EXS74539: A New LSD1 Inhibitor for Hard-to-Treat Solid Tumors, Including Prostate Cancer

EXS74539, also called REC-4539, is an experimental cancer drug designed to block LSD1, a protein that helps some cancer cells grow and survive even when standard treatments fail. It is being tested in a phase 1 trial on people with selected solid tumors, including small-cell lung cancer, prostate cancer, ovarian cancer and others. This early-stage study is all about finding that right dose first, before proving the drug works against tumors.

What stands out about EXS74539 is its design to reach the brain, which could help with cancers that spread there, like small-cell lung cancer, a fast-growing type that often involves the brain early on. It is also built to cause fewer blood-related problems than some similar drugs, since low platelets have been a big issue in this drug class before. The plan includes testing it alone and combined with an immune therapy drug, which might boost its effects in tough cases.

From a prostate cancer viewpoint, LSD1 is especially relevant because it helps aggressive, treatment-resistant prostate tumors to keep growingafter hormone therapies stop working. Studies show LSD1 drives a deadly gene network in prostate cancer and can make cells switch to harder-to-treat forms. Since prostate cancer is part of this trial, EXS74539 could test whether blocking LSD1 slows those resistant tumors in real patients.

Clinical trial.