Familial hypercholesterolemia is a genetic disease affecting about 10 million people around the world. Those who carry the disease have a very high risk of developing cardiovascular diseases and commonly encounter myocardial infarction at the early age of 40. Therefore, a diagnosis and immediate treatment are very important for these patients. Despite many combinations of available drugs, there are many patients who still cannot reach the desired cholesterol levels. Mipomersen is a new lipid-lowering drug which inhibits the synthesis of apolipoprotein B, a common component of lipoproteins such as low-density lipoprotein. Inhibition of this protein leads to reduced production of these lipoproteins and reduces the risk of cardiovascular diseases. The drug is currently only indicated for treating patients with homozygous familial hypercholesterolemia.  Unfortunately, there have been many reports of adverse events in patients using mipomersen which has proven problematic.         The aim of this thesis is to analyze the efficacy and safety of mipomersen when treating patients with familial hypercholesterolemia. This has been done by searching for five clinical trials in the database Web of Science. The studies were required to include patients with familial hypercholesterolemia, use mipomersen as the study drug and analyze its effect and safety.   The studies showed that mipomersen has a very good effect in decreasing low-density lipoproteins as well as other lipoproteins in comparison to placebo. Many of the patients who were treated with mipomersen displayed several adverse events and the most common were injection-site reaction and influenza-like symptoms. Elevated levels of aminotransaminase and increased fat deposit in the liver were also common. Based on the five clinical trials analyzed in this thesis, mipomersen is an effective lipid-lowering drug which reduces low density lipoprotein cholesterol, apolipoprotein B and lipoprotein (a) in patients with familial hypercholesterolemia. Elevations in alanine aminotransferase and aspartate aminotransferase are common in patients treated with mipomersen. This could indicate a negative impact on the liver. To be more certain of its safety profile, more research could be needed. There are however, new treatments that combines statins and a proprotein convertase subtilisin/kexin 9 inhibitor, which could be the future of lipid-lowering treatments and mipomersen would then likely be substituted.