A phase I, first-time-in-human (FTIH), randomized, double-blind, placebo controlled, dose-escalation study is conducted to determine the safety, tolerability, and pharmacokinetic (PK) profile of GSK3342830 after administration of single intravenous (IV) infusion in Part 1 and repeat IV infusion in Part 2 in healthy subjects. Part 1 will investigate escalating single IV doses of GSK3342830. Part 2, will investigate escalating repeat IV doses of GSK3342830 with repeat dosing for 15 days as follows: a single IV infusion on Day 1, TID (three times a day) IV infusions on Days 2 through 14 (approximately every 8 hours), and a single IV infusion on Day 15. The planned starting GSK3342830 dose in Part 1 is 250 milligram (mg) administered as a single IV infusion. The dose is planned to increase in subsequent cohorts to 500, 1000, 2000, 4000, and less than or equal to (≤) 6000 mg. Part 1 will be divided into 6 cohorts (A-F) and each cohort will enroll 10 subjects (6 in active and 2 in placebo). Dose escalation will be conducted only if it is supported by the preliminary safety, tolerability, and PK results from the preceding dose levels in the study. The repeat dose escalation component (Part 2) of this study will be planned to be initiated after completion and evaluation of the all single dose cohorts up to and including 4000 mg.