The first part of the study is called a "Phase I" study. Phase I studies use drugs starting at low doses and slowly increase the amounts of the study drugs that are given to people until the side effects of the drugs are too high to give more. This means that not all people in the study will get the same dose of IRX5183. Doses at the beginning of the study will be lower than doses at the end of the study. Because of the design of the study, some people may get doses that are too low to have an effect, and other people will probably get doses that cause side effects.