Chordoma Foundation

New clinical trial tests therapeutic vaccine to improve the effectiveness of radiation for chordoma patients

Chordoma patients planning to have radiation therapy have a new treatment option to consider that is intended to improve the effectiveness of radiation.

Researchers at the National Cancer Institute are now recruiting chordoma patients planning to have radiation in the near future to participate in a Phase 2 clinical trial testing whether a new therapeutic vaccine, called GI-6301, given in combination with radiation is more effective than radiation alone. The trial is designed specifically for chordoma patients who are at high risk of tumor regrowth following radiation, including:

  • Patients who have residual tumor remaining after surgery
  • Newly diagnosed patients who are unable to have surgery
  • Patients who have a local recurrence following previous surgery

The vaccine, called GI-6301, is designed to stimulate a patient’s immune system to seek out and destroy cancer cells that contain a protein called brachyury, which is present at very high levels in nearly all chordomas. Unlike “prophylactic” vaccines designed to prevent disease (such as the flu vaccine), therapeutic vaccines like GI-6301 are intended to help the immune system fight disease more effectively. Research in other cancers suggests that the combination of radiation plus therapies that stimulate the immune system can have powerful antitumor effects. Therefore, in this trial, researchers are seeking to determine whether stimulating the immune system with GI-6301 in combination with radiation can cause tumor shrinkage and/or prevent further tumor growth to a greater degree than radiation alone.

This trial follows a recently completed Phase 1 clinical trial of GI-6301 at the National Cancer Institute, which demonstrated that the vaccine could be delivered safely without serious adverse reactions, and that it was capable of inducing immune responses against brachyury in chordoma patients. Of the eight patients whose tumors were growing when they entered the phase 1 trial, five stopped growing and one shrunk by more than 30% while on the study.

To be eligible to participate in this study, patients must have only localized tumor (no metastases) and be able to receive “definitive” radiation therapy, meaning at least 70Gy. Participants in the trial will initially be randomized to receive radiation plus the vaccine or radiation plus a blinded placebo. Those randomized to receive radiation plus placebo will have the option to “cross-over” and begin receiving the vaccine if their tumor grows while on the study, meaning that everyone who enters the study will be given the opportunity to receive the vaccine if radiation alone is not stopping the growth of the tumor.

The trial is taking place at the National Institutes of Health (NIH) Clinical Center in Bethesda, Maryland. Participants will need to visit the Clinical Center multiple times while on the study to receive vaccine injections and follow-up scans. The NCI will pay for transportation costs (including airfare) and a portion of lodging costs for enrolled patients. Radiation treatments are performed at an institution of the patient’s choice as part of routine care, and will not be covered by the NCI.

For additional details about this trial see the following resources:

Note to patients:

To help you make sense of this trial, we have worked with the National Cancer Institute to create a downloadable trial FAQ sheet, available here. A Chordoma Foundation patient navigator is also available to answer your questions about this trial. Please feel free to request help.

To enroll in this trial, contact the NCI Patient Referral Office at 866-611-6310 or email Laura Otten at or Cynthia Boyle at You may also contact the principal investigator of this study, Christopher Heery, MD, directly or through your physician at

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