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ISL

Phase 2

HIV-1 Infection | Small molecule | Infectious Disease |Gilead Sciences, Inc.|Last Updated: Feb 4, 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedCONTROLLEDDMC
Total Trials1
Total Enrollment142

FDA Designations

No designations recorded

Clinical trial landscape

ISL · 1 trial · 1 indication

Phase 2 1
NCT05052996Study Evaluating the Safety and Efficacy of Islatravir in Combination With Lenacapavir in Virologically Suppressed People With HIVHIV-1 Infection
ACTIVE NOT_RECRUITING142 Analytics
PHASE2ACTIVE NOT_RECRUITING
Study Evaluating the Safety and Efficacy of Islatravir in Combination With Lenacapavir in Virologically Suppressed People With HIV
HIV-1 InfectionUnlock trial analytics

Study Endpoints

Primary Endpoints

Percentage of Participants With HIV-1 RNA ≥ 50 Copies/mL at Week 24 as Determined by the US Food and Drug Administration (FDA)-Defined Snapshot Algorithm
Week 24

The percentage of participants with HIV-1 RNA ≥ 50 copies/mL at Week 24 was analyzed using the snapshot algorithm, which defines a participant's virologic response status using only the viral load at the predefined time point within an allowed window of time, along with the applicable study drug discontinuation status. Week 24 window was between Day 148 and 189 (inclusive). Percentages were rounded off.

Secondary Endpoints

Percentage of Participants With HIV-1 RNA ≥ 50 Copies/mL at Week 12 as Determined by the US FDA-defined Snapshot Algorithm
Week 12
Percentage of Participants With HIV-1 RNA ≥ 50 Copies/mL at Week 48 as Determined by the US FDA-defined Snapshot Algorithm
Week 48
Percentage of Participants With HIV-1 RNA < 50 Copies/mL at Week 12 as Determined by the US FDA-defined Snapshot Algorithm
Week 12
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Cohort 1 (ISL+LEN)EXPERIMENTALParticipants will receive the following for at least 48 weeks: * Day 1 and Day 2: ISL 40 and LEN 600 mg * Day 8 and weekly thereafter (ie, every 7 days): ISL 20 mg and LEN 300 mg
Cohort 1 (B/F/TAF to ISL+LEN)EXPERIMENTALParticipants will receive bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) 50/200/25 mg once daily for at least 48 weeks After 48 weeks, participants will switch from B/F/TAF to ISL+LEN * ISL 40 and LEN 600 mg on Day 1 and Day 2 * ISL 20 mg and LEN 300 mg weekly Participants who do not switch from B/F/TAF to ISL+LEN at Week 48 will be discontinued from the study.
Cohort 2 (ISL+LEN)EXPERIMENTALParticipants will receive the following for at least 48 weeks * Day 1: LEN oral 600 mg (2 x 300 mg) and ISL 2 mg (2 x 1 mg) * Day 2: LEN only oral 600 mg (2 x 300 mg) * Day 8 and weekly thereafter (ie, every 7 days): LEN oral 300 mg (1 x 300 mg) and ISL 2 mg
Cohort 2 (B/F/TAF to ISL+LEN)EXPERIMENTALParticipants will receive B/F/TAF 50/200/25 mg once daily for at least 48 weeks.
Extension Phase Cohort 2 of ISL/LEN Fixed Dose Combination (FDC)EXPERIMENTALAfter 48 Weeks of randomized treatment, all participants will be given an option to participate in an Extension Phase to receive ISL+LEN or ISL/LEN FDC tablet (when available) until ISL/LEN becomes available or until the sponsor elects to discontinue the study, whichever occurs first. Participants receiving ISL+LEN during the randomized phase will continue to take ISL + LEN weekly. Participants receiving B/F/TAF during the randomized phase will switch to ISL+LEN: * Day 1: LEN oral 600 mg (2 x 300 mg) and ISL 2 mg (2 x 1 mg) * Day 2: LEN only oral 600 mg (2 x 300 mg) * Day 8 and weekly thereafter (ie, every 7 days): LEN oral 300 mg (1 x 300 mg) and ISL 2 mg Participants who do not switch from B/F/TAF to ISL+LEN at Week 48 will be discontinued from the study. All participants in the extension phase will be transitioned to weekly ISL/LEN FDC (Dose A) tablet when it becomes available.

Interventions

NameTypeDescription
ISLDRUGCapsules administered orally without regard to food
LENDRUGTablets administered orally without regard to food
B/F/TAFDRUGTablets administered orally without regard to food
ISL/LEN FDCDRUGTablets administered orally without regard to food
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites44

Key Inclusion Criteria: * Received bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) for ≥ 24 weeks at screening. * Documented plasma human immunodeficiency virus type 1 (HIV-1) ribonucleic acid (RNA) \< 50 copies/mL (or undetectable HIV-1 RNA level according to the local assay being used i...

Countries:United States
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Frequently asked questions about ISL

What is ISL used for in HIV-1 infection?

ISL, also known as ISL/LEN, is an investigational small molecule being developed for the treatment of HIV-1 infection. It is studied as a combination regimen with lenacapavir for virologically suppressed people with HIV-1. The drug is currently in Phase 2 and Phase 3 clinical trials.

What does ISL target?

ISL is a small molecule antiviral that targets HIV-1. It is being studied in combination with lenacapavir as an oral weekly regimen for the treatment of HIV-1 infection. The combination is intended to maintain viral suppression in people living with HIV-1.

Who makes ISL?

ISL is being developed by Gilead Sciences, Inc., a biopharmaceutical company traded on NASDAQ under the ticker GILD. Gilead is conducting clinical trials to evaluate the safety and efficacy of ISL in combination with lenacapavir for the treatment of HIV-1 infection.

What phase is ISL in?

ISL is in Phase 2 and Phase 3 clinical development. It is an investigational drug and has not been approved by regulatory authorities. The ongoing trials are evaluating its safety and efficacy as part of an oral weekly regimen for virologically suppressed people with HIV-1.

What clinical trials is ISL in?

ISL is being studied in three active clinical trials. NCT05052996 is a Phase 2 trial evaluating islatravir with lenacapavir in 142 participants. NCT06630286 and NCT06630299 are Phase 3 trials comparing the oral weekly regimen with standard of care in over 1,200 participants across multiple countries.

Is ISL the same as ISL/LEN?

Yes, ISL is also known as ISL/LEN. The name ISL/LEN refers to the combination of islatravir and lenacapavir, which is being studied as an oral weekly regimen for the treatment of HIV-1 infection. The drug is being developed by Gilead Sciences.