NCT06490198

Phase 2 Study: OBI-833/OBI-821 Maintenance for Globo H+ Advanced Biliary Tract Cancer After Gemcitabine/Cisplatin

A Single-Arm, Phase 2 Study to Evaluate OBI-833/OBI-821 Maintenance Therapy in Patients With Globo H-Positive Advanced Biliary Tract Cancer Not Progresseding Under First-Line Gemcitabine and Cisplatin

• Status: Not Yet Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 30 (estimated)
• Sponsor: Chang Gung Memorial Hospital · Academic / Other
• Sex: All
• Age: 20 Years – 99 Years
• Healthy volunteers: Not accepted

Summary

A Phase 2 clinical trial protocol for evaluating the efficacy and safety of OBI-833/OBI-821, a carbohydrate-conjugate vaccine combined with an immune adjuvant, as maintenance therapy in combination with first-line gemcitabine and cisplatin chemotherapy for patients with Globo H-positive advanced biliary tract cancer. The study is designed as a single-arm trial with 30 patients who have achieved stable disease, partial response, or complete response after 3±1 months of initial chemotherapy. The primary endpoint is progression-free survival, with secondary endpoints including overall survival, tumor response, and safety profile. The treatment regimen involves subcutaneous injections of OBI-833/OBI-821 on a gradually decreasing frequency schedule for up to 80 weeks. The trial also includes exploratory objectives to assess immune responses and biomarkers. This study aims to address the unmet need for improved treatment options in advanced biliary tract cancer by leveraging the potential of immunotherapy targeting the Globo H antigen.

Detailed description

This clinical trial is a single-arm, phase 2 study evaluating OBI-833/OBI-821 as maintenance therapy in patients with Globo H-positive advanced biliary tract cancer who have not progressed on first-line gemcitabine and cisplatin chemotherapy. The study is grounded in the challenging prognosis of biliary tract cancer, including cholangiocarcinoma, which has limited treatment options. Currently, the standard first-line therapy is gemcitabine plus cisplatin, but progression-free survival remains short at around 6 months, highlighting the need for improved treatment strategies. The investigational therapy, OBI-833, is a glycoconjugate vaccine targeting Globo H, a tumor-associated carbohydrate antigen expressed in many epithelial cancers. It is used in combination with OBI-821, an adjuvant designed to enhance the immune response. Previous studies have demonstrated that OBI-833/OBI-821 can elicit immune responses and provide disease stabilization in some cancer patients. Notably, Globo H expression has been detected in about 41% of intrahepatic cholangiocarcinoma specimens, providing a rationale for investigating this approach in biliary tract cancer. The study design involves enrolling 30 patients in a single-arm trial. Eligible patients must have Globo H-positive advanced biliary tract cancer that has not progressed after 3±1 months of first-line gemcitabine/cisplatin therapy. Patients will receive OBI-833/OBI-821 subcutaneously on a gradually decreasing frequency schedule for up to 80 weeks, while continuing their gemcitabine/cisplatin regimen. The primary endpoint of the study is progression-free survival, with secondary endpoints including overall survival, tumor response, safety, and correlations between Globo H expression/antibodies and survival outcomes. To ensure safety, the study incorporates a lead-in safety cohort of 6 patients before proceeding to full enrollment. Following the treatment period, patients will be followed for survival for up to 12 months after the end of treatment. This single-arm design allows for an efficient assessment of efficacy signals that could inform potential further development of this therapeutic approach. The overall aim of the study is to evaluate whether adding OBI-833/OBI-821 maintenance therapy can prolong disease control in this patient population with high unmet medical need. By focusing on patients with Globo H-positive tumors who have initially responded to standard chemotherapy, the study seeks to explore a potentially targeted approach to maintaining and extending the benefits of first-line treatment in advanced biliary tract cancer.

Conditions

• Cholangiocarcinoma
• Chemotherapy Effect
• Immunotherapy

Interventions

Type	Name	Description
DRUG	OBI-833/OBI-821	OBI-833 is a glycoconjugate that consists of Globo H, a unique tumor-associated carbohydrate antigen (TACA), covalently linked to cross-reacting material 197 (CRM197), an inactive and nontoxic form of diphtheria toxin (DT) acting as the carrier protein. OBI-821 is a saponin-based adjuvant derived from the bark of the Quillaja saponaria Molina tree. It is a purified saponin adjuvant structurally similar to adjuvant QS-21. The OBI-833/OBI-821 combination represents a carbohydrate-conjugate vaccine combined with an immune adjuvant, intended to serve as an active cancer immunotherapy.

Timeline

• Start date: 2024-07-31
• Primary completion: 2026-07-31
• Completion: 2027-07-31
• First posted: 2024-07-08
• Last updated: 2024-07-08

Locations

2 sites across 1 country: Taiwan