Targeting RET

Consider ARROW – a clinical trial of pralsetinib (formerly known as BLU-667) for RET-altered non-small cell lung cancer (NSCLC), medullary thyroid cancer (MTC) and other RET-altered cancers.

About the ARROW clinical trial

The ARROW clinical trial will test an investigational drug called pralsetinib (formerly known as 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 1/2 trial designed to test the safety and the initial clinical activity of pralsetinib.

Information about RET-altered cancers

All cancers begin when one or more genes are mutated (altered) and the cell starts to divide and grow out of control. Identifying these genes is important, because drugs can be developed to target them.

RET fusions and mutations are specific alterations that are sometimes found in a gene called RET. This gene provides the instructions for making the RET protein that is involved in important cell functions. RET alterations have been shown to cause non-small cell lung cancer, medullary thyroid cancer and other solid tumors in some people. Pralsetinib is an investigational drug that was specifically designed to inhibit (block) altered forms of RET.

Who is eligible to participate in the ARROW clinical trial?

You may be eligible to take part in the ARROW clinical trial if you:

Have non-small cell lung cancer (NSCLC) with a known RET fusion or mutation
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Are at least 18 years old
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Have medullary thyroid cancer (MTC). A known RET alteration is not required
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Are not eligible for surgery and have exhausted all standard therapy options
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Have another solid tumor with a known RET fusion or mutation

Other eligibility criteria apply and these will be assessed at screening

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

About the investigational drug

If you take part in the ARROW clinical trial, you would receive the investigational drug pralsetinib. Pralsetinib comes in a capsule or tablet form, and should be swallowed whole with water.

What does taking part in the ARROW clinical trial involve?

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Up to 28 days

To assess your suitability for the trial.

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Dosing period

28-day cycles*

All participants will receive the investigational drug for a minimum of 28 days (1 cycle)

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Follow up period

All participants must have a follow-up visit 14 days after their last dose of investigational drug. At 30 days, we will give participants a follow-up call and then again every 3 months until disease progression.

*There is no maximum duration for this trial. You will continue with your cycles of treatment until:
*Your disease worsens * You can’t tolerate any side effects you may have *You decide to leave the trial * The trial doctor decides you should leave the trial * The trial sponsor decides to discontinue the trial

ARROW Trial Clinic Visits

During the trial, a variety of health assessments will be conducted to see how you are responding to the investigational drug. In most cases, these assessments will be done at a clinical site.

Health assessments will vary between visits, but may include:

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MRI or CT scan

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Vital signs

(temperature, blood pressure, heart rate and weight)

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(painless heart scan)

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Blood tests

How often will these visits take place?*

6 times

Cycle 1

Cycle 2

2 times

Cycle 3 onwards

Once per cycle

More information about health assessments and visit length will be found in the informed consent form, which you will need to read and sign if you want to take part in the ARROW clinical trial.

*Please note that these numbers are approximate. One treatment cycle is 28 days.

    How can I learn more about the ARROW 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: +1 888-BLU-PRNT (+1 888-258-7768) (US/Canada only) or email: A member of our team will connect you to a suitable trial site.

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