Effect of GSK3640254 on the Pharmacokinetics of a Combination Oral Contraceptive

This is an open-label, single-sequence, 1-way drug-drug interaction study to investigate the effect of GSK3640254 on the pharmacokinetics of a combination oral contraceptive containing ethinyl estradiol (EE) and levonorgestrel (LNG). Effective contraception for women infected with human immunodeficiency virus (HIV) is important in the prevention of unplanned pregnancies. The study will consist of a screening period of 28 days, check-in (Day -4), a run-in period and a treatment period. During the run-in period, subjects will be administered Portia® (0.03 milligrams \[mg\] EE/0.15 mg LNG) once daily on Days -3 to -1. Subjects will then be administered Portia once daily on Days 1 to 10 of treatment period A followed by administration of Portia once daily along with GSK3640254 200 mg on Days 11 to 21 of treatment period B. The duration of the study is approximately 8 weeks, including Screening and Run-in. Portia is a registered trademark of Teva Pharmaceuticals USA.


Eligibility Criteria:
Inclusion Criteria:

* Subject must be 18 to 50 years of age inclusive, at the time of signing the informed consent.
* Subjects who are healthy as determined by the investigator or medically qualified designee based on a medical evaluation including medical history, physical examination, laboratory tests, and cardiac monitoring (history and ECG).
* Body weight \>=45.0 kilograms (kg) (99 pounds \[lbs\]) and body mass index (BMI) within the range 18.5 to 31.0 kilograms per meter square (kg/m\^2) (inclusive).
* Contraceptive use should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.
* Female subjects will be included.
* Subject must not be pregnant or breastfeeding.
* Subject is a woman of childbearing potential (WOCBP) with intact ovarian function, as determined by medical history. Subjects must use Portia for the duration of the run-in and treatment periods.
* WOCBP must have been on an acceptable form of contraceptive for at least 28 days prior to start of study intervention. Acceptable forms of contraception prior to study intervention include the following: Intrauterine device or intrauterine system; Combined estrogen and progestogen oral contraceptive; Contraceptive vaginal ring; Percutaneous contraceptive patches (if used, the patch must be removed during study participation); Bilateral tubal occlusion; Male partner sterilization with documentation of azoospermia prior to the female subject's entry into the study, and this male is the sole partner for that subject. The documentation on male sterility can come from the site personnel's review of subject's medical records, medical examination and/or semen analysis, or medical history interview provided by her or her partner.; Sexual abstinence.
* Subjects who have been on a stable regimen of an oral contraceptive for at least 3 consecutive months must be without evidence of breakthrough bleeding or spotting.
* Subjects who have been taking oral contraceptives should continue their current regimen until check-in to the clinic for the run-in period. Subjects not currently taking an oral contraceptive are eligible, provided all other eligibility criteria are met.
* Subjects may proceed to the treatment period provided the toxicity profile during the run-in period with Portia is acceptable in the opinion of the investigator.
* Subjects must agree to use an additional method of contraception from the following list of contraceptive methods for the run-in period, treatment period, and for 28 days after the last dose of study intervention: Non hormonal Intrauterine device; Bilateral tubal occlusion; Male partner sterilization with documentation of azoospermia prior to the female subject's entry into the study, and this male is the sole partner for that subject. The documentation on male sterility can come from the site personnel's review of subject's medical records, medical examination and/or semen analysis, or medical history interview provided by her or her partner.; Sexual abstinence. For the 28 days after study exit, women may resume oral contraceptives but double barrier methods (a combination of male condom with either cervical cap, diaphragm, or sponge with spermicide) must be used in addition.
* Women of childbearing potential must have a negative highly sensitive serum pregnancy test on Day -4 and Day -1.
* Additional requirements for pregnancy testing during and after study intervention as outlined in protocol.
* Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form and protocol.

Exclusion Criteria:

* History of jaundice associated with taking oral contraceptives or with pregnancy.
* History of clinically significant irregular bleeding while taking oral contraceptives.
* History of past deep venous thrombosis, pulmonary embolism, stroke, transient ischemic attack, phlebitis, or migraine headaches with prolonged aura.
* History of cerebrovascular or coronary artery disease.
* History of retinal vascular lesions.
* History of carcinoma of the breast, endometrium, or other known estrogen-dependent neoplasia.
* Current or chronic history of liver disease or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones).
* A pre-existing condition interfering with normal gastrointestinal (GI) anatomy or motility (e.g., gastroesophageal reflux disease, gastric ulcers, gastritis), hepatic and/or renal function, that could interfere with the absorption, metabolism, and/or excretion of the study drugs or render the subject unable to take oral study intervention.
* Any history of significant underlying psychiatric disorder, including, but not limited to, schizophrenia, bipolar disorder with or without psychotic symptoms, other psychotic disorders, or schizotypal (personality) disorder.
* Any history of major depressive disorder with or without suicidal features, or anxiety disorders that required medical intervention (pharmacologic or not) such as hospitalization or other inpatient treatment and/or chronic (\>6 months) outpatient treatment. Subjects with other conditions such as adjustment disorder or dysthymia that have required shorter term medical therapy (\<6 months) without inpatient treatment and are currently well-controlled clinically or resolved may be considered for entry after discussion and agreement with the ViiV Healthcare/GlaxoSmithKline (GSK) Medical Monitor.
* Any pre-existing physical or other psychiatric condition (including alcohol or drug abuse), which, in the opinion of the investigator (with or without psychiatric evaluation), could interfere with the subject's ability to comply with the dosing schedule and protocol evaluations or which might compromise the safety of the subject.
* Medical history of cardiac arrhythmias, prior myocardial infarction in the past 3 months, or cardiac disease or a family or personal history of long QT syndrome.
* Presence of hepatitis B surface antigen at Screening or within 3 months prior to starting study intervention.
* Positive hepatitis C antibody test result at Screening or within 3 months prior to starting study intervention AND positive on reflex to hepatitis C ribonucleic acid (RNA).
* Positive HIV-1 and -2 antigen/antibody immunoassay at Screening.
* ALT \>1.5 times upper limit of normal (ULN). A single repeat of ALT is allowed within a single screening period to determine eligibility.
* Bilirubin \>1.5 times ULN (isolated bilirubin \>1.5 times ULN is acceptable if bilirubin is fractionated and direct bilirubin \<35%).
* Any acute laboratory abnormality at Screening which, in the opinion of the investigator, should preclude participation in the study of an investigational compound.
* Any Grade 2 to 4 laboratory abnormality at Screening, with the exception of creatine phosphokinase (CPK) and lipid abnormalities (e.g., total cholesterol, triglycerides, etc), and ALT (described above), will exclude a subject from the study unless the investigator can provide a compelling explanation for the laboratory result(s) and has the assent of the sponsor. A single repeat of any laboratory abnormality is allowed within a single screening period to determine eligibility.
* A positive test result for drugs of abuse (including marijuana), alcohol, or cotinine (indicating active current smoking) at Screening or before the first dose of study intervention.
* Unable to refrain from the use of prescription or nonprescription 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 intervention and for the duration of the study (acetaminophen/paracetamol at doses of \<=2 grams/day and hydrocortisone cream 1% are permitted for use any time during the study).
* Treatment with any vaccine within 30 days prior to receiving study intervention.
* Unwillingness to abstain from excessive consumption of any food or drink containing grapefruit and grapefruit juice, Seville oranges, blood oranges, or pomelos or their fruit juices within 7 days prior to the first dose of study intervention(s) until the end of the study.
* Participation in another concurrent clinical study or prior clinical study (with the exception of imaging trials) 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 investigational product (whichever is longer).
* Where participation in the study would result in donation of blood or blood products in excess of 500 milliliters (mL) within 56 days.
* Any positive (abnormal) response confirmed by the investigator on a screening clinician- or qualified designee-administered Columbia Suicide Severity Rating Scale (C-SSRS).
* Any significant arrhythmia or ECG finding (e.g., symptomatic bradycardia, non-sustained or sustained atrial arrhythmias, non-sustained or sustained ventricular tachycardia, second-degree atrioventricular block Mobitz Type II, or third-degree atrioventricular block) which, in the opinion of the investigator or ViiV Healthcare/GSK Medical Monitor, will interfere with the safety for the individual subject.
* Exclusion criteria for screening ECG (a single repeat is allowed for eligibility determination): heart rate-\<50 or \>100 beats per minute and QTcF-\>450 milliseconds.
* History of regular alcohol consumption within 6 months of the study defined as: an average weekly intake of \>14 units. One unit is equivalent to 8 g of alcohol: a half-pint (equivalent to 240 mL) of beer, 1 glass (125 mL) of wine or 1 (25 mL) measure of spirits.
* Unable to refrain from tobacco- or nicotine-containing within 3 months prior to Screening.
* 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.