A Taiwanese research team has discovered that cyproheptadine, the active ingredient in the widely used antihistamine Periactin, may enhance the immune system’s ability to combat cancer.

In a six-year study, researchers found that cyproheptadine, commonly prescribed for allergies, asthma, and dermatitis, suppresses bladder tumor growth and improves the tumor’s immune environment.

The drug regulates epigenetic activity in cancer cells, increasing immune recognition markers on their surfaces, which makes them more detectable and destructible by natural killer (NK) cells. In mouse models, cyproheptadine slowed tumor growth and boosted NK cell infiltration in tumors.

Given its established safety profile, the drug shows promise for repurposing as an immunotherapy, particularly for bladder cancer, with potential applications for other challenging tumors.

Source.