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Pfizer Inc.

Drugmaker with rare disease work · based in New York, United States · founded 1849 · ticker PFE · pfizer.com

Pfizer Inc. works on 69 rare diseases we track, including Achondroplasia, Acromegaly and 67 more. It has 28 active clinical trials, and 21 are looking for volunteers now. It also has 21 FDA-approved rare disease drugs.

Pfizer's rare disease medicines include Vyndamax (tafamidis) for transthyretin amyloid cardiomyopathy, Hympavzi (marstacimab) for hemophilia A and B, Somavert (pegvisomant) for acromegaly and Elelyso (taliglucerase alfa) for Gaucher disease. Its rare disease pipeline includes dazukibart for dermatomyositis in Phase 3. The company discontinued its Beqvez gene therapy for hemophilia B in February 2025.

Pfizer Inc. pipeline

Each row lists the diseases Pfizer Inc. is studying at that stage, from the ones closest to approval down to the earliest work.

Approved
Drugs the FDA has approved.

Caduet (amlodipine and atorvastatin) · Cyklokapron (tranexamic acid) · Daurismo (glasdegib) · Doxorubicin Hydrochloride (doxorubicin hydrochloride) · Elelyso (taliglucerase alfa) · Elrexfio (elranatamab-bcmm) · Genotropin (somatropin) · Hympavzi (marstacimab-hncq) · Idamycin PFS (idarubicin hydrochloride) · Mylotarg (gemtuzumab ozogamicin) · 11 more

Phase 3
Large studies, usually the last step before a company asks the FDA for approval.

Apnea 2 trials recruiting · Hemophilia A 2 trials recruiting · Multiple Myeloma recruiting · Myositis recruiting · Dermatomyositis recruiting · Sickle Cell Disease recruiting · HER2-positive Breast Cancer

Phase 2
Mid-size studies that check whether a drug works and at what dose.

Multiple Myeloma 5 trials recruiting · Acute Myeloid Leukemia 2 trials recruiting · Hodgkin Lymphoma recruiting · Pheochromocytoma · Cholangiocarcinoma

Phase 1
First studies in people, mostly checking safety.
Other studies
Studies with no phase listed, such as registries and natural history studies.

Amyloidosis Transthyretin recruiting · Hematologic Disorder recruiting · Acute Myeloid Leukemia recruiting · Wild-Type ATTR Cardiac Amyloidosis recruiting · Ankylosing Spondylitis (AS) / Radiographic Axial SpA (r-axSpA) recruiting · Multiple Myeloma 2 trials

Pfizer Inc. clinical trials

These are Pfizer Inc. trials for the rare diseases we track, from ClinicalTrials.gov. Statuses there can lag behind company news, so confirm with the study team before you plan around one.

21 trials looking for volunteers now

Looking for volunteersNo phaseRecently updatedNCT04535349

Quantitative Analysis of Myocardial Uptake of Bone Radiopharmaceuticals in Patients With Cardiac ATTR Amyloidosis

Tests Whole-body & CZT bone tracer imaging (SPECT)

For Amyloidosis Transthyretin

Introduction: Transthyretin cardiac amyloidosis (ATTR) is an important cause of heart failure. Cardiac planar radionuclide imaging using 99mTc-labeled bone seeking radiopharmaceuticals is used as a noninvasive diagnostic criterion in patients without detectable monoclonal protein. The visual assessment remains the main noninvasive criterion for the diagnosis. Medical therapy using tafamidis meglumine that binds to transthyretin and prevents amyloidogenesis, recently demonstrated a reduction in all-cause mortality and cardiovascular-related hospitalizations. As a consequence, there is a need for quantitative approaches that would be useful for diagnosis and prognosis assessment but also for the evaluation of patient therapeutic response. Materials and methods: The investigators aim to include 35 patients with a suspected diagnosis of cardiac ATTR amyloidosis in whom a cardiac planar radionuclide imaging using 99mTc-labeled bone seeking radiopharmaceuticals is planned as part of routine noninvasive diagnosis work-up. Using a test-retest approach, the aim is to compare a quantitative method vs. conventional semi-quantitative approaches for the assessment of cardiac uptake of bone radiopharmaceuticals using new 3D CZT-based SPECT-CT cameras in patients with suspected cardiac ATTR amyloidosis. The investigators estimated that 20 patients will have a diagnosis of cardiac ATTR amyloidosis. In the latter patients, the aim is to evaluate the impact of 6-month therapy using tafamidis on quantitative and semi-quantitative assessment of cardiac uptake of bone radiopharmaceuticals Perspectives: This new non invasive imaging techniques for the quantitative assessment of the amyloid burden in patients with cardiac ATTR amyloidosis may help identify the responders and the patients who should benefit from dose intensification.

Ages 18 Years - 100 Years2 locations
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Looking for volunteersPhase 3Recently updatedNCT07881757

A Study to Learn About the Monthly Dosing Study Medicine Called Berobenatide in Adults With Breathing Problems During Sleep and Overweight or Obesity Who Do Not Use a Breathing Machine (PAP) (VESPER-OSA 2)

Tests Berobenatide, Placebo

For Apnea, Sleep Disorders and Overweight and/or Obesity

This study is being done to learn about the safety and effects of a study medicine called berobenatide (bear-oh-BEN-uh-tide). The study will see if berobenatide can help adults with breathing problems during sleep (obstructive sleep apnea \[OSA\]) and overweight or obesity who are not using a breathing machine (positive airway pressure \[PAP\] machine). People may be able to take part if they are adults with moderate to severe OSA, have overweight or obesity, and have been unable or unwilling using PAP therapy before joining the study. Participants will be assigned by chance to receive either berobenatide or a placebo (a treatment that looks like the study medicine but contains no active medicine). The study treatment will be given as an injection under the skin approximately once a month. Participants will receive study treatment at study sites and may administer some doses at home after receiving training. During the study, participants will attend study visits, undergo sleep studies, complete questionnaires, and have health assessments performed. Researchers will compare the effects of berobenatide and placebo on sleep apnea, body weight, and other health measures.

Ages 18 Years+4 locations
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Looking for volunteersPhase 3Recently updatedNCT07823608

A Study to Learn About the Monthly Dosing Study Medicine Called Berobenatide in Adults With Breathing Problems During Sleep and Overweight or Obesity Who Use a Breathing Machine (PAP) (VESPER-OSA 1)

Tests Berobenatide, Placebo

For Apnea, Sleep Disorders and Overweight and/or Obesity

This study is being done to learn about the safety and effects of a study medicine called berobenatide (bear-oh-BEN-uh-tide). The study will see if berobenatide can help adults with breathing problems during sleep (obstructive sleep apnea \[OSA\]) and overweight or obesity who use a breathing machine (positive airway pressure \[PAP\] machine). People may be able to take part if they are adults with moderate to severe OSA, have overweight or obesity, and have been using PAP therapy before joining the study. Participants will be assigned by chance to receive either berobenatide or a placebo (a treatment that looks like the study medicine but contains no active medicine). The study treatment will be given as an injection under the skin approximately once a month. Participants will receive study treatment at study sites and may administer some doses at home after receiving training. During the study, participants will attend study visits, undergo sleep studies, complete questionnaires, and have health assessments performed. Researchers will compare the effects of berobenatide and placebo on sleep apnea, body weight, and other health measures.

Ages 18 Years+8 locations
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Looking for volunteersPhase 3Recently updatedNCT05145127

Open-Label Extension Study of Marstacimab in Hemophilia Participants With or Without Inhibitors

Tests PF-06741086

For Hemophilia A and Hemophilia B

Study B7841007 is an open-label extension study to assess the long-term safety, tolerability, and efficacy of prophylaxis treatment with marstacimab in participants who did not require "Early Termination" from the Phase 3 Study B7841005 and from the Phase 3 Study B7841008. Study B7841005: approximately 145 adolescent and adult participants 12 to \<75 years of age with severe hemophilia A or moderately severe to severe hemophilia B (defined as FVIII activity \<1% or FIX activity ≤2%, respectively) with or without inhibitors are expected to be enrolled in Study B7841005 during which they will receive prophylaxis (defined as treatment by SC injection of marstacimab). Study B7841008: this is an ongoing Phase 3, open-label study in pediatric participants \<18 years of age with severe hemophilia A (FVIII Coagulation Factor Activity \<1%) or moderately severe to severe hemophilia B (FIX Coagulation Factor Activity ≤2%). A sequential approach will be used in enrolling at least 100 pediatric participants, at least 20 of which will be aged ≥12 to \<18 years and at least 80 participants will be aged ≥1 to \<12 years. At the start of study B7841008, the dosing and data available in adolescent and adult participants in Study B7841005 supported the initiation of B7841008 study in participants aged ≥12 to \<18 years. Subsequently, additional safety and efficacy data from adolescent participants in Study B7841005 became available for benefit/risk assessment in support of dosing participants aged ≥6 to \<12 years. Based on the positive benefit/risk assessment conducted by both internal Pfizer review and eDMC review, dosing of the ≥6 to \<12 years age group was initiated in June 2023 in B7841008 Study. Data from participants ≥6 years from B7841008 Study and Study B7841005 will support the dosing of participants aged ≥1 to \<6 years. All participants will be provided the prefilled pen (PFP) for administration of marstacimab in the study. Use of the prefilled syringe (PFS) will be permitted at the investigator's discretion for those participants who have difficulty with administration of the PFP. Additionally, participants will be provided the PFS for use in this study in countries where the PFS is anticipated to be the only presentation available commercially. An optional, open-label, single arm, substudy using the PFP was completed in the first 23 participants rolled over from Study B7841005 who agreed to participate in the substudy.

Ages 1 Year - 74 Years78 locations
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Looking for volunteersPhase 3Recently updatedNCT05611801

A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B

Tests marstacimab

For Hemophilia A and Hemophilia B

The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called marstacimab) for the potential treatment of hemophilia in pediatric patients. This study will enroll pediatric participants from ages 1 to 17 years in a sequential manner. The study opened the enrollment to adolescent participants aged 12 to 17 years first. Then children aged 6 to 11 years erere permitted to enroll. Lastly, children aged 1 to 5 years are permitted to enroll. This study will enroll male participants who: * have severe Hemophilia A or moderately severe to severe Hemophilia B (with or without inhibitors) * have accurate historical records documenting all factor VIII, factor IX, or bypass agent infusions and hemophilia bleed events for at least 1 year prior to entering the study for participants from 6 to 17 years of age, and at least 3 months prior to entering the study for participants from 1 to 5 years of age * if a non-inhibitor patient, must be on a stable routine prophylaxis regimen with factor VIII or factor IX replacement products for at least 12 months prior to study entry for participants from 6 to 17 years of age, and least 3 months for participants aged from 1 to 5 years of age * if an inhibitor patient, must be on an on-demand bypass treatment regimen during the 12 months prior to study entry for participants from 6 to 17 years of age, and during the 3 months prior to study entry for participants aged from 1 to 5 years of age All participants in this study will receive marstacimab to use prophylactically. Marstacimab will be given once a week as a subcutaneous (under the skin) shot. The first dose of marstacimab will be given at the study site by the study site staff. During the 12-month treatment period, weekly doses of marstacimab can be given at home, or if preferred, the doses may be given by the study site staff. To help us determine if the study medicine is safe and effective, we will compare participant experiences when they are taking the study medicine to a historical period when they were not. Researchers want to see if the study medicine works to prevent the bleeding episodes commonly experienced by patients with Hemophilia. Participants will be in this study for about 14 months (approximately 1 month in a Screening period, 12 months receiving treatment, and 1 month in a follow-up period) during which they will visit the study site at least 10 times. If preferred, and if local regulations allow it, 2 of the study visits can be completed at the participant's home instead of at the study site. There will also be 6 scheduled telephone calls approximately every 2 months.

Ages 1 Year - 17 Years63 locations
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Looking for volunteersPhase 3Recently updatedNCT06918002

Elranatamab/Lenalidomide Consolidation and/or Elranatamab Maintenance Versus Standard of Care After D-VRd Induction in Transplant-eligible NDMM Patients

Tests Elranatamab, Lenalidomide (Revlimid®), Daratumumab SC (Darzalex), Autologous Stem Cell Transplantation, Bortezomib (Velcade®), Dexamethasone

For Multiple Myeloma, Newly Diagnosed

This study is designed as a multicenter, randomized, parallel groups, open-label, phase 3 study in subjects with untreated newly diagnoses Multiple Myeloma eligible for ASCT. 824 patients will be enrolled in this study from approximately 70 study sites. The 2 parts in the Treatment Phase are described below. Part 1: Induction/ASCT/Consolidation Phase (1:1 Randomization) After the screening period, patients will be randomly allocated (1:1) to either: * Arm A (standard of care arm): standard induction therapy with 4 cycles of D-VRd, followed by HDCT (Melphalan) + ASCT, D-VRd consolidation therapy * Arm B (experimental arm): standard induction therapy with 4 cycles of D-VRd, followed by elranatamab and lenalidomide consolidation therapy. Part 2: Maintenance Phase (1:1 Re-randomization) Patients will be re-randomized (1:1) and will enter the Maintenance Phase upon completion of consolidation therapy. • Arm C (standard of care arm): daratumumab + lenalidomide approx 2 years. Subjects with a negative MRD (for at least 12 months) after 24 cycles of daratumumab-lenalidomide will discontinue daratumumab and continue with lenalidomide monotherapy until disease progression, or study cut-off date (whichever occurs first). Subjects who did not achieve MRD negativity for at least 12 months after 24 cycles of daratumumab-lenalidomide will continue to receive daratumumab-lenalidomide until: * MRD negativity for at least 12 months is reached. Subjects will then continue with lenalidomide monotherapy until disease progression, or study cut-off date (whichever occurs first). * Disease progression * Or study cut-off date (whichever occurs first). * Arm D (experimental arm): elranatamab. Approx 2 years. Subjects with a negative MRD (for at least 12 months) after receiving M22 administration of elranatamab will discontinue study treatment with elranatamab. Subjects who did not achieve MRD negativity for at least 12 months after M22 elranatamab administration will continue to receive elranatamab, every 24 weeks, until MRD negativity for at least 12 months is reached, disease progression, or study cut-off date (whichever occurs first).

Ages 18 Years - 69 Years69 locations
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Looking for volunteersPhase 2Recently updatedNCT02693535

TAPUR: Testing the Use of Food and Drug Administration (FDA) Approved Drugs That Target a Specific Abnormality in a Tumor Gene in People With Advanced Stage Cancer

Tests Sunitinib (CLOSED TO ENROLLMENT), Trastuzumab and Pertuzumab (CLOSED TO ENROLLMENT), Vemurafenib and Cobimetinib (CLOSED TO ENROLLMENT), Olaparib (CLOSED TO ENROLLMENT), Nivolumab and Ipilimumab (CLOSED TO ENROLLMENT), Abemaciclib (CLOSED TO ENROLLMENT), Talazoparib (CLOSED TO ENROLLMENT), Atezolizumab and Talazoparib (CLOSED TO ENROLLMENT), Tucatinib plus Trastuzumab Subcutaneous (SC) (CLOSED TO ENROLLMENT), Futibatinib, Dabrafenib plus Trametinib, Fam-Trastuzumab Deruxtecan-Nxki (TDxD)

For Lymphoma, Non-Hodgkin, Multiple Myeloma and Advanced Solid Tumors

The purpose of the study is to learn from the real world practice of prescribing targeted therapies to patients with advanced cancer whose tumor harbors a genomic variant known to be a drug target or to predict sensitivity to a drug. NOTE: Due to character limits, the arms section does NOT include all TAPUR Study relevant biomarkers. For additional information, contact TAPUR@asco.org, or if a patient, your nearest participating TAPUR site (see participating centers). \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* Results in publication or poster presentation format are posted as they become available for individual cohorts at www.tapur.org/news. The results may be accessed at any time. All results will be made available on clinicaltrials.gov at the end of the study. Indexing of available results on PubMed is in progress. \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*

Ages 12 Years+181 locations
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Looking for volunteersPhase 2Recently updatedNCT06832865

ELISA in Relapsed/Refractory MM

Tests elranatamab, Isatuximab SC, Isatuximab SC-OBDS

For Relapsed Refractory Multiple Myeloma (RRMM) and Relapsed Refractory Multiple Myeloma

This is an open-label phase 2 study of elranatamab in combination with isatuximab administered subcutaneously in patients with relapsed and refractory multiple myeloma (RRMM) who have received at least one prior line of therapy and who have had previous treatment with both immunomodulatory drugs (IMiDs) and a proteasome inhibitor (PI). The subcutaneous injection method of isatuximab administration, including the device used to administer isatuximab, is investigational.

Ages 18 Years+3 locations
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FDA-approved drugs from Pfizer Inc.

From the openFDA database. Tap a drug for side effects, dosing and help paying.

Caduet amlodipine and atorvastatin

For Homozygous Familial Hypercholesterolemia. Approved Jan 30, 2004. Taken by mouth.

Cyklokapron tranexamic acid

Approved Dec 30, 1986. Taken by intravenous route.

Daurismo glasdegib

For Acute Myeloid Leukemia. Approved Nov 21, 2018. Taken by mouth.

Doxorubicin Hydrochloride doxorubicin hydrochloride

For Hodgkin Lymphoma. Approved Dec 23, 1987. Taken by intravenous route.

Elelyso taliglucerase alfa

For Gaucher Disease. Approved May 1, 2012. Taken by intravenous route.

Elrexfio elranatamab-bcmm

For Multiple Myeloma. Approved Aug 14, 2023. Taken by subcutaneous route.

Genotropin somatropin

For Prader-Willi Syndrome and Turner Syndrome. Approved Aug 24, 1995.

Hympavzi marstacimab-hncq

For Hemophilia A and Hemophilia B. Approved Oct 11, 2024. Taken by subcutaneous route.

Idamycin PFS idarubicin hydrochloride

For Acute Myeloid Leukemia. Approved Feb 17, 1997. Taken by intravenous route.

Mylotarg gemtuzumab ozogamicin

For Acute Myeloid Leukemia. Approved Sep 1, 2017. Taken by intravenous route.

Nivestym filgrastim-aafi

For Acute Myeloid Leukemia. Approved Jul 20, 2018. Taken by subcutaneous, intravenous route.

Revatio sildenafil citrate

For Pulmonary Arterial Hypertension. Approved Jun 3, 2005. Taken by mouth.

Ruxience rituximab-pvvr

For Granulomatosis with Polyangiitis and Pemphigus Vulgaris. Approved Jul 23, 2019. Taken by intravenous route.

Somavert pegvisomant

For Acromegaly. Approved Mar 25, 2003.

Sutent sunitinib malate

For Gastrointestinal Stromal Tumor and Neuroendocrine Tumors. Approved Jan 26, 2006. Taken by mouth.

Vyndaqel tafamidis meglumine

Approved May 3, 2019. Taken by mouth.

Atgam antithymocyte globulin (horse)

For Aplastic Anemia.

Cutaquig immunoglobulin g

For Common Variable Immunodeficiency and Wiskott-Aldrich Syndrome. Taken by subcutaneous route.

Octagam Immune Globulin (Human) immune globulin

For Immune Thrombocytopenia and Dermatomyositis. Taken by intravenous route.

Ticovac tick-borne encephalitis vaccine (inactivated)

For Tick-Borne Encephalitis.

More about Pfizer Inc.

Within its broader pharmaceutical portfolio, Pfizer Inc. has active clinical trial programs and drug development efforts across 69 rare diseases, including Achondroplasia, Acromegaly, Acute Myeloid Leukemia, Adrenocortical Carcinoma, Amyotrophic Lateral Sclerosis, and 64 additional rare conditions. These programs may span orphan drug designation, novel therapeutic mechanisms, and precision medicine approaches targeting the underlying causes of each disease.

The clinical trials section below shows active and recruiting rare disease studies sponsored by Pfizer Inc., sourced live from ClinicalTrials.gov. Each trial includes its current recruitment status, study phase (Phase 1 through Phase 4), conditions under investigation, and the number of active trial sites.

The FDA-approved drugs section lists treatments that have received U.S. Food and Drug Administration approval, with brand names, generic names, approval dates, and matched rare disease indications from the openFDA database.

Pfizer Inc. is headquartered in New York, United States, founded in 1849, publicly traded under the ticker symbol PFE. The company maintains a dedicated rare disease division alongside its broader therapeutic portfolio, working to bring innovative treatments to patients with conditions that have historically had limited or no treatment options.

Where Pfizer Inc. trials take place

The trials above run at 1,372 study sites in 40 countries. Tap a country to see its states, cities and hospitals.

United States
769▼
France
113▼
China
65▼
Japan
57▼
Germany
34▼
Turkey (Türkiye)
27▼
United Kingdom
25▼
Spain
24▼
Italy
23▼
Canada
21▼
South Korea
19▼
Taiwan
19▼

Rare diseases Pfizer Inc. works on

Each disease page lists every open trial, not only Pfizer Inc.'s, plus approved treatments.

Achondroplasia

Achondroplasia is the most common form of short-limbed dwarfism, caused by a mutation in the FGFR3 gene that disrupts the conversion of cartilage to bone in the growth plates.

How common: Approximately 1 in 25,000 live births; estimated 25,000 to 30,000 people in the United States

Acromegaly

Acromegaly is a rare hormonal disorder caused by excessive growth hormone production, typically from a pituitary adenoma, resulting in abnormal growth of hands, feet, and facial features.

How common: About 50 to 70 people per million, according to NORD, with 3 to 11 new cases per million people each year

Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a fast-growing cancer of the bone marrow in which immature white blood cells called blasts crowd out normal blood cells, causing fatigue, infections and bleeding...

How common: The National Cancer Institute's SEER program estimates 22,720 new US cases and 11,500 deaths in 2026, about 1.1% of new cancers, and 83,311 people were living with AML in 2023

Adrenocortical Carcinoma

Adrenocortical carcinoma is a rare, aggressive cancer of the adrenal cortex, the outer layer of the adrenal glands that sit on top of each kidney.

How common: About 1-2 per million people per year; approximately 600 new cases per year in the U.S

Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive neurodegenerative disease destroying motor neurons in the brain and spinal cord.

How common: About 5,000 new cases per year in the U.S.; CDC's National ALS Registry estimates about 33,000 Americans were living with ALS in 2022, a number projected to pass 36,000 by 2030

Aplastic Anemia

Aplastic anemia is a rare bone marrow failure syndrome characterized by pancytopenia resulting from absent or severely reduced hematopoiesis.

How common: 1-2 cases per 1 million people per year

ATTR Amyloidosis (Transthyretin Amyloidosis)

ATTR amyloidosis is a rare progressive disease where abnormal transthyretin protein accumulates as amyloid deposits in the heart, nerves, and other organs.

How common: Approximately 5,000 to 7,000 new cases diagnosed annually in the U.S

Becker Muscular Dystrophy

Becker Muscular Dystrophy (BMD) is an X-linked inherited muscular dystrophy caused by mutations in the dystrophin gene that produce a partially functional dystrophin protein.

How common: Approximately 1 to 5 per 100,000 males; about 1/3 to 1/2 the prevalence of Duchenne Muscular Dystrophy

Cholangiocarcinoma

Cholangiocarcinoma is a rare and aggressive cancer that forms in the bile ducts, the thin tubes that carry digestive fluid (bile) from the liver to the small intestine.

How common: About 8,000 new cases per year in the U.S.; rising incidence worldwide

Chronic Graft-versus-Host Disease

Chronic graft-versus-host disease is an immune-mediated complication after allogeneic stem cell or bone marrow transplant, in which donor immune cells attack the recipient's tissues.

How common: Affects 30-70% of patients who receive allogeneic hematopoietic stem cell transplant; about 14,000 Americans were living with chronic GVHD in 2016, according to a claims study funded in part by Kadmon (Bachier et al., Transplantation and Cellular Therapy, 2021)

Chronic Inflammatory Demyelinating Polyneuropathy

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is an autoimmune disorder affecting the peripheral nerves, causing progressive weakness and impaired function in the legs and arms.

How common: About 2.8 per 100,000 people in a 2019 pooled analysis of 9 studies (Broers et al., Neuroepidemiology); NORD estimates 5 to 7 per 100,000, and NIH's GARD estimates about 50,000 people in the U.S

Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia comprises rare autosomal recessive disorders of cortisol synthesis.

How common: Classic form about 1 in 15,000 newborns (MedlinePlus Genetics); the milder non-classic form is more common

Cystic Fibrosis

Cystic fibrosis is an autosomal recessive genetic disorder affecting the CFTR protein, which normally regulates chloride transport.

How common: Nearly 40,000 children and adults in the U.S.; 1 in 2,500 to 3,500 births among Caucasians

Dermatomyositis

Dermatomyositis is a rare autoimmune inflammatory disease causing muscle weakness and distinctive skin rashes, particularly over joints.

How common: About 9.6 new cases per million people a year, according to NORD; juvenile-onset incidence about 0.4 cases per 100,000 children

Diffuse Intrinsic Pontine Glioma

Diffuse intrinsic pontine glioma (DIPG) is an aggressive childhood brain tumor that grows in the pons, the part of the brainstem controlling breathing, swallowing, and movement.

How common: About 300 children diagnosed in the U.S. each year, most often between ages 5 and 10

Dilated Cardiomyopathy

Dilated cardiomyopathy is a condition where the heart's main pumping chamber, the left ventricle, becomes enlarged and weakened, reducing the heart's ability to pump blood efficiently.

How common: Approximately 1 in 250 to 1 in 500 people; accounts for about 30-40% of heart failure cases

Duchenne Muscular Dystrophy

Duchenne muscular dystrophy is an X-linked genetic disorder causing progressive muscle weakness and degeneration, beginning in early childhood.

How common: 1 in 3,500 to 5,000 male births

Eosinophilic Esophagitis

Eosinophilic Esophagitis is a rare allergic/immune-mediated inflammatory disease of the esophagus characterized by eosinophil infiltration causing progressive narrowing and dysfunction.

How common: About 142.5 per 100,000 people in the United States, about 1 in 700 or an estimated 472,380 people, in a 2025 insurance claims study (Thel et al., Clin Gastroenterol Hepatol 2025)

Inherited Erythromelalgia

Inherited erythromelalgia is a rare autosomal dominant pain disorder caused by gain-of-function mutations in the SCN9A gene, which encodes the Nav1.7 voltage-gated sodium channel.

How common: Exact prevalence is unknown

Essential Thrombocythemia

Essential Thrombocythemia is a myeloproliferative neoplasm characterized by overproduction of platelets by bone marrow, resulting in very high platelet counts.

How common: About 1 new case per 100,000 people each year, with an estimated 30 to 60 per 100,000 living with it (NORD); average age at diagnosis is in the mid-fifties

Fabry Disease

Fabry disease is a rare inherited lysosomal storage disorder where a missing enzyme causes fatty substances called globotriaosylceramide to accumulate in cells throughout the body.

How common: 1 in 40,000 to 60,000 males; higher in females when accounting for carrier status

Familial Chylomicronemia Syndrome

Familial Chylomicronemia Syndrome is a rare inherited metabolic disorder where the body cannot break down certain fats (triglycerides) normally, causing dangerously high blood fat levels.

How common: 1 to 2 per 1,000,000 people globally

Focal Epilepsy

Focal epilepsy is a neurological disorder characterized by recurrent seizures that originate in a specific area of the brain.

How common: Up to about 61% of people with epilepsy have focal seizures; about 2.9 million U.S. adults and 456,000 children have active epilepsy

Focal Segmental Glomerulosclerosis

Focal Segmental Glomerulosclerosis (FSGS) is a kidney disease characterized by scarring of some glomeruli, the tiny filtering units that remove waste from the blood.

How common: Approximately 7% of all kidney biopsies in the United States show FSGS; incidence is 0.2-1.7 cases per 100,000 person-years

Friedreich Ataxia

Friedreich ataxia is an autosomal recessive neurodegenerative disease causing progressive damage to the nervous system, resulting in loss of coordination (ataxia), weakness, and heart problems.

How common: 1 in 50,000 people

Facioscapulohumeral Muscular Dystrophy

Facioscapulohumeral Muscular Dystrophy (FSHD) is an inherited muscular dystrophy characterized by progressive weakness of the facial, shoulder, and upper arm muscles.

How common: About 1 in 20,000 people (MedlinePlus Genetics); one of the most common hereditary muscular dystrophies

Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, arising from the interstitial cells of Cajal or their precursors.

How common: About 6,000 new cases per year in the U.S. (American Cancer Society); true incidence may be higher as small GISTs are often incidentally discovered

Gaucher Disease

Gaucher disease is a rare inherited lysosomal storage disorder caused by deficiency of the enzyme glucocerebrosidase, resulting in accumulation of fatty substances in the spleen, liver, and bone...

How common: 1 in 40,000 to 60,000 in general population; 1 in 850 among Ashkenazi Jewish population

Generalized Pustular Psoriasis

Generalized pustular psoriasis (GPP) is the rarest form of psoriasis and behaves like a different disease.

How common: Roughly 2 to 7 new cases per million people a year worldwide (NORD); published estimates range from 2 to 124 per million, lower in Europe and higher in parts of Asia; about half of people with GPP also have ordinary plaque psoriasis

Granulomatosis with Polyangiitis

Granulomatosis with Polyangiitis is a rare autoimmune disease causing inflammation of small and medium blood vessels in the lungs, kidneys, and upper respiratory tract.

How common: An estimated 3 in 100,000 people in the United States, according to MedlinePlus Genetics

Hemophilia A

Hemophilia A is an X-linked bleeding disorder caused by deficiency or dysfunction of clotting factor VIII.

How common: 1 in 4,000 to 5,000 males worldwide; very rare in females

Hemophilia B

Hemophilia B is an X-linked bleeding disorder caused by deficiency or dysfunction of clotting factor IX.

How common: 1 in 25,000 to 33,000 males; very rare in females

Hereditary Diffuse Gastric Cancer

Hereditary diffuse gastric cancer is an autosomal dominant cancer predisposition syndrome caused by germline CDH1 mutations.

How common: Estimated at 1 in 1,000 gastric cancer cases; ~1 in 100,000 in general population

Hodgkin Lymphoma

Hodgkin lymphoma is a cancer of the lymphatic system characterized by the presence of abnormal Reed-Sternberg cells.

How common: About 8,920 new cases expected in the U.S. in 2026 (American Cancer Society); approximately 2.6 per 100,000 people

Homozygous Familial Hypercholesterolemia

Homozygous Familial Hypercholesterolemia is a severe genetic disorder causing extremely high cholesterol levels from birth, leading to early heart disease and cholesterol deposits in tendons and...

How common: Approximately 1 in 250,000 to 1 in 360,000 people globally

Huntington Disease

Huntington disease is an autosomal dominant neurodegenerative disorder caused by an expanded CAG trinucleotide repeat in the huntingtin gene.

How common: About 3-7 per 100,000 people of European ancestry, according to MedlinePlus Genetics; less common in people of Japanese, Chinese and African descent

Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis is a chronic, progressive lung disease characterized by scarring (fibrosis) of lung tissue.

How common: About 100,000 people in the U.S., with 30,000 to 40,000 new cases a year (MedlinePlus Genetics)

IgA Nephropathy

IgA nephropathy is the most common primary glomerulonephritis worldwide, caused by abnormal IgA1 antibodies depositing in the kidney's mesangium, activating complement pathways and triggering...

How common: About 2 new cases per 100,000 people each year in the U.S., and an estimated 199,000 to 208,000 Americans were living with IgA nephropathy in 2021 (Otsuka-funded study, Clinical Nephrology, 2025)

Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is a rare autoimmune disorder in which the immune system destroys platelets, the blood cells that stop bleeding, and slows their production.

How common: Estimated 9 to 20 per 100,000 people; children often have a temporary form that resolves within months

Light Chain Amyloidosis

Light Chain Amyloidosis is a rare, serious blood disorder caused by plasma cells producing misfolded immunoglobulin light chains that accumulate in tissues as amyloid fibrils, progressively damaging...

How common: Approximately 600-1,000 new cases per year in the United States; median age of diagnosis is 63 years

Limb-Girdle Muscular Dystrophy

Limb-Girdle Muscular Dystrophy (LGMD) refers to a genetically heterogeneous group of muscular dystrophies characterized by progressive weakness of the hip and shoulder girdle muscles.

How common: Approximately 1 per 14,500 to 1 per 123,000 people depending on geographic region; exact prevalence varies by subtype

Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare progressive lung disease characterized by proliferation of abnormal smooth muscle-like cells (LAM cells) in the lungs, lymph nodes, and kidneys.

How common: Approximately 1 per 400,000 women; 30-40% of women with TSC develop LAM

Mantle Cell Lymphoma

Mantle cell lymphoma is a rare type of non-Hodgkin lymphoma that starts in B cells, a kind of white blood cell.

How common: About 1 in 200,000 people (Cleveland Clinic)

Merkel Cell Carcinoma

Merkel cell carcinoma is a rare, aggressive skin cancer that arises from Merkel cells, specialized touch receptors in the skin.

How common: About 3,000 new cases per year in the U.S.; incidence has tripled over the past 2 decades

Mesothelioma

Mesothelioma is a rare, aggressive cancer that develops in the mesothelium, the thin layer of tissue covering most internal organs.

How common: About 3,000 new cases per year in the U.S

Morphea

Morphea is a localized form of scleroderma characterized by hardened patches of skin with hyperpigmentation or hypopigmentation.

How common: About 0.4 to 2.7 new cases per 100,000 people each year; by age 80 about 2 in 1,000 people have had it (Peterson et al., J Rheumatol 1997)

Multiple Myeloma

Multiple myeloma is a cancer of plasma cells, the white blood cells that make antibodies.

How common: About 36,000 new US diagnoses expected in 2026 and roughly 203,000 people living with it, which puts myeloma right at the edge of the US rare disease threshold; it is 1.7% of all new cancers (NCI SEER)

Multiple Sclerosis

Multiple sclerosis is a chronic autoimmune disease where the immune system attacks the protective myelin sheath surrounding nerve fibers in the brain and spinal cord.

How common: Approximately 1 million people in the U.S.; about 1 in 300

Myelodysplastic Syndromes

Myelodysplastic syndromes are a group of blood cancers in which the bone marrow fails to produce enough healthy blood cells.

How common: 10,000 to 15,000 new cases annually in the U.S.; estimated 60,000 to 170,000 Americans living with MDS

Myelofibrosis

Myelofibrosis is a myeloproliferative neoplasm in which bone marrow develops scarring (fibrosis), leading to anemia, enlarged spleen, and abnormal blood cell counts.

How common: Approximately 0.5-1.5 cases per 100,000 people; median age of diagnosis is 65 years

Neurofibromatosis Type 1

Neurofibromatosis type 1 is a genetic disorder caused by mutations in the NF1 gene on chromosome 17, which encodes neurofibromin, a tumor suppressor protein.

How common: 1 in 2,500 to 3,500 people in the U.S., making it one of the most common genetic conditions

Paraganglioma

Paragangliomas are rare neuroendocrine tumors arising from chromaffin tissue outside the adrenal medulla.

How common: 1 in 300,000 to 1,000,000; ~30% are hereditary

Pemphigus Vulgaris

Pemphigus Vulgaris is a rare, potentially life-threatening autoimmune blistering disorder where the body produces antibodies against cell-to-cell adhesion molecules, causing blisters and erosions in...

How common: Approximately 0.5-3.2 cases per 100,000 people; higher incidence in certain ethnic groups (Ashkenazi Jews, Mediterranean, Indian populations)

Pheochromocytoma

Pheochromocytoma is a rare neuroendocrine tumor arising from chromaffin cells of the adrenal medulla that produces excessive catecholamines (epinephrine and norepinephrine).

How common: About 2 to 8 new cases per million people a year (National Cancer Institute)

Polycystic Kidney Disease

Polycystic Kidney Disease is a genetic disorder characterized by the growth of thousands of cysts in the kidneys, gradually replacing normal kidney tissue and leading to kidney failure.

How common: Autosomal dominant PKD affects about 1 in 400 to 1,000 people worldwide and the recessive form about 1 in 20,000 children; about 500,000 people in the United States have PKD (NIDDK)

Polycythemia Vera

Polycythemia Vera is a myeloproliferative neoplasm in which bone marrow produces too many red blood cells, leading to thick blood that carries oxygen less effectively and increases clot risk.

How common: About 44 to 57 per 100,000 people in the US, from 2 large health plans in 2008 to 2010 (Mehta et al., Leukemia and Lymphoma 2014); median age of diagnosis is 65 years

Prader-Willi Syndrome

Prader-Willi Syndrome is a rare genetic disorder affecting chromosome 15 that results in weak muscle tone, low hormone levels, incomplete sexual development, intellectual disability, and a constant...

How common: Approximately 1 in 10,000 to 30,000 live births

Primary Central Nervous System Lymphoma

Primary central nervous system lymphoma (PCNSL) is a fast-growing lymphoma that starts in the brain, spinal cord, eyes or the membranes around them and usually stays there.

How common: About 5 new cases per million people a year in the US (Ono Pharmaceutical and Deciphera); more than half of patients are 60 or older

Pulmonary Arterial Hypertension

Pulmonary arterial hypertension is a rare disease characterized by abnormally high blood pressure in the pulmonary arteries, causing progressive heart and lung damage.

How common: About 26 to 52 per million people in a Scottish national study, with about 7 new cases per million people each year (Peacock et al., European Respiratory Journal, 2007)

Sarcoidosis

Sarcoidosis is an inflammatory disease characterized by formation of granulomas (clusters of immune cells) in multiple organs, most commonly the lungs and lymph nodes.

How common: An estimated 150,000 to 200,000 people in the United States, about 60 per 100,000, with rates that vary by ethnicity and geography (NORD)

Sickle Cell Disease

Sickle cell disease is an inherited blood disorder where hemoglobin polymerizes under low oxygen, causing red blood cells to become rigid, sickle-shaped, and prone to hemolysis and vaso-occlusion.

How common: About 100,000 Americans with SCD; about 1 in 365 Black or African American births and 1 in 16,300 Hispanic American births

Spinocerebellar Ataxia

Spinocerebellar ataxias are a group of inherited neurodegenerative disorders caused by mutations in various genes, leading to progressive degeneration of the cerebellum and its connections.

How common: Collectively about 1-5 per 100,000 people; SCA3 (Machado-Joseph disease) is the most common subtype worldwide

Systemic Juvenile Idiopathic Arthritis

Systemic juvenile idiopathic arthritis is a severe autoinflammatory disease characterized by daily spiking fevers, a salmon-pink rash, and joint inflammation.

How common: Accounts for 10-20% of all juvenile idiopathic arthritis cases; estimated 1 in 32,000 children in the U.S

Systemic Sclerosis

Systemic sclerosis (scleroderma) is a rare autoimmune disease in which the immune system triggers scarring (fibrosis) of the skin and internal organs while also damaging small blood vessels.

How common: About 276 per million U.S. adults in a large Detroit-area study; about 19 new cases per million adults each year

Tick-Borne Encephalitis

Tick-borne encephalitis is a viral infection of the brain spread by ticks across parts of Europe and northern Asia.

How common: About 5,000 to 10,000 cases a year in Europe and Asia

Tuberous Sclerosis

Tuberous sclerosis is an autosomal dominant genetic disorder caused by mutations in TSC1 or TSC2 genes, resulting in dysregulated mTOR signaling and widespread benign tumor growth.

How common: 1 in 6,000 to 1 in 10,000 people

Turner Syndrome

Turner syndrome results from complete or partial absence of an X chromosome in females, causing short stature, gonadal dysgenesis, cardiac and renal abnormalities.

How common: 1 in 2,000 to 3,000 live female births

Von Willebrand Disease

Von Willebrand disease is the most common inherited bleeding disorder, caused by quantitative or qualitative deficiency of von Willebrand factor.

How common: 1-3% of the general population; 1 in 10,000 with clinically significant disease

Wild-Type ATTR Cardiac Amyloidosis

Wild-type ATTR cardiac amyloidosis is an age-related disease where normal transthyretin protein spontaneously misfolds and accumulates in the heart, causing progressive heart failure.

How common: Estimated to affect up to 13% of males aged 85 and older; substantially underdiagnosed

Where to get support

Patient groups can explain a diagnosis, point you to specialists and tell you about trials before they open. Pfizer Inc.'s own site is pfizer.com, and our help paying for treatment page lists drugmaker programs and charity funds.

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