While we mostly think of disease as being caused by external factors like bacteria and viruses, an illness can also occur when the body’s own defenses turn against themselves. In this article, we take a look at some rare autoimmune diseases you may not have heard of and what biotechs are doing to treat them.  

The body’s immune system can be just as toxic to its own tissues as it can be to foreign organisms. A hyperactive immune system can wreak havoc on the body, with patients often afflicted by more than one autoimmune disease at once. 

While you may already be aware of some of the more well-known rare autoimmune diseases, such as multiple sclerosis, which results from an immune attack on the myelin sheath of nerve cells, type 1 diabetes, where the immune system destroys insulin-producing pancreatic cells, or rheumatoid arthritis, in which the joints suffer from inflammation, there are many other rare autoimmune diseases out there that take a great toll on patients.  

Here, we review eight of these lesser-known, rare conditions that biotech companies are also fighting to treat. 

Graves’ Disease 

There are different types of rare autoimmune diseases that cause inflammation of the thyroid gland, which can lead to hormonal imbalances. Graves’ disease occurs when antibodies induce the thyroid to secrete too much thyroid hormone, which can lead to tremors, red skin, and an irregular heartbeat. 

The incidence of Graves’ disease is between 20 to 50 cases per 100,000 persons per year. It is typically treated by removing the thyroid gland and giving patients lifelong hormone replacement therapy. However, synthetic thyroxine can induce hypothyroidism, a condition where the thyroid gland is not active enough. Due to this, new treatment methods are pivotal in tackling the disease. 

Fortunately, several promising new treatment approaches for Graves’ disease are emerging, including antigen-specific immunotherapy, B-cell depletion therapies, and targeted therapies against the TSH receptor, a protein found on thyroid cells that binds to thyroid-stimulating hormone (TSH), prompting the release of thyroid hormones, or IGF-1R, a protein found on the surface of cells that plays a crucial role in cell growth, survival, and metabolism. These approaches aim to address the underlying autoimmune cause of Graves’ disease, rather than just managing its symptoms.  

One of the leading companies in the field right now is Immunovant, as it progresses two candidates for Graves’ disease: batoclimab and IMVT-1402. In September 2024, the company reported positive phase 2a results from a clinical trial investigating the monoclonal antibody batoclimab in patients with Graves’ disease who had hypothyroidism despite receiving antithyroid therapy. The high dose of batoclimab achieved a 76% response rate in patients, and by the end of 12 weeks of the higher dose, 56% achieved an antithyroid drug (ATD)-Free Response. Furthermore, Immunovant’s other candidate, IMVT-1402, which is designed to avoid the albumin reductions and LDL cholesterol increases observed with batoclimab while maintaining comparable IgG-lowering efficacy, received an Investigational New Drug (IND) clearance from the U.S. Food and Drug Administration (FDA) last year.  

Another promising candidate being looked at for Graves’ disease is the drug rituximab, which works by targeting and depleting B-cells and has already received approval for the treatment of cancer and other autoimmune diseases. It is primarily being investigated as a potential treatment for young people with Graves’ disease in the hope that it will increase remission rates and reduce the need for long-term treatments like surgery or radioactive iodine.  

Psoriasis 

A common misconception of dermatological conditions like psoriasis is that they only cause cosmetic discomfort. However, the skin damage can be very serious during flare-ups of the disease. This results in the inability to regulate body temperature, which makes psoriasis patients vulnerable to life-threatening infections.  

Standard treatments currently include topical creams like corticosteroids, phototherapy – where light is used to slow down the production of skin cells – and biological medicines that target inflammation. But biotech companies have been on the hunt in the last few years for treatments that are more effective and cause less side effects; for example, corticosteroid creams lead to only onset skin thinning and pose a small risk of patients experiencing topical steroid withdrawal, a skin condition that can occur after discontinuing or reducing the use of topical corticosteroids, especially after prolonged or high-potency use. 

Several recent advancements have been made in psoriasis treatment, including the approval of new biologics and a new oral medication. Bimekizumab (Bimzelx), a biologic that blocks both IL-17A and IL-17F, was approved by the FDA in 2023 and has shown promising results with high rates of complete skin clearance in clinical trials. Meanwhile, the first-ever oral allosteric tyrosine kinase 2 (TYK2) inhibitor, deucravacitinib, was also approved by the FDA in 2022 for the treatment of moderate-to-severe plaque psoriasis in adults.  

Furthermore, another drug, Spevigo (spesolimab), was approved in 2022 for the treatment of adults with generalized pustular psoriasis (GPP) flares. This is a rare form of psoriasis that, as the name suggests, leads to pus-filled blisters on the body, which is often triggered by stress, infections, exposure to too much ultraviolet (UV) light, and certain medications like steroids. 

Uveitis 

Uveitis is a rare autoimmune disease that causes inflammation of the pigmented layer of the eye called the uvea, the optic nerve, and the gel that gives the eye its shape, known as the vitreous. The disease, which can cause pain, redness, and blurry vision, is usually treated with anti-inflammatory topical, intravenous, and oral corticosteroids. If it is left untreated, it can lead to long-term complications such as vision loss and blindness. 

As with psoriasis, biotechs have been focusing on new treatments for uveitis, and some have already been successful. In October 2021, the FDA approved Xipere, a therapy to treat macular edema associated with uveitis, which is characterized by the accumulation of fluid in the eye. Administered via injection, the drug demonstrated success in clinical studies. The therapy is a collaboration between healthcare companies Bausch + Lomb and Clearside Biomedical. 

More recently, ANI Pharmaceuticals received FDA approval for an expanded label for Iluven, a fluocinolone acetonide intravitreal implant, meaning that it can now be used to treat chronic non-infectious uveitis affecting the posterior segment of the eye.  

Meanwhile, systemic oral therapies and local novel injections have so far shown strong promise in clinical trials. Priovant Therapeutics’ drug brepocitinib, which is a dual TYK2 and JAK1 inhibitor, is progressing particularly well, having achieved positive results in a phase 2 study last year for the treatment of non-anterior non-infectious uveitis, and is now being investigated in a phase 3 trial for the same indication.  

Sarcoidosis 

Sarcoidosis causes inflammatory cells to build up in certain tissues, particularly the lungs, to form granulomas. Symptoms of the autoimmune condition include shortness of breath and bumps on the skin, and sometimes, when other organs are affected, it can lead to irregular heart rhythm, also known as arrhythmia. 

The mainstay treatment for sarcoidosis is corticosteroids, usually in the form of pills like prednisone, to reduce inflammation. However, if steroids are ineffective or cause undesirable side effects, immunosuppressants like methotrexate or azathioprine may be used. In some cases, other medications like antimalarials (hydroxychloroquine) or TNF inhibitors may also be considered, and, for severe cases, treatments like oxygen therapy, pulmonary rehabilitation, or even a lung transplant may be necessary. 

The sarcoidosis field is not awash with new treatments or clinical candidates, but there is one investigative therapy on the horizon that could offer hope to patients. This is aTyr Pharma’s efzofitimod, a neuropilin‑2 (NRP2) modulator that was granted FDA fast track designation in 2022 for the treatment of pulmonary sarcoidosis. It is now being tested in a phase 3 study, which enrolled 268 patients at 85 centers in nine countries last year. Topline data from this study are expected in the third quarter of 2025. 

Addison’s 

Addison’s disease affects the endocrine system, which controls the release of hormones. It occurs when the adrenal glands are damaged, resulting in their inability to produce sufficient amounts of the hormones cortisol and adrenaline. This can cause a range of symptoms, including weakness, pain, low blood pressure (due to salt loss), and hyperpigmentation in areas of the skin. Acute attacks can also occur when the hormone levels drop too low. 

Addison’s disease is treatable with regular hormone replacement therapy to replace cortisol. However, this can be cumbersome since, like diabetics, patients have to carry around syringes of cortisol for emergency use. 

Although no significant clinical candidates are being tested for Addison’s disease yet, one area of preclinical exploration that could provide some hope is regenerative therapies – or, more specifically, stem cell therapy, as it holds promise for regenerating destroyed adrenal tissues. Allogeneic stem cell transplantation, in particular, is a promising approach for Addison’s Disease, and preclinical studies are underway using embryonic, bone marrow-derived, and mesenchymal stem cells from adipose tissue and umbilical cord. 

In fact, according to a report, this research is expected to drive market growth for Addison’s disease, with the global Addison’s disease therapeutics market size estimated to grow by $442.4 million from 2024 to 2028. 

Vitiligo 

Vitiligo is often mistaken for hyperpigmentation of the skin but is in fact the opposite – the loss of skin pigment. It is commonly treated with corticosteroids and light therapy, which can lead to premature skin aging and increase the risk of skin cancer. And long-term corticosteroid use has a range of side effects, from osteoporosis to increased risk of infection and diabetes. Therefore, finding alternative treatment options can only benefit patients, and European biotechs have some promising candidates. 

In 2022, the FDA approved the first at-home treatment for this rare autoimmune disease. Global biopharma Incyte’s ruxolitinib cream, Opzelura, is a topical JAK inhibitor that targets the overactive immune system and helps in the growth of healthy skin cells to restore pigment to the area. The treatment performed well in clinical trials, where 30% of the participants had regained at least 75% skin repigmentation on their faces in 24 weeks, which increased to 50% of people after six months. 

Other JAK inhibitor treatments for vitiligo are also on the horizon – in the coming months, we can hopefully expect further data from phase 3 trials for the likes of povorcitinib, upadacitinib, and ritlecitinib. Plus, we can expect topline results from biologic drugs like the monoclonal antibody EB06 and the topical BET inhibitor VYN201.  

Granulomatosis with polyangiitis 

Granulomatosis with polyangiitis is a rare autoimmune disease characterized by inflammation of blood vessels that primarily affects the upper respiratory tract, lungs, and kidneys. It’s a form of vasculitis, a group of disorders that cause blood vessel inflammation and can affect various organs, potentially leading to serious complications if left untreated. 

The disease is generally treated with a combination of medications, primarily to induce remission and then maintain remission. Induction therapy typically involves corticosteroids and another immunosuppressant drug, such as cyclophosphamide or rituximab.  

In 2021, the FDA also approved Tavneos as an add-on therapy that targets pro-inflammatory proteins to decrease blood vessel damage. The clinical trials were met with positive efficacy results, but some adverse side effects were noticed, which included nausea and vomiting. 

Additionally, CAR-T cell therapy is emerging as a potential approach to treating antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (granulomatosis with polyangiitis is a form of ANCA-associated vasculitis). In June 2025, it was announced that a new phase 1 study will evaluate the efficacy of universal allogeneic anti-CD19/BCMA CAR T-cells in relapsed or refractory autoimmune diseases, including ANCA-associated vasculitis. The study is expected to be completed in May 2027.  

If successful, this trial could end up opening the door to a significant new treatment option for patients with granulomatosis with polyangiitis and other forms of ANCA-associated vasculitis.  

Chronic inflammatory demyelinating polyneuropathy (CIDP) 

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare autoimmune disorder affecting the peripheral nervous system, causing nerve damage and inflammation. This leads to progressive weakness and sensory changes, primarily in the arms and legs. The standard-of-care treatments for CIDP are currently corticosteroids, intravenous immunoglobulin, and plasma exchange, which aim to reduce inflammation, slow disease progression, and improve or stabilize function. 

However, due to the heterogeneous clinical course of CIDP and the limitations of currently available therapies, such as the high cost of intravenous immunoglobulin, the potential side effects of long–term corticosteroid use, and the logistical challenges of plasma exchange, there is a growing interest in novel therapies to treat the disease. As a result, therapeutic innovations such as FcRn antagonists and interferon-beta-based approaches have emerged.  

In 2024, the FDA approved Argenx’s drug Vyvgart Hytrulo (efgartigimod alfa and hyaluronidase‑qvfc) for the treatment of CIDP, making it the first neonatal Fc receptor blocker to be given the green light for the indication.  

Elsewhere in the space, Sanofi-backed Nuvig Therapeutics raised $161 million in December to help it advance its lead candidate for CIDP into phase 2 trials. The candidate, NVG-2089, is a recombinant Fc fragment immunomodulator designed to bind type II Fc receptors and improve autoimmune dysregulation. It is being developed to address autoimmune conditions without weakening the immune system.  

The outlook on rare autoimmune diseases 

As more people are diagnosed with rare autoimmune diseases worldwide, developing new treatments could help decrease the toll these conditions take on the quality of life and reduce side effects from other therapies. While many biotechs are focusing their efforts on antibody treatments, other technologies like cell therapy are also paving the way forward in fighting rare autoimmune diseases.