Irvine, Calif., April 16, 2026 — For people living with rare inflammatory diseases, finding a treatment that actually works can be frustrating and painful. That is especially true for patients with Familial Cold Autoinflammatory Syndrome, or FCAS, a rare condition in which the body’s immune system overreacts and causes repeated flare-ups of inflammation due to an over-active NLRP3 inflammasome. A direct inhibitor of NLRP3, MCC950, has severe off-target effects. Although MCC950 can inhibit normal NLRP3, a particular FCAS mutant is resistant. Instead, patients can take Anakinra, and IL-1 receptor antagonist. However, this is downstream of NLRP3 and limits protective responses from other inflammasomes against pathogens. New research from the lab of Assistant Professor Reginald McNulty at the UC Irvine Charlie Dunlop School of Biological Sciences offers new hope by identifying a different compound, called TH5487, that worked in patient cells when MCC950 did not and can directly interact with NLRP3 unlike Anakinra.
Recently published in Communications Biology, the study found that TH5487 blocks the activity of NLRP3, a molecule that helps set off harmful inflammation in the body. The researchers tested the compound in healthy human peripheral blood mononuclear cells (PBMCs), human monocytes and, most importantly, PBMCs from FCAS patients. In those patient cells, TH5487 lowered the release of IL-1b, a major inflammation-causing signal, while MCC950 did not. The findings suggest that TH5487 could one day lead to a new treatment option for people with forms of inflammatory disease that are difficult to control.
McNulty said one of the most exciting parts of the study was seeing this approach work in patient cells that had resisted earlier drug strategies. “This is the first demonstration that drugs directly targeting NLRP3 are effective in human patient cells carrying the FCAS L353P mutation which are resistant to the canonical NLRP3 direct inhibitor MCC950,” he said.
Beyond showing that TH5487 can reduce harmful inflammation, the researchers also found clues about how it works. Their results suggest that the drug blocks an early step in the chain reaction that leads to excessive inflammation. The drug also remained effective in a more severe form of the disease in a mouse model producing a similar protection to human patient cells, adding to the evidence that this strategy could be broadly useful for severe cancers where NLRP3 is upregulated.
For first author Angela Lackner, the findings also open the door to future advances. “Our lab is actively investigating how the upregulation of type-I interferons observed in response to our NLRP3 inhibitors, a signal that is frequently protective, can be exploited to achieve stronger inflammasome suppression at lower compound doses and reduce off-target effects,” she said. In simpler terms, the team is now studying how to make this kind of treatment work even better and more precisely, while minimizing unwanted side effects.
Although more research is needed before this approach could help patients directly, the study highlights the promise of more targeted treatments for inflammatory disease. For families affected by rare disorders like FCAS, that progress offers real reason for hope. Continued investment in basic biomedical research, patient-centered collaboration and drug development will be essential to turning discoveries like this one into real treatments that improve lives.
About the University of California, Irvine Charlie Dunlop School of Biological Sciences:
Recognized for its pioneering research and academic excellence, the Charlie Dunlop School of Biological Sciences plays a crucial role in the university’s status among the nation’s top 10 public universities, as ranked by U.S. News & World Report. It offers a broad spectrum of degree programs in the biological sciences, fostering innovation and preparing students for leadership in research, education, medicine and industry. Nestled in a globally acclaimed and economically vibrant community, the school contributes to the university’s impact as Orange County’s largest employer and a significant economic contributor. Through its commitment to exploring life’s complexities, the Dunlop School embodies the UC Irvine legacy of innovation and societal impact. For more on the Charlie Dunlop School of Biological Sciences, visit https://www.bio.uci.edu/.