A Study to Investigate the Safety, Tolerability, and Pharmacokinetics of Oral GSK4172239D Compared With Placebo in Sickle Cell Disease Participants Aged 18 to 50 Years

This will be a first time in human (FTIH) study in sickle cell diseases (SCD) participants. The FTIH study is planned to evaluate the safety, tolerability, and pharmacokinetics of GSK4172239D. The study will be composed of 3 periods for all participants (Screening, Treatment, and Follow up). Participants will be screened and, prior to first dose on Day 1, will be randomized to receive either GSK4172239D or placebo. GSK4172239D is a prodrug that is converted in vivo into GSK4106401. This study will be a single dose, dose-escalation study. The initial dosing for all cohorts will be staggered so that 2 participants will be dosed as sentinel participants. Provided there are no safety concerns in 48 hours (h), the remaining 6 participants scheduled for the cohort may be dosed. One selected cohort of participants will also receive an additional single dose of GSK4172239D (or matching placebo) under fed (high calorie and high fat) conditions after a washout period of a minimum of 20 days or 5 half-lives, whichever is longer, designated as the Food Effect Cohort.