Clinical trials

56

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Condition / disease
Location
Status: Not yet recruiting

Discovering Determinants of Food Intake by Application of Artificial Intelligence to Complex, High-Dimensional Data

Background: Many people in the United States are overweight or obese. Researchers want to learn why some people can overeat and not gain weight, whereas others who do not overeat still gain weight. Objective: To study factors related to food intake that can lead to weight gain over time. Eligibility: Healthy adults aged 18 to 60 years. Design: Participants will have 6 to 8 clinic visits over 2 years. The first 3 or 4 study visits will be 1 week apart. Procedures during visits may include the following: Collection of blood, hair, urine, and stool samples. Measurement of the waist, neck, thighs, and other parts of the body. Dual energy x-ray absorption (DXA) scan: Participants will lie still on a padded table while they are scanned to measure body fat. Physical activity monitor: Participants will wear a monitor on the wrist for 2 weeks. Cognitive tests: Participants will perform tasks to measure attention, memory, and brain function. Continuous glucose monitor. Participants will wear a device that measures their blood glucose for 1 week. Mixed meal test and stomach emptying test. Participants will drink a breakfast shake and swallow a dose of acetaminophen. Blood will be drawn over the next 4 hours. Resting metabolic rate: Participants will wear a clear hood over their head while they rest for 20 minutes. The hood will measure the gases they breathe. Breakfast and lunch test. Participants will eat a standard breakfast. They will be allowed to select from foods and eat as much as they like at lunch. They will be asked how hungry or full they are. Questionnaires. Participants will answer questions about their health, sleep, physical activity, and eating.

Participants needed: 800
Trial details
Age: 18-60Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Stated willingness to comply with all study procedures and availability for the... [+2]

Weight >=204 kg (>=450 pounds, maximum weight of the iDXA machine as per manufac... [+4]

Status: Not yet recruiting

Longitudinal Immunophenotyping of Patients With Inflammatory Bowel Disease

Background: Inflammatory bowel disease (IBD) is a term used to describe disorders that cause long-term inflammation in the digestive tract. Symptoms include stomach pain, diarrhea, and bleeding. Crohn's disease and ulcerative colitis are the 2 main types of IBD. Researchers want to conduct a natural history study to learn more about whether genetic factors can cause IBD; how immune cells contribute to IBD; and how diet, drugs, and disease affect those cells. Objective: To better understand IBD over time. Eligibility: Adults aged 18 to 85 years with Crohn's disease, ulcerative colitis, or another IBD. Their healthy relatives are also needed. Design: Affected participants will have clinic visits every 6 months for 3 years. Once a year, they will have these procedures: A physical exam with blood and stool samples. Ultrasound of the abdomen. A wand will be rolled over the skin. It uses sound waves to capture images of the intestines. Magnetic resonance imaging (MRI) scan. They will lie on a table that slides into a tube. Magnetic fields will capture images of the intestines. Colonoscopy. A long, flexible tube with a video camera will be inserted into the rectum to view the entire colon. Up to 12 tissue samples may be taken. Upper endoscopy, for those with Crohn's disease. A long, thin tube with a camera will be inserted through the mouth and into the first part of the small intestine. Up to 12 small tissue samples may be taken. Questionnaires. Participants will answer questions about their disease and their diet. Midyear visits will include a physical exam, blood and stool collection, ultrasound, and questionnaires Healthy relatives will have 1 blood draw for genetic tests.

Participants needed: 100
Trial details
Age: 18-85Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Adults 18 - 85 years of age [+6]

Unable or unwilling to provide informed consent [+1]

Status: Not yet recruiting

Evaluation of the Clinical Spectrum of Diabetes and Obesity in Youth and Adults

Background: Diabetes and obesity are chronic diseases. They can affect blood flow and how the body processes nutrients, and complications over time can lead to early death. Diabetes can affect children as well as adults, but the disease seems to be more severe and to progress faster when it appears in younger people. Researchers want to understand more about how diabetes and obesity develop and change over time. Objective: To collect data and samples regularly from people with obesity and diabetes. Eligibility: People aged 8 to 65 years. They must be overweight or obese; or have high blood sugar; or have problems with how their body uses food for energy. Design: Participants will have additional procedures during routine care visits at the NIH clinic. Data collected for the study will include the following: Information from the participant s medical chart will be kept for research. Questionnaires will ask about participant s eating habits, feelings, sleep, and substance use. They will take 30 to 60 minutes. Care providers will address any issues revealed in these surveys. Blood, saliva, urine, and stool samples will be collected. Samples may be used for genetic tests. Data and samples will be kept for future research. Participants may remain in the study up to 30 years.

Participants needed: 1,000
Trial details
Age: 8-65Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Age 8 years to 65 years

History of significant medical illnesses that the investigators feel may interfe... [+2]

Status: Not yet recruiting

Effects of Meal Macronutrients on Postprandial Lipids

Background: Abnormal fats in the blood can lead to many problems, including heart disease. Researchers want to learn more about how eating meals with different levels of nutrients affects fats in the blood. Specifically, they want to study people with too much body fat, too little body fat, and a kidney problem called nephrotic syndrome. Objective: To learn more about how different types of foods affect fat levels in the blood. Eligibility: People aged 18 years or older with a health condition that affects how their body handles fats. Healthy volunteers are also needed. Design: Participants will have 2 overnight stays in the clinic within 6 months. At each visit, after staying overnight, they will eat a breakfast casserole. At 1 visit, breakfast will be a high-fat, low carbohydrate meal. At the other, it will be a high-carbohydrate, low-fat meal. Participants will have a tube inserted into a vein in their arm. They will have blood drawn via the tube 12 times in 8 hours: 2 times before they eat the breakfast and 10 times after. Participants will have other tests during their stays: * A resting metabolic test captures the air they exhale and measures how much energy they use at rest. * A dual energy X-ray absorptiometry (DXA) scan measures how much fat and muscle they have. * A Fibroscan is a special type of ultrasound of the liver. * A body surface scan uses lasers to measure the total area of the body. * A bioelectric impedance (BIS) exam measures how fast small electric currents move through their body. Participants may opt to have a third visit. At this visit, the breakfast will be high in protein....

Participants needed: 100
Trial details
Phase: Phase 2Age: 18-120Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Age >= 18 years [+35]

Consuming extreme macronutrient diet (e.g., very low-carbohydrate, high fat diet... [+23]

Status: Recruiting

Hepatic Lipid Metabolism-Alcohol Use Disorder

Patients with hepatic steatosis due to alcohol will be offered liver biopsies when they enter a detoxification program. The first biopsy will occur in the first week of admission and the second in the fourth week when the steatosis has resolved. The hepatic transcriptome will be compared,

Participants needed: 25
Trial details
Age: 18-100Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Any individual >=18 years of age who is enrolled in 14-AA-0181 and is seeking in... [+1]

Pregnancy [+11]

Status: Not yet recruiting

177Lu-DOTA-EB-TATE in Adult Patients With Metastatic, Radioactive Iodine Non-Responsive Oncocytic (Hurthle-Cell) Thyroid Cancer

Background: Oncocytic (Hurthle cell) thyroid cancer (HTC) is a rare disease with few treatment options. Researchers are developing a radioactive drug that targets a protein that appears in high numbers on HTC cancer cells. Objective: To test a radioactive drug (177LuDOTA-EB-TATE) in people with HTC. Eligibility: People aged 18 years and older with HTC. The HTC must have failed to respond to conventional radioactive treatment; it must also have spread to other parts of the body. Design: Participants will be screened. They will have a physical exam with blood tests. They will have imaging scans and a test of their heart function. 177LuDOTA-EB-TATE is infused into a vein. Participants will receive 4 infusions spaced 8 to 12 weeks apart. They will stay in the hospital for 4 to 10 days after each infusion. During and after each infusion, participants will remain in a lead-lined room until their radiation levels go down; this usually takes about 24 hours. Participants will have 4 to 6 follow-up visits in the weeks after each infusion. Procedures will vary at each visit, but may include more imaging scans; blood and urine tests; and tests of heart function. Participants will have 2 single-photon emission computerized tomography (SPECT) scans. SPECT scans show where the study drug is sticking to tumors or maybe other parts of their body. They will lie on a table while a machine rotates around them. Participants will fill in questionnaires about how their thyroid condition affects their life. Participants will have follow-ups visits for 5 years after their last study treatment.

Participants needed: 18
Trial details
Phase: Phase 1, Phase 2Age: 18-100Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Aged 18 years or older. [+3]

Pregnant or breastfeeding. [+33]

Status: Not yet recruiting

Assessing the Impact of Perceptions of Unpredictability on Objective Measures of Food Consumption and Metabolism

Background: Many people in the United States are overweight or obese. This natural history study will look into how life events during childhood can impact eating behaviors and weight gain as adults. Objective: To explore how childhood experiences affect adult eating behaviors. Eligibility: Healthy people aged 18 to 60 years. Design: Participants will have 3 clinic visits. They will be screened with blood tests. They will answer questions about their alcohol and tobacco use. At the next visit, participants will undergo these activities: Parts of their body (such as waist, neck, and thighs) will be measured with a tape. They will have an imaging scan to find out how much body fat they have. They will start wearing a device like a wristwatch that measures their physical activity. They will wear this device for up to 10 days. They will wear a device on their upper arm or belly that measures blood glucose (sugar) levels. Participants will wear this for 7-10 days. They will answer questions about their education, childhood, and routines. They will receive a kit to collect a stool sample at home. At the last visit, participants will have these tests: Participants will relax and breathe normally while wearing a clear, plastic canopy that fits over their entire head. Blood samples will be taken before and after participants drink a sugary drink. Participants will be offered a large selection of foods for lunch. They will eat as much as they want. Then they will answer questions about how they feel about food and themselves.

Participants needed: 110
Trial details
Age: 18-60Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Stated willingness to comply with all study procedures and availability for the... [+2]

Diabetes [+22]

Status: Not yet recruiting

Prevalence and Development of Liver Dysfunction in Hematopoietic Stem Cell Transplant

Background: Hematopoietic stem cell transplant (HSCT) is a common treatment for many cancers and other illnesses. But many people who have HSCT go on to develop liver dysfunction. Researchers want to know more about how and why this happens. In this natural history study, they will try to learn what factors lead to liver dysfunction; how underlying liver disease may affect the results of HSCT; and how HSCT may contribute to liver dysfunction. Objective: To understand the links between HSCT and liver dysfunction. Eligibility: Adults aged 18 years or older and children 3 to 17 years who are being evaluated for HSCT. Design: This study involves 11 visits in 4 years. Most visits will be in the first year. Before and after their HSCT, participants will undergo these tests: Physical exam, including blood tests and a test of heart function. Participants will provide stool samples. Liver biopsies. Samples of liver tissue will be removed. This may be done either by inserting a needle through the right side of the chest, or with a thin tube threaded to the liver from a vein in the neck. Adult participants will undergo this procedure 2 times: once before the HSCT and once about a year later. Imaging scans. Participants will lie on a bed that moves into either a cylinder or a donut-shaped machine. Ultrasound. Participants will lie still. A probe that uses sound waves will be slid over their skin to get pictures of the liver. Fibroscan exam. This is like an ultrasound that uses a special probe to measure the toughness of the liver. ...

Participants needed: 500
Trial details
Age: 3-90Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Male and female adults >=18 years of age and children 3-17 years of age [+1]

Pregnancy or lactation [+2]

Status: Not yet recruiting

Trial of the Combination of Alpha-Lipoic Acid and Mirabegron in Women and in Men With Obesity

Background: Obesity and related illnesses cause at least 2.8 million deaths each year worldwide. Few treatments exist for obesity that are safe and widely available. A study drug (mirabegron \[MG\]) combined with a supplement (alpha-lipoic acid \[ALA\]) may help. Objective: To learn how MG and ALA can help the body process food. Eligibility: People aged 18 to 65 years with a body mass index between 30 and 45 kg/m2. Design: Participants will be screened. They will have a physical exam. They will have blood and urine tests and a test of their heart function. They will speak with a dietician. The study has two phases. Each phase begins with a 2-day stay in the clinic; then the participant will take the study drugs at home for about 4 weeks, followed by another 2-day stay in the clinic. They will also have outpatient visits about 2 weeks after each clinic stay. During the clinic stays, participants will undergo many tests: They will have a plastic tube (catheter) inserted into a vein in each arm. These will be used to draw blood and to infuse glucose (sugar) and insulin. They will have imaging scans. They will have a clear hard plastic shield placed over their head to measure oxygen and carbon dioxide as they breathe. Participants will take the study drugs at home. Both MG and ALA are taken by mouth with water. During one phase, participants will take MG plus a placebo. A placebo looks like the study drug but doesn t contain medicine....

Participants needed: 60
Trial details
Phase: Phase 2Age: 18-65Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Adults 18 to 65 years of age [+1]

Hypersensitivity and associated allergic reactions to mirabegron or alpha-lipoic... [+27]

Status: Recruiting

Evaluation of Adults With Endocrine and Metabolic-Related Conditions

Background: There are many endocrine and metabolic-related conditions. Two well-known disorders include diabetes and thyroid disease. Some of these diseases are caused by a change in genes. Researchers want to identify the genes involved in these disorders. They hope this will help them learn more about these diseases. Objectives: To learn more about conditions that affect the hormone-secreting glands (endocrine glands) in adults. To train doctors to diagnose and treat people with endocrine or metabolic conditions. Eligibility: Adults age 18 years and older with a known or suspected endocrine disorder. Relatives ages 18 years and older. Doctors will review all requests and available medical records to determine final eligibility for the protocol. Design: Participants will have a medical history and physical exam. Most participants will have 1 visit, and may have follow up visits if necessary. They may have tests, surgery, or other procedures to help diagnose or treat their condition. These could include: * Blood, urine, and saliva tests * Imaging tests. These may include X-ray, ultrasound, or scans. * Sleep study * Medical photographs * Visits with other specialists at NIH Participants will provide blood, urine, saliva, or tissue samples. Some of these samples may be stored in the freezer for future studies. Participants may be asked to participate in genetic testing. They will give a blood or saliva sample for this.

Participants needed: 1,250
Trial details
Age: 18-100Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 21, 2026Locations: 1
Eligibility criteria

Participants with known or suspected endocrine disorder age 18 years and older a... [+1]

Anyone under the age of 18 years old [+1]

Status: Recruiting

Clinical and Genetic Studies in Familial Non-medullary Thyroid Cancer

Background: \- Researchers are studying types of thyroid cancer that seem to cluster in families. Non-medullary thyroid cancer accounts for the vast majority of all types of thyroid cancer, but little is known about possible genes that may cause the cancer. More research is needed to develop the best ways to screen for familial non-medullary thyroid cancer (FNMTC) so that it can be diagnosed and treated at an early stage. Objectives: * To evaluate the natural history of FNMTC. * To determine the best screening strategy for FNMTC. * To identify genes that may indicate susceptibility to FNMTC. Eligibility: \- Individuals at least 7 years of age who have two first-degree relatives (e.g., parents, children, siblings) who have or have had non-medullary thyroid cancer or a documented diagnosis of non-medullary thyroid cancer and one living relative with documented non-medullary thyroid cancer. Design: * Participants will be evaluated by family history pedigree, physical examination, imaging (including possible neck ultrasound and radioactive iodine scans), and laboratory testing. * Participants who agree to have blood or other biological samples collected will be asked to enroll in an additional study to provide the appropriate samples and tissues. * After the initial study evaluation, participants who are not found to have a malignant thyroid tumor will be re-screened every year with non-invasive imaging studies. Participants who are found to have a malignant thyroid tumor will be informed of possible treatment options.

Participants needed: 500
Trial details
Age: 7-90Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 20, 2026Locations: 1
Eligibility criteria

Adults or minor (>= 7 years+), males and females. [+4]

Status: Recruiting

Diagnosing and Treating Low Blood Sugar Levels

Hypoglycemia is the term used to refer to lower than normal levels of blood sugar. This study will continue to research the causes of hypoglycemia. Patients involved in the study will be admitted to the Clinical Center of the National Institutes of Health and undergo tests for evaluating blood sugar. Patients will be required to refrain from eating for a set period of time and will undergo blood tests for insulin levels and several other specific diagnostic tests related to insulin secretion. The patients will be under supervision and will be provided with appropriate medical and surgical attention as needed.

Participants needed: 1,500
Trial details
Age: 18-120Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 20, 2026Locations: 1
Eligibility criteria

Male, females ages >= 18. [+1]

Patients with significant cardiac disease will be excluded. [+2]

Status: Recruiting

Studies on Tumors of the Thyroid

Participants in this study will be patients diagnosed with or suspected to have a thyroid nodule or thyroid cancer. The main purpose of this study is to further understand the methods for the diagnosis and treatment of thyroid nodules and thyroid cancer. Many of the test performed are in the context of standard medical care that is offered to all patients with thyroid nodules or thyroid cancer. Other tests are performed for research purposes. In addition, blood and tissue samples will be taken for research and genetic studies.

Participants needed: 2,500
Trial details
Age: 6-98Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 20, 2026Locations: 1
Eligibility criteria

Male or female, adults or children >= 6 months+. [+2]

Status: Recruiting

Natural History of Thyroid Function Disorders

Participants in this study will be patients diagnosed with or suspected to have a thyroid function disorder. These conditions may include: hypothyroidism, hyperthyroidism, thyroid hormone resistance, Graves' Dermopathy, and thyroid-stimulating hormone (TSH) secreting pituitary adenomas. The main purpose of this study is to further understand the natural history, clinical presentation, and genetics of thyroid function disorders. Many of the tests performed are in the context of standard medical care that is offered to all patients with thyroid function disorders. In addition, blood and tissue samples may be taken for research and genetic studies.

Participants needed: 2,500
Trial details
Age: 6-98Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 20, 2026Locations: 1
Eligibility criteria

Patients with known or suspected thyroid abnormalities (e.g. hypothyroidism, hyp... [+4]

Stated willingness to comply with all study procedures and availability for the... [+14]

Status: Recruiting

A Natural History Study of Metabolic Sizing in Health and Disease

Background: Scientists have long used simple measures (such as height and weight) to estimate how much a person s body uses food (calories) as energy, as commonly called the metabolic rate. But metabolism varies among people with similar body sizes. Scientists now believe the old formulas for estimating metabolic rates may not work well for all people. Researchers want to find more accurate ways to measure a person s metabolism. Objective: This natural history study will examine the relationships between metabolism, body composition, and body surface area in a wide range of people. Eligibility: Healthy children and adults aged 2 years or older. Also, people aged 2 years or older with conditions that may alter metabolism. These may include diabetes, obesity, renal disease, or cancer. Design: Participants will spend 2 days and 1 night in the hospital. They will provide a medical history and answer questions about their activity levels, the foods they eat, and their lifestyle. They will also eat a special diet. Participants will undergo many tests: They will lie in a bed with a clear hood covering their head for 30 to 45 minutes to measure the gases in their breath. They will lie on a padded table for about 15 minutes while their body is scanned. They will stand on a platform while a 3D scanner measures their body. They will have a test to measure how fast an electric signal moves through their body. They will grip an instrument to measure the strength of their hands. They will drink salty water and provide blood and urine samples. Participants may be invited to return for these 2-day visits up to 8 times per year. Return visits must be at least 2 weeks apart.

Participants needed: 2,000
Trial details
Age: 2-99Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 19, 2026Locations: 1
Eligibility criteria

Male or female, aged >=2 years [+3]

Participants over 200 kg due to the weight limit of the equipment. [+6]

Status: Recruiting

The Physiological Responses and Adaptation of Brown Adipose Tissue to Chronic Treatment With Beta3-Adrenergic Receptor Agonists

Background: Brown adipose tissue (BAT) is a type of fat in the body. It may prevent weight gain, improve insulin sensitivity, and reduce fatty liver. Researchers want to see if BAT helps the body burn energy. Objective: To learn more about how BAT works to burn energy. Eligibility: People ages 18-40 with a body mass index between 18 and 40 Design: Participants will be screened with: Medical history Physical exam Blood, urine, and heart tests Dietitian interview Participants will have an overnight baseline visit. This includes: Repeats of screening tests Exercise test Scans. For one scan, a radioactive substance is injected into the arm. FSIVGIT: An IV is inserted into veins in the right and left arms. Glucose and insulin are injected in one arm. Blood glucose and insulin levels are measured from the other. Metabolic suite: Participants stay 18-19 hours in a room that measures their metabolic rate. Monitors on the body measure heart rate, movement, and temperature. Optional fat biopsy: A small piece of tissue is removed with a needle. Participants will take 2-4 pills daily for 4 weeks. All women will take the drug mirabegron. Men will be randomly get either the drug or a placebo. All participants will have a visit after 2 weeks of the pills. They will repeat the screening tests. Participants will have an overnight visit 2 weeks later. They will repeat the baseline tests. Participants will keep food and medication diaries. Participants will have a follow-up visit 2 weeks after stopping the pills. This includes heart tests.

Participants needed: 100
Trial details
Phase: Phase 1Age: 18-40Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 19, 2026Locations: 1
Eligibility criteria

Female [+17]

Hypersensitivity and associated allergic reactions to mirabegron (or similar dru... [+28]

Status: Recruiting

Variability In Mixed Meal Tests: Fixed Versus Adjusted to Energy Needs Caloric Dose

Background: Researchers use mixed meal tolerance tests (MMTTs) to look at how people s bodies respond to eating a meal. However, researchers do not agree on how to decide the number of calories to give in each meal. Some use fixed meals, which are the same size for everyone, and some use adjusted meals, based on the size of the person s body. Researchers want to know which MMTT is best to use for future research. Objective: To learn how fixed vs adjusted meals affect blood glucose levels in healthy people. Eligibility: Healthy people aged 18 years or older. Design: Participants will have 3 or 4 clinic visits of up to 8 hours in 8 weeks. Participants will have baseline tests: Their height, weight, and waist size will be measured. They will have an oral glucose tolerance test: A needle attached to a tube (IV) will be inserted into a vein in the arm. They will have a sugary drink. Blood samples will be taken from the tube at intervals up to 3 hours after the drink. They will have a body scan. Participants will have 2 MMTT visits. One will include a fixed meal and one will include an adjusted meal. They will have tests at both visits: Resting metabolic rate: A clear hood will be placed over the participant s head while they rest for 20 minutes. This will measure the oxygen they breathe in and out. MMTT. Participants will have 5 minutes to drink a liquid meal. Blood samples will be taken at intervals for the next 4 hours....

Participants needed: 79
Trial details
Age: 18-99Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

Provision of signed and dated informed consent form. [+3]

Current use of medications, dietary supplements, or alternative therapies known... [+10]

Status: Recruiting

VIR-2218 and Peginterferon Alfa-2a for Chronic Hepatitis B

Background: Chronic hepatitis B virus (HBV) infection affects 292 million people worldwide; 887,000 die each year from cirrhosis, liver cancer, and related issues. Treatment options are limited. Objective: To test 2 drugs (VIR-2218 and peginterferon) in people with mild or inactive HBV infection. Eligibility: People aged 18 to 65 years with mild or inactive HBV infection. Design: Participants will be screened. They will have blood tests and an eye exam. They will have imaging scans of the liver to check the health of the liver. Participants will be in the study for over 2 years. VIR-2218 is an injection given under the skin of the stomach, upper arm, or thigh. Participants will come to the clinic to receive this injection once a month for 6 months. Peginterferon is also injected under the skin. Participants will have this shot once a week for 6 months. They may either inject themselves at home or come to the clinic to get the injections. Participants will get just the VIR-2218 for 3 months, then both shots for 3 months, then just the peginterferon for 3 months. Participants will have two 3-day stays in the hospital. Tests will include: Liver biopsy. A sample of tissue will be taken from their liver. After the procedure, participants will lie on their right side for 2 hours and then on their back for 4 hours. Fine needle aspiration. A small needle will be used to collect cells from the liver. After the last injection of peginterferon, follow-up visits will continue in the outpatient clinic every 4 to 12 weeks.

Participants needed: 50
Trial details
Phase: Phase 2Age: 18-65Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

Age >=18-65 years [+4]

Pregnancy or lactation [+28]

Status: Recruiting

Feasibility of Adipose Tissue Triglyceride (TG) Labelling in Familial Partial Lipodystrophy (FPLD)

Background: People with familial partial lipodystrophy (FPLD) do not store fat in the body normally. This can lead to serious illnesses such as diabetes and heart disease. To learn more about FPLD, researchers want to compare the fat tissue in people with this disease to the fat tissue of healthy people. Objective: To collect and analyze samples of fat tissue in people with and without FPLD. Eligibility: People aged 18 to 65 years with FPLD. Healthy adults are also needed. Design: Participants will be screened. They will have a physical exam. The size and shape of their body will be measured. They will have an imaging scan to measure their bones, muscle, and fat. Participants will be given heavy water to drink at home. The water contains a tracer to help measure the fat in their blood. They will drink 1 vial 3 times a day. After drinking the water for 9 days, participants will come to the clinic for a 3-day stay. They will eat only foods provided by the hospital; the foods will contain tracers. A needle will be inserted into a vein in the arm; participants will receive infusions of other tracers through this needle into their blood; this needle will also be used to draw blood samples for testing. On their third day in the clinic, participants will have biopsies: Small samples of fat will be removed from under the skin on the belly and thigh. Participants may return for a follow-up visit 8 days after leaving the clinic. Blood draws and fat tissue biopsies will be repeated.

Participants needed: 14
Trial details
Age: 18-65Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

Stated willingness to comply with all study procedures and availability for the... [+10]

Uncontrolled diabetes, defined as HbA1C >8% at screening. [+15]

Status: Recruiting

Study of Growth Hormone Inhibition Using Pegvisomant in Severe Insulin Resistance

Background: Lipodystrophy (LD) syndromes are a group of rare disorders that affect how a person s body can store and use fat tissue. Many people with LDs become severely insulin resistant. Some people are insulin resistant because of a variant in the insulin receptor gene. Insulin resistance causes many health problems. Objective: To learn if blocking the effects of growth hormone in the body will help people with severe insulin resistance. Eligibility: Adults aged 18 to 65 years with either a known variant in the insulin receptor gene or with a diagnosis of partial LD. Design: Participants will have 2 hospital stays, about 1 month apart. Each stay will be 3 or 4 nights. During each hospital stay, participants will have many tests. They will have a physical exam with blood tests. They will have all of their urine collected for a 24-hour period. They will have scans to measure their muscle, bone, and fat tissues. They will have tests to measure metabolism and insulin sensitivity. They may have an optional biopsy of fat tissue. During the first hospital visit, participants will learn how to give themselves shots of a drug (pegvisomant) that blocks growth hormone. The drug is injected under the skin. Participants will continue to give themselves these shots once a day at home. After the first hospital visit, participants will talk on the phone with members of the study team once each week. After 2 weeks they will have blood drawn for tests. Participants will stop the shots after the second hospital visit.

Participants needed: 25
Trial details
Phase: Phase 2Age: 18-70Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

Either [+4]

Use of niacin or other drugs that directly affect lipolysis within 8 weeks prior... [+14]

Status: Recruiting

Natural History of Pregnancy and Pregnancy Outcomes in Metreleptin-Treated vs Untreated Subjects With Lipodystrophy

Background: Lipodystrophy is a health problem in which the body does not have enough fat tissue. People with lipodystrophy may not make enough of the hormone leptin. Leptin regulates hunger. Low leptin levels trigger hunger. People with lipodystrophy can have many health problems. They may take a drug (metreleptin) that mimics leptin. Little is known about how taking metreleptin may affect a pregnancy. Metreleptin may be helpful or harmful to pregnant women. It may also affect the health of the child who is born. Objective: This natural history study will collect data about the effects of taking metreleptin while pregnant. Eligibility: Women aged 18 years or older with lipodystrophy who have been pregnant. Women who did and who did not take metreleptin during their pregnancies are needed. Children of women with lipodystrophy who took this drug during pregnancy are also needed. Design: Participants will have 1 study visit. This visit may be by phone, by telehealth, or in-person. Participants will answer questions about their pregnancies. They will discuss any health problems they had. They will be asked about any medicines they took before and during their pregnancies. They will be asked about the health of their children. Participants medical records will be reviewed. Participants may need to provide a blood sample. They may also be asked to provide a sample of breastmilk. Participants children may also be asked to provide a blood sample....

Participants needed: 90
Trial details
Age: 6-98Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

Female, aged >= 18 years [+5]

Inability of subject or guardian to understand or the unwillingness to sign a wr... [+2]

Status: Recruiting

Unraveling the Mechanisms Underlying Primary Sclerosing Cholangitis Through a Multidisciplinary, Integrative Research Approach

Background: Primary sclerosing cholangitis is a rare chronic liver disease. It affects the bile ducts of the liver. It can result in bile duct infections, cirrhosis, cancer, and end stage liver disease. Researchers want to learn more about this disease. Objective: To understand the biological causes of primary sclerosing cholangitis. Eligibility: Adults age 18 and older who have primary sclerosing cholangitis. Design: Participants will be screened with a medical history, physical exam, and blood tests. Participants will give blood, saliva, urine, and stool samples. They will have nasal swabs. They will complete surveys. Participants will get an intravenous (IV) catheter. A plastic tube is inserted into an arm vein. Participants will have a colonoscopy. A tube with a video camera at the end is inserted into the rectum. Participants will have an upper endoscopy. A scope with a light and camera at its tip is used to look inside the upper digestive tract. Participants will have a liver biopsy, entering through the chest wall or a neck vein. Blood is drawn from a blood vessel that carries blood to the liver. A liver tissue sample is taken. Participants will have magnetic resonance imaging or spectroscopy. They will get a contrast agent through an IV. Participants may have an optional bone marrow aspiration. A large needle is inserted into the hip to withdraw marrow. Participants will have a liver ultrasound. Participants will complete a 3-day food diary. They will have a nutrition assessment. Participants may give contact details for people who live with them, to also take part in this study. Participation will last for 12 months.

Participants needed: 143
Trial details
Age: 18-90Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

Stated willingness to comply with all study procedures and availability for the... [+3]

Pregnant or lactating women or females of child-bearing age not taking measures... [+31]

Status: Recruiting

The Use of 124-I-PET/CT Whole Body and Lesional Dosimetry in Differentiated Thyroid Cancer

Study rationale High risk patients with differentiated thyroid cancer (DTC) require therapy with 131 I under thyroid stimulating hormone (TSH) stimulation. There are two methods of TSH stimulation endogenous by thyroid hormone withdrawal (THW) leading to hypothyroidism and exogenous by injection of human recombinant TSH (rhTSH Thyrogen). The appropriate 131-I activity utilized for treatment is either based on empiric fixed dosage choice or individually determined activity based on 131 I dosimetric calculations. Although dosimetry utilizing radioactive iodine isotope 131 I enables calculation of maximum safe dose, it does not estimate the tumoricidal activity necessary to destroy the metastatic lesions. The alternative radioactive isotope of iodine -124 I, used for positron emission tomography (PET) imaging, might be used for calculation not only the maximum safe131 I dose, but also to predict the absorbed dose in the metastatic lesions. Study objectives The primary objective of this study is to compare the 124 I -PET/CT lesional and whole body dosimetry in each individual patient with metastatic radioiodine (RAI)-avid thyroid cancer under preparation with rhTSH and THW. The secondary objective is to evaluate the predicted by PET/CT lesional uptake with the early response to therapy. Study design This is a phase 2 pilot prospective cohort study comparing the lesional and whole body dosimetry within each patient undergoing exogenous (rhTSH) and endogenous (THW) TSH stimulation and followed for 5 years. Interventions Each study participant will undergo rhTSH and THW-aided 124 I-PET/CT dosimetric evaluations and will be subsequently treated with THW-aided RAI activity based on dosimetric calculations enabling maximum safe dosage. The patients will be followed in 12+/-3 months intervals for 5 years. Sample size and population This pilot study will include 30 patients with high risk differentiated thyroid cancer presenting with distant and/or loco-regional metastases. ...

Participants needed: 30
Trial details
Phase: Phase 2Age: 18-90Biological sex: AllType: InterventionalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

underwent total thyroidectomy plus or minus neck lymph node dissection as clinic... [+8]

Serious underlying medical conditions that restrict diagnostic testing or therap... [+3]

Status: Recruiting

Natural History of Familial Carcinoid Tumor

This study will evaluate members in families with a history of small bowel carcinoid cancer to study the natural history of those family members that have the disease, determine ways to improve early detection by performing surveillance on those at risk but without disease and to identify the gene(s) that may cause the tumors. Familial carcinoid tumors usually originate in hormone-producing cells that line the small intestine or other cells of the digestive tract. The tumors are slow-growing and usually take many years before they cause symptoms. It is known that these tumors occur more often in some families and are then passed from one generation to the next by inherited genes. Members of families, including all siblings and offspring in which two or more immediate blood relatives have had small bowel carcinoid tumors are eligible for this study. In some cases unaffected spouses of family members diagnosed with carcinoid cancer are also requested to participate by donating a sample of blood only. Participants undergo a medical evaluation every 3 years during a 3- to 5-day hospital stay at the NIH Clinical Center. All participants have a personal and family medical history obtained and undergo a physical examination, blood and urine tests. People who already have a small bowel carcinoid tumor or are at risk of developing a carcinoid tumor have some or all of the following procedures to determine the presence of carcinoid tumor and its (omit next two words- location or) spread to other areas of the body: * Video Capsule Endoscopy: Visualization of the gastrointestinal tract by ingesting a disposable, "vitamin-pill sized" video capsule that has its own camera and light source. * CT of the chest abdomen and pelvis with oral and IV contrast : X-ray examination of the chest, abdominal and pelvis organs. * 18 FDOPA Positron emission tomography (PET) with CT for localization: Nuclear imaging scan to look at tumor activity. * MRI Liver with contrast - to determine if disease has spread to liver * Gallium 68 PET/CT-limited to individuals that have residual tumor. * Clinical and research blood work Should mid gut carcinoid tumors be found every participant will be assisted in determine what the best course of treatment will be for them. ...

Participants needed: 1,600
Trial details
Age: 18-100Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

Male and female subjects >= 18 years of age [+10]

Members of families with multiple endocrine neoplasia (MEN) I, MEN II or other f... [+3]

Status: Recruiting

Blood Sampling for Research Related to Sickle Cell Disease

This study will collect representative blood samples from healthy children and adults and from children and adults who have unique red blood cell features that are related to sickle cell disease. Sickle cell disease is a blood disease that limits the ability of red blood cells to carry oxygen throughout the body. The purpose of the study is to collect a variety of blood samples that may then be used to investigate advances and potential new drug treatments for sickle cell disease. Volunteers must be at least 18 years of old. Samples will be taken both from healthy volunteers and from volunteers who have unique red blood cell features that are related to sickle cell disease. Candidates will be screened with a medical history. During the study, participants will undergo a one- to two-hour outpatient procedure at the National Institutes of Health Clinical Center. Once researchers have explained the study and obtained the participant s consent, participants will donate 8 cc (approximately 2 teaspoons) of blood. Because repeat testing helps researchers validate study findings, participants who have the unique red blood cell features mentioned above may also be asked if they are willing to return and donate another 2 cc to 8 cc of blood for additional studies. The amount of blood drawn will not exceed 50 ml with any eight-week period for adults or 7 cc within any six-week period for children....

Participants needed: 250
Trial details
Age: 18-100Biological sex: AllType: ObservationalSponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Updated: Aug 18, 2026Locations: 1
Eligibility criteria

Patients with sickle cell trait [+3]

Subjects who are unable to comprehend the investigational nature of the laborato... [+1]