The US Food and Drug Administration (FDA) has granted orphan drug designation to HCB101 for the treatment of gastric cancer, including advanced gastric adenocarcinoma across both HER2-positive and HER2-negative subtypes, according to a press release from HanchorBio, Inc.
FDA orphan drug designation broadens development optionality for HCB101 across advanced gastric adenocarcinoma irrespective of HER2 status, supporting U.S. and ex-U.S. regulatory and partnering strategies.
The regulatory milestone follows early-phase data indicating that the next-generation SIRPα-Fc pathway inhibitor protein may overcome the hematological toxicity limitations of prior CD47-directed therapies. Most recently, data from the ongoing phase 1b/2a HCB101-201 trial (NCT06771622) were presented at the 2026 ASCO Gastrointestinal Cancers Symposium.
Clinical Efficacy
Findings from the HCB101-201 trial demonstrated significant antitumor activity when HCB101 was combined with standard-of-care ramucirumab (Cyramza) and paclitaxel in the second-line setting.
- Response Rates: Among 13 efficacy-evaluable patients with advanced gastric adenocarcinoma who had progressed after first-line therapy, the combination produced an overall objective response rate (ORR) of 100% at the 5.12 mg/kg and 8 mg/kg dose levels (0% at 2.56 mg/kg).
- Disease Control: Across all doses, the disease control rate (DCR) was 100%.
- Tumor Shrinkage: In the 5.12 mg/kg cohort (n = 3), the mean tumor shrinkage was 42.6%, and in the 8 mg/kg cohort (n = 7), it was 37.2%. The maximum tumor reduction observed was 78.2%.
The efficacy signals were particularly pronounced in the mid-dose cohorts, where 8 of 10 patients experienced a partial response. Among patients who received the lower dose of 2.56 mg/kg, the mean tumor shrinkage was 6.0%.
Additionally, among the 5 patients with first-line gastric cancer enrolled as of December 19, 2025, 3 were efficacy evaluable at the 8 mg/kg dose level. Of those 3 patients, 2 achieved partial responses and 1 achieved stable disease.
Trial Breakdown
The HCB101-201 study is a multicenter, open-label, dose-escalation and expansion trial designed to evaluate the safety and preliminary efficacy of HCB101 in combination with:
- HER2-targeted therapy in first-line HER2-positive gastric cancer; or
- Ramucirumab plus paclitaxel in second-line gastric cancer.
