To evaluate the effect of coadministered cyclosporine on the pharmacokinetics of brincidofovir following simultaneous administration of SyB V-1901 with cyclosporine, or coadministration of cyclosporine at 2 hours after the completion of SyB V-1901 infusion in healthy adult subjects

This study is an open-label, randomized and crossover study designed to evaluate the effect of cyclosporine on the pharmacokinetics of SyB V-1901. Healthy adult subjects will receive an IV dose of SyB V-1901 alone, simultaneous administration of SyB V-1901 with cyclosporine, and coadministration of cyclosporine at 2 hours after completion of SyB V-1901 infusion. Eligible subjects will be randomized to one of two groups, to receive the treatment sequence of assigned group.

Main Inclusion Criteria:

• Healthy adult male aged between 20 to 55 years at informed consent
• BMI from 18 to 32 kg/m2 with a body weight of ≥ 50 kg
• Creatinine Clearance ≥ 60 mL/min at screening
• Judged to be in good general health, based on the review of medical history and the screening and Pre-Day1 examination

Main Exclusion Criteria:

• Positive for HIV antibody, or HBs antigen, or HCV antibody at the screening or within 6 months prior to the start of screening
• Have a history of infection of SARS-CoV-2, or subjects who have close contact with infected patients of SARS-CoV-2 within 2 weeks prior to screening or visit to epidemic area of SARS-CoV-2 infection in outside of Japan or have close contact with person who visit to epidemic area of SARS-CoV-2 infection within 2 weeks prior to screening
• Positive for SARS-CoV-2 polymerase chain reaction (PCR) in lower respiratory tract specimens, nasopharyngeal swabs or saliva and so on at screening or have a fever ≥ 37.5 °C and respiratory symptoms
• Have a history of drug abuse or alcohol dependence within 2 years prior to the start of screening
• Have a history of gastrointestinal disorders or cholecystectomy etc., which could interfere with the absorption of cyclosporine or could interfere with normal gastrointestinal anatomy or motility, but except for uncomplicated appendectomy.
• Have a history or symptoms of cardiovascular disease, including but not limited to coronary artery disease, hypertension, congestive heart disease, and clinically significant cardiac disorder.
• Have a history of hematological disorders or have a risk of gastrointestinal bleeding
• Have a history of chronic liver disease or hepatic impairment, including but not limited to alcoholic liver disease, chronic viral hepatitis, autoimmune hepatitis, steatosis or hemochromatosis.
• Have increased Alanine aminotransferase (ALT) or Aspartate aminotransferase (AST) greater than ULN at screening or Pre-Day1
• History of Gilbert's syndrome or increased total bilirubin greater than 1.5x the upper limit of the normal range at screening or Pre-Day1
• Have symptoms of infection within 2 weeks prior to Pre-Day1
• Have clinically significant abnormal hemoglobin at the screening or Pre-Day1, or a clinically significant iron deficiency
• Have a history of blood donation or had clinically significant blood loss within 30 days prior to Day 1, or platelet/plasma donation within 7 days prior to Day 1
• Have received any investigational drug, or device within 30 days prior to Day1
• History of tobacco- or nicotine-containing product use within 6 months prior to Day1