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A study comparing dotinurad and allopurinol for lowering uric acid levels in adults with gout and high uric acid in the blood.

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What is this trial about?

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

This study involves people with hyperuricemia associated with gout. Hyperuricemia means having too much uric acid in the blood, which can lead to gout, a condition that causes painful swelling in the joints. Gout occurs when uric acid crystals build up in the joints, leading to sudden attacks of pain, redness, and swelling. The study will compare two medications that lower uric acid levels in the blood. One medication is dotinurad, also known by its code name FYU-981, which is being tested to see how well it works. The other medication is allopurinol, which is already used to treat high uric acid levels and gout. Some participants will receive placebo instead of one of the active medications.

The purpose of this study is to evaluate how well dotinurad works in lowering uric acid levels in the blood at week 24 when compared with allopurinol in adults with hyperuricemia associated with gout. The study will measure the percentage of participants whose uric acid level drops below a certain target level. It will also look at how often gout attacks occur during the study and whether participants can maintain low uric acid levels without experiencing gout attacks that need treatment.

Participants in this study will take their assigned medication by mouth in capsule form for up to 64 weeks. The study medications will be given in a way that neither the participants nor the doctors will know which treatment each person is receiving until the study is complete. During the study, participants will have regular visits where blood tests will be done to measure uric acid levels, and any gout attacks will be recorded. The study will track how well the medications work in lowering uric acid and preventing gout attacks over time.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Treatment assignment and medication start

    On Day 1, you will be assigned to one of the treatment groups. This assignment will be done randomly, similar to flipping a coin.

    You will receive either dotinurad tablets or allopurinol tablets. Both medications are taken by mouth.

    The medication you receive will be in capsule form to ensure that neither you nor the study staff know which treatment you are taking.

    You will stop taking your current allopurinol medication and begin taking the assigned study medication according to the instructions provided.

  2. Step 2

    Initial treatment period

    You will take the assigned study medication daily by mouth for the first 24 weeks.

    During this period, regular visits will be scheduled to monitor your serum uric acid levels, which is the amount of uric acid in your blood.

    Your serum uric acid levels will be measured at Week 16, Week 20, and Week 24.

    The study staff will assess whether your serum uric acid level drops below 6.0 milligrams per deciliter at Week 24. This is the main measurement the study is evaluating.

  3. Step 3

    Extended treatment period

    After Week 24, you will continue taking the study medication daily by mouth.

    This extended period will last from Week 36 through Week 64, which is an additional 28 weeks.

    During this time, any gout flares (sudden episodes of joint pain and swelling caused by gout) that require treatment will be recorded.

    The frequency of gout flares requiring treatment during this period will be monitored and compared between treatment groups.

  4. Step 4

    Final assessments

    At Week 64, final measurements will be taken to evaluate the overall effectiveness of the treatment.

    The study staff will assess whether your serum uric acid level remained below 5.0 milligrams per deciliter at Week 24 and whether you experienced any gout flares requiring treatment between Week 36 and Week 64.

    Safety assessments will be conducted throughout the entire study period to monitor for any side effects or adverse reactions to the medication.

  5. Step 5

    Study completion

    The study will conclude after Week 64 and all final assessments are completed.

    Your participation in the study will end approximately 30 days after taking the last dose of study medication.

    The total duration of your participation in the study will be approximately 64 weeks, plus the 30-day follow-up period.

Who can join the trial?

8 criteria

  • You must provide written consent to participate in the study and agree to any required legal authorizations.
  • You must be between 18 and 75 years old at the time you sign the consent form.
  • You must have a diagnosis of gout, which is a type of arthritis that causes sudden pain and swelling in the joints, based on specific medical criteria for at least 1 year. This diagnosis must follow the 2015 standards set by medical organizations.
  • You must have had at least 2 gout flares in the 12 months before joining the study. A gout flare is a sudden episode when your gout symptoms get worse.
  • You must be taking allopurinol, which is a medicine that lowers uric acid in your blood, at a stable dose of at least 300 milligrams per day, or 200 milligrams per day if you have moderate kidney problems. The dose can be up to 600 milligrams per day. You must have been taking this same dose for at least 3 months before joining the study.
  • Your serum uric acid level, which is the amount of uric acid in your blood, must be 6.5 milligrams per deciliter or higher at two separate screening visits.
  • If you are a woman who can become pregnant, you must have a negative pregnancy test at two screening visits and on the first day of the study. You must not be breastfeeding.
  • If you are a man who can father children or a woman who can become pregnant, you must agree to either completely avoid sexual intercourse or use acceptable birth control methods from the time you sign the consent form until 30 days after taking the last dose of the study medicine.

Who cannot join the trial?

5 criteria

  • The source data does not contain specific exclusion criteria information for this clinical trial
  • Exclusion criteria are reasons why someone cannot participate in a research study, but these details were not provided in the available information
  • This study is testing a medication called dotinurad compared to allopurinol for people with hyperuricemia, which means having too much uric acid in the blood that is linked to gout
  • Gout is a condition that causes painful swelling in the joints due to high levels of uric acid forming crystals
  • The study includes both male and female adult participants
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Investigated drugs

  • Dotinurad

    is a medication being tested to lower the level of uric acid in the blood. Uric acid is a substance that can build up in the body and cause gout, which is a painful condition that affects the joints. This medication works by helping the body get rid of excess uric acid through urine.

  • Allopurinol

    is a medication that is already commonly used to treat high uric acid levels in people with gout. It works by reducing the amount of uric acid that the body produces. In this study, it is being used as a comparison to see how well the new medication works.

What is already known about the treatment

  • Dotinurad

    Dotinurad is an oral medication being studied in clinical trials for the treatment of high uric acid levels in the blood (hyperuricemia) that occurs in people with gout. This drug works by blocking a specific protein in the kidneys called URAT1, which helps the body get rid of excess uric acid through urine. It belongs to a class of medications known as selective uric acid reabsorption inhibitors, and research is comparing its effectiveness to allopurinol, a commonly used gout medication. The main goal of current studies is to determine how well dotinurad can lower uric acid levels in the blood over a 24-week treatment period.

  • Allopurinol

    Allopurinol is an established oral medication widely used in medical practice to lower high uric acid levels in patients with gout and to prevent gout attacks. This drug works by blocking an enzyme called xanthine oxidase, which is responsible for producing uric acid in the body, thereby reducing the amount of uric acid that accumulates in the blood and joints. It is classified as a xanthine oxidase inhibitor and has been a standard treatment option for gout management for many years. In this clinical trial, allopurinol serves as the comparison medication to evaluate how well the newer drug dotinurad performs.

Investigated diseases

Hyperuricemia associated with gout – Hyperuricemia is a condition characterized by abnormally high levels of uric acid in the blood. Uric acid is a waste product that forms when the body breaks down substances called purines, which are found in certain foods and drinks. When uric acid levels become too high, crystals can form and deposit in joints and surrounding tissues. This leads to gout, a type of arthritis that causes sudden and severe episodes of pain, swelling, redness, and tenderness in the affected joints. The condition typically progresses through periods of acute flares followed by symptom-free intervals. Over time, if uric acid levels remain elevated, gout attacks may become more frequent and involve multiple joints.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-520206-19-00Protocol codeFYU-981-CRYS-301Estimated enrolment500 patientsSponsorCrystalys Therapeutics Inc.

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