Antengene Corporation Limited ("Antengene", SEHK: 6996.HK), a leading innovative global biopharmaceutical company dedicated to discovering, developing and commercializing first-in-class and/or best-in-class therapeutics in hematology and oncology, today announced dosing in Australia of the first subject in the Phase I PROBE Trial, a first-in-human study of ATG-101 in patients with metastatic/advanced solid tumors and B-cell non-Hodgkin's lymphoma (B-NHL). The primary objective of the study is to evaluate the safety and tolerability of ATG-101 and to determine the maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of ATG-101; the secondary objective is to evaluate preliminary anti-tumor activity of ATG-101.

ATG-101 is a novel bispecific antibody that was designed to block the binding of immunosuppressive PD-1/PD-L1 and conditionally induce 4-1BB stimulation, thus activating anti-tumor immune effectors, while delivering enhanced anti-tumor activity, with an improved safety profile. ATG-101 demonstrated significant anti-tumor activity in animal models of resistant tumors as well as those that progressed on anti-PD-1/L1 treatment. Furthermore, no liver toxicity was observed in GLP toxicology studies in cynomolgus monkeys with doses up to 100 mg/kg.

"ATG-101 has been specifically designed to combine the proven activity of PD-1 inhibition with the immune stimulating activity of 4-1BB. Our intent is to further enhance the role of immune-oncological drugs, by turning "cold" tumors "hot" and thereby improve outcomes for patients who do not respond to anti-PD-1/PD-L1 monotherapies, or regain control of disease that has become resistant or refractory to these drugs. This has become a growing and increasingly important medical need." said Dr. Kevin Lynch, Chief Medical Officer of Antengene. "PROBE is Antengene's first global trial of an in-house developed, novel drug. The program is now enrolling patients in Australia, thereafter expanding to the U.S. where the IND has been cleared by the FDA. Dosing of the first subject is an important milestone, highlighting our cross-regional Discovery and Clinical execution capabilities. We are very grateful to the patients, investigators and study site staff for their dedication and support for this program and hope we will be able to make an important difference in cancer with ATG-101."

"As many patients with malignancies are resistant or refractory to current therapies, including chemotherapy, targeted therapy and monoclonal antibodies, there remains a need for novel treatments for this patient population," said Dr. Charlotte Lemech, Medical Director of Scientia Clinical Research in Sydney, Australia.

Dr. Lemech continued, "Accumulating evidence suggests that bispecific antibodies will fill an important role as one of these novel strategies. We are excited to be leading this clinical trial, the first to administer ATG-101 – a novel PD-L1/4-1BB bispecific antibody - bringing together a group of highly experienced Australian investigators to collaborate with Antengene. The design of ATG-101 incorporates a high affinity for PD-L1 and conditional activation of 4-1BB, which potentially reduces the risk of 4-1BB related liver toxicity. We are looking forward to assessing whether this bispecific antibody can provide enhanced efficacy with a better safety profile and a new option for these patients."