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Evaluation of safety and efficacy of 19CP02 combined with cyclophosphamide and fludarabine phosphate in adults with treatment‑refractory active systemic lupus erythematosus

Fast replyRegistered drugNo placebo
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What is this trial about?

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

Systemic lupus erythematosus is a chronic autoimmune disease in which the body’s immune system mistakenly attacks its own tissues, leading to inflammation of the joints, skin, kidneys and other organs. When the disease stays active despite standard medicines, it is described as treatment‑refractory active disease. This study evaluates a new investigational drug called GLPG5101, which is administered by intravenous infusion.

The purpose of the study is to assess the safety, tolerability and efficacy of the investigational therapy in adults with treatment‑refractory active systemic lupus erythematosus.

Participants first enter a dose‑finding phase in which different amounts of the drug are given to determine a safe level, followed by a dose‑expansion phase where the selected dose is given for up to two years. The medication is delivered through an IV on scheduled visits, and participants are regularly checked for side effects and for signs that the disease is under control, including whether they achieve a state of remission (very low disease activity) after one year, with continued follow‑up through the study period.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline visit

    After enrollment, you will attend a baseline visit where medical history, physical examination, and laboratory tests are performed to confirm eligibility for the study.

  2. Step 2

    Administration of background medicines

    On the scheduled day, you will receive an intravenous infusion of fludarabine phosphate at a dose of 30 mg/m2.

    You will also receive an intravenous infusion of cyclophosphamide at a dose of 300 mg/m2. the infusion is given through a vein over a short period as instructed by the study staff.

  3. Step 3

    Infusion of the investigational product

    Following the background medicines, you will receive an intravenous infusion of 19cp02 at a dose of 250 million organisms. the product is supplied as a dispersion for infusion and is administered through a vein.

  4. Step 4

    Short‑term safety monitoring (dose‑finding phase)

    For up to three months after the infusions, you will attend regular clinic visits to assess adverse events and any dose‑limiting toxicities.

    During these visits, blood tests, physical examinations, and questionnaires will be completed to record any side effects.

  5. Step 5

    Continued treatment (dose‑expansion phase)

    If the short‑term safety assessment is acceptable, you will continue receiving the study drug glpg5101 according to the protocol schedule.

    The exact dosing schedule follows the study plan and is administered by intravenous infusion.

  6. Step 6

    Long‑term efficacy follow‑up

    You will be followed for up to two years to evaluate the effectiveness of the treatment.

    At the year 1 visit, the primary efficacy outcome is whether you meet the remission criteria defined for systemic lupus erythematosus without using additional drugs.

    Periodic assessments, including laboratory tests and clinical evaluations, will continue throughout the study period.

Who can join the trial?

6 criteria

  • You must agree to follow the study rules, sign the consent form, and give your permission before any tests are done.
  • Your body mass index (BMI)—a measure of weight relative to height—must be between 18 and 32 kilograms per square meter when you are screened.
  • You need to be willing to follow the study’s limits on medicines you have taken before and any medicines you take during the study, including slowly reducing (tapering) any steroids.
  • You must have a documented diagnosis of systemic lupus erythematosus (SLE) that meets the 2019 European Alliance of Associations for Rheumatology/American College of Rheumatology classification criteria, and the disease must have been diagnosed at least 24 weeks (about 6 months) before the screening visit.
  • Your SLE must be active and affect a major internal organ such as the kidney, heart, lungs, stomach/intestines, liver, or cause low blood cell counts, as shown by a score of at least one “A” or two “B” on the BILAG (British Isles Lupus Assessment Group) organ activity system.
  • Lab tests must show that your disease is active, meaning you have positive results for antibodies such as anti‑dsDNA, anti‑Sm, or anti‑nucleosome, as measured by the study’s central laboratory.

Who cannot join the trial?

6 criteria

  • People who have had a serious clotting disorder called catastrophic or severe antiphospholipid syndrome in the past year are not allowed. This includes anyone who experienced a major clot such as a pulmonary embolism (clot in the lungs), a stroke (clot in the brain), or a deep vein thrombosis (clot in a leg vein), or who had an unexplained miscarriage or three or more consecutive miscarriages in the past year. (If this condition is well‑controlled with blood‑thinning medication for at least three months, the person may still be eligible.)
  • Anyone with active disease affecting the brain or nerves, called central nervous system (CNS) lupus, or with unstable nervous‑system symptoms of lupus, psychiatric illness with antibodies that attack the body’s own cells (antinuclear antibodies), lupus caused by medication (drug‑induced lupus), or a serious non‑lupus blood‑vessel inflammation (vasculitis) or skin problem is excluded.
  • People who have serious damage to specific organs (kidney, heart, lung, stomach/intestines, or liver) that meets two or more of the Systemic Lupus International Collaborating Clinics (SLICC) criteria for those organs are not allowed to join.
  • Anyone with an active hepatitis B infection is excluded. This is true if they test positive for the hepatitis B surface protein (HBsAg) or if they have a positive core antibody test (HBcAb) together with detectable hepatitis B virus DNA (the virus’s genetic material measured by a test called PCR).
  • Anyone with an active hepatitis C infection is excluded. This means they have a positive hepatitis C antibody test (HCV Ab) and detectable hepatitis C virus RNA (the virus’s genetic material measured by PCR).
  • People who have a history of, or currently have, another condition that weakens the immune system (an immunosuppressive condition) besides lupus, such as infection with the human immunodeficiency virus (HIV), cannot participate.
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Investigated drugs

  • Fludarabine phosphate

    is a medicine given through an IV that helps suppress the activity of the immune system. In this study it is used as part of the background treatment to lower the number of immune cells before the new therapy is given, which can help the body accept the experimental treatment.

  • Cyclophosphamide

    is an IV chemotherapy drug that also reduces immune system activity. It is included in the background regimen of the trial to further control the over‑active immune response that characterizes severe lupus, creating a safer environment for testing the new therapy.

  • 19CP02

    is an experimental infusion that contains a very small amount of living organisms designed to affect the immune system. It is the test product being studied in the trial to see if it can safely improve the symptoms of treatment‑refractory lupus.

  • GLPG5101

    is the investigational drug being evaluated for up to two years in adults whose lupus has not responded to other treatments. The study is looking at how well it works to control disease activity and how safe it is for patients.

What is already known about the treatment

  • Fludarabine Phosphate

    It is given by intravenous infusion, usually as a short drip. It is an approved drug for certain blood cancers and is also studied for other conditions. It works by mimicking a building block of DNA, which stops cells from copying their DNA and growing. It belongs to the antimetabolite class of chemotherapy drugs.

  • Cyclophosphamide

    It is administered by intravenous infusion, often over a short period. It is an established medicine used for many cancers and for severe autoimmune diseases such as lupus. It works by adding chemical groups to DNA, which prevents cells from dividing and also reduces immune activity. It is classified as an alkylating agent and an immunosuppressant.

  • 19CP02

    It is given as an intravenous infusion of a dispersion containing live cells. It is an experimental therapy that is not yet approved and is being tested in clinical trials for lupus. It is designed to modify the immune system by introducing cells that can calm over‑active immune responses. It is classified as an investigational cellular therapy.

Investigated diseases

Treatment‑refractory active systemic lupus erythematosus - Systemic lupus erythematosus is an autoimmune disorder in which the immune system mistakenly attacks the body’s own tissues, causing inflammation in the skin, joints, kidneys, and other organs. In the active form, patients experience symptoms such as joint pain, skin rash, fatigue, and kidney problems. When the disease is treatment‑refractory, standard therapies fail to control the inflammation, and symptoms continue despite treatment. The condition can flare, with periods of worsening symptoms followed by calmer phases. Ongoing inflammation may gradually affect organ function over time.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-504422-19-00Protocol codeGLPG5101-CL-104Estimated enrolment20 patientsSponsorGalapagos

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