A Safety Assessment of Oral Letermovir in Infants With Symptomatic Congenital Cytomegalovirus

Conditions

• Congenital Cytomegalovirus Infection

Eligibility Criteria

Sex

ALL

Age

0 Days - 90 Days

Healthy Volunteers

Not accepted

Interventions

• Letermovir — DRUG
  Letermovir is a novel inhibitor targeting the cytomegalovirus (CMV) viral enzyme, effectively disrupting the production of additional CMV virions. Letermovir has demonstrated potent, selective, and reversible inhibition of CMV activity in preclinical studies.

Study Details

This is a Phase 1 single-arm open-label study of letermovir in neonates with symptomatic congenital Cytomegalovirus (CMV) disease. There will be two groups enrolled. Group 1 will be comprised of 4 subjects. Following documentation study inclusion and signing of informed consent, Group 1 subjects will receive one dose of oral letermovir (Study Day 0), using the dose bands. A full pharmacokinetics (PK) profile will then be obtained over the next 24 hours, and blood specimens will be shipped immediately to the University of Alabama at Birmingham (UAB) Pharmacokinetic Lab and processed in real time. Within = 7 days, pharmacokinetics (PK) results will be conveyed to the study site. If the Area Under the Curve (AUC24) is =100,000 ngxhr/mL (see footnote a in Table 1), the subject will initiate a 14-day course of once-daily oral letermovir at the same dose as utilized on Dose Finding Day. This duration of letermovir therapy was selected based upon our earlier observation in this population that patients with symptomatic congenital Cytomegalovirus (CMV) disease who achieve viral suppression to =2.5 log by day 14 of valganciclovir therapy and then maintain it over the next 4 months are statistically more likely to have improved hearing across the first two years of life (22). If the observed letermovir exposure of the subject is \> 100,000 ngxhr/mL, the once-daily oral letermovir dose that will be used will be adjusted down in 2.5 mg increments. Oral valganciclovir (16 mg/kg/dose BID) will begin within the first month of life, as standard of care; initiation of valganciclovir can be concomitant with or prior to initiation of the 14-day course of letermovir (but will not start before obtaining the pharmacokinetics (PK) specimens following the single dose of letermovir on the Dose Finding Day). This is similar to the intensification approach that has been evaluated in the management of patients infected with human immunodeficiency virus (23-25). The day that the 14-day course of letermovir begins for Group 1 subjects will be known as Study Day 1. Serial blood samples will be obtained on Study Days 1, 5, 10, and 14 for safety chemistry and hematology labs and for Cytomegalovirus (CMV) viral loads. Cytomegalovirus (CMV) viral load will be followed as well on Study Days 21 and 42 to assess for rebound in Cytomegalovirus (CMV) following cessation of letermovir treatment on Study Day 14. Saliva and urine viral loads will be followed at these timepoint as well. Full pharmacokinetics (PK) profiles for both letermovir and ganciclovir will be obtained on Study Day 10. In addition, sparse pharmacokinetics (PK) sampling will be obtained on Study Days 1, 5, and 14. Adverse events will be assessed at each study visit during treatment, and at Study Days 21 and 42 (4 weeks after the last study drug dose). Subjects then will continue on oral valganciclovir as routine clinical care to complete an anticipated 6 month duration of total therapy. The primary Objective is to determine the systemic exposure (AUC24) of letermovir following administration of oral letermovir granules in infants with symptomatic congenital CMV disease.

Key Dates

Start date

Feb 19, 2025

Status verified

Jul 2025

Primary completion

May 15, 2026

Completion

Aug 31, 2026

Study Design

Enrollment

12 participants (estimated)

Allocation

NON_RANDOMIZED

Intervention model

SEQUENTIAL

Primary purpose

TREATMENT

Arms

• Experimental: Group 1
  Neonates (\</= 83 days) with symptomatic congenital Cytomegalovirus (CMV) disease will receive one dose of oral letermovir, using weight dose banding. All subjects also will receive valganciclovir as standard of care. A dose safety evaluation will occur to ensure the safety data support subjects proceeding. If the observed letermovir exposure is \</= 100,000 ngxhr/mL, the subject will initiate a 14-day course of once-daily oral letermovir at the same dose as utilized on the Dose Finding Day. If the observed letermovir exposure of the subject is \> 100,000 ngxhr/mL, the once-daily oral letermovir dose that will be used will be adjusted down in 2.5 mg increments from the dose utilized on the Dose Finding Day. N = 4
• Experimental: Group 2
  Neonates (\</= 90 days) with symptomatic congenital Cytomegalovirus (CMV) disease will initiate a 14-day course of once-daily oral letermovir, using weight dose banding. All subjects also will receive valganciclovir as standard of care. A dose escalation safety evaluation will occur to ensure the safety data support subjects proceeding. If the median of observed letermovir exposures of subjects in Group 1 is below 34,400 ngxhr/mL (or above 100,000 ngxhr/mL), then the subjects enrolled in Group 2 will receive once-daily oral letermovir at a dose that has been adjusted upward (or downward) in 2.5 mg increments. N=8

Primary Outcome Measure

Plasma letermovir area under the curve (AUC24) concentrations [ Time Frame: Through Day 14 ]

Central Contacts

• David W. Kimberlin
  12056382530
  [email protected]

Locations (10)

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