, GC Biopharma continues to drive innovation by leveraging its core R&D capabilities in engineering of proteins, mRNAs, and lipid nanoparticle (LNP) drug delivery platform to develop therapeutics for the field of rare disease as well as I&I (Immunology & Inflammation). To learn more about the company, visit https://www.gcbiopharma.com/eng/

This press release may contain biopharmaceuticals in forward-looking statements, which express the current beliefs and expectations of GC Biopharma's management. Such statements do not represent any guarantee by GC Biopharma or its management of future performance and involve known and unknown risks, uncertainties, and other factors. GC Biopharma undertakes no obligation to update or revise any forward-looking statement contained in this press release or any other forward-looking statements it may make, except as required by law or stock exchange rule.

GC Biopharma Contacts (Media)

Sohee Kim
shkim20@gccorp.com

Yelin Jun
yelin@gccorp.com

Yoonjae Na
yjy6520@gccorp.com