To Assess the Relative Bioavailability (BA) of TRIUMEQ® and Dolutegravir and Lamivudine (DTG/3TC) Pediatric Dispersible Tablet Formulations in Healthy Volunteers

The study is 2-Part. Part 1 is dose escalation phase and Part 2 is dose expansion phase.
Every part subject will receive 2 treatments, A and B. Treatment A, subjects will receive
GSK2857916, at dose of 2.5 mg/kg, if well tolerated escalated to 3.4 mg/kg, in next cohort of
subjects to determine RP2D dose. If not tolerated, lower dose, 1.9 mg/kg may be given. As
SOC, subjects will receive lenalidomide, as 25 mg or 10 mg orally daily; with dexamethasone
as 40 mg or 20 mg. Treatment B, subjects will receive GSK2857916, as the same way as in Part
1, with 21-Day cycle alongwith, bortezomib, at a dose of 1.3 mg/m^2, subcutaneously (SC) or
intravenously (IV), with dexamethasone at a dose of 20 mg orally, or IV, which can be reduced
later. Part 2 will occur post Part 1, whereRP2D dose from Part 1 will be given with Treatment
A with lenalidomide, 25 or 10 mg and dexamethasone 40 or 20 mg and for Treatment B, the RP2D
dose alongwith bortezomib 1.3 mg/m^2, and dexamethasone at 20 mg.

Inclusion Criteria:

- Between 18 and 65 years of age, inclusive, at the time of signing the informed
consent.

- Healthy subjects as determined by the investigator or medically qualified designee
based on a medical evaluation, including medical history, physical examination,
laboratory tests, and cardiac evaluation (history and ECG).

- Body weight >=50 kilogram (kg) for males and >=45 kg for females and body mass index
(BMI) within the range 18.5 - 31.0 kilogram per square meter (kg/m^2) (inclusive).

- Male and female subjects where the male subjects must agree to use contraception
during the TP and for at least 2 weeks plus an additional 90 days (a spermatogenesis
cycle) after the last dose of study treatment and refrain from donating sperm during
this period. For the female subjects, female subject is eligible to participate if she
is not pregnant (as confirmed by a negative serum human chorionic gonadotrophin [hCG]
test), not lactating, and at least 1 of the following conditions applies: Female with
non-reproductive potential, defined as Premenopausal females with one of the following
like documented tubal ligation, documented hysteroscopic tubal occlusion procedure
with follow-up confirmation of bilateral tubal occlusion, documented hysterectomy,
documented bilateral oophorectomy, the Postmenopausal defined as 12 months of
spontaneous amenorrhea [in questionable cases a blood sample with simultaneous
follicle stimulating hormone and estradiol levels consistent with menopause. Females
on hormone replacement therapy (HRT), and whose menopausal status is in doubt will be
required to use one of the highly effective contraception methods if they wish to
continue their HRT during the study. Otherwise, they must discontinue HRT to allow
confirmation of post-menopausal status prior to study enrolment; Females with
reproductive potential and agrees to follow one of the options for avoiding pregnancy
in females of reproductive potential, from 30 days prior to the first dose of study
medication and until 2 weeks after dosing with study medication and completion of the
follow-up visit; the investigator is responsible for ensuring that subjects understand
how to properly use these methods of contraception; All female subjects participating
in the study should be counselled on safer sexual practices including the use and
benefit/risk of effective barrier methods (e.g., male condom) and on the risk of human
immune virus (HIV) transmission to an uninfected partner.

- Subjects capable of giving signed informed consent.

- For participation in Part 1, documentation that the subject is negative for the human
leukocyte antigen (HLA)-B*5701 allele.

Exclusion Criteria:

- The medical conditions included where ALT and bilirubin >1.5 × upper limit of normal
(ULN) (isolated bilirubin >1.5 × ULN is acceptable if bilirubin is fractionated and
direct bilirubin < =35%).

- Current or chronic history of liver disease, or known hepatic or biliary abnormalities
(with the exception of Gilbert's syndrome or asymptomatic gallstones).

- Exclusion criteria for screening ECG (a single repeat is allowed for eligibility
determination) where the heart rate for the male subjects be <45 and >100 beats per
minute (bpm) and that for females be < 50 and > 100 bpm; the PR interval for both be <
120 and > 220 millisecond (msec); the QRS interval be < 70 and > 120 msec and the
corrected Q-T interval (QTc) obtained using the Fridericia's formula (QTcF) be >450
msec ; ECG with evidence of previous myocardial infarction (does not include ST
segment changes associated with repolarization; any conduction abnormality (including
but not specific to left or right complete bundle branch block, atrioventricular block
[2nd degree or higher], Wolf-Parkinson-White syndrome); Sinus pauses > 3 seconds; any
significant arrhythmia which, in the opinion of the principal investigator or
ViiV/GlaxoSmithKline (GSK) medical monitor, will interfere with the safety of the
individual subject; non-sustained or sustained ventricular tachycardia (3 consecutive
ventricular ectopic beats).

- Subjects with use of prior or concomitant therapy who are unable to refrain from the
use of prescription (e.g., dofetilide) or non-prescription drugs, including vitamins,
herbal and dietary supplements (including St John's wort) within 7 days (or 14 days if
the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to
the first dose of study medication, unless in the opinion of the Investigator and ViiV
Healthcare Medical Monitor the medication will not interfere with the study procedures
or compromise subject safety.

- History of regular alcohol consumption within 6 months of the study, defined as an
average weekly intake of >14 drinks for males or > 7 drinks for females. One drink is
equivalent to 12 gram of alcohol: 12 ounces (360 milliliter [mL]) of beer, 5 ounces
(150 mL) of wine, or 1.5 ounces (45 mL) of 80 proof distilled spirits.

- Urinary cotinine levels indicative of smoking or history or regular use of tobacco- or
nicotine-containing products within 1 month prior to screening.

- Contraindications like history of sensitivity to any of the study medications, or
components thereof or a history of drug or other allergy that, in the opinion of the
investigator or medical monitor, contraindicates their participation. The subject has
participated in a clinical trial and has received an investigational product (IP)
within the following time period prior to the first dosing day in the current study:
30 days, 5 half-lives or twice the duration of the biological effect of the IP
(whichever is longer).

- The subject has participated in a clinical trial and has received an IP within the
following time period prior to the first dosing day in the current study: 30 days, 5
half-lives or twice the duration of the biological effect of the IP (whichever is
longer).

- Creatinine clearance (CrCL) < 90 mL per minute.

- Presence of hepatitis B surface antigen (HBsAg), positive hepatitis C antibody test
result at screening or within 3 months prior to first dose of study treatment.

- A positive pre-study drug/alcohol/cotinine screen.

- A positive test for HIV antibody.

- Where participation in the study would result in donation of blood or blood product in
excess of 500 mL within 60 days.

- Exposure to more than four new chemical entities within 12 months prior to the first
dosing day.