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OBI-821

OBI-821 is being investigated in clinical trials as an innovative immunotherapy approach for various advanced cancers. This drug works as an adjuvant combined with OBI-833 (also known as Globo H-CRM197), creating a carbohydrate-conjugate vaccine that targets Globo H, a tumor-associated carbohydrate antigen found in many cancer types. Current trials are examining this combination’s effectiveness as maintenance therapy for biliary tract cancer and as a treatment for advanced gastric, lung, colorectal, and breast cancers. The treatment aims to stimulate the immune system to recognize and attack cancer cells, potentially offering new hope for patients with limited treatment options.

Table of Contents

What is OBI-821?

OBI-821 is a medical treatment being studied for various types of cancer. It’s not used alone but is combined with another medication called OBI-833 (also known as Globo H-CRM197) to create a special type of cancer treatment called an immunotherapy vaccine. This combination is designed to help your immune system fight cancer cells.[1]

OBI-821 is specifically a saponin-based adjuvant derived from the bark of the Quillaja saponaria Molina tree. In simple terms, it’s a substance that helps boost the effectiveness of the vaccine. It’s structurally similar to another adjuvant called QS-21 and is used to enhance your body’s immune response to the treatment.[2]

How Does OBI-821 Work?

The OBI-833/OBI-821 combination works as an active cancer immunotherapy. This means it trains your immune system to recognize and attack cancer cells. Here’s how it works:[1]

  • OBI-833 contains a substance called Globo H, which is a type of marker (called a tumor-associated carbohydrate antigen or TACA) found on many cancer cells but not normally found on healthy cells.
  • This Globo H is attached to a carrier protein called CRM197, which is a harmless form of diphtheria toxin.
  • OBI-821 is added as an adjuvant to strengthen your immune system’s response to the vaccine.

When given to patients, this combination helps the immune system recognize the Globo H marker on cancer cells and attack them. It’s like training your immune system to spot and fight the cancer on its own.[2]

What Conditions Does OBI-821 Treat?

Based on the current clinical trials, OBI-833/OBI-821 is being studied for treating several types of advanced or metastatic cancers (cancers that have spread from where they started). These include:[1][2]

  • Biliary tract cancer (including cholangiocarcinoma) – these are cancers that form in the bile ducts, which carry digestive fluid bile from the liver to the small intestine
  • Gastric cancer (stomach cancer)
  • Lung cancer
  • Colorectal cancer (cancer of the colon or rectum)
  • Breast cancer

The treatment appears to be specifically targeted at cancers that are Globo H-positive, meaning the cancer cells have the Globo H marker on their surface. For example, about 41% of intrahepatic cholangiocarcinoma (a type of bile duct cancer) specimens have been found to express Globo H.[1]

Current Clinical Research

OBI-833/OBI-821 is currently being studied in clinical trials, which are research studies that test how well new medical approaches work in people. Two important studies are:[1][2]

  1. Phase 2 study for advanced biliary tract cancer: This trial is evaluating OBI-833/OBI-821 as a maintenance therapy for patients with Globo H-positive advanced biliary tract cancer who have responded to initial chemotherapy with gemcitabine and cisplatin. The study aims to see if adding this treatment can help maintain and extend the benefits of first-line chemotherapy.
  2. Open-label study for various advanced/metastatic cancers: This trial is assessing the safety, tolerability, and effectiveness of OBI-833/OBI-821 in patients with advanced or metastatic gastric, lung, colorectal, or breast cancer.

These clinical trials are crucial to understanding how well this treatment works and for which patients it might be most beneficial.[1][2]

How is OBI-821 Administered?

OBI-833/OBI-821 is given as a subcutaneous injection, which means it’s injected just under the skin. The treatment schedule varies depending on the specific clinical trial, but generally follows a pattern of more frequent injections at the beginning, then gradually decreasing in frequency.[1][2]

For example, in the biliary tract cancer study, injections are given on a schedule of:

  • Weekly for the first 4 weeks (Weeks 1, 2, 3, 4)
  • Every 2 weeks for the next 4 weeks (Weeks 6, 8)
  • Every 4 weeks for the next 16 weeks (Weeks 12, 16, 20, 24)
  • Every 8 weeks thereafter (Weeks 32, 40, 48, 56, 64, 72, 80)

The total treatment period can last up to 80 weeks in some cases. Throughout this time, patients are regularly monitored for both safety and treatment response.[1]

Effectiveness of OBI-821

Since OBI-833/OBI-821 is still in clinical trials, comprehensive data on its effectiveness isn’t yet available. However, the research is looking at several important outcomes to measure how well it works:[1][2]

  • Progression-free survival: This measures how long patients live without their cancer getting worse. This is the primary goal of the biliary tract cancer study.
  • Overall survival: This measures how long patients live after starting the treatment.
  • Tumor response: This looks at whether tumors shrink or stop growing in response to the treatment.
  • Immune response: Researchers are measuring antibody responses against Globo H to see if there’s a correlation between immune response and survival.

Previous studies have shown that OBI-833/OBI-821 can trigger immune responses and help stabilize disease in some cancer patients, which is promising for future research.[1]

Safety Profile

As with any medical treatment, especially one still in clinical trials, monitoring for side effects is important. The current trials are carefully tracking any adverse reactions that patients might experience.[1][2]

Researchers are specifically monitoring:

  • General adverse events and serious adverse events
  • Local injection site reactions (such as redness, swelling, or pain where the injection was given)
  • Changes in laboratory tests, including blood counts and chemistry
  • Changes in vital signs
  • Changes in physical examination findings

In the biliary tract cancer study, there’s a specific “lead-in safety cohort” of 6 patients that will be evaluated first before moving to full enrollment, which shows the careful approach being taken to ensure patient safety.[1]

It’s important to remember that the safety and effectiveness of OBI-833/OBI-821 are still being evaluated through these clinical trials, and the treatment is not yet approved for general use outside of research studies.[1][2]

Feature Details
Drug Combination OBI-833 (Globo H-CRM197) and OBI-821 (saponin-based adjuvant)
Mechanism of Action Carbohydrate-conjugate vaccine that targets Globo H (tumor-associated carbohydrate antigen) combined with an immune adjuvant
Administration Subcutaneous injections on a gradually decreasing frequency schedule
Cancer Types in Trials Biliary tract cancer (cholangiocarcinoma), gastric cancer, lung cancer, colorectal cancer, breast cancer
Phase 2 Biliary Tract Cancer Trial Single-arm study with 30 patients who have Globo H-positive advanced disease and haven’t progressed on first-line gemcitabine/cisplatin
Other Trial Open-label study in advanced/metastatic gastric, lung, colorectal, or breast cancer with dose escalation and cohort expansion
Primary Outcomes Progression-free survival, safety (number of participants with treatment-emergent adverse events)
Secondary Outcomes Overall survival, tumor response, safety profile, immune response (anti-Globo H antibodies), biomarker correlations
Treatment Duration Up to 80 weeks in the biliary tract cancer trial; various schedules in other trials
Target Population Patients with Globo H-positive tumors (Globo H is expressed in approximately 41% of intrahepatic cholangiocarcinoma specimens)

FAQ

  • What is OBI-821 and how does it work? OBI-821 is a saponin-based adjuvant derived from the bark of the Quillaja saponaria Molina tree. It works as part of a combination therapy with OBI-833, which is a glycoconjugate containing Globo H (a tumor-associated carbohydrate antigen) linked to a carrier protein. Together, they form a cancer vaccine that helps stimulate your immune system to recognize and attack cancer cells that express the Globo H antigen on their surface.
  • What types of cancer is OBI-821 being tested for? OBI-821 is currently being tested in clinical trials for several types of advanced or metastatic cancers. These include biliary tract cancer (including cholangiocarcinoma), gastric (stomach) cancer, lung cancer, colorectal cancer, and breast cancer. The trials focus particularly on patients whose cancers express the Globo H antigen, which is the target of this treatment.
  • How is OBI-821 administered to patients? OBI-821 is administered as a subcutaneous injection (an injection under the skin), typically in combination with OBI-833. The treatment schedule varies by trial but generally involves multiple injections over time. For example, in the biliary tract cancer trial, injections are given on weeks 1, 2, 3, 4, 6, 8, 12, 16, 20, 24, and then every 8 weeks until week 80. This gradually decreasing frequency is designed to build and maintain an immune response.
  • What are the potential benefits of OBI-821 treatment? The potential benefits being investigated include extended progression-free survival (time without cancer growing or spreading), improved overall survival, and disease stabilization. For example, in biliary tract cancer, where current treatments typically only control the disease for about 6 months, OBI-821/OBI-833 maintenance therapy aims to extend this period. Previous studies have shown that this combination can elicit immune responses and provide disease stabilization in some cancer patients.
  • What are researchers measuring in these clinical trials? Researchers are measuring several important outcomes in these trials. The primary measurements include safety and tolerability (tracking side effects and how well patients handle the treatment), progression-free survival (how long until the cancer grows or spreads), and overall survival. They're also monitoring immune responses by measuring anti-Globo H antibody levels, tumor responses using imaging, and correlations between biomarkers and survival outcomes. This comprehensive approach helps determine both if the treatment works and how it works.

Ongoing Clinical Trials on OBI-821

  • Study of Adagloxad Simolenin/OBI-821, Capecitabine, and Pembrolizumab for Patients with High-Risk, Early-Stage Triple Negative Breast Cancer

    Not recruiting

    1 1 1 1
    Investigated diseases:
    Investigated drugs:
    Poland

Glossary

  • Globo H: A tumor-associated carbohydrate antigen (TACA) that is expressed on the surface of many types of cancer cells, including biliary tract, breast, gastric, colorectal, and lung cancers. It serves as the target for the OBI-833/OBI-821 therapy.
  • Adjuvant: A substance added to a vaccine to enhance the body's immune response. In this case, OBI-821 is the adjuvant component of the treatment.
  • Glycoconjugate: A molecule formed by attaching a carbohydrate (sugar) to another type of molecule. OBI-833 is a glycoconjugate that links Globo H to a carrier protein (CRM197).
  • CRM197: Cross-reacting material 197, an inactive and non-toxic form of diphtheria toxin used as a carrier protein in OBI-833 to help enhance the immune response against Globo H.
  • Biliary Tract Cancer: A rare type of cancer that occurs in the bile ducts, which connect the liver to the small intestine. Cholangiocarcinoma is a type of biliary tract cancer.
  • Cholangiocarcinoma: A type of cancer that forms in the bile ducts, which are slender tubes that carry the digestive fluid bile from the liver to the small intestine.
  • Progression-Free Survival (PFS): The length of time during and after treatment that a patient lives with cancer without it getting worse. This is a primary endpoint in many cancer clinical trials.
  • Overall Survival (OS): The length of time from the start of treatment until death from any cause. This is a key measure of treatment effectiveness in cancer trials.
  • Metastatic Cancer: Cancer that has spread from its original site to other parts of the body. The clinical trials for OBI-821 include patients with metastatic forms of various cancers.
  • Subcutaneous Injection: An injection given just under the skin. OBI-833/OBI-821 is administered via subcutaneous injections during the clinical trials.
  • Maintenance Therapy: Treatment that is given to help keep cancer from coming back after it has disappeared or been reduced following initial therapy. In the biliary tract cancer trial, OBI-833/OBI-821 is being tested as maintenance therapy after gemcitabine/cisplatin chemotherapy.
  • RECIST 1.1: Response Evaluation Criteria In Solid Tumors version 1.1, a standardized way to measure how well a cancer patient responds to treatment by tracking changes in tumor size.
  • IgM and IgG: Types of antibodies produced by the immune system. In the OBI-833/OBI-821 trials, researchers measure anti-Globo H IgM and IgG antibodies to assess the immune response to treatment.
  • Biomarker: A measurable substance or characteristic that indicates a biological state or condition. In these trials, Globo H expression and anti-Globo H antibodies are biomarkers being studied to predict treatment response.
  • Active Immunotherapy: A type of treatment that stimulates the body's own immune system to recognize and destroy cancer cells. OBI-833/OBI-821 is considered an active cancer immunotherapy.

References

  1. https://clinicaltrials.gov/study/NCT06490198
  2. https://clinicaltrials.gov/study/NCT02310464