Rare Diseases
Progress in Fighting Rare Diseases
Rare diseases, when taken together, are not that rare at all. According to the National Institutes of Health (NIH), 30 million Americans and 400 million worldwide have one of the approximately 7,000 known rare diseases. A disease is defined as a rare or orphan disease when it affects fewer than 200,000 people in the United States. The need for new treatments and cures is reflected in the unique hardships and challenges that patients and their families face. Obtaining a diagnosis can be a long arduous process due to lack of physician awareness and access to screening. And once a diagnosis is obtained, often later in disease progression, the prognosis may be life threatening. The burden of rare disease is a driving factor in the commitment of the biopharmaceutical industry to help these patients and their families.
7,000
Approximately 7,000 different rare diseases are known to exist today.
<10%
Less than 10% of the known rare diseases have an approved treatment available.
800
The FDA has approved over 800 orphan drugs since the passage of the Orphan Drug Act.
Progress & Unmet Need
We’ve seen incredible advances in the development of medicines to treat patients with rare diseases as researchers uncover the molecular and genomic drivers of many conditions. Rare diseases are biologically complex and scientists are working hard to uncover the underlying causes and the clinical course of individual rare diseases. America’s biopharmaceutical researchers are leveraging new technologies and the growing understanding of the genetic basis for many rare diseases to develop groundbreaking therapies to meet this unmet need.
Biopharmaceutical industry researchers continue are making progress in the fight against rare diseases as innovative science has opened new opportunities. Today, there are and more than 700 medicines are in the current biopharmaceutical pipeline. Despite recent progress, there is still much more work to be done. In fact, less than 10% of rare diseases have an approved treatment option
Spurring Innovation
The Orphan Drug Act (ODA) has been instrumental to increasing research into rare diseases. Prior to the ODA enactment, only 10 medicines had been FDA approved for rare diseases, today that figure is over 800.
The ODA provides incentives for rare disease R&D, as it can be especially challenging to develop new treatments for rare diseases. Specifically, these incentives help increase the chances that companies who invest in rare disease research, and manage to get an orphan drug approved, will recoup their costs. Among other incentives, the ODA provides a 7-year market exclusivity period during which the FDA may not approve the same drug for the same orphan indication. These incentives help protect investments and encourage companies to embark on the necessary highly risky research when market based incentives are insufficient.
Challenges in Rare Disease Drug Development
Developing medicines to treat rare diseases presents scientific and operational challenges. The complex biology of many rare diseases presents unique hurdles for scientists, making it difficult to design and implement a drug development program. Within a particular rare disease, there can be many variations or subtypes resulting in different clinical manifestations and disease progressions. Additionally, due to the inherently small population of patients with a rare disease, recruiting for and conducting clinical trials can be difficult.
Despite these challenges, America’s biopharmaceutical researchers have leveraged new technologies and the growing scientific understanding of many rare diseases to develop groundbreaking therapies in recent years, including:
- The first treatments directed at treating the underlying causes of cystic fibrosis
- Significant advances in targeted therapies for many forms of blood cancer, including chronic lymphocytic leukemia, chronic myelogenous leukemia, and multiple myeloma
- New medicines that can prevent or slow the impact of several extremely rare, devastating conditions including pulmonary arterial hypertension, hereditary angioedema, and Gaucher disease
- The first therapies available to treat many rare pediatric diseases, including a progressive, metabolic disease called hypophosphatasia (HPP), an inherited genetic disease called lysosomal acid lipase (LAL) deficiency, and neuroblastoma, a rare form of cancer that occurs in nerve cells and the brain
Related Resources
Spurring Innovation in Rare Diseases
Although rare diseases each may individually only impact a relatively small number of patients, defined as less than 200,000 in the United States, their impact on public health is far-reaching. While the median number of patients with each rare disease is less than 10,000, rare diseases affect 30 million Americans – about 1 in 10.
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Disease
Fact Sheet
World Sickle Cell Day: Recognizing the promise of gene therapy
Today is World Sickle Cell Day, an opportunity to recognize the patients, families and communities affected by sickle cell disease — and to underscore the biopharmaceutical industry's ongoing efforts to advancing new treatments for this life-altering condition.
Background: Sickle cell disease (SCD) is an inherited rare blood disorder caused by a mutation in the gene that tells the body how to make hemoglobin, which is the protein in red blood cells that carries oxygen.
People living with SCD can experience chronic, severe and unpredictable pain, resulting in frequent, expensive hospital visits, limiting patients' ability to participate in everyday activities. The disease typically manifests in children before they turn one, with life expectancy averaging just 54 years, about 20 years shorter than average U.S. life expectancy.
Who is affected: SCD affects approximately 100,000 people in the United States and disproportionately impacts people of Black or African-American descent, who make up more than 90% of the SCD population in the United States.
Changing the game for patients: For decades, treatment options for SCD primarily helped to manage symptoms. That all changed in 2023 when the FDA approved two cell-based gene therapies to treat SCD — marking a major breakthrough and offering new hope to patients across the country to alter the trajectory of this disease and its debilitating consequences.
Why it matters: Gene therapies target SCD’s genetic cause and offer long-term, or even curative benefits with a single treatment. These advances could also help patients build a better future, including in the workplace:
- More than half of patients with SCD report that chronic pain and other disease burdens affect their employment status, forcing some to cut back their hours or leave the workforce altogether.
- By reducing painful complications from SCD, gene therapy can help patients avoid disruptions that could affect their ability to work and maintain employment.
Maintaining American leadership: To ensure patients can continue to get new, life-saving treatments, the U.S. must remain at the forefront of cell and gene therapy development. Continued progress depends on pro-innovation policies that:
- Support research and development
- Protect America's world-leading intellectual property ecosystem
- Help bring the next generation of treatments to patients
The bottom line: The 2023 FDA approvals of the first sickle cell gene therapies were a significant milestone, but sustaining this momentum requires smart, pro-innovation policy choices that protect the research ecosystem making breakthroughs like these possible.
Read PhRMA’s Future of Medicine report to learn more about the future of cell and gene therapy.
Drew Voytal
Celebrating rare disease innovation: Progress and the path forward
Every year on February 28 we observe Rare Disease Day, a moment to recognize those living with rare diseases around the world and to highlight the scientists, patients, caregivers and biopharmaceutical researchers working to transform lives. Rare diseases may be individually uncommon, but collectively they affect an estimated 25–30 million Americans and hundreds of millions globally.
What is a rare disease?
The Orphan Drug Act of 1983 (ODA) generally defines a rare disease as a condition that affects fewer than 200,000 people nationally. There are approximately 7,000 known rare diseases, ranging from genetic disorders and metabolic conditions to rare cancers and immunological diseases. Many have severe, life-threatening symptoms, and only about 5% of known rare diseases have an approved treatment option.
Developing treatment is challenging
Drug development is a lengthy and complex process, and rare diseases pose unique hurdles:
- Small patient populations: Recruiting enough participants for clinical trials can be extremely difficult when only a few hundred or thousand people worldwide have a condition.
- Treatment complexity: Many rare diseases are genetic in origin and require cutting-edge biomedical innovation and new scientific approaches to develop treatments. With some rare diseases, there is limited understanding of the disease's progression and how the disease affects a patient, which imposes unique complexities for developing treatments.
- Economic uncertainty: Because of the limited market size due to small patient populations, it can be difficult to encourage the immense investments necessary to advance rare disease research and development.
- Regulatory challenges: Standard trial designs are often not feasible and endpoints are not always fully developed. As a result, companies must explore innovative approaches and trial designs that regulators will consider for review.
Innovation is advancing
The ODA created several incentives to spur rare disease research and development, and these have helped fuel tremendous progress to address unmet medical need. The biopharmaceutical industry is investing in research, resulting in new medicines for rare diseases every year:
- In the decade before the ODA was passed, only 10 drugs for rare diseases were brought to market. Over the past four decades since the ODA, the FDA has granted orphan drug designation to thousands of molecules and therapies, leading to about 800 approved rare disease medicines.
- In 2025, approximately 50% of new drug approvals were for rare diseases.
These medicines aren’t just statistics — they represent new and additional options for patients with conditions that once had no therapy.
Cutting-edge technologies drive progress
Transformative treatments like gene therapy and precision medicine are becoming reality. With 438 cell and gene therapies in development in the U.S. at the end of 2025, these targeted treatments are now moving from research labs into clinical trials and eventually into doctors’ offices, offering potential treatments for many rare diseases that arise from specific genetic defects.
PhRMA member companies are investing not only in rare disease research and development but domestic manufacturing of rare disease treatments as well — accelerating development and delivery of life-saving treatments while also creating high-skilled jobs and strengthening the U.S. drug development ecosystem.
Looking ahead: Innovation built on collaboration
Rare Disease Day is a reminder that though we’ve seen major achievements in rare disease drug development, there are still millions of patients with no treatment options. The path forward depends on continued collaboration among industry, patients, policymakers and researchers to remove obstacles and accelerate meaningful breakthroughs.
Progress also requires sustained support for policies that fuel investment while ensuring patients can access new therapies. The recent enactment of the Orphan Cures Act, which helped address the disincentives for orphan drug development that were implemented as part of the Inflation Reduction Act as originally enacted, represents an important step forward in ensuring future progress for patients with rare diseases.
PhRMA member companies remain committed to bringing more life-changing treatments to those who need them most. Learn more at PhRMA.org/RareDiseases.
Mike Ybarra
A Decade of Innovation in Rare Diseases
Over the past decade, a new era of innovation has pushed the frontiers of science, leading to remarkable progress for patients with a wide range of rare diseases. Collectively, these diseases impact 30 million Americans and 400 million people worldwide. Despite the challenges, throughout the last decade, America's biopharmaceutical researcher companies have made significant progress in the development of groundbreaking therapies.
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Disease
Report