MK-5172 (C-SURFER)

There are two parts to this study. In the first part, participants will be randomly assigned to one of two groups. One group will receive 100 mg of MK-5172 + 50 mg of MK-8742 once daily for 12 weeks. The other group will receive MK-5172 placebo + MK-8742 placebo once daily for 12 weeks. Participants have a 1 in 2 chance of receiving placebo only. Neither the participant nor the study doctor will know to which group the participant was assigned. However, in case of an emergency, the study doctor can get that information. Once dosing is completed, if the participant does not continue to the second part of the study, they will be asked to follow-up with the study doctor for an additional 24 weeks. For those who continue into the second part of the study, there will be a 4 week period where the participant will not receive any study medication. Once the 4 week period is over, they will be assigned to receive open-label (both the participant and the study doctor know what study drugs are being taken) 100 mg of MK-5172 and 50 mg of MK-8742 for 12 weeks, and will then be followed for an additional 24 weeks. Participants also have the opportunity to agree to participate in a future biomedical research sub-study. The purpose of the sub-study is to find out more about what causes disease and the differences in the way that people respond to drugs and therapies.