Researchers have discovered a new drug that significantly reduces the risk of relapse of IgG4 immunoglobulin-associated disease, a rare chronic immune condition often misdiagnosed as cancer.
In an international trial conducted by a team from Stanford University School of Medicine, it was found that patients who received the drug "Obexelimab" had half the risk of relapse compared to patients who received a placebo.
Patients with IgG4 suffer from severe inflammation and fibrosis, leading to the appearance of tumor-like masses throughout their bodies. Affected organs include the pancreas, salivary glands, kidneys, and lymph nodes.
They are usually treated with drugs that destroy B cells, a vital part of a healthy immune system, but in these patients, these cells become overactive and mistakenly attack the body's own tissues. However, eliminating these cells can leave patients vulnerable to serious infections, especially since the effects of these drugs can last for many months and cannot be stopped quickly.
The drug "upixilimab," developed by Zenas BioPharma, takes a completely different approach. It binds to a specific marker on B cells, but instead of destroying these cells, it inhibits their activity and temporarily stops them from working, thus preserving the presence of B cells to protect the body from infection while preventing them from attacking healthy tissues.
In the study, which included 194 patients from 114 sites in 19 countries, all participants initially received steroid treatment to achieve disease remission (a period of symptom-free illness). They were then randomly divided into two groups: one group received weekly injections of upixilimab for 52 weeks, and the other group received a placebo.
During the first eight weeks, the steroids were gradually reduced until they were stopped completely.
The results showed that the relapse rate in the ubixilimab group was only 26.8%, compared to 54.6% in the placebo group. Patients treated with the new drug were also nearly twice as likely to achieve complete remission after one year (37.1% compared to 19.6% in the other group) and required less emergency steroid treatment during the study period.
“IgG4 patients can spend years trying to get an accurate diagnosis while their organs are being damaged,” says Dr. Matthew Baker, associate professor of immunology and rheumatology at Stanford and one of the study’s lead authors. “Even after diagnosis, treatment options have been very limited. To have a treatment that works this effectively, and may be safer than the treatments currently available, is a real and important advance.”
It is worth noting that current treatments for this disease include the drug "Enablezimab", which was approved in 2025, and the drug "Rituximab", which is used to treat some cancers and autoimmune diseases.
Although these drugs are effective in eliminating B cells, their long-term use can lead to serious infections, as Baker explains: "When we eliminate B cells, the disease improves, but if the patient gets an infection while taking this type of drug, his body cannot fight the infection effectively."
Baker believes that ubixilimab, if approved by the FDA, would be an ideal option for patients with mild to moderate disease, especially those with enlarged salivary or tear glands or lymph nodes. Patients with masses causing blockages in the bile ducts or kidneys would still require more aggressive treatments.
