The ARROW trial

A clinical trial of BLU-667 for NSCLC, MTC and other RET-altered tumors


About the ARROW clinical trial

ARROW will test an investigational drug called BLU-667 in people who have RET-altered non-small cell lung cancer (NSCLC), medullary thyroid cancer (MTC) or another solid tumor that has a RET fusion or mutation*. It is a phase 1 trial designed to test the safety and preliminary clinical activity of BLU-667, and to identify the best dose for future clinical trials.

BLU-667 is designed to block the activity of the mutated RET gene. In certain forms of cancer, gene or DNA alterations may occur and cause tumors to grow. RET fusions and mutations are specific genetic alterations that sometimes occur in people with NSCLC, MTC and other solid tumors. BLU-667 is an oral drug taken by mouth daily. It is an investigational drug only available through clinical trials.

*RET fusions and mutations may be identified by your doctor with a tumor biopsy or a blood test.

What is the ARROW clinical trial?

Trial phase: Phase 1

Trial status: Active and recruiting participants

Enrollment goal: 115 people

Chance of receiving active treatment

Who is eligible to participate in the ARROW clinical trial?

NSCLC with a known RET fusion*

MTC (a known RET mutation is not required)*

Other solid tumor with a known RET fusion or mutation*

At least 18 years old

Unresectable disease (not eligible for surgery) for which all standard therapy options have been exhausted**

  • RET fusions and mutations may be identified by your doctor with a tumor biopsy or a blood test. People with MTC may enroll in the ARROW trial without prior identification of a RET mutation because RET mutations occur more frequently in MTC compared to other types of cancer.
  • This means that the disease has not responded to or has progressed following standard therapy; standard therapy is intolerable or has been declined; or no standard therapy exists.

What does participation in the ARROW clinical trial involve?

  • Informed consent

    Before you can enroll in ARROW, you will need to review and sign an informed consent form with your doctor. The purpose of the informed consent form is to ensure you understand the risks and benefits of taking part.

  • Screening visit

    To assess your eligibility to take part. Screening assessments will take place at a trial site.

  • Dosing period

    All participants will receive the investigational drug. We will also need to carry out some health assessments to see how you are responding to the investigational drug.

  • You will continue with your cycles of investigational drug until:

    • Your disease worsens
    • You can’t tolerate any side effects you may have
    • The trial doctor decides you should leave the trial
    • You decide to leave the trial
    • The company running the trial decides to end it

What health assessments will take place during the ARROW clinical trial?

Health assessments will vary from visit to visit, but may include:

Physical exam

Blood tests

Tumor imaging by computerized tomography (CT)

Heart monitoring (ECG)

Safety monitoring

Additional assessments may be required and will be explained to you by the trial doctor.

Where is the ARROW clinical trial taking place?

  • United States

    • UC Irvine Medical Center
      Orange, CA
    • University of Colorado Cancer Center
      Aurora, CO
    • University of Miami Hospital and Clinics, Sylvester Comprehensive Cancer Center
      Miami, FL
    • Massachusetts General Hospital
      Boston, MA
    • University of Michigan,
      Ann Arbor, MI
    • Washington University School of Medicine, Siteman Cancer Center
      Saint Louis, MO
    • Duke University Medical Center
      Durham, NC
    • Oregon Health and Science University
      Portland, OR
    • University of Pennsylvania
      Philadelphia, PA
    • MD Anderson Cancer Center
      Houston, TX
    • University of Washington, Seattle Cancer Care Alliance
      Seattle, WA
    • Georgetown University
      Washington, District of Columbia

  • Italy

    • Istituto Europeo di Oncologia (IEO)
    • Grande Ospedale Metropolitano Niguarda
  • Singapore

    • National Cancer Center Singapore
  • Spain

    • Hospital Universitari Vall d'Hebron
  • United Kingdom

    • Guy's Hospital St. Thomas NHS Foundation Trust
    • NIHR UCLH Clinical Research Facility, University College of London NHS Foundation Trust
  • Republic of Korea

    • Seoul National University Hospital
    • Asan Medical Center
  • Taiwan

    • National Taiwan University Hospital
      Taipei City

Additional clinical sites in the United States and other countries are planned.

A travel support program is available for participants and caregivers to reduce out-of-pocket expenses and ensure travel to the trial site is simple and comfortable.

More information about this clinical trial, including participating trial sites, is available on

Where do I get more information about the ARROW clinical trial?

If you think you meet the criteria specified above and are interested in taking part in the ARROW trial, or you would simply like more information, please call: 617-714-6707 or email

A member of our team will talk you through the next steps, and will connect you to a suitable trial doctor.