The clinical trial (NCT02783482; GC5107B_P3) was an open-label, single-arm, historically controlled, multi-center phase III study to assess the efficacy and safety of ?GC5107? in patients with a confirmed diagnosis of primary immunodeficiency (PI). The study was designed in accordance with current FDA guidance for clinical trials of IGIV products in support of their marketing as replacement therapy for PI. The clinical trial was conducted at 17 study sites (10 in the US and 7 in Canada). The study followed 49 patients aged 3 to 70 years who received infusions of ?GC5107? doses ranging from 319 to 881 mg/kg body weight every 21 or 28 days for 12 months, according to their previous IGIV maintenance therapy. Key findings from the Phase III Clinical Trial of GC5107 include:

• Primary Efficacy Endpoint: An incidence of 0.02 acute serious bacterial infection (aSBI) events per patient year, meeting the FDA efficacy requirement of <1 aSBI per patient year.
• Primary Safety Endpoint: The study met the FDA safety requirement of <40% of infusions having temporally associated adverse events occurring within 72 hours after the infusion.

The trial also met all of its secondary efficacy and safety endpoints including the following:

• Quality of life measures comprising days absent from work or school due to an infection (mean of 7.1 days), hospitalization due to infection (mean of 0.1 days) and days of unscheduled visits to a physician (mean 2.3 days) were all low and compared favorably to study results in other IVIG products.
• More than 98% of the infusions were completed without discontinuation or interruption or rate reduction.
• More than 98% of all adverse events that occurred throughout the 12-month study period were mild to moderate; the most common treatment-related adverse events were headache, fatigue and nausea.
• There were no patients who experienced a treatment-related serious adverse event, hemolysis, thromboembolism or renal failure.

?The peer-reviewed publication of the GC5107 study demonstrates that this novel 10% IgG formulation is safe, effective and well tolerated in adolescent and adult primary immunodeficiency patients. I look forward to the addition of this product to the armamentarium of therapies available for the treatment of primary immunodeficiency patients.? said Dr. Richard Wasserman, MD, PhD of Allergy Partners of North Texas, Corresponding Author of the study. In February 2021, GC Pharma had submitted a Biologics License Application (BLA) to the United States Food and Drug Administration (FDA) based on the clinical trial results. The Prescription Drug User Fee Act (PDUFA) goal date for a decision by the FDA on the application is in February 2022. ?Completion and publication of our phase III clinical trial along with the submission of our BLA to the US FDA are significant milestones bringing us steps closer to our ultimate goal of expanding our plasma business to the US marketplace,? said E. C. Huh, Ph.D., President of GC Pharma. ?This trial further validates GC Pharma?s expertise while providing a safe and effective therapeutic option for patients with primary immunodeficiency. GC Pharma is well equipped to support the unmet needs of patients with rare diseases.? About GC5107 GC5107 (Immune Globulin Intravenous [Human]) is a 10% liquid IGIV manufactured from pooled human plasma from adult U.S. donors. Viral inactivation and removal steps include solvent/detergent treatment, precipitation, and nanofiltration. GC5107 contains approximately 100 mg/mL IgG and 250 mM glycine, and has a pH of 4.8. GC5107 contains not less than 96% IgG monomers and dimers. About Primary Immunodeficiency Primary immunodeficiency disease comprises a large, heterogenous group of disorders resulting from inborn errors of immunity. Patients with PID are unable to mount an immune response to pathogens and can experience recurrent bacterial, viral, fungal and protozoal infections as a result.Global estimates project that up to 6 million people may be living with PI, but only 650,000 people worldwide have been diagnosed.^1,2,3 About GC Pharma GC Pharma (formerly known as Green Cross Corporation) is a biopharmaceutical company that delivers life-saving and life-sustaining protein therapeutics and vaccines. Headquartered in Yongin, South Korea, GC Pharma is one of the leading plasma protein and vaccine product manufacturers in the world and has been dedicated to quality healthcare solutions for more than half a century. Green Cross Corporation updated its corporate brand to GC Pharma in early 2018. Green Cross Corporation remains the company's legal name. This press release may contain forward-looking statements, which express the current beliefs and expectations of GC Pharma's management. Such statements do not represent any guarantee by GC Pharma or its management of future performance and involve known and unknown risks, uncertainties and other factors. GC Pharma 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. ¹?Rezaei N et al. Introduction on Primary Immunodeficiency Diseases. In: Rezaei N, Aghamohammadi A, and Notarangelo LJ (Eds.), Primary Immunodeficiency Diseases 2017:1-81. ²?Parvaneh L. et al. Eur Ann Allergy Clin Immunol 2019; 51(1):32-37. ³?Lindegren M.L. et al. MMWR Recomm Rep 2004; 53:1-2