The objective of the study is to assess the PK, safety and tolerability of a single dose of mirabegron alone and in combination with repeat doses of rifampin, a potent CYP3A4 inducer.

A single group of patients will receive both mirabegron alone and in combination with rifampin

Inclusion Criteria:

• Weighs at least 45 kg and body mass index (BMI) between 18 and 32 kg/m2 at Screening
• Normal or not clinically significant 12 lead ECG and clinical laboratory test results at Screening
• Female subjects must be post-menopausal, surgically sterile since at least 1 month prior to screening, or practicing effective non-hormonal contraceptive methods. All females must be non-lactating, and should have a negative result for the pregnancy test at Screening and on Day -1
• Negative drug and alcohol screens

Exclusion Criteria:

• Has known or suspected hypersensitivity to mirabegron or rifampin
• Liver enzyme test abnormalities (ALT, AST, or bilirubin) above the upper limit of normal
• History or presence of psychiatric illness, serious active or recurrent infection or hepatitis
• Previous history of cancer other than basal cell carcinoma or Stage 1 squamous cell carcinoma that has not been in remission for at least 5 years prior to the dose of study drug
• Donation or loss of ≥ 450 mL blood within 56 days prior to study drug administration or has donated plasma within 7 days prior to study drug administration
• Received or is anticipated to receive a prescription drug within 14 days prior to Day -1 or within 30 days prior to Day -1 for any long acting treatments. Use of any over-the-counter medications, including complementary and alternative medicines (except for occasional use of acetaminophen of up to 2000 mg/day but not more than 4 days per week) within 14 days prior to Day -1
• History of substance abuse within 6 months prior to Screening
• Current participation in another clinical trial or is taking or has been taking an investigational drug in the 30 days or 10 half lives of the drug, whichever is longer, prior to dosing
• Known to have hepatitis or HIV-1 and/or HIV-2 or is positive for hepatitis A antibody IgM, hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibody at Screening
• Subject has consumed alcohol, caffeine-containing food or beverages, grapefruit juice, grapefruit-containing products or Seville oranges within 48 prior to Day -1