Repurposing Mefloquine for Pancreatic Cancer Treatment

Pancreatic cancer (specifically pancreatic ductal adenocarcinoma, PDAC) is a very aggressive disease that is often diagnosed too late for surgery, and the medicines currently available, mainly two chemotherapy combinations called modified FOLFIRINOX (mFFX) and gemcitabine + nab-paclitaxel (GnP), can extend life but rarely cure patients. This study examines mefloquine, a well-studied antimalarial drug, as a new way to attack pancreatic cancer. Laboratory work has shown that mefloquine can block an enzyme (TYMS) that cancer cells need to make DNA, and unlike many existing drugs it does not cause the cancer cells to produce more of that enzyme and become resistant. In several mouse models, as well as tumors grown from human patients, oral mefloquine at doses that were well tolerated (up to 300 mg/kg) slowed tumor growth and helped the animals live longer. This trial aims to find a safe dose of mefloquine for PDAC patients. A classic "3 + 3" design will be used in three separate arms: one taking mFFX, one taking GnP, and one taking mefloquine as monotherapy after exhausting standard of care treatment options. The main goals are to determine the recommended Phase 2 dose and to collect early signals that the drug might help shrink tumors when combined with existing chemotherapy. If the trial shows that mefloquine can be given safely and hints at improved tumor control, it would pave the way for larger studies that could eventually add an established and already-approved drug to the existing treatment options for advanced pancreatic cancer.