Significant palliative benefits of single agent mifepristone for advanced lung cancer that previously failed standard therapy

Abstract

A large variety of cancers have been found to make a unique immunomodulatory protein called the progesterone induced blocking factor (PIBF), which is utilized by the fetal-placental unit to escape cellular immune surveillance. The progesterone receptor involved in PIBF production is a membrane receptor. Thus, it is present in cancers, whether the classic nuclear progesterone receptor is present, or not. Controlled studies involving mice with spontaneous cancers, showed increased longevity and palliation when they were gavaged with mifepristone. Similarly, single agent mifepristone promoted extension of life and palliation in several end stage patients with a variety of different cancers. Based on these studies, the FDA granted an investigator initiated 40 patient study entitled “A phase II study of treatment with oral mifepristone as salvage therapy in patients with advanced or metastatic non-small lung cancer who have failed two or more previous chemotherapy regimens”. The first case enrolled is a 65 year old male with stage IV non-small cell lung adenocarcinoma with a brain metastasis. He progressed despite 3 rounds of chemotherapy cocktails. Because his tumor was devoid of any markers that would respond to targeted therapy, his oncologist referred him for the single agent oral mifepristone trial (300mg per day). This patient has completed 4 years of therapy. He feels great, despite the fact that over the last 6 months there has been progression of his lung nodules. There has not been any more brain metastases. He has no side effects from the mifepristone. Very rarely a patient with end stage lung cancer will have a complete response. Thus, the main objective of the study is to provide treatment that will provide a decent and extended quality of life with no suffering from the treatment itself. At least in this case, mifepristone therapy seems to meet these criteria.