Behçet’s Disease

Overview

Behçet’s disease is a chronic, relapsing inflammatory disorder in which inflammation of blood vessels can affect the mouth, genitals, skin, joints, eyes, nervous system, gastrointestinal tract, and arteries or veins. Recurrent painful mouth sores are especially common; inflammation inside the eye (uveitis), blood clots, neurologic disease, and intestinal ulcers can cause permanent disability or become life-threatening. It is rare in the United States and more common in parts of the Middle East and Asia; onset often occurs in young adulthood. There is currently no cure, although many people can achieve periods of remission and avoid major damage with specialist care. National Eye Institute overview

Current care is tailored to the organs involved and the risk of irreversible injury. It includes topical corticosteroids and colchicine for less severe mouth, genital, skin, or joint disease; systemic corticosteroids for flares; and immune-suppressing medicines such as azathioprine, cyclosporine, interferon-alpha, tumor necrosis factor (TNF) inhibitors, and other biologic drugs for eye, vascular, neurologic, intestinal, or otherwise refractory disease. The newest European recommendations continue to emphasize rapid, organ-specific suppression of inflammation rather than one universal treatment plan. EULAR 2025 management update

Scope of Recent Research (2020–present)

From 2020 through October 10, 2026, Behçet’s research has become more rigorous in severe disease, with randomized trials comparing established biologics and newer work aimed at restoring immune regulation rather than simply suppressing inflammation. The central questions are which immune pathways drive distinct disease forms, how to predict drug response, and whether durable drug-free remission can be induced. The field is not close to a proven curative therapy: current advances improve control of inflammation and prevent organ damage, but none has demonstrated permanent elimination of the disease process. BIO BEHÇET’S randomized trial Low-dose IL-2 phase 2 trial

Major Breakthroughs and Emerging Therapies

Targeted cytokine blockade remains the strongest near-term strategy. The most consequential recent advance is better evidence for anti-TNF therapy in severe Behçet’s disease. In a French phase 2 randomized trial of people with vascular or neurologic involvement, 81% of participants receiving infliximab achieved complete response at week 22, compared with 56% receiving cyclophosphamide; adverse events were also less frequent with infliximab. This is an important shift toward more effective and potentially less toxic induction treatment for organ-threatening disease, but it represents disease control—not cure. Infliximab versus cyclophosphamide

Anti-TNF treatment is also being refined for mucocutaneous disease. A 2024 multicenter phase 3 study in people whose mouth, genital, or skin manifestations persisted despite conventional immune suppression reported responses in 64% of the infliximab group and 94% of the adalimumab group over six months, with improved quality of life in both groups. These results support earlier use of biologics for difficult disease, while the small sample means they should not be interpreted as proof that one agent is universally superior. Infliximab or adalimumab phase 3 trial

Immune rebalancing with low-dose interleukin-2 (IL-2) is a notable emerging approach. IL-2 at low doses preferentially expands regulatory T cells—immune cells that help restrain excessive inflammation. In a double-blind phase 2 trial of 60 participants with active oral ulcers, low-dose IL-2 reduced the average oral-ulcer count at week 12 versus placebo, improved pain, activity scores, and quality of life, and increased regulatory T cells without reported serious adverse events or infections. This is promising because it aims to correct an immune imbalance rather than broadly deplete immune cells, but the study was short and focused mainly on mucosal disease; it has not shown durable treatment-free remission or prevention of eye, vascular, or neurologic disease. Low-dose IL-2 phase 2 trial

Pathway-directed small molecules and biologics remain exploratory outside established anti-TNF treatment. Research continues on the IL-23/IL-17 inflammatory pathway, phosphodiesterase-4 inhibition with apremilast, and Janus kinase (JAK) inhibition. However, the clinical evidence for IL-17 or IL-23 blockade is mixed and phenotype-dependent, with disappointing results in Behçet’s uveitis despite signals of benefit for some mucocutaneous, joint, and neurologic manifestations. Single-cell work has also found an inflammatory C1q-high monocyte population that was reduced in patients treated with the JAK inhibitor tofacitinib, supporting further investigation of precision immune targeting rather than supporting routine curative use today. IL-23/IL-17 therapeutic review C1q-high monocyte study

There is no clinical gene-replacement therapy, gene-editing treatment, RNA therapeutic, or engineered cell therapy that has been shown to cure Behçet’s disease. This is unsurprising because Behçet’s is generally a complex, polygenic and environmentally influenced immune disorder rather than a condition caused by one correctable mutation. Genetic and cellular studies are therefore being used chiefly to identify patient subgroups and drug targets, not yet to design a one-time genetic cure. Genetic architecture study

Clinical Trials and Experimental Approaches

The recent trial landscape includes several high-value head-to-head studies. The French Ministry of Health–funded phase 2 trial of infliximab versus cyclophosphamide enrolled 52 people with severe vascular or neurologic Behçet’s disease between 2018 and 2021 and reported superior complete response with infliximab at week 22. Separately, the Italian multicenter phase 3 trial compared infliximab with adalimumab in 40 patients with refractory mucocutaneous disease and found clinically meaningful responses with both drugs. Infliximab versus cyclophosphamide Infliximab or adalimumab phase 3 trial

The completed phase 2 low-dose IL-2 study, registered as NCT04065672, was led by investigators at Peking University People’s Hospital and listed HeJing as sponsor. Its positive ulcer and regulatory-T-cell findings make it one of the clearest recent experimental attempts to induce a more tolerant immune state, although confirmatory multicenter trials with longer follow-up are needed. Low-dose IL-2 phase 2 trial

For severe eye disease, a 2024 randomized open-label trial at the First Affiliated Hospital of Chongqing Medical University compared combinations of immunomodulatory therapies to prevent uveitis relapse in people already receiving corticosteroids. Such studies illustrate a key theme in Behçet’s research: protecting vision and other organs through optimized combinations and relapse prevention while investigators search for biomarkers that can match individuals to the safest effective regimen. Uveitis relapse-prevention trial

Methodologies and Scientific Approaches

Researchers are moving beyond blood tests and broad clinical categories by using single-cell RNA sequencing, which measures gene activity cell by cell. Blood-based single-cell analysis identified expansion of inflammatory C1q-high monocytes in Behçet’s disease and linked them to interferon-gamma signaling, while a 2026 intestinal study created a single-cell atlas from paired inflamed and non-inflamed ileal biopsies. The intestinal work identified stromal activation, extracellular-matrix remodeling, and possible endothelial–neutrophil signaling pathways that may distinguish intestinal Behçet’s disease from Crohn’s disease. C1q-high monocyte study Intestinal single-cell atlas

Other platforms combine microbiome sequencing, metabolomics—the measurement of small molecules produced by cells and microbes—and genetic data. A 2024 study comparing intestinal Behçet’s disease with Crohn’s disease, ulcerative colitis, and healthy controls found distinct microbial and metabolic patterns, including reduced Bacteroides fragilis in intestinal Behçet’s disease. These approaches may eventually yield biomarkers for diagnosis, prognosis, and individualized treatment, but they remain hypothesis-generating and are not microbiome cures. Microbiome and metabolome study

Leading Institutions and Funding

Major recent clinical programs include Pitié-Salpêtrière University Hospital and collaborating French centers, which conducted the infliximab-versus-cyclophosphamide trial with funding from the French Ministry of Health; University of Pisa–associated Italian centers, which led the infliximab-versus-adalimumab study; and Peking University People’s Hospital, which led the low-dose IL-2 trial and associated immune-monitoring work. Infliximab versus cyclophosphamide Infliximab or adalimumab phase 3 trial Low-dose IL-2 phase 2 trial

The United Kingdom’s National Behçet’s Centres and allied clinics supported the NIHR-funded BIO BEHÇET’S trial comparing infliximab and interferon-alpha. Patient organization Behçet’s UK has also reported that Professor Robert Moots secured £700,000 from Novartis for a major secukinumab trial, showing how pharmaceutical funding and patient organizations can enable studies in a rare disease where conventional trial recruitment is difficult. BIO BEHÇET’S randomized trial Behçet’s UK conference report

Strengths, Limitations, and Challenges

The field’s main strength is that it now has randomized evidence that can improve care in high-risk disease, particularly for anti-TNF therapy, rather than relying solely on uncontrolled case series. Low-dose IL-2 also offers a biologically credible route toward restoring immune restraint. At the same time, successful suppression of active inflammation is not the same as resetting the underlying susceptibility to relapse, and no trial has established a durable, medication-free cure. Infliximab versus cyclophosphamide Low-dose IL-2 phase 2 trial

Key obstacles are the disease’s rarity, fluctuating course, and extreme variation among patients: a drug that protects vision may not control intestinal ulcers, and a treatment that works for mouth sores may be inadequate for neurologic or vascular disease. Studies are often small, enroll mixed clinical phenotypes, use different outcome measures, and have limited long-term follow-up. Immune-suppressing treatments can also carry infection, infusion, laboratory-monitoring, fertility, cost, and access burdens. Biomarker studies are promising but remain too early to reliably determine which therapy will work for a particular patient. EULAR 2025 management update BIO BEHÇET’S randomized trial

Outlook and Future Directions

As of October 10, 2026, Behçet’s disease is not close to a proven cure, but recent trials have materially improved the prospects for preventing damage and achieving clinical remission. The milestones to watch are larger and longer low-dose IL-2 studies; validation of cell, genetic, metabolic, and microbiome biomarkers; trials that enroll patients by organ-specific phenotype; and evidence that an intervention can maintain remission after therapy is withdrawn. A true cure will likely require a safe, durable restoration of immune tolerance across the disease’s diverse genetic and clinical forms—not merely a stronger anti-inflammatory drug. Low-dose IL-2 phase 2 trial Intestinal single-cell atlas

References

• Behçet’s Disease — National Eye Institute, 2024.
• EULAR recommendations for the management of Behçet’s syndrome: 2025 update — European Alliance of Associations for Rheumatology, 2026.
• Infliximab versus Cyclophosphamide for Severe Behçet’s Syndrome — Saadoun et al., 2024.
• Efficacy and safety of infliximab or adalimumab in severe mucocutaneous Behçet’s syndrome — Talarico et al., 2024.
• Efficacy and safety of low-dose interleukin 2 for Behçet’s syndrome — Liu et al., 2026.
• Low-dose IL-2 Treatment on Behcet’s Disease, NCT04065672 — ClinicalTrials.gov, 2026.
• Combinations of immunomodulatory agents for prevention of uveitis relapse in severe Behçet’s disease — Zhong et al., 2024.
• The IL-23/IL-17 axis in Behçet’s syndrome pathogenesis — Frontiers in Immunology, 2026.
• Single-cell analyses highlight the proinflammatory contribution of C1q-high monocytes to Behçet’s disease — Zheng et al., 2022.
• Genetics of Behçet’s Disease: Functional Genetic Analysis and Estimating Disease Heritability — Takeuchi et al., 2021.
• Single-cell RNA sequencing of intestinal Behçet’s disease identifies putative pathogenic programs and potential therapeutic targets — Lyu et al., 2026.
• Integrated Analysis of Microbiome and Metabolome Reveals Disease-Specific Profiles in Intestinal Behçet’s Disease — Park et al., 2024.
• Infliximab versus alpha interferon in the treatment of Behçet’s disease: the BIO BEHÇET’S RCT — Moots et al., 2024.
• Behçet’s UK 2022 Conference and AGM report — Behçet’s UK, 2022.