Explore popular diseases in clinical trials

Check which popular diseases are currently being frequently studied.

See also our rare diseases glossary and drug database.

Starting by letter

To open the diseases glossary, select a letter from the list below.

Most popular diseases

The list below features the most popular diseases currently involved in ongoing clinical trials.

Disease trials
Non-small cell lung cancer 228
Breast cancer 94
Obesity 86
Prostate cancer 73
Colorectal cancer 69
Ovarian cancer 66
Non-small cell lung cancer metastatic 66
Crohn’s disease 61
Type 2 diabetes mellitus 54
Rheumatoid arthritis 54
Triple negative breast cancer 52
Hormone receptor positive HER2 negative breast cancer 52
Asthma 51
Acute myeloid leukaemia 50
Squamous cell carcinoma of head and neck 50
Chronic kidney disease 49
Neoplasm 48
Colorectal cancer metastatic 47
Hepatocellular carcinoma 47
Systemic lupus erythematosus 40
Colitis ulcerative 40
Multiple sclerosis 39
Overweight 39
Dementia Alzheimer’s type 39
Gastric cancer 38
Myelodysplastic syndrome 37
Parkinson’s disease 37
HER2 positive breast cancer 37
Glioblastoma 37
Atrial fibrillation 34
Bladder cancer 34
Chronic obstructive pulmonary disease 33
Ischaemic stroke 33
Prostate cancer metastatic 33
Myasthenia gravis 32
Renal transplant 31
Type 1 diabetes mellitus 31
Head and neck cancer 31
Endometrial cancer 31
Malignant melanoma 31
Non-small cell lung cancer stage IV 31
Diffuse large B-cell lymphoma 31
Breast cancer metastatic 31
HIV infection 30
Dermatitis atopic 28
Cholangiocarcinoma 28
Coronary artery disease 28
Plasma cell myeloma 28
Pulmonary arterial hypertension 28
Neoplasm malignant 27
Rectal cancer 27
Renal cell carcinoma 26
Pancreatic carcinoma 26
Schizophrenia 26
Duchenne muscular dystrophy 25
Non-small cell lung cancer stage III 25
Follicular lymphoma 25
COVID-19 25
Migraine 24
Hormone receptor positive breast cancer 24
Idiopathic pulmonary fibrosis 24
Non-small cell lung cancer stage IIIB 24
Sepsis 24
Chronic lymphocytic leukaemia 24
Soft tissue sarcoma 24
Mantle cell lymphoma 23
Small cell lung cancer extensive stage 23
Colon cancer 23
Fallopian tube cancer 23
Influenza 22
Small cell lung cancer 21
Interstitial lung disease 21
Acute myocardial infarction 21
Oesophageal adenocarcinoma 21
Amyotrophic lateral sclerosis 21
Chronic rhinosinusitis with nasal polyps 20
Cystic fibrosis 20
Glioma 20
Myelofibrosis 19
Neuroblastoma 19
B-cell lymphoma 19
Sickle cell disease 19
Major depression 19
Procedural pain 19
Axial spondyloarthritis 18
Osteoarthritis 18
Breast cancer female 17
Critical illness 17
Acute kidney injury 17
Hereditary angioedema 17
Relapsing-remitting multiple sclerosis 16
Acute coronary syndrome 16
IgA nephropathy 16
Psoriasis 16
Gastrooesophageal cancer 16
Ewing’s sarcoma 16
Cardiac failure 16
Vitiligo 16
Transitional cell carcinoma 15
Giant cell arteritis 15

Diseases starting with p

  • 1

    Peritoneal carcinoma metastatic

    Peritoneal carcinoma metastatic occurs when cancer from another organ spreads to the peritoneum, the membrane lining the abdominal cavity. While this condition is serious and typically represents advanced disease, modern treatments combining surgery and specialized chemotherapy are helping patients live longer and improve their quality of life.

  • 1

    Peritoneal dialysis

    Peritoneal dialysis is a treatment that allows people with kidney failure to clean their blood at home, using the natural lining of their abdomen as a filter instead of relying on a machine outside the body.

  • 2

    Peritoneal mesothelioma malignant

    Peritoneal mesothelioma is a rare and aggressive cancer that affects the tissue lining the abdomen. While there is no cure, advances in treatment combining surgery and specialized chemotherapy have transformed survival from less than a year to several years for many patients.

  • 2

    Peritoneal neoplasm

    Peritoneal neoplasm is a rare cancer that affects the peritoneum, a thin membrane lining the abdomen and covering the organs inside it. Most people don’t notice symptoms until the disease has progressed to a later stage, making early detection challenging. Treatment typically involves surgery combined with specialized chemotherapy, offering hope for improved survival and quality of life.

  • 0

    Peritoneal sarcoma

    Peritoneal sarcoma is a rare type of cancer that develops when sarcoma tumors appear in or spread to the peritoneum, the thin lining inside the abdomen that covers organs and produces lubricating fluid.

  • 3

    Peritonitis

    Peritonitis is a serious inflammation of the tissue lining the inside of your belly that requires immediate medical attention and can become life-threatening without prompt treatment.

  • 1

    Persistent corneal epithelial defect

    When the clear outer layer of the eye fails to heal properly after an injury, it can lead to a challenging condition that requires prompt attention to prevent serious complications including infection, scarring, and vision loss.

  • 0

    Persistent depressive disorder

    Persistent depressive disorder is a long-lasting form of depression where feelings of sadness and emptiness persist for years rather than weeks or months, affecting daily life, relationships, and the ability to find joy even during happy moments.

  • 0

    Perthes disease

    Perthes disease is a childhood hip condition where blood supply to the ball-shaped head of the thigh bone is temporarily interrupted, causing the bone to break down and then gradually heal over several years.

  • 1

    Pertussis

    Pertussis, commonly called whooping cough, is a highly contagious respiratory infection that can cause severe coughing fits lasting for weeks or even months. While it affects people of all ages, it poses the greatest danger to babies, who may experience life-threatening complications.

  • 0

    Petit mal epilepsy

    Petit mal epilepsy, now known as absence seizures, causes brief episodes where a person suddenly stares blankly and loses awareness for just a few seconds, often going unnoticed by observers and sometimes mistaken for daydreaming.

  • 2

    Peyronie’s disease

    Peyronie’s disease is a condition that causes the penis to curve or bend abnormally during erections due to scar tissue formation beneath the skin. This can lead to pain, difficulty with sexual activity, and emotional distress for many men.

  • 2

    Phaeochromocytoma

    Phaeochromocytoma is a rare tumor that develops in the adrenal glands and causes the body to produce too much adrenaline, leading to high blood pressure, headaches, and other serious symptoms that can be life-threatening if not treated.

  • 1

    Pharyngeal cancer stage I

    Pharyngeal cancer stage I is an early form of cancer that starts in the pharynx, the middle part of your throat. At this stage, the cancer is small and has not spread, which means there are several effective treatment options available.

  • 1

    Pharyngeal cancer stage II

    Stage II pharyngeal cancer is a middle-stage cancer where the tumor is larger than 2 centimeters but no larger than 4 centimeters, and treatment options include surgery, radiation therapy, or a combination of treatments depending on the specific location in the throat.

  • 1

    Pharyngeal cancer stage III

    Stage 3 pharyngeal cancer represents an advanced form of throat cancer where the tumor has grown larger or spread to nearby lymph nodes, requiring comprehensive treatment approaches that often combine multiple therapies.

  • 2

    Phenylketonuria

    Phenylketonuria is a rare inherited disorder that, without treatment, can cause serious brain damage. With early diagnosis through newborn screening and lifelong management, people with PKU can live healthy, full lives.

  • 1

    Philadelphia chromosome positive

    Philadelphia chromosome positive is a genetic abnormality that occurs when two chromosomes in the body swap pieces, creating a harmful protein that causes certain blood cancers. This condition is found in most cases of chronic myeloid leukemia and in some cases of acute lymphoblastic leukemia, primarily affecting adults.

  • 2

    Philadelphia positive acute lymphocytic leukaemia

    Philadelphia positive acute lymphocytic leukaemia is a serious blood cancer that has seen dramatic improvements in treatment and survival rates thanks to modern targeted therapies that have transformed what was once considered nearly incurable into a disease with much better outcomes.

  • 2

    Philadelphia positive chronic myeloid leukaemia

    Philadelphia chromosome-positive chronic myeloid leukaemia is a rare blood cancer that occurs when pieces of two chromosomes swap places, creating an abnormal chromosome that changes how white blood cells grow in the bone marrow.

  • 1

    Pigmentary glaucoma

    Pigmentary glaucoma is a form of eye disease that often strikes at a younger age than typical glaucoma, primarily affecting people in their twenties to forties. It occurs when tiny pigment particles from the colored part of the eye break loose and clog the drainage system, potentially leading to vision loss if left untreated.

  • 5

    PIK3CA related overgrowth spectrum

    PIK3CA-related overgrowth spectrum (PROS) is a group of rare conditions that cause unusual growth in different parts of the body. These conditions share a common cause: changes in a gene called PIK3CA that controls how cells grow and divide.

  • 2

    PIK3CA-activated mutation

    PIK3CA-activated mutations are among the most common genetic changes found in cancer, affecting how cells grow, divide, and survive. These mutations lead to increased activity of a key protein that helps control cell growth, which can contribute to tumor development and affect how well certain treatments work.

  • 2

    Piriformis syndrome

    Piriformis syndrome causes pain in the buttocks that can travel down the leg. It happens when a small muscle deep in your buttock presses on your sciatic nerve. While not very common, affecting only about 0.3% to 6% of people with lower back pain, it can significantly impact your daily activities.

  • 1

    Pituitary tumour benign

    Benign pituitary tumours are unusual growths in the pituitary gland that are not cancer and grow slowly, but they can affect your hormone levels and cause various health problems throughout your body.

  • 1

    Pituitary-dependent Cushing’s syndrome

    Pituitary-dependent Cushing’s syndrome is a rare hormonal disorder that occurs when a tumor in the pituitary gland causes the body to produce too much cortisol, leading to changes in appearance, weight gain, and numerous health complications.

  • 1

    Placenta praevia

    Placenta praevia is a pregnancy complication where the placenta blocks the exit for the baby, affecting about 1 in 200 pregnancies and requiring careful management to protect both mother and child.

  • 2

    Plasma cell leukaemia

    Plasma cell leukaemia is the rarest and most aggressive form of plasma cell cancers, where abnormal plasma cells circulate through the bloodstream instead of staying confined to bone marrow as in typical multiple myeloma.

  • 34

    Plasma cell myeloma

    Plasma cell myeloma is a cancer that develops in a type of white blood cell called a plasma cell, where abnormal cells build up in bone marrow and can affect bones, kidneys, and blood cells throughout the body.

  • 1

    Plasma cell myeloma recurrent

    When multiple myeloma comes back after treatment, it is called relapsed or recurrent myeloma. Most people with this disease will experience several cycles of remission and relapse throughout the course of their illness, requiring ongoing treatment to control symptoms and improve quality of life.

  • 16

    Plasma cell myeloma refractory

    When multiple myeloma stops responding to treatment or never responds at all, doctors call it refractory myeloma. This challenging form of the disease requires new treatment strategies and ongoing monitoring to manage symptoms and slow progression.

  • 1

    Plasmablastic lymphoma

    Plasmablastic lymphoma is a rare and aggressive type of cancer that affects white blood cells. It poses significant challenges in diagnosis and treatment, often occurring in people with weakened immune systems, particularly those with HIV infection.

  • 1

    Pleomorphic leiomyosarcoma

    Pleomorphic leiomyosarcoma is a rare and aggressive form of cancer that develops in smooth muscle tissue, characterized by cancer cells that vary greatly in size and shape, making it particularly challenging to diagnose and treat.

  • 1

    Pleomorphic liposarcoma

    Pleomorphic liposarcoma is a rare and aggressive cancer that develops in fat tissue, most commonly in the arms and legs. It is the least common but most aggressive type of liposarcoma, characterized by abnormally shaped fat cells and a high risk of spreading to other parts of the body.

  • 4

    Pleural mesothelioma

    Pleural mesothelioma is a rare and aggressive cancer that forms in the lining of the lungs and chest wall, caused primarily by asbestos exposure, often decades before symptoms appear.

  • 8

    Pleural mesothelioma malignant

    Pleural mesothelioma malignant is a rare and aggressive cancer that develops in the tissue lining the lungs and chest wall, almost always linked to asbestos exposure that may have occurred decades earlier.

  • 1

    Pleural mesothelioma malignant recurrent

    Recurrent pleural mesothelioma occurs when this rare cancer returns after treatment. While this aggressive disease poses serious challenges, understanding available treatment options and living with recurrence can help patients make informed decisions about their care.

  • 1

    Pneumococcal infection

    Pneumococcal infection is a serious bacterial disease caused by Streptococcus pneumoniae that can affect people of all ages, causing illnesses ranging from ear infections to life-threatening pneumonia and meningitis.

  • 7

    Pneumonia

    Pneumonia is a lung infection that causes inflammation and fluid buildup in the air sacs, making it hard to breathe. While it can affect anyone, it poses the greatest risk to young children, older adults, and people with certain health conditions.

  • 4

    Pneumonia bacterial

    Bacterial pneumonia is a serious lung infection that can range from mild to life-threatening, affecting millions of people each year and requiring prompt medical attention to prevent complications and ensure full recovery.

  • 1

    Pneumonia chlamydial

    Chlamydia pneumoniae is a type of bacteria that can cause respiratory infections ranging from mild cold-like symptoms to more serious pneumonia, though most people recover on their own without treatment.

  • 1

    Pneumothorax

    A pneumothorax, commonly called a collapsed lung, occurs when air leaks into the space between your lung and chest wall, causing the lung to deflate and leading to sudden chest pain and breathing difficulties that require immediate medical attention.

  • 3

    Polycystic liver disease

    Polycystic liver disease is a rare genetic condition where numerous fluid-filled sacs develop throughout the liver, often without symptoms but sometimes causing significant discomfort as the cysts grow larger over time.

  • 6

    Polycystic ovarian syndrome

    Polycystic ovary syndrome affects millions of women worldwide, causing irregular periods, hormonal imbalances, and fertility challenges—yet up to 70% of cases remain undiagnosed.

  • 6

    Polycythaemia vera

    Polycythaemia vera is a rare blood cancer that causes your bone marrow to produce too many red blood cells, making your blood thicker and increasing the risk of serious complications like blood clots, heart attack, and stroke.

  • 8

    Polymyalgia rheumatica

    Polymyalgia rheumatica is an inflammatory condition that causes sudden pain and stiffness in the shoulders, neck, and hips, mainly affecting people over 50 years of age.

  • 5

    Polymyositis

    Polymyositis is a rare disease that causes your immune system to attack your muscles, leading to chronic inflammation and weakness that affects both sides of the body. While there is no cure, understanding the condition and available treatments can help you manage symptoms and maintain your quality of life.

  • 3

    Polyneuropathy

    Polyneuropathy is a condition where multiple peripheral nerves throughout the body become damaged at the same time, causing problems with sensation, movement, or other body functions. It affects between 1% and 7% of people in the United States, with higher rates among those over 50 years of age.

  • 0

    Polypoidal choroidal vasculopathy

    Polypoidal choroidal vasculopathy is a disease affecting the blood vessel layer beneath the retina, causing fluid leakage and bleeding that can lead to vision loss if left untreated. While it shares features with age-related macular degeneration, this condition requires specialized diagnosis and treatment approaches.

  • 0

    Poor quality sleep

    Poor quality sleep affects millions of people, disrupting daily life and contributing to serious health problems. Understanding what defines poor sleep and how to improve it can make a significant difference in your overall health and wellbeing.

  • 0

    Porphyria non-acute

    Non-acute porphyrias are a group of rare inherited conditions that primarily affect the skin, causing it to become sensitive to sunlight and leading to symptoms like pain, blistering, and scarring in sun-exposed areas.

  • 2

    Portal hypertension

    Portal hypertension is a serious complication that develops when blood pressure rises dangerously high in the portal vein, the major vessel that carries blood from your digestive organs to your liver. This condition, most commonly caused by liver scarring from cirrhosis, can lead to life-threatening internal bleeding and other severe complications that require careful medical management.

  • 1

    Porto-sinusoidal vascular disorder

    Porto-sinusoidal vascular disorder is a rare liver condition that causes increased pressure in the blood vessels of the liver without the presence of cirrhosis, often remaining undetected until serious complications arise.

  • 0

    Post breast therapy pain syndrome

    Chronic pain after breast surgery affects between 20 and 68% of women who have undergone breast procedures, significantly impacting their quality of life and daily activities.

  • 1

    Post cardiac arrest syndrome

    Post cardiac arrest syndrome is a serious condition that can develop after a person’s heart is successfully restarted following cardiac arrest. This complex medical situation affects multiple organs throughout the body and requires immediate, specialized care to improve chances of survival and recovery.

  • 5

    Post procedural complication

    Post procedural complications are unwanted or unexpected conditions that develop after a surgical procedure or medical intervention. These complications can occur immediately after surgery or even years later, affecting recovery and overall health outcomes.

  • 0

    Post procedural hypotension

    Low blood pressure after surgery is a common problem that can lead to serious complications if not properly managed. Understanding its causes and knowing how to respond can help patients recover safely.

  • 1

    Post procedural infection

    An infection after surgery is a complication that can occur when bacteria enter the body through surgical incisions. While healthcare providers take strict precautions to prevent these infections, they remain a significant concern, affecting between 1 and 3 out of every 100 surgical patients and contributing to increased hospital stays, healthcare costs, and health complications.

  • 0

    Post procedural oedema

    Swelling after surgery is one of the most common experiences patients face during recovery, yet understanding what’s happening in your body and how to manage it can significantly improve your healing journey and overall comfort.

  • 1

    Post procedural pulmonary embolism

    Post procedural pulmonary embolism is a serious and potentially life-threatening complication that can occur after surgical procedures, ranking as the third most common cause of cardiovascular death worldwide.