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Letermovir Treatment for Refractory or Resistant Cytomegalovirus Infection

A Phase 2 Study of Letermovir Treatment for Patients Experiencing Refractory or Resistant Cytomegalovirus Infection or Disease With Concurrent Organ Dysfunction

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03728426
Enrollment
10
Registered
2018-11-02
Start date
2019-01-11
Completion date
2022-03-28
Last updated
2023-03-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Cytomegalovirus Infections

Keywords

Cytomegalovirus Infections, CMV

Brief summary

The trial will evaluate the safety and efficacy of letermovir antiviral treatment of active cytomegalovirus infection or cytomegalovirus disease in patients with infections that are refractory or resistant to available treatments or who are experiencing organ dysfunction that makes unsafe the use of available antiviral treatments.

Detailed description

This is a Phase II clinical trial. Phase II clinical trials test the safety and effectiveness of an investigational drug to learn whether the drug works in treating a specific disease. Investigational means that the drug is being studied. The FDA (the U.S. Food and Drug Administration) has not approved letermovir for treatment of cytomegalovirus infection, but it has approved letermovir for the prevention of cytomegalovirus infection in bone-marrow transplantation patients. This is the first time that letermovir will be administered to children in a clinical trial. Cytomegalovirus (CMV) is a common virus, which a majority of people acquire at some time in their life. CMV remains in your body, but does not cause symptoms in the majority of people. Patients with a weakened immune system (a system that protects you from infections) may be more at risk for the virus becoming active and causing damage to some of your organs, especially in the gut and lungs. If the virus becomes present above a certain quantity, the doctor usually prescribes a drug to treat the infection at this stage to avoid damage to the organs. In this case, the virus is no longer responding to the prescribed drug, and other drug options will be harmful to the participant's health. Participants are being invited to take part in a research study for an investigational drug called letermovir. The purpose of this study is to find out whether letermovir is as effective and as safe in treating CMV infection in patients who cannot tolerate standard treatments such as ganciclovir or foscarnet.

Interventions

DRUGLetermovir

Patients will receive intravenous or oral letermovir at a dose of 480mg/day. Patients weighing 40 or more kilograms will receive a second, loading, dose 12 hours after the first dose of letermovir treatment. For patients receiving concomitant cyclosporine treatment, the letermovir dose will be 240mg/day.

Sponsors

Merck Sharp & Dohme LLC
CollaboratorINDUSTRY
Amy C. Sherman, MD
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
12 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Age ≥12 years * Weight ≥30 kg * Transplant recipient (HCT, SOT) or other immunocompromised patients including those with HIV infection that require antiviral treatment for CMV. * Documented CMV disease or persistent CMV infection (CMV virus load above 500 IU/mL on consecutive measurements, at least one day apart). * CMV infection is refractory to treatment (defined as ≥14 days of standard CMV treatment without clinical improvement for CMV disease, or failure to achieve \>1 log reduction in CMV VL after ≥14 days of standard treatment for CMV infection)16,17 * Current CMV infection has documented genotypic resistance to ganciclovir or foscarnet. * For patients with any prior CMV infection episode that broke through letermovir prophylaxis, but not during the current CMV infection, documentation of letermovir susceptibility testing should demonstrate absence of letermovir mutations known to confer resistance to letermovir. * Severe myelosuppression (ANC \<1000/µL, Hemoglobin \<8g/dL, or Platelets \<25,000/µL)17 or renal dysfunction (estimated creatinine clearance \<60 mL/min by MDRD in adults or \< 60 ml/min/1.73 m2 by bedside Schwartz equation in \< 18 years-old) at baseline or which develops during antiviral treatment. --Patients who develop severe myelosuppression or renal dysfunction during antiviral treatment as defined above are eligible without having to meet the refractoriness/antiviral resistance criterion. * Combinations of genotypic antiviral resistance and organ dysfunction that lead to eligibility are presented in the full protocol eligibility table. * The effects of letermovir on the developing human fetus are unknown. For this reason, women of child-bearing potential and men must agree to use adequate contraception (barrier method of birth control; abstinence) prior to study entry, for the duration of study participation, and 3 months after completion of letermovir administration. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 3 months after completion of letermovir administration. --Patients of childbearing potential must have a negative serum or urine pregnancy test. * Able to understand and the willingness to sign a written informed consent document.

Exclusion criteria

* History of allergic reactions attributed to compounds of similar chemical or biologic composition to letermovir. * Known history of cirrhosis with Child-Pugh Class C hepatic insufficiency at screening. * Acute liver injury at baseline meeting Hy's law. * Current CMV infection broke through letermovir prophylaxis. * Patients with life expectancy of less than a week. Determination of life expectancy will be discussed with the patient's primary treatment physician. * Patient taking strong inhibitors or inducers of hepatic CYP enzymes including rifampicin, phenytoin, clarithromycin, ritonavir, or cobicistat. * HIV patients who are receiving antiretroviral treatment protease inhibitors (darunavir, lopinavir, etc) whether by themselves or boosted with ritonavir or cobicistat, or HIV patients receiving cyclosporine treatment due to strong drug-drug interactions. * Combinations of genotypic antiviral resistance and organ dysfunction that do not meet eligibility criteria are described in the full protocol eligibility table.

Design outcomes

Primary

MeasureTime frameDescription
Virological Response on Treatment Week 66 weeksThe virologic response milestones are defined as: 1) Any decrease in CMV DNA from baseline (Week 0), measured on week 3 and 2) A ≥2 log decrease in CMV DNA from baseline, or an undetectable CMV DNA, measured on week 6. For patients with clinical CMV disease, the clinical response milestones are defined as: 1) Stabilization of clinical disease by week 3 (i.e. no worsening signs or symptoms compared to week 1) as assessed by the site investigator and 2) Improvement or resolution of clinical disease by week 6 (i.e., improvement in signs and symptoms of affected organs \[resolution of diarrhea, pneumonia, hepatitis, retinitis, etc.\]) 3) Patients with clinical CMV disease should also meet virological response milestones outlined above to support the continuation of letermovir therapy. Patients who enter the study based solely on documented CMV disease by histopathology in the absence of quantifiable CMV virus load should remain nonquantifiable (less than 137 IU/mL).

Secondary

MeasureTime frameDescription
Overall Survival6 monthsnumber of patients alive
CMV Progression-free Survival6 monthsTime from study enrollment to CMV progression or death whichever occurs first
Kinetics of Viral Clearance6 monthstime to undetectable plasma CMV DNA
Percent of Patients With a Clinically Meaningful Treatment Response to Letermovir Treatment6 WeeksVirological response and a concomitant clinical response in patients with CMV disease by Week 6 of treatment. For patients with clinical CMV disease, the clinical response milestones are defined as: 1. Stabilization of clinical disease by week 3 (i.e. no worsening signs or symptoms compared to week 1) as assessed by the site investigator and 2. Improvement or resolution of clinical disease by week 6 (i.e., improvement in signs and symptoms of affected organs \[resolution of diarrhea, pneumonia, hepatitis, retinitis, etc.\]) 3. Patients with clinical CMV disease should also meet virological response milestones outlined above to support the continuation of letermovir therapy. Patients who enter the study based solely on documented CMV disease by histopathology in the absence of quantifiable CMV virus load should remain nonquantifiable (less than 137 IU/mL).
Emergence of Letermovir-resistant CMV Virus in Patients Treated in This Setting6 monthsNumber of participants with breakthrough letermovir-resistant CMV infection in patients receiving letermovir treatment who experienced an initial virological response.

Countries

United States

Participant flow

Recruitment details

163 individuals were screened, 10 were enrolled in the study from Dana-Farber Cancer Institute inpatient and outpatient settings.

Participants by arm

ArmCount
Letermovir
Open label letermovir will be administered daily for up to 12 weeks. The study allows an optional additional 12 weeks of treatment for secondary prophylaxis if clinically indicated. Letermovir: Patients will receive intravenous or oral letermovir at a dose of 480mg/day. Patients weighing 40 or more kilograms will receive a second, loading, dose 12 hours after the first dose of letermovir treatment. For patients receiving concomitant cyclosporine treatment, the letermovir dose will be 240mg/day.
10
Total10

Withdrawals & dropouts

PeriodReasonFG000
Overall StudyDeath3

Baseline characteristics

CharacteristicLetermovir
Age, Continuous62.15 years
Baseline CMV viral load1272 IU/mL
Ethnicity (NIH/OMB)
Hispanic or Latino
0 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
9 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
1 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
Race (NIH/OMB)
Asian
1 Participants
Race (NIH/OMB)
Black or African American
2 Participants
Race (NIH/OMB)
More than one race
0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
Race (NIH/OMB)
Unknown or Not Reported
1 Participants
Race (NIH/OMB)
White
6 Participants
Region of Enrollment
United States
10 participants
Sex: Female, Male
Female
5 Participants
Sex: Female, Male
Male
5 Participants

Adverse events

Event typeEG000
affected / at risk
deaths
Total, all-cause mortality
3 / 10
other
Total, other adverse events
10 / 10
serious
Total, serious adverse events
6 / 10

Outcome results

Primary

Virological Response on Treatment Week 6

The virologic response milestones are defined as: 1) Any decrease in CMV DNA from baseline (Week 0), measured on week 3 and 2) A ≥2 log decrease in CMV DNA from baseline, or an undetectable CMV DNA, measured on week 6. For patients with clinical CMV disease, the clinical response milestones are defined as: 1) Stabilization of clinical disease by week 3 (i.e. no worsening signs or symptoms compared to week 1) as assessed by the site investigator and 2) Improvement or resolution of clinical disease by week 6 (i.e., improvement in signs and symptoms of affected organs \[resolution of diarrhea, pneumonia, hepatitis, retinitis, etc.\]) 3) Patients with clinical CMV disease should also meet virological response milestones outlined above to support the continuation of letermovir therapy. Patients who enter the study based solely on documented CMV disease by histopathology in the absence of quantifiable CMV virus load should remain nonquantifiable (less than 137 IU/mL).

Time frame: 6 weeks

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
LetermovirVirological Response on Treatment Week 65 Participants
Secondary

CMV Progression-free Survival

Time from study enrollment to CMV progression or death whichever occurs first

Time frame: 6 months

Population: 5 participants had CMV progression or death

ArmMeasureValue (MEDIAN)
LetermovirCMV Progression-free Survival13 days
Secondary

Emergence of Letermovir-resistant CMV Virus in Patients Treated in This Setting

Number of participants with breakthrough letermovir-resistant CMV infection in patients receiving letermovir treatment who experienced an initial virological response.

Time frame: 6 months

Population: All participants analyzed for letermovir breakthrough infections

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
LetermovirEmergence of Letermovir-resistant CMV Virus in Patients Treated in This Setting0 Participants
Secondary

Kinetics of Viral Clearance

time to undetectable plasma CMV DNA

Time frame: 6 months

Population: All participants

ArmMeasureValue (MEDIAN)
LetermovirKinetics of Viral Clearance166 days
Secondary

Overall Survival

number of patients alive

Time frame: 6 months

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
LetermovirOverall Survival7 Participants
Secondary

Percent of Patients With a Clinically Meaningful Treatment Response to Letermovir Treatment

Virological response and a concomitant clinical response in patients with CMV disease by Week 6 of treatment. For patients with clinical CMV disease, the clinical response milestones are defined as: 1. Stabilization of clinical disease by week 3 (i.e. no worsening signs or symptoms compared to week 1) as assessed by the site investigator and 2. Improvement or resolution of clinical disease by week 6 (i.e., improvement in signs and symptoms of affected organs \[resolution of diarrhea, pneumonia, hepatitis, retinitis, etc.\]) 3. Patients with clinical CMV disease should also meet virological response milestones outlined above to support the continuation of letermovir therapy. Patients who enter the study based solely on documented CMV disease by histopathology in the absence of quantifiable CMV virus load should remain nonquantifiable (less than 137 IU/mL).

Time frame: 6 Weeks

Population: 1 participant met the definition for CMV disease

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
LetermovirPercent of Patients With a Clinically Meaningful Treatment Response to Letermovir Treatment0 Participants

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026