Study to Confirm of the Safety and Tolerability of Brincidofovir in Subjects With BK Virus Infection (Viremia) After Kidney Transplantation

Inclusion Criteria:

• Male or female, at least 18 years of age at the time of signing the informed consentat screening.

• Kidney transplant recipient. "BK viral load increase and ≥ 3.6 log IU/mL" at 2 weekspost immunosuppression reduction or "BK viral load does not decrease by ≥ 0.3 logIU/mL" at 4 weeks post immunosuppression reduction during prescreening.

(Note: Immunosuppressant reduction needs to be continued during the screening period).

• eGFR ≥ 30 mL/min.

• Subjects under immunosuppression with tacrolimus, MMF/Myfortic, and/orcorticosteroid.

Exclusion Criteria:

• Subjects who weigh ≥ 120 kg.

• National Institutes of Health/NCI CTCAE Grade 2 or higher diarrhea (ie, increase of ≥ 4 stools per day over usual pretransplant stool output) within 7 days before Day

• Poor clinical prognosis, including active malignancy or use of vasopressors otherthan low dose (eg, ≤ 5 μg/kg/min) dopamine for renal perfusion within 7 days beforeDay 1.

• Use of renal replacement therapy within 7 days before Day 1.

• History of intolerance to cidofovir or related compounds (ie, other nucleotidederivatives [adefovir or tenofovir])