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A study to evaluate the effectiveness and safety of zasocitinib in patients with moderate to severe hidradenitis suppurativa

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What is this trial about?

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

This study is designed to evaluate the efficacy and safety of zasocitinib in people living with Hidradenitis Suppurativa. Hidradenitis Suppurativa is a long-term skin condition that causes painful lumps, abscesses (pus-filled bumps), and inflammatory nodules (red, swollen lumps under the skin) to form, typically in areas where skin rubs together. The study focuses on individuals experiencing moderate to severe symptoms of this condition.

Participants in this trial will be assigned to receive either the study drug, zasocitinib, which is taken in the form of an oral capsule, or a placebo. This is a double-blind study, meaning that neither the participants nor the researchers will know which treatment is being administered until the study is completed. This method is used to ensure that the results are not influenced by expectations or biases.

During the course of the study, the progress of the condition will be monitored over several weeks. The main goal is to see how well the medication reduces the number of painful lumps and skin lesions compared to the placebo. The study will also track any adverse events, which are unintended medical problems or side effects that may occur during the treatment period.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Study participation

    Participation begins with the administration of either zasocitinib, which is a capsule taken by mouth, or a placebo, which is an inactive substance used for comparison.

    The assignment of the medication or placebo is randomized, meaning it is decided by chance, and double-blind, meaning neither the patient nor the medical staff knows which substance is being administered.

  2. Step 2

    Treatment period

    The treatment continues for a period of 16 weeks.

    During this time, the effectiveness of the zasocitinib is measured by tracking the reduction in the number of abscesses (painful, pus-filled bumps) and inflammatory nodules (swollen lumps under the skin).

  3. Step 3

    Assessment of results

    At week 16, a clinical response is evaluated to see if there has been at least a 75% reduction in the total count of abscesses and inflammatory nodules, with no increase in draining tunnels (narrow passages under the skin caused by the condition).

Who can join the trial?

11 criteria

  • You must have had signs and symptoms of hidradenitis suppurativa (a skin condition that causes painful lumps under the skin) for at least 6 months before the study starts.
  • A dermatologist (a doctor who specializes in skin, hair, and nails) must confirm your diagnosis during your first visit.
  • Your skin symptoms must have remained stable for at least 2 months before the study begins.
  • You must have skin lesions (areas of skin that are damaged or abnormal, such as bumps or sores) in at least 2 different parts of your body.
  • At least one of those body areas must show signs of Hurley Stage II or III, which refers to more advanced stages of the disease involving deeper tunnels or more frequent scarring under the skin.
  • You must have at least 5 inflammatory lesions (painful, swollen bumps such as abscesses, which are collections of pus, or nodules, which are hard lumps) at the start of the study.
  • You must have a history of not responding well to oral antibiotics (pills used to fight bacterial infections) or have experienced the disease returning, side effects, or being unable to take the medicine.
  • You must be at least 18 years old.
  • If you are able to become pregnant, you must either have had a surgery to prevent pregnancy, be in postmenopausal status (the stage of life after a woman's monthly periods have permanently stopped), or agree to use a highly effective method of contraception (methods used to prevent pregnancy).
  • You must be willing and able to follow all study rules, including using digital tools and phone applications.
  • You must provide written informed consent (a signed document showing you understand and agree to participate) and privacy authorization before any study activities begin.

Who cannot join the trial?

26 criteria

  • You have more than 20 draining tunnels, which are narrow pathways under the skin that leak fluid, at the start of the study.
  • Your ECG, which is a test that records the electrical activity of your heart, shows abnormalities that could make participating unsafe.
  • Your kidney, liver, or pancreas (an organ that helps with digestion) are not working correctly based on blood tests.
  • Your blood tests show low levels of hemoglobin (a protein in red blood cells that carries oxygen), white blood cells (cells that fight infection), neutrophils (a type of white blood cell), lymphocytes (another type of white blood cell), or platelets (cells that help blood clot).
  • Your thyroid levels, which are hormones that control how your body uses energy, are outside the normal range.
  • Your triglyceride levels (a type of fat in your blood) are too high.
  • Your CPK levels, which is an enzyme found in muscles, are too high.
  • You have difficulty having blood drawn through a vein, known as venipuncture.
  • You have a history of severe allergic reactions, such as anaphylaxis (a life-threatening allergic reaction), or you are allergic to the study medicine.
  • You are pregnant, breastfeeding, or planning to become pregnant or donate eggs or sperm during the study.
  • You have used drugs or substances excessively within the last 12 months.
  • You have donated a large amount of blood or plasma (the liquid part of blood) recently or plan to do so during the study.
  • You are currently in a hospital or institution against your will due to mental or physical health reasons.
  • You are an employee of the study site or a close family member of someone working on the study.
  • You have another skin condition, such as a bacterial infection or fungus, that might make it hard to judge your progress with the main disease.
  • You have had cancer in the last 5 years, unless it was a specific, successfully treated type of skin cancer.
  • You have a history of heavy smoking or excessive alcohol use.
  • You have been diagnosed with sarcoidosis (an inflammatory disease), lupus (an immune system disease), or inflammatory bowel disease (a condition affecting the intestines).
  • You have other inflammatory conditions like psoriasis or rheumatoid arthritis (conditions where the immune system attacks joints).
  • You have tuberculosis (a serious bacterial infection), or you have a history of it or a test showing you might have a hidden infection.
  • You have an active herpes infection or a history of severe herpes infections.
  • You have Hepatitis B, Hepatitis C, or HIV (viral infections that affect the immune system).
  • You have had a recent serious infection that required hospitalization or strong medicine.
  • You have a history of chronic infections, such as long-term lung or skin infections.
  • You have an infected joint prosthesis (an artificial joint) that has not been replaced.
  • You have any other medical condition that makes your health unstable or puts you at risk during the study.
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Investigated drugs

Zasocitinib is an oral capsule being tested to see if it can help treat people with moderate to severe hidradenitis suppurativa, a condition that causes painful lumps and inflammation on the skin.

What is already known about the treatment

Zasocitinib - This medication is an experimental drug taken by mouth in the form of a capsule. Currently being studied in clinical trials, it is being tested to see if it can help treat moderate to severe hidradenitis suppurativa, a painful skin condition. It belongs to a class of drugs known as JAK inhibitors, which work by blocking specific proteins inside cells that trigger inflammation and swelling. By stopping these signals, the medicine aims to reduce the skin lesions and discomfort caused by the disease.

Investigated diseases

Hidradenitis suppurativa - This is a chronic skin condition that causes painful lumps to form under the skin. These lumps typically appear in areas where skin rubs together, such as the armpits or groin. Over time, these bumps can develop into larger, inflamed nodules or abscesses. As the condition progresses, these lesions may rupture and create tunnels under the skin. These tunnels can connect different areas and lead to more frequent drainage.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-522831-33-00Protocol codeTAK-279-HS-2001Estimated enrolment90 patientsSponsorTakeda Development Center Americas Inc.

sourced from the EU Clinical Trials Register and site verification

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