Skin Kaposi Sarcoma

This phase II trial studies how well nirogacestat works in treating patients with skin Kaposi sarcoma (KS). Several anti-cancer drugs work well in treating KS, but there is no treatment that cures KS. Nirogacestat binds to a protein called gamma secretase, which blocks the activation of other proteins called Notch receptors. Blocking these proteins may help keep tumor cells from growing and may kill them. Nirogacestat is a type of gamma secretase inhibitor. Nirogacestat may be effective in shrinking the size of KS lesions and reducing the spread of lesions.