Orphan Drugs, also known as Rare Disease Drugs, refers to pharmaceutical products developed for the prevention, diagnosis, and treatment of rare diseases or conditions. Orphan Drug Designations by the U.S. FDA are meant to support the development of drug candidates that could potentially bring substantial therapeutic benefits to patients with rare diseases (a condition with a prevalence of less than 200,000 in the U.S.), and to provide incentives to the subsequent development, registration and commercialization to designated drugs. Those incentives include tax credit on expenditures incurred in clinical studies, a waiver of the New Drug Application (NDA) fee, and 7-year market exclusivity in the U.S. regardless of the patent status of the designated drug.

ATG-022 is an antibody-drug-conjugate targeting Claudin 18.2. Claudins are cell adhesion molecules normally expressed within the tight junctions between cells to form a barrier that regulates cell permeability. In cancer, Claudins are expressed at the cell surface due to changes in cell polarity. The Claudin 18.2 isoform is overexpressed in various primary malignant tumors including gastric, esophageal and pancreatic cancers. The Phase I CLINCH study of ATG-022 in patients with advanced or metastatic solid tumors, already approved by the China National Medical Products Administration (NMPA) and Bellberry Human Research Ethics Committee (HREC) in Australia, is currently ongoing in China and Australia.

"We believe the that Orphan Drug Designation represents an important regulatory milestone for ATG-022, recognizing the significant and urgent unmet need for new treatments to help patients who are fighting difficult to treat and devastating diseases such as pancreatic and gastric cancers," said Dr. Amily Zhang, Antengene's Chief Medical Officer. "We are enthusiastic about the potential for ATG-022 to treat gastric and pancreatic cancers. Moving forward, Antengene will work closely with regulators and clinical investigators to advance the CLINCH trial and fully assess ATG-022's therapeutic potential for solid tumors."