A Drug Drug Interaction (DDI) Study of Pirtobrutinib (LOXO-305) and Digoxin (P-Glycoprotein Substrate) in Healthy Participants

A Phase I, Open-label, Fixed-sequence, Drug Interaction Study to Investigate the Effect of Single and Multiple Oral Doses of LOXO-305 on the Pharmacokinetics of Multiple Oral Doses of Digoxin (P-Glycoprotein Substrate) in Healthy Subjects

The main purpose of this study is to evaluate the effect of Pirtobrutinib (LOXO-305) on multiple oral doses of digoxin (P-gp substrate) when administered as single and multiple doses by collecting the blood samples and conducting the blood tests to measure how much digoxin is in the bloodstream and how the body handles and eliminates it in healthy participants. The study will also evaluate the safety and tolerability of Pirtobrutinib. Participants will stay in this study for up to 58 days, including screening.

Inclusion Criteria:

• Must have Body mass index (BMI) within the range of 18.0 to 32.0 kilograms per square meter (kg/m²), inclusive
• Male and female participants in good health, determined by no clinically significant findings from medical history, 12-lead Electrocardiogram (ECG), vital sign measurements, or clinical laboratory evaluations as assessed by the investigator
• Female participants of non-childbearing potential and male participants who follow standard contraceptive methods
• Must have comply with all study procedures, including the 20-night stay at the Clinical Research Unit (CRU) and follow-up phone call

Exclusion Criteria:

• History or presence of any diseases or conditions of clinical significance by the Investigator (or designee) and/or Sponsor
• Positive serologic test for hepatitis B surface antigen (HBsAg), hepatitis B virus immunoglobulin M (HBV IgM) core antibody, hepatitis C virus (HCV) antibody, or human immunodeficiency virus (HIV) antibody at Screening
• Positive polymerase chain reaction (PCR) test for COVID-19 at Screening or Check-in (Day -1)
• Known ongoing alcohol and/or drug abuse within 2 years prior to Screening
• History of significant hypersensitivity, intolerance, or allergy to any drug compound, food, or other substance, unless approved by the Investigator (or designee)
• Have previously completed or withdrawn from any other study investigating Pirtobrutinib (LOXO-305) and have previously received the investigational product