A Study of Doravirine/Islatravir (DOR/ISL, MK-8591A) for the Treatment of Human Immunodeficiency Virus 1 (HIV-1) Infection in Participants Who Previously Received DOR/ISL (MK-8591A-054)

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the safety and tolerability of DOR/ISL in adult participants with HIV-1 who had been previously treated with DOR/ISL in earlier clinical studies. There are no formal hypotheses to be tested in this study.

Official Title
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A Phase 3 Open-label Clinical Study of Doravirine/Islatravir (DOR/ISL [100 mg/0.25 mg]) Once Daily for the Treatment of HIV-1 Infection in Participants Who Previously Received DOR/ISL (100 mg/0.75 mg) QD in a Phase 3 Clinical Study

Conditions
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HIV Infection

Intervention / Treatment
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* Drug: DOR/ISL


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Is currently receiving doravirine/islatravir (DOR/ISL) adult fixed dose combination (FDC) tablet in Merck Sharp & Dohme (MSD)-sponsored clinical studies (MK-8591A-017, -018, -020, and -033 [except for heavily treatment-experienced (HTE) participants]). Exclusion Criteria: Has confirmed HIV-1 RNA ≥200 copies/mL in MSD DOR/ISL (100 mg/0.75 mg) MK-8591A-017 /-018 /-020, or at screening for participants entering from DOR/ISL (100 mg/0.75 mg) MK-8591A-033. Has confirmatory laboratory findings for cluster of differentiation 4+ (CD4+) T-cell counts or lymphocyte counts in the prior DOR/ISL study that meet criteria for discontinuation of DOR/ISL. Is a HTE participant receiving treatment in MK-8591A-019 or -033.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: DOR/ISL<br>Participants will receive fixed dose combination (FDC) tablet of DOR/ISL (100 mg/0.25 mg) taken once daily (QD) orally from Day 1 to Week 96. | Drug: DOR/ISL<br>* FDC tablet of 100 mg doravirine (DOR)/0.25 mg islatravir (ISL) taken once daily<br>* Other names: Doravirine/islatravir;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants with One or More Adverse Event (AE) | An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The percentage of participants who experience an AE through Week 102 will be presented. | Up to 102 Weeks | 
| Percentage of participants who Discontinue Study Intervention Due to an AE | An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The percentage of participants who discontinue study intervention due to an AE through Week 96 will be presented. | Up to 96 Weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants with HIV-1 Ribonucleic Acid (RNA) ≥50 copies/mL at Week 96 | The percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 96 will be reported. | Week 96 | 
| Percentage of Participants with HIV-1 RNA <50 copies/mL at Week 96 | The percentage of participants with HIV-1 RNA <50 copies/mL at Week 96 will be reported. | Week 96 | 
| Percentage of Participants with HIV-1 RNA ≥200 copies/mL at Week 96 | The percentage of participants with HIV-1 RNA ≥200 copies/mL at Week 96 will be reported | Week 96 | 
| Percentage of Participants with Evidence of Viral Drug Resistance-Associated Substitutions | Viral drug resistance is defined as participants with HIV-1 RNA ≥400 copies/mL and/or genotypic or phenotypic data showing evidence of resistance to the study intervention. The percentage of participants who demonstrate drug resistance through Week 96 will be presented. | Up to Week 96 |