HanchorBio Achieves FDA Breakthrough: First SIRPα-IgG4 Fc Fusion Protein Granted Orphan Status for Gastric Cancer

In a significant regulatory milestone that validates innovative approaches to cancer immunotherapy, Taiwan-based HanchorBio announced today that the U.S. Food and Drug Administration has granted Orphan Drug Designation to HCB101 for the treatment of gastric cancer. This designation marks the first FDA recognition of a SIRPα-IgG4 Fc fusion protein in gastric cancer, positioning HanchorBio at the forefront of next-generation innate immune checkpoint inhibition.

The FDA's decision encompasses gastric cancer broadly, including both HER2-positive and HER2-negative advanced gastric adenocarcinoma subtypes, reflecting the agency's recognition of the significant unmet medical need in this patient population. For HanchorBio, this represents not only their first FDA Orphan Drug Designation but also strategic validation of their differentiated approach to CD47-SIRPα pathway inhibition.

Revolutionary Approach to Innate Immune Checkpoint Inhibition

HCB101 represents a sophisticated evolution in cancer immunotherapy through its design as an affinity-optimized and toxicity-mitigated SIRPα-IgG4 Fc fusion protein. Unlike earlier CD47-targeting approaches that faced significant hematologic toxicities, HCB101 is engineered to restore macrophage-mediated phagocytosis while minimizing the red blood cell binding that historically limited clinical utility of CD47-directed therapies.

The molecule's innovative design leverages AI-assisted structural modeling to achieve differentiated binding profiles. This precision engineering enables HCB101 to maintain high affinity for CD47 on cancer cells while demonstrating reduced binding to CD47 on red blood cells, potentially solving one of the field's most persistent challenges in developing effective CD47-targeted therapies.

"Receiving our first FDA Orphan Drug Designation is a major milestone for HanchorBio and important validation of our scientific, regulatory, and development strategy," said Dr. Scott Liu, Founder, Chairman, and CEO of HanchorBio. "Gastric cancer remains an area of profound unmet medical need, and this designation reinforces our commitment to developing differentiated immunotherapies that can meaningfully improve outcomes for patients."

Addressing Critical Unmet Need in Gastric Cancer

Gastric cancer represents a particularly challenging therapeutic area, with limited treatment options and poor outcomes, especially in second-line settings. Despite advances in targeted therapy and immune checkpoint inhibition, patients continue to face substantial treatment-related toxicity with limited durability of response. The disease's classification as rare in the United States, with prevalence well below the FDA's statutory threshold for orphan designation, underscores both the specialized nature of this patient population and the urgent need for innovative therapeutic approaches.

Current treatment paradigms in advanced gastric cancer often provide modest survival benefits, creating a compelling rationale for novel mechanisms of action. HCB101's approach to innate immune checkpoint inhibition offers a fundamentally different strategy by targeting the CD47-SIRPα "don't eat me" signal that allows cancer cells to evade macrophage-mediated destruction.

Clinical Validation and Development Progress

HanchorBio is currently advancing HCB101 through multiple clinical studies, including a Phase 1b/2a trial evaluating the therapy in combination with ramucirumab and paclitaxel in second-line advanced gastric cancer. Early clinical findings have demonstrated promising antitumor activity with a safety profile consistent with the molecule's differentiated design, supporting continued global development.

Dr. Alvin Luk, President & Chief Medical Officer and CEO of HanchorBio's U.S. operations, emphasized the clinical rationale underlying the development program: "The FDA's decision reflects the seriousness of gastric cancer and the clinical rationale underlying HCB101's development. HCB101's IgG4-based SIRPα-Fc design was intentionally selected to support repeated dosing and combination strategies as an innate immune checkpoint backbone in solid tumors."

Strategic Implications and Market Positioning

The Orphan Drug Designation provides HanchorBio with significant regulatory advantages, including eligibility for tax credits on qualified clinical trial expenses, exemption from FDA user fees, and the potential for seven years of market exclusivity upon approval. These benefits could substantially accelerate the development timeline while reducing costs associated with bringing HCB101 to market.

Beyond the immediate regulatory benefits, this designation strengthens HanchorBio's position in engaging with healthcare systems, potential partners, and multinational pharmaceutical companies. The company has indicated active exploration of collaboration and licensing opportunities for HCB101 and its broader immunotherapy pipeline, suggesting this milestone could catalyze strategic partnerships.

The designation also validates HanchorBio's broader platform approach to developing Fc-based designer biologics. The company's proprietary FBDB platform enables development of unique biologics with diverse multi-targeting modalities, potentially unleashing both innate and adaptive immunity to overcome current limitations of anti-PD1/L1 therapies.

Looking Ahead: Global Development and Platform Expansion

As HanchorBio continues advancing HCB101 through global clinical development, the company is simultaneously exploring the therapy's potential as a backbone immunotherapy across multiple solid tumor indications. The molecule's safety profile, receptor occupancy characteristics, and pharmacologic properties are designed to support integration with established oncology regimens without disrupting standard dosing or clinical workflows.

For the gastric cancer community, HCB101 represents hope for a differentiated treatment approach that could address the fundamental limitations of current therapies. As the first SIRPα-IgG4 Fc fusion protein to receive FDA orphan status in this indication, HCB101 may establish a new paradigm for innate immune checkpoint inhibition in solid tumors, potentially benefiting patients across multiple cancer types who have exhausted conventional treatment options.