The AdAPT Trial; Adenovirus After Allogeneic Pediatric Transplantation

Inclusion Criteria:

1. Aged at least 2 months and less than 26 years-old on Day 1 (US only) ages 2 months or
less than 18 years old on day one (ROW) AND

2. Have received a T cell-depleted allogeneic (i.e., non-autologous) HCT within the
previous 100 days.

3. First detectable AdV DNA plasma viremia since the qualifying transplant occurred
within 21 days prior to Day 1.

4. Have EITHER:

A) Confirmed AdV viremia of ≥ 1000 copies/mL and rising, defined as two consecutive AdV DNA
polymerase chain reaction (PCR) test results ≥ 1000 copies/mL from the designated central
virology laboratory, with the second result being greater than the first. The second sample
must be drawn at least 48 hours after the first sample and no more than 7 days prior to Day
1. OR B) Single AdV viremia measurement of ≥ 10,000 copies/mL reported by the designated
central virology laboratory from a sample drawn no more than 7 days prior to Day 1.

Exclusion Criteria:

1. Any CTCAE Grade 4 diarrhea (i.e., life-threatening consequences with urgent
intervention indicated) within 7 days prior to Day 1

2. Any CTCAE Grade 2 or 3 diarrhea (i.e., increase of ≥ 4 stools per day over baseline),
unless attributed to AdV, within 7 days prior to Day 1

3. NIH Stage 4 acute GVHD of the skin (i.e., generalized erythroderma with bullous
formation) within 7 days prior to Day 1

4. NIH Stage 2 or higher acute GVHD of the liver (i.e., bilirubin > 3 mg/dL [SI: > 51
μmol/L]) within 7 days prior to Day 1

5. NIH Stage 2 or higher acute GVHD of the gut (i.e., diarrhea > 556 mL/m2/day, or severe
abdominal pain with or without ileus) within 7 days prior to Day 1

6. Active malignancy (with the exception of non-melanoma skin cancer), including relapse
or progression of the underlying disease for which qualifying transplant was performed

7. Use of vasopressors within 7 days prior to Day 1

8. PT-INR > 2x upper limit of normal reference range (ULN) in the absence of
anticoagulation within 7 days prior to Day 1

9. Requirement for mechanical ventilation within 7 days prior to Day 1, or sustained
oxygen delivery for > 24 hours within 7 days prior to Day 1, or any oxygen requirement
within 48 hours prior to Day 1

10. Estimated creatinine clearance < 30 mL/min or use of renal replacement therapy (e.g.,
hemodialysis, continuous renal replacement therapy, peritoneal dialysis) within 7 days
prior to Day 1

11. ALT > 5x ULN, AST > 5x ULN, or total bilirubin > 3 mg/dL [SI: > 51 μmol/L] within 7
days prior to Day 1

12. Human immunodeficiency virus (HIV) infection as detected through any laboratory method
(e.g., enzyme-linked immunosorbent assay, Western Blot, RNA PCR). [Note: Testing to
confirm the absence of HIV infection is required at screening unless testing was
performed by the local laboratory within 6 months prior to screening.]

13. Females who are pregnant or breastfeeding or planning to become pregnant within 90
days after their last anticipated dose of BCV

14. Receiving or anticipated to receive medications prohibited in the protocol.

15. Hypersensitivity (not including renal dysfunction or eye disorder) to CDV or to BCV or
its formulation excipients

16. Participation in another interventional clinical trial unless prior approval has been
received from the Chimerix Medical Monitor (or designee).

17. Received any cell-based anti-AdV therapy within 6 weeks prior to Day 1 or previously
received an anti-AdV vaccine at any time.