Active not recruitingPHASE4INTERVENTIONAL

A Study of Two Different Doses of Cabozantinib (XL184) in Progressive, Metastatic Medullary Thyroid Cancer

This study is investigating a medication called cabozantinib for people with a specific type of thyroid cancer, known as medullary thyroid cancer (MTC). This is for patients whose cancer has spread and is progressing, meaning it's getting worse. The main goal is to compare two different doses of cabozantinib: 60 mg and 140 mg. We want to find out if the lower dose (60 mg) can keep the cancer from growing for a similar amount of time and shrink the tumors just as effectively as the higher dose (140 mg). Importantly, we also want to see if this lower dose causes fewer side effects. The information gathered will help doctors understand the best way to use this medication for MTC patients.

At a glance

Status

Active not recruiting

Phase

PHASE4

Sponsor

Exelixis

Enrolment target

247

Start

25 Feb 2015

Estimated completion

01 Jan 2035

Medullary Thyroid Cancer

Results

Results from this study

Posted September 2025

Results have been published for this study.

Primary outcome

Progression Free Survival (PFS) Per Blinded Independent Radiology Committee (BIRC) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1)

PFS per BIRC per RECIST 1.1 was measured from randomization until the date of first documented disease progression or date of death from any cause, whichever came first, and was assessed for up to 31 months. The prespecified primary analysis was triggered by the required number of at least 150 events occurring in the ITT population, The data cutoff date for this event-driven analysis in the ITT population was when a total of 155 events were reported. Median PFS was calculated using the Kaplan-Meier estimates.

Full results on the registry

What is this study about?

This research is looking into a medication called cabozantinib, which is used to treat a specific type of thyroid cancer known as medullary thyroid cancer (MTC). This trial is for people whose MTC has spread to other parts of their body (metastatic) and is continuing to grow or get worse despite previous treatments.

The main aim of this study is to compare two different dose strengths of cabozantinib: 60 mg and 140 mg. We want to see if taking the lower 60 mg dose is just as effective as the higher 140 mg dose. 'Effective' means how well it stops the cancer from growing and how much it might shrink the tumors. A key part of this research is also to find out if the lower dose causes fewer unwanted side effects, which could make it easier for patients to take.

By carefully comparing these two doses, doctors hope to find the best balance between controlling the cancer and keeping side effects to a minimum. This would help improve how medullary thyroid cancer is treated in the future.

Key takeaways

This study is for medullary thyroid cancer that has spread and is getting worse.
It compares two doses of cabozantinib (60 mg and 140 mg) to a dummy pill (placebo).
The goal is to find if a lower dose works as well with fewer side effects.
Regular hospital visits, blood tests, and scans will track your health.
You won't know which treatment you are receiving.
Participation is voluntary, and you can leave at any time.

Who may be eligible?

To be considered for this study, you would need to have a confirmed diagnosis of medullary thyroid cancer that has spread and is getting worse. Doctors would also check your tumor to see if it has a specific change called a RET mutation, as the drug targets this. Your doctors must also be able to measure your cancer on scans, and you should have generally recovered from any side effects of your past treatments.

You would also need to be able to complete daily activities mostly on your own, have healthy organ function, and be willing to follow all the study rules. For safety, if you are able to have children, you and your partner would need to use reliable contraception during and for a period after the study.

Things that would mean you couldn't join include having taken cabozantinib before or having recently used similar cancer medications. The research team will carefully review your medical history to make sure the study is a good fit for you.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Do I have medullary thyroid cancer that has spread?
Has my cancer gotten worse recently?
Have I mostly recovered from side effects of previous treatments?
Am I generally able to carry out daily activities?
Have I taken cabozantinib before? (If yes, you likely can't join)
Am I willing to use contraception if I can have children?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you will be taking either a 60 mg or 140 mg dose of cabozantinib, or a 'dummy' tablet (placebo), orally (by mouth). You won't know which one you are taking. You will have regular visits to the hospital for check-ups, blood tests, and scans (like CT or MRI) to monitor your health and how the treatment is affecting your cancer. Doctors will also ask you about any side effects you might be experiencing. The total length of your participation, including follow-up, will be determined by how your cancer responds to the treatment and your overall health, but involves ongoing monitoring while on the treatment and afterwards.

Potential risks and benefits

Participating in this study might offer potential benefits, such as receiving a treatment that could help control your medullary thyroid cancer or slow its progression. This study also contributes to understanding how to best use cabozantinib, which could help future patients. However, like all medications, cabozantinib can have side effects, which could range from mild to severe. These will be carefully explained to you. You are free to withdraw from the study at any time, for any reason, without it affecting your usual medical care.

Locations (49)

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St Leonards, Australia
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Herston, Australia
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Kurralta Park, Australia
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Parkville, Australia
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Québec, Canada
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Toronto, Canada
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Osijek, Croatia
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Zagreb, Croatia
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Zagreb, Croatia
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Bordeaux, France
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Angers, France
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Lyon, France

Common questions

What is medullary thyroid cancer (MTC)?

It's a specific type of thyroid cancer that starts in cells different from those in more common thyroid cancers.

What is cabozantinib?

It's a medication that targets certain pathways in cancer cells to help stop their growth.

Will I know if I'm getting the drug or a placebo?

No, this study is 'blinded,' meaning you won't know if you're receiving cabozantinib or a placebo.

What does 'progressive, metastatic' mean?

It means the cancer has spread beyond the thyroid to other parts of the body and is continuing to grow or get worse.

Can I stop the study at any time?

Yes, you have the right to withdraw from the study at any point without it affecting your future medical care.