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A Study Testing Casdatifan and Cabozantinib Compared to Placebo and Cabozantinib in Patients With Advanced Clear Cell Kidney Cancer

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is looking at advanced clear cell renal cell carcinoma and metastatic clear cell renal cell carcinoma, which are types of kidney cancer that have spread beyond the kidney or cannot be removed by surgery. The study will use casdatifan, which is also known by its code name AB521, and cabozantinib. Some people in the study will receive casdatifan combined with cabozantinib, while others will receive placebo combined with cabozantinib. Both medications are taken by mouth as tablets.

The purpose of the study is to compare how long people live without their cancer getting worse when they take casdatifan with cabozantinib compared to when they take placebo with cabozantinib. During the study, patients will take their assigned treatment for up to 120 months. The study will check how well the treatment works by using imaging scans to see if the tumors have grown, shrunk, or stayed the same size. These scans will be reviewed by independent experts who are not directly involved in treating the patients.

The study will also look at other important outcomes, including how long people live overall, how many people see their tumors shrink, how long the tumor response lasts, and how many people have their disease stay under control for at least 16 weeks. The study team will carefully monitor any side effects that occur and will track changes in symptoms related to the kidney cancer using questionnaires that ask about disease-related symptoms. Treatment can continue for up to 10 years, and the study is expected to be completed by mid-2029.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Treatment assignment

    You will be assigned by chance to one of two treatment groups. This process is called randomization and works like flipping a coin.

    One group will receive casdatifan combined with cabozantinib.

    The other group will receive placebo (an inactive substance with no medication) combined with cabozantinib.

    Neither you nor your doctor will know which group you are in. This is called a double-blind study and helps ensure accurate results.

  2. Step 2

    Daily medication intake

    You will take your assigned medications by mouth in the form of tablets.

    The medications should be taken according to the schedule provided by the study team.

    Both cabozantinib and either casdatifan or placebo will be taken orally.

    You will continue taking the study medications for as long as the treatment is beneficial and tolerable.

  3. Step 3

    Regular imaging scans

    You will undergo regular imaging tests using computed tomography or magnetic resonance imaging. These are scanning methods that create detailed pictures of the inside of your body.

    These scans will measure how your cancer is responding to treatment.

    The scans will be reviewed by independent experts who do not know which treatment group you are in.

  4. Step 4

    Safety monitoring

    You will have regular check-ups to monitor your health and any side effects from the medications.

    Blood tests will be performed to check your organ function and blood cell counts.

    Any side effects or health changes will be recorded and assessed for severity.

  5. Step 5

    Quality of life assessments

    You will be asked to complete questionnaires about your symptoms and how you are feeling.

    These questionnaires focus on symptoms related to kidney cancer and how they affect your daily life.

    The questionnaire used is called the National Comprehensive Cancer Network/Functional Assessment of Cancer Therapy-Kidney Symptom Index.

  6. Step 6

    Treatment continuation

    You will continue receiving the study treatment until your cancer progresses, side effects become too severe, or you decide to stop participating.

    Cancer progression means the cancer has grown or spread despite treatment.

    The study team will regularly evaluate whether continuing treatment is appropriate for you.

  7. Step 7

    Follow-up period

    After stopping the study treatment, you will continue to be monitored.

    Information about your overall health and survival will be collected.

    This follow-up period helps researchers understand the long-term effects of the treatment.

Who can join the trial?

5 criteria

  • You must have kidney cancer that cannot be removed by surgery and has spread to other parts of the body or is advanced, with a specific type called clear cell
  • You must have a Karnofsky Performance Status score of at least 80%, which means you are able to carry out normal activities and work without needing special care
  • You must have at least one tumor that can be measured using imaging tests such as CT scan (a special type of X-ray) or MRI (a scan using magnets), and this tumor must not have been treated with radiation therapy before
  • Your organs and bone marrow must be working well enough, which will be checked with blood tests done within 72 hours before joining the study
  • If you are a woman who can become pregnant, you must have a negative pregnancy test done using a blood sample

Who cannot join the trial?

3 criteria

  • The study does not list specific exclusion criteria in the provided information, which means the detailed reasons why patients cannot participate are not available in this data
  • To understand if you can participate in this study, you would need to review the complete study documentation or speak with the research team conducting the trial
  • Generally, clinical trials have exclusion criteria to ensure patient safety and that the study results are reliable, but these specific details are not included in the information provided
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Investigated drugs

  • Casdatifan

    is an investigational medication being studied in combination with cabozantinib for the treatment of advanced clear cell renal cell carcinoma, which is a type of kidney cancer. This medication is being tested to see if it can help slow down the progression of the disease when used together with cabozantinib.

  • Cabozantinib

    is a cancer medication that works by blocking certain proteins that help cancer cells grow and spread. In this trial, it is being given to all participants, either alone with a placebo or in combination with casdatifan, to treat advanced clear cell renal cell carcinoma.

What is already known about the treatment

  • Casdatifan

    Casdatifan is an investigational medication currently being studied in clinical trials for the treatment of advanced and metastatic clear cell renal cell carcinoma (a type of kidney cancer). In this phase 3 trial, it is being administered in combination with cabozantinib and compared against placebo plus cabozantinib to evaluate its effectiveness in slowing disease progression. The specific form of administration and exact mechanism of action at the molecular level are being evaluated as part of ongoing research, though it is being developed as a targeted therapy for patients with this specific type of kidney cancer. The main goal of the study is to determine whether adding casdatifan to standard treatment can help patients live longer without their cancer getting worse.

  • Cabozantinib

    Cabozantinib is an approved oral medication taken by mouth in tablet form that is used to treat advanced kidney cancer, including clear cell renal cell carcinoma. It works by blocking specific proteins called tyrosine kinases, which are involved in helping cancer cells grow and form new blood vessels that feed tumors. This medication belongs to a class of drugs known as tyrosine kinase inhibitors or targeted therapy agents. In this clinical trial, cabozantinib serves as the active control treatment and is being given to all participants, either alone with placebo or in combination with the investigational drug casdatifan.

Investigated diseases

  • Advanced Clear Cell Renal Cell Carcinoma

    This is a type of kidney cancer that has progressed beyond its early stages and involves clear cells, which appear pale or clear when examined under a microscope. Clear cell renal cell carcinoma originates in the lining of the small tubes in the kidney that filter waste from the blood and produce urine. In the advanced stage, the cancer has grown larger or spread to nearby tissues beyond the kidney. The disease may affect kidney function and cause symptoms such as blood in the urine, pain in the side, or a mass in the abdomen. As it progresses, the cancer cells continue to multiply and can interfere with normal organ function.

  • Metastatic Clear Cell Renal Cell Carcinoma

    This is an advanced form of kidney cancer where clear cell cancer has spread from the kidney to other parts of the body. The cancer cells travel through the bloodstream or lymphatic system to form new tumors in distant organs such as the lungs, bones, liver, or brain. This represents the most progressed stage of clear cell renal cell carcinoma. The spreading process occurs when cancer cells break away from the original tumor in the kidney and establish themselves in other locations. Symptoms may vary depending on which organs are affected by the spreading cancer. The disease continues to progress as cancer cells multiply in multiple locations throughout the body.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-515023-11-00Protocol codePEAK-1Estimated enrolment736 patientsSponsorArcus Biosciences Inc.

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