#None #Harbour BioMed #Tislelizumab #HBM4003

Harbour BioMed's Promising Phase II Results

On October 22, 2025, Harbour BioMed, a globally recognized biopharmaceutical enterprise, announced the results from its Phase II clinical trial involving HBM4003 and tislelizumab. This combination aims to address microsatellite stable metastatic colorectal cancer (MSS mCRC), a condition notoriously challenging to treat.

Overview of the Clinical Trial

The research, identified as study NCT05167071, assessed the effectiveness of HBM4003, a next-generation fully human anti-CTLA-4 antibody, when used alongside tislelizumab. In total, 24 patients suffering from MSS mCRC participated in this open-label, multi-center trial. Notably, all enrolled individuals had previously undergone at least two lines of therapy, while 66.7% had lung metastases, indicating the advanced nature of their conditions.

HBM4003 was administered at a dosage of 0.3 mg/kg in conjunction with 200 mg of tislelizumab, given every 21 days. The primary goal of the study was to measure the objective response rate (ORR) based on RECIST 1.1 criteria. The results were promising, showcasing significant antitumor activity, along with a safety profile described as manageable for the participants.

Key Findings from the Study

Among the 23 evaluable patients, the study highlighted the following outcomes:

• - Objective Response Rate (ORR): 34.8%, translating to 8 individuals achieving partial responses.
• - Disease Control Rate (DCR): 60.9%, comprising 8 partial responses and 6 instances of stable disease.
• - Median Progression-Free Survival (mPFS): The data indicated a median duration of 4.2 months without disease progression.

When considering safety, the regimen was generally well-received with no severe Grade 4 or life-threatening treatment-emergent adverse events reported. However, it’s worth noting that 87.5% of participants experienced treatment-related adverse events (TRAEs), predominantly mild to moderate such as liver function test abnormalities, hematologic issues, and fever. Serious adverse events were recorded in 37.5% of the group, highlighting the need for ongoing observation and management of side effects during treatment.

Expert Insights

Dr. Jingsong Wang, founder, chairman, and CEO of Harbour BioMed, commented on the groundbreaking nature of this development, especially in light of the recent Nobel Prize awarded for key insights into the role of regulatory T cells in immune regulation. He stated that HBM4003’s development is a direct result of foundational research that underscores its therapeutic potential. The successful Phase II results have positioned Harbour BioMed as a significant player in the immuno-oncology landscape, with ambitions to continue advancing their innovative treatments globally to benefit patients battling cancer.

About HBM4003

HBM4003, also known as porustobart, stands as a revolutionary treatment developed using the HCAb Harbour Mice platform. This novel antibody demonstrates unique advantages over conventional CTLA-4 treatments, such as substantial depletion of Treg cells and enhanced pharmacokinetics for improved safety. Furthermore, it boosts antibody-dependent cellular cytotoxicity (ADCC), which facilitates precise targeting and destruction of tumor-infiltrating Treg cells, potentially overcoming limitations observed in existing therapies.

Harbour BioMed has also laid out globally applicable development strategies for various solid tumors using adaptive treatment methodologies. Encouraging efficacy and safety results in earlier trials involving monotherapy and combinations with PD-1 inhibitors for other cancer types reinforce their commitment to innovation in this area.

Future Directions

The company is poised to continue their work with HBM4003 and explore its application across diverse cancer treatments. With ongoing studies and patient-focused research, Harbour BioMed is dedicated to harnessing the potential of this promising therapeutic avenue to address unmet medical needs in oncology. As the biopharmaceutical landscape evolves, collaborations, and inventive approaches will be crucial in ushering in effective cancer treatments for the future.

For more detailed information regarding Harbour BioMed and their innovative approach to antibody development, please visit Harbour BioMed.