This study measured how much of the study drug got into the blood stream and how long it took the body to get rid of it. Information about any side effects that may have occurred was also collected. This study was a randomized dose-rising study which means that the first group of research participants was assigned by chance to receive either the study drug or placebo. Placebo is a solution that looks like the study drug but has no active ingredient. The lowest dose of the study drug or placebo was given to the 1st group of participants (1st cohort) and a higher dose was given to the next group until all the doses of the study drug were tested. TAK-648 was dosed in 5 sequential cohorts with escalating doses from the lowest dose given in Cohort 1 to higher doses given in the subsequent cohort. Doses could be adjusted based on available safety, tolerability, and pharmacokinetic (PK) data.