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- The results of the trial demonstrate the efficacy, safety, and tolerability of GC5107 in patients with PI

YONGIN, SOUTH KOREA– GC Biopharma (006280. KS) today announced that Frontiers in Immunology had published the safety and final efficacy results from the pivotal Phase III clinical trial of GC5107, its 10% Immune Globulin product for intravenous administration.

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 following 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:

1. 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.
2. 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.
3. 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, Ph.D. of Allergy Partners of North Texas, Corresponding Author of the study.

In February 2021, GC Biopharma 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 Biopharma. This trial further validates GC Biopharma's expertise while providing a safe and effective therapeutic option for patients with primary immunodeficiency." "GC Biopharma 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 US 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, heterogeneous group of disorders resulting from inborn errors of immunity. Patients with PID cannot 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 Biopharma

GC Biopharma (formerly known as Green Cross Corporation) is a biopharmaceutical company that delivers lifesaving and life-sustaining protein therapeutics and vaccines. Headquartered in Yongin, South Korea, GC Biopharma 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 Biopharma in early 2018. Green Cross Corporation remains the company's legal name.

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