This clinical trial is focused on studying a type of infection called invasive fungal infection, which can be serious and is caused by fungi entering the body. The study is testing a medication called Posaconazole, also known by its code name MK-5592. Posaconazole is used to treat fungal infections and is being tested in two forms: an oral suspension, which is a liquid taken by mouth, and a solution for infusion, which is given through a vein. The purpose of the study is to understand how the body processes Posaconazole in young children under the age of two who have these infections.

The study will involve children who are suspected or confirmed to have an invasive fungal infection. Participants will receive Posaconazole either as an oral suspension or through an intravenous infusion. The study will monitor how the medication is absorbed and processed in the body, as well as its safety and any side effects. The study is divided into different panels, with some children receiving a single dose and others receiving multiple doses over a period of time.

Throughout the study, researchers will collect information on how the medication affects the children, including any adverse events or side effects. The study aims to provide valuable information on the use of Posaconazole in very young children, which could help improve treatment options for those with serious fungal infections. The study is expected to continue until 2025, allowing researchers to gather comprehensive data on the medication’s effects in this age group.