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Study of KAI-9531 in Adults With Obesity or Overweight and Weight-Related Health Problems Without Diabetes

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What is this trial about?

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

This study is being done in people with obesity or overweight who also have other health problems linked to body weight and who do not have diabetes. The treatment being studied is KAI-9531, given as a subcutaneous injection under the skin once a week. Some people in the study will receive a placebo.

The purpose of the study is to see how well KAI-9531 works and how safe it is. Participants are assigned by chance to receive either KAI-9531 or placebo, and neither the participants nor the study team know which treatment is being given during the study. The study continues for a long period while regular injections are given and health is followed over time.

During the study, body weight and other health measures are checked at planned visits. The study looks at changes in weight, waist size, blood pressure, blood fats such as triglycerides and cholesterol, blood sugar, and quality of life related to physical function. Safety is also monitored through medical checks, blood tests, heart tracing with ECG, and review of any side effects.

The research process

"{\n \"timeline\": [\n {\n \"step\": \"study start and group assignment\",\n \"step_number\": \"1\",\n \"details\": [\n \"After you join the study, you are assigned to one of the study groups by chance. This is called randomization, which means a computer-like process decides the group, not the patient or the study team.\",\n \"The study is double-blind, which means you do not know whether you are receiving KAI-9531 or placebo. A placebo is a liquid injection that looks the same as the study medicine but does not contain the active drug.\",\n \"The study medicine is given as a subcutaneous injection, which means an injection under the skin.\"\n ]\n },\n {\n \"step\": \"weekly treatment period\",\n \"step_number\": \"2\",\n \"details\": [\n \"You receive the study treatment once weekly for up to 76 weeks.\",\n \"If you are assigned to the active treatment group, you receive KAI-9531 as a solution for injection under the skin. The source data list the dose as 00 mg.\",\n \"If you are assigned to the comparison group, you receive placebo instead of the active drug. The placebo is described as identical to the KAI-9531 solution for injection without active drug.\",\n \"The trial compares the effect of KAI-9531 with placebo on change in body weight over time.\"\n ]\n },\n {\n \"step\": \"study measurements during treatment\",\n \"step_number\": \"3\",\n \"details\": [\n \"During the trial, your body weight is measured and compared with your starting weight.\",\n \"Your waist size is measured.\",\n \"Your body mass index, or bmi (a measure based on height and weight), is measured.\",\n \"Your blood pressure is measured, including sbp (top blood pressure number) and dbp (bottom blood pressure number).\",\n \"Blood tests are taken to check fats in the blood, including triglycerides, hdl-cholesterol (often called good cholesterol), non-hdl-cholesterol, total cholesterol, ldl-cholesterol (often called bad cholesterol), and vldl-cholesterol.\",\n \"Blood tests are also taken to check fasting insulin and fasting blood glucose, which means blood sugar measured after not eating for a period of time.\",\n \"You complete questionnaires about physical function and quality of life, including iwqol-lite-ct and coeq. These are study questionnaires about how weight affects daily life and overall health experience.\",\n \"You have ecgs, or electrocardiograms, which are tests that record the heart's electrical activity.\",\n \"Your vital signs are checked. Vital signs are basic body measurements such as pulse, blood pressure, and temperature.\",\n \"The study also checks for teaes, which means treatment-emergent adverse events. These are health problems that appear or worsen after treatment starts.\",\n \"The study measures ada nab, which means antibodies against the drug that may be made by the body.\",\n \"The study also evaluates population pk, which means how the study medicine moves through the body.\"\n ]\n },\n {\n \"step\": \"end of week 76 evaluation\",\n \"step_number\": \"4\",\n \"details\": [\n \"At week 76, your change in body weight from the start of the study is assessed.\",\n \"The study checks how many participants have lost at least 5%, 10%, 15%, 20%, 25%, or 30% of body weight.\",\n \"The study also measures changes in your waist size, body mass index, body weight, blood pressure, blood fats, fasting insulin, fasting blood glucose, and questionnaire scores.\"\n ]\n },\n {\n \"step\": \"study duration\",\n \"step_number\": \"5\",\n \"details\": [\n \"The study is planned to run from 2026-06-25 to 2028-03-27.\"\n ]\n }\n ]\n}"

Who can join the trial?

2 criteria

  • Body mass index (BMI) must be 30 kg/m² or higher, or 27 kg/m² or higher if the person has had at least one of these conditions before: high blood pressure (hypertension), abnormal blood fats (dyslipidemia), obstructive sleep apnea (a condition where breathing repeatedly stops during sleep), or heart and blood vessel disease (cardiovascular disease).
  • The person must have had at least one unsuccessful attempt to lose weight using diet and exercise within the past 6 months.

Who cannot join the trial?

10 criteria

  • A current diagnosis of diabetes mellitus or a past history of diabetes. Diabetes mellitus is a condition where blood sugar is too high.
  • Use of semaglutide, tirzepatide, a GLP-1 receptor agonist, a GLP-1/GIP medicine, or a glucagon receptor agonist within 3 months before screening. These are medicines that affect blood sugar and weight.
  • Starting any medicine within 3 months before screening that may cause major weight gain, including tricyclic antidepressants (older medicines for depression), atypical antipsychotics (medicines for some mental health conditions), or mood stabilizers (medicines that help control mood changes).
  • Unstable weight, meaning the person says their body weight changed by more than 5% in the 3 months before screening.
  • A family or personal history of multiple endocrine neoplasia type 2 or medullary thyroid cancer. Multiple endocrine neoplasia type 2 is a rare inherited condition that can cause tumors in hormone-producing glands, and medullary thyroid cancer is a type of thyroid cancer.
  • Uncontrolled hypertension or unstable cardiovascular disease. Hypertension means high blood pressure, and cardiovascular disease means heart or blood vessel disease.
  • A history of chronic pancreatitis or acute pancreatitis. Pancreatitis is swelling and irritation of the pancreas, an organ that helps with digestion and blood sugar control.
  • A known clinically significant problem with gastric emptying, meaning the stomach does not empty food normally, or ongoing treatment with medicines that directly affect gastrointestinal motility, meaning the movement of food through the stomach and intestines.
  • A history of suicide attempt.
  • A history of significant active or unstable major depressive disorder or another severe psychiatric disorder. Major depressive disorder is a serious form of depression, and psychiatric disorder means a mental health condition.
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Investigated drugs

  • KAI-9531

    is the study medicine being tested in this trial. It is given as a subcutaneous injection, which means it is injected under the skin once a week. The goal of the study is to see whether it helps people with obesity or overweight and related health problems lose weight safely and effectively.

  • Identical placebo injection

    is a look-alike injection that does not contain any active medicine. It is used for comparison so the researchers can better tell whether KAI-9531 is working. It is given in the same way as the study medicine so neither the participants nor the study team knows who is receiving the real treatment or the placebo during the trial.

What is already known about the treatment

KAI-9531 - KAI-9531 is given as a solution for injection under the skin, usually once weekly, using a subcutaneous injection. It is an experimental medicine in current clinical research, so its full place in routine medical care is not yet established in the medical literature. It is being studied for weight loss in people with obesity or overweight, especially those with weight-related health problems but without diabetes. Based on its very long peptide structure, it appears to act by helping control appetite and body weight through hormone-like signals in the body, and it is best classified as an investigational anti-obesity agent.

Investigated diseases

Obesity - Obesity is a condition in which a person has too much body fat and body weight above what is considered healthy for their height. It usually develops over time when energy intake is greater than energy use. The condition can continue to progress gradually, with further increases in body weight and waist size if the imbalance persists. It may also be linked with changes in body measurements and blood fat levels over time.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-523486-17-00Protocol codeK9531-3103Estimated enrolment2 409 patients

sourced from the EU Clinical Trials Register and site verification

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