AbClon announced on the 4th that AC101 (Henlius code name HLX22), which was licensed to Henlius, showed long-term efficacy exceeding two years after administration in a Phase 2 clinical trial for patients with HER2-positive advanced gastric cancer. These results were presented at the American Society of Clinical Oncology (ASCO) annual meeting, which took place in Chicago, USA, from May 29th to early this month.

According to the latest results from the HLX22-GC-201 Phase 2 clinical trial, long-term treatment effects were stably maintained in the patient group that received AC101 in combination with other drugs. This achievement surpasses previously reported results, once again proving AC101's excellent therapeutic efficacy. The HLX22-GC-301 Phase 3 clinical trial is also underway in the United States, Europe, Japan, South Korea, China, South America, and Australia. To date, no similar dual HER2 blockade therapy for HER2-positive gastric cancer treatment has received marketing authorization worldwide.

Gastric cancer is a fatal disease with nearly 1 million new patients annually worldwide and over 660,000 deaths. Particularly, the 5-year survival rate for advanced gastric cancer is only 6%, highlighting a critical need for innovative treatments that surpass existing therapies.

According to the ASCO presentation, follow-up over two years showed that the AC101 combination group demonstrated an excellent effect, reducing the risk of disease progression by 80% compared to the control group. The median progression-free survival (PFS) in the AC101 combination group has not yet been reached, while it was 8.3 months in the control group. The 12-month and 24-month progression-free survival (PFS) rates were 77.1% and 54.8%, respectively, compared to 40.8% and 17.5% in the control group, indicating a more than threefold increase in survival rate after two years. The objective response rate (ORR) was 87.1% for the AC101 combination group and 80.6% for the control group. The duration of response (DOR) has not reached the median in the combination group, while it was 9.7 months in the control group. Overall survival (OS) has also not reached the median in the combination group, while it was 16.4 months in the control group, demonstrating AC101's excellent survival-prolonging effect.

Due to these innovative therapeutic effects, AC101 has simultaneously received Orphan Drug Designation (ODD) for gastric cancer treatment from the U.S. Food and Drug Administration (FDA) and European regulatory authorities. Furthermore, it has met the criteria for accelerated approval from the U.S. FDA, and received positive evaluations from major global regulatory bodies, including conditional marketing authorization and priority medicine designation from the European Medicines Agency (EMA), and innovative drug designation from China's National Medical Products Administration (NMPA).

At ASCO, the design and synopsis of the HLX22-GC-301 Phase 3 clinical trial were also introduced. The trial is being conducted into 550 HER2-positive gastric cancer patients worldwide, with participation from leading medical institutions such as MD Anderson Cancer Center, Japan's National Cancer Center, and Peking University Cancer Hospital. The study is designed to compare the efficacy and safety between AC101 + trastuzumab + XELOX combination therapy and trastuzumab + XELOX ± pembrolizumab combination therapy. Additionally, precise analysis based on HER2 expression levels, region (Asia, Europe, North America), and PD-L1 expression levels (CPS) will be performed, aiming to establish a new standard treatment for HER2-positive gastric cancer.

A Phase 3 clinical trial for AC101 is also underway in South Korea. It received clinical approval from the Ministry of Food and Drug Safety on April 16th and involves 10 domestic hospitals as part of the global multi-national clinical trial. Some patients will directly receive AC101 in South Korea.

Clinical trials for expanding AC101's indications to other cancer types are also actively progressing. A Phase 2 clinical trial combining AC101 with trastuzumab Deruxtecan (T-DXd) for HER2-low expression and hormone receptor (HR)-positive locally advanced or metastatic breast cancer patients is underway in China, with the first patient having completed treatment.

An AbClon official stated, "The ASCO presentation will be a new turning point for AC101 in the treatment of HER2-positive gastric cancer. We plan to accelerate AC101's global clinical development and commercialization to provide effective and affordable treatment options to patients worldwide."

They added, "Henlius expects AC101's peak annual sales target to be $10 billion, and AbClon anticipates securing over 700 billion won in annual royalties. Given the recent pace of progress, we believe we are approaching the commercialization stage through conditional marketing authorization by country."