Anti-Obesity Drug Orlistat (Xenical) Is a Novel Antitumor Medication

Background: Orlistat (Xenical) is an approved medication for treating obesity. Recent studies suggested a new application for orlistat as an antitumor agent. Objectives: The aim of this review was to describe the effect of orlistat as an antitumor agent on growth of cancer cells. Patients and Methods: Articles were identified in data-bases such as Google Scholar, PubMed, Scopus and Proquest. Forty-nine articles were found with key words such as orlistat and obesity, orlistat and neoplasm, orlistat and proliferation, antitumor and orlistat, and fatty acid synthase and orlistat. Finally 25 articles were selected that were published from 2005 until the present and investigated orlistat functions on cancer progression. Results: Orlistat reduced cancer cells growth in vitro and in vivo. Orlistat inhibited approximately 50% of proliferation and decreased tumor size compared with control groups. It seems that, antitumor effects of orlistat are dose dependent and its high concentrations inhibit proliferation of cells more than low concentrations. Conclusions: Orlistat inhibited fatty acid synthase, decreased tumor cells proliferation, stimulated tumor cell apoptosis and decreased viability. Thus it can act as an anti-tumor drug. By changing the formulation of oral orlistat, we can produce a novel drug with more bioavailability for absorption from the gastrointestinal tract and more anti-tumor activity.