The purpose of this study is to assess the bioequivalence of the second generation dutasteride and tamsulosin hydrochloride (HCL) combination capsule versus currently available commercial combination of dutasteride 0.5 milligram (mg) and tamsulosin HCL 0.4 mg capsule in healthy adult male subjects. Subjects in this study will receive either a single oral dose of the second generation dutasteride 0.5 mg and tamsulosin 0.4 mg combination capsule or a single dose of commercially available combination of dutasteride 0.5 mg and tamsulosin HCL 0.4 mg followed by a 28-day washout period both in fasted state. The study will enroll approximately 92 healthy adult male subjects in order to complete approximately 76 evaluable subjects. The total duration of a subject's involvement in this study is anticipated to be approximately 12 weeks.

Inclusion Criteria:

• Males who are 18 to 50 years of age, inclusive.
• Weight range 55 to 95 kg (inclusive) and body mass index (BMI) 18 to 30 kilogram/meter^2 (kg/m^2) (inclusive).
• Healthy subjects defined as individuals who are free from clinically significant illness or disease as determined by the investigator based on their medical history, physical examination, vital signs, laboratory studies, and electrocardiograms (ECGs).
• Single QT interval corrected (QTc) <450 millisecond (msec) or QTc <480 msec in subjects with Bundle Branch Block, no clinically relevant abnormal finding on the screening ECG.
• Serum creatinine <1.5 x upper limit of normal (ULN) at screening.
• Cytochrome P450 enzyme 2D6 (CYP2D6) Extensive Metabolizers only at screening
• Willing and able to give written informed consent.
• Able to swallow and retain oral medication.
• Male subjects with female partners of child-bearing potential must agree to use 1 of the contraception methods. - Aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatise (ALP), and bilirubin <=1.5 x ULN (isolated bilirubin >1.5 x ULN is acceptable if bilirubin is fractionated and direct bilirubin <35%).

Exclusion Criteria:

• History of postural hypotension, dizziness, poor hydration, vertigo, vaso-vagal reactions or any other signs and symptoms of orthostasis, which in the opinion of the investigator could be exacerbated by tamsulosin and result in putting the subject at risk of injury.
• History of any serious and/or unstable pre-existing medical, psychiatric disorder, or other conditions that could interfere with a subject's safety, or interfere with the subject's ability to follow indications or study procedures, or the interpretation of study results or obtaining informed consent or compliance to study procedures in the opinion of the Investigator or GlaxoSmithKline (GSK) Medical Monitor.
• History of myocardial infarction, coronary bypass surgery, unstable angina, cardiac arrhythmias, clinically evident congestive heart failure, or cerebrovascular accident prior to Screening visit; or diabetes or peptic ulcer disease which is uncontrolled by medical management.
• History of breast cancer or clinical breast examination finding suggestive of malignancy, malignancy within the past 5 years, except for basal cell carcinoma of the skin. Subjects with a prior malignancy who have had no evidence of disease for at least the past 5 years are eligible.
• Prior medical history or evidence of prostate cancer. Subjects with suspicious ultrasound or Digital Rectal Examination (DRE) who have had a negative biopsy within the preceding 6 months and stable prostate specific antigen (PSA) are eligible for the study.
• Current or chronic history of liver disease, or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones).
• A positive pre-study Hepatitis B surface antigen or positive Hepatitis C antibody result within 3 months of screening.
• Positive human immunodeficiency virus (HIV) test at screening.
• Use of prescription or non-prescription drugs.
• Strong Cytochrome P450 enzyme 3A4 (CYP3A4) inhibitors (e.g. ketoconazole) and/or strong CYP2D6 inhibitors (e.g. paroxetine) usage throughout the study.
• History of sensitivity to heparin or heparin-induced thrombocytopenia.
• History of regular alcohol consumption exceeding 21 drinks/week for men (1 unit is equivalent to 8 gram of alcohol: a half-pint (equivalent to 240 millilitre [mL]) of beer, 1 glass (equivalent to 125 mL) of wine or 1 (equivalent to 25 mL) measure of spirits) within 6 months of screening. Subjects must be able and willing to abstain from beverages and foods containing alcohol 24 hours prior to the first dose of study medication and until the completion of the final PK sample during each period.
• A positive urine drug or alcohol screen result at screening and at Day -1. A minimum list of drugs that will be screened for include amphetamines, barbiturates, cocaine, opiates, cannabinoids, and benzodiazepines.
• Subjects must be able and willing to stop using of any tobacco or nicotine containing products 24 hours prior to each dose and for the duration of confinement. At the discretion of the Investigator, light smokers (smoking <=10 cigarettes a day) would be considered for the study inclusion.
• The subject has received an investigational product or participated in any other research trial within 6 months or 5 half-lives, or twice the duration of the biological effect of any drug (whichever is longer) prior to the first dose of current study medication or anytime during the study period, exposure to more than 4 new chemical entities within 12 months prior to the first dosing day.
• Previous donation of blood or blood products in excess of 500 mL within a 90 day prior to the first dose of investigational products and the subject agrees not to donate blood during this study.
• History or presence of allergy, intolerance, contraindication or sensitivity to alpha blockers (e.g., tamsulosin), or 5 alpha reductase inhibitors (e.g., dutasteride) or drugs of these therapeutic classes, soya or peanuts, or any ingredients of Combodart, or a history of drug or other allergy (including true sulfonamide allergy) that, in the opinion of the investigator, contraindicates your participation in the study.

IPD for this study will be made available via the Clinical Study Data Request site.

IPD is available via the Clinical Study Data Request site (click on the link provided below)

Access is provided after a research proposal is submitted and has received approval from the Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension can be granted, when justified, for up to another 12 months.