Islatravir (MK-8591) With Doravirine and Lamivudine in Participants Infected With Human Immunodeficiency Virus Type 1 (MK-8591-011): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Islatravir (MK-8591) With Doravirine and Lamivudine in Participants Infected With Human Immunodeficiency Virus Type 1 (MK-8591-011) (NCT03272347), a randomized phase 2 study. The primary outcome is Percentage of Participants With HIV-1 RNA <50 Copies/mL at Week 24.

2. Clinical Question

The trial record describes a dose-ranging evaluation of islatravir used with doravirine and lamivudine in treatment-naïve adults. Its primary comparison concerns the proportion meeting the specified viral-load threshold at Week 24, rather than a direct measure of change in viral load or a time-to-event outcome. The posted results give the group percentages and sponsor-reported treatment differences, while unadjusted recalculations provide another way to describe the observed contrasts.

The record also lists later outcomes, including viral suppression after regimen changes, CD4+ T-cell counts, and adverse events. Those outcomes address different questions and timeframes. They do not replace the primary Week 24 question, and they should not be treated as if they were interchangeable measures of the same endpoint.

3. Trial Design

This was a randomized, double-blind, active-comparator-controlled, parallel-group phase 2B trial. The registry record lists enrollment of 123 participants. Participants were assigned to one of three islatravir dose groups, each with doravirine and lamivudine, or to DOR/3TC/TDF. The record describes the study as evaluating safety, tolerability, antiretroviral activity, and pharmacokinetics.

The initial study regimens were intended to continue for a minimum of 24 weeks. The arm descriptions state that lamivudine and corresponding placebo could be discontinued between Week 24 and Week 52 in the islatravir groups; the comparator description also describes possible discontinuation of placebo treatments during that period. The registry record further identifies later open-label doravirine/islatravir treatment and continued or switch groups in Part 4. These later treatment periods are distinct from the randomized Week 24 primary endpoint.

The study was completed. The record lists a start date of 2017-11-27 and a primary completion date of 2021-03-08. It does not report the randomization procedure in further detail, such as the method used to generate the allocation sequence or whether allocation was stratified. The specific statistical analysis plan, including any prespecified model for the primary comparison, is not reported in the registry record.

The primary analysis population is described as all randomized participants who received at least one dose of study treatment and had baseline data for analyses that require baseline data. This definition matters when interpreting results: it is not simply a statement that every randomized participant was included in every analysis. For the primary endpoint, missing values were counted as failure, as specified in the endpoint description.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All randomized participants who received at least 1 dose of study treatment and have baseline data for those analyses that require baseline data.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants With HIV-1 RNA <50 Copies/mL at Week 24, measured over Week 24.

The primary endpoint is the percentage of participants with HIV-1 RNA below 50 copies/mL at Week 24. Blood samples were collected, and plasma HIV-1 RNA was quantified with a real-time polymerase chain reaction assay. The assay’s lower limit of detection was 40 copies/mL. The registry record states that missing values were counted as failure.

This endpoint expresses whether each participant met a defined viral-load threshold at the assessment time. It is a binary outcome at the participant level: the result is either below the stated threshold or it is not. Reporting the percentage meeting the threshold makes the group results interpretable as proportions, while a treatment difference describes the contrast between group proportions. The endpoint does not, by itself, describe the distribution of viral-load values among participants, the timing of suppression, or whether suppression was maintained after Week 24.

Missing-as-failure is part of the endpoint’s reported handling rule and affects how the percentage should be understood. It treats participants without an observed qualifying value as not meeting the endpoint, rather than removing them from the calculation. The registry record does not provide further details about reasons for missing values or alternative analyses of missing data. Accordingly, the primary result describes the endpoint under the stated rule, not a separate estimate that assumes missing outcomes were suppressed.

The endpoint is used to assess antiretroviral activity at the specified visit. It should be interpreted alongside the group sizes, treatment differences, and uncertainty intervals. A high group percentage alone does not establish that one regimen differs from another; the comparative estimate and its precision are relevant to that question.

7. Results Posted in the Registry

• Islatravir 0.75 mg: 100.0% (30/30) versus 93.1% (27/29) on control; risk difference 6.9 percentage points (95% CI -2.3 to 16.1), risk ratio 1.07 (0.97–1.19); unadjusted two-proportion z-test p = 0.143.
• Islatravir 2.25 mg: 90.3% (28/31) versus 93.1% (27/29) on control; risk difference -2.8 percentage points (95% CI -16.7 to 11.1), risk ratio 0.97 (0.83–1.13); unadjusted two-proportion z-test p = 0.697.
• DOR/3TC/TDF: 90.3% (28/31) versus 93.1% (27/29) on control; risk difference -2.8 percentage points (95% CI -16.7 to 11.1), risk ratio 0.97 (0.83–1.13); unadjusted two-proportion z-test p = 0.697.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Percentage of Participants With HIV-1 RNA <50 Copies/mL up to 48 Weeks After Starting Open-label Doravirine/Islatravir Regimen (Part 4)

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • DOR/ISL Switch (Part 4): 95.5% (21/22) versus 85.1% (57/67) on control; risk difference 10.4 percentage points (95% CI -1.8 to 22.6), risk ratio 1.12 (0.98–1.28); unadjusted two-proportion z-test p = 0.199.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between DOR/ISL Switch (Part 4) and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants Experiencing AEs From Week 96 Through Study Duration

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Islatravir 0.75 mg: 63.3% (19/30) versus 41.4% (12/29) on control; risk difference 22.0 percentage points (95% CI -2.9 to 46.8), risk ratio 1.53 (0.92–2.55); unadjusted two-proportion z-test p = 0.091.
  • Islatravir 2.25 mg: 35.5% (11/31) versus 41.4% (12/29) on control; risk difference -5.9 percentage points (95% CI -30.5 to 18.7), risk ratio 0.86 (0.45–1.63); unadjusted two-proportion z-test p = 0.639.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Islatravir 0.75 mg and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Islatravir 2.25 mg and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants Experiencing AEs During Open Label Doravirine/Islatravir Treatment After Week 144 up to Week 192 (Part 4)

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • DOR/ISL Switch (Part 4): 63.6% (14/22) versus 53.7% (36/67) on control; risk difference 9.9 percentage points (95% CI -13.5 to 33.3), risk ratio 1.18 (0.80–1.74); unadjusted two-proportion z-test p = 0.417.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between DOR/ISL Switch (Part 4) and the control. The interval gives the range of effects that remain compatible with the data.

The registry record lists secondary outcomes across viral suppression, CD4+ T-cell counts, and adverse events. The listed timeframes extend beyond the Week 24 primary endpoint, including later follow-up and open-label treatment periods. The record indicates that 14 secondary outcomes were posted. These outcomes broaden the descriptive picture of follow-up, but they address different questions from the primary randomized comparison.

Some secondary results come from later continued or switch groups, including open-label doravirine/islatravir treatment. Such results describe outcomes in those later groups and periods; they should not be interpreted as direct confirmation of the original randomized Week 24 contrast. Treatment changes and the timing of assessment matter when comparing outcomes across the trial’s phases. The registry record does not report a complete analysis plan that establishes how those later analyses relate to the primary estimand.

Secondary endpoints can help characterize longer-term patterns and other dimensions of the trial, but they generally carry less confirmatory weight when the record does not specify a multiplicity strategy. Testing or examining many outcomes creates more opportunities for apparently notable results to arise by chance. Unadjusted secondary p-values, where present, do not account for that broader set of analyses. The registry record does not report a multiplicity adjustment or a hierarchy of secondary hypotheses.

Accordingly, the secondary findings are best treated as supportive and descriptive rather than as independent proof of the primary conclusion. They may be useful for generating questions about later viral suppression, immune-cell measures, or adverse events, but their interpretation depends on the population, treatment period, missing-data handling, and analysis method for each endpoint. Those details are not fully reported in the registry record.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Percentage of Participants With HIV-1 RNA <50 Copies/mL up to 24 Weeks After 3TC and Placebo Are Discontinued From the Regimen
• Percentage of Participants With HIV-1 RNA <50 Copies/mL up to 48 Weeks After 3TC and Placebo Are Discontinued From the Regimen
• Percentage of Participants With HIV-1 RNA <50 Copies/mL up to 48 Weeks After Starting Open-label Doravirine/Islatravir Regimen (Part 4)
• Change From Baseline in Mature T-helper (CD4+ T)-Cell Count at Week 24
• Change From Baseline in CD4+ T-cell Count at Week 48
• Change From Baseline in CD4+ T-cell Count at Week 96
• Change From Baseline in CD4+ T-cell Count at Week 144
• Change From Baseline in CD4+ T-cell Count at Week 192 (Part 4)

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is binary at the participant level: a participant either had HIV-1 RNA below 50 copies/mL at Week 24 or did not. A percentage summarizes the share meeting that endpoint in each group. A treatment difference compares two such proportions. The recalculated risk differences are expressed on a proportion scale, so an estimate of 0 represents equal observed proportions. Positive values indicate a higher observed proportion in the comparison group relative to the reference group as coded in the recalculation; negative values indicate a lower one.

What does a confidence interval describe?

General statistical explanation: A confidence interval describes the uncertainty around an estimated effect under the assumptions of the analysis. A narrower interval indicates greater precision; a wider interval indicates less precision. If an interval for a difference includes zero, the data do not clearly distinguish that contrast from no difference at the confidence level used. This is not proof that the groups are identical. It also does not mean that every value inside the interval is equally likely or that the interval accounts for every possible source of bias.

The sponsor’s reported treatment differences are accompanied by 95% confidence intervals, while p-values are not reported for those analyses. The unadjusted recalculations include confidence intervals and unadjusted p-values. A p-value describes how incompatible the observed data are with a specified null hypothesis under the calculation’s assumptions; it is not the probability that the null hypothesis is true, nor a measure of the size or importance of an effect. The recalculated p-values are unadjusted and should not be read as having accounted for multiple comparisons.

Why distinguish reported and recalculated estimates?

The sponsor’s reported analysis and a simple recalculation can differ because they may use different contrasts, analysis populations, or statistical methods. The sponsor’s method and full specification are not reported in the registry record. The posted recalculations are explicitly unadjusted summaries based on the available group counts and are useful as a transparent descriptive comparison, but they do not reproduce an unreported sponsor model. Because the discrepancy flag is false, no discrepancy is identified in the record; the sponsor’s own analysis nevertheless remains the primary reported analysis.

The Week 24 endpoint description says that missing values were counted as failure. This rule classifies missing endpoint values as not meeting the threshold, rather than treating them as observed successes or excluding them under a complete-case calculation. The registry record does not give a breakdown of missing data or explain the reasons for missing values. It also does not report sensitivity analyses under alternative assumptions. The stated rule is therefore important context, but it does not reveal how much the result would change under another missing-data approach.

How should planning illustrations be read?

The planning illustrations use an observed effect and a stated fraction of that effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. For the Week 24 comparison of islatravir 2.25 mg with DOR/3TC/TDF, the illustration lists participants per arm for 80% and 90% power at 100%, 75%, and 50% of the observed effect. These are hypothetical planning quantities derived from the observed effect, not the trial’s original design calculations and not observed power. The registry record does not report the original sample-size justification, the assumptions used to plan enrollment, or whether the trial was powered for the primary endpoint.

Such planning calculations depend on the assumed effect and analysis conditions. When the observed effect is uncertain, using it as a planning input can produce unstable illustrations. Shrinking the effect in a planning scenario describes a hypothetical target; it does not change what the trial observed. The listed participants-per-arm values should therefore be read only as illustrations under their stated assumptions, not as evidence that the current trial had adequate or inadequate power.

What role do the later outcomes play?

The registry record includes secondary outcomes covering viral suppression at later timepoints and after regimen changes, CD4+ T-cell count changes, and adverse events. Different outcome types answer different statistical questions. Percentages with an event remain binary outcomes, while a count of participants with an adverse event records how many participants experienced an event over the specified period. Results from later open-label periods should not be treated as though they were randomized comparisons from the initial Week 24 period. The record does not report enough detail to establish that every secondary analysis used a common population or a common statistical model.

11. Confidence Intervals and Precision

The primary group percentages are based on 29 participants in the 0.25 mg group, 30 in the 0.75 mg group, 31 in the 2.25 mg group, and 31 in the DOR/3TC/TDF group. The registry’s sponsor-reported 95% confidence intervals for treatment differences extend from -12.5 to 18.3 for 0.25 mg versus DOR/3TC/TDF, from -3.8 to 23.0 for 0.75 mg versus DOR/3TC/TDF, and from -16.0 to 16.3 for 2.25 mg versus DOR/3TC/TDF. Each interval spans zero and allows for uncertainty in either direction.

For the recalculated comparison of 0.75 mg with 0.25 mg, the risk difference is 0.069 and its interval is -0.023 to 0.161. For 2.25 mg compared with 0.25 mg, the risk difference is -0.028 and its interval is -0.167 to 0.111. The interval for DOR/3TC/TDF compared with 0.25 mg is also -0.167 to 0.111 around an estimate of -0.028. These recalculated intervals describe uncertainty for those specific unadjusted contrasts; they are not the sponsor’s intervals for its comparisons against DOR/3TC/TDF.

General statistical explanation: Precision concerns how tightly the data locate an estimate, not whether an estimate is important or whether a treatment should be used. Confidence intervals that include zero do not prove no effect. They indicate that the data, under the analysis assumptions, do not rule out zero at the stated confidence level. A small trial can produce estimates that look substantial but remain imprecise, particularly when outcomes are common and group counts are limited.

The registry record does not report confidence intervals around the individual group percentages. Therefore, the uncertainty descriptions available for the primary endpoint are the sponsor’s intervals for its treatment differences and the intervals from the unadjusted recalculations. The sponsor’s intervals should be read with their stated comparator, not substituted for the recalculated contrasts.

12. Analyses Reported by the Sponsor

The sponsor-reported analyses compare each islatravir dose group with DOR/3TC/TDF. The reported treatment differences are 2.9 for 0.25 mg, 9.6 for 0.75 mg, and 0.2 for 2.25 mg, with 95% confidence intervals of -12.5 to 18.3, -3.8 to 23.0, and -16.0 to 16.3, respectively. The registry record does not report p-values or the statistical method for these analyses.

The unadjusted recalculations use a different reference group: islatravir 0.25 mg. They report risk differences, confidence intervals, and unadjusted p-values for the other groups against that reference. Since the reference groups differ, the recalculated values are not direct reproductions of the sponsor’s contrasts. A difference in estimates cannot be attributed to a particular analytical choice without the sponsor’s full method and estimand details, which are not reported in the registry record.

The discrepancy indicator is false. In any case, the sponsor’s own analysis is the primary reported analysis, while the recalculations are descriptive, unadjusted re-calculations from posted summary statistics. Neither set of estimates should be treated as establishing equivalence or noninferiority, which are not reported as the primary objective.

13. Multiplicity, Missing Data and Analysis Populations

The registry record describes the primary endpoint’s missing-value rule: missing values were counted as failure. This is a clear rule for the reported Week 24 viral-suppression outcome, but the record does not provide the number or reasons for missing endpoint values, nor does it report sensitivity analyses using alternative assumptions. The primary population is defined as randomized participants who received at least one dose and had baseline data for analyses that require baseline data. The record does not specify in further detail how the population was implemented for each analysis.

The record lists multiple outcome measures and analyses, including several secondary outcomes across different timeframes. It does not report whether the primary endpoint was protected from multiplicity through a prespecified testing hierarchy, adjustment, or other procedure. Nor does it state whether secondary analyses were intended to be confirmatory or exploratory. Without that information, nominal or unadjusted statistical results should be interpreted cautiously: repeated testing can increase the chance of observing apparently unusual results even when there is no corresponding underlying effect.

The sponsor-reported primary treatment differences do not include p-values in the registry record. The recalculated primary p-values are explicitly unadjusted. The record also does not report the full statistical analysis plan, details of interim analyses, or a sample-size justification. These omissions limit assessment of whether the reported comparisons align with prespecified hypotheses and how the trial’s design addressed precision or multiple testing.

These reporting gaps do not invalidate the posted outcome values. They do limit what can be concluded about missing-data sensitivity, confirmatory status, and control of false-positive findings across outcomes. The appropriate reading is to give greatest weight to the defined primary endpoint and its reported uncertainty, while treating the secondary findings as less definitive unless their analysis procedures and multiplicity handling are documented.

14. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: suicide attempt (6.7%), covid-19 (4.5%), atrial fibrillation (3.4%), burkitt's lymphoma (3.4%), lymphadenopathy (3.3%).

The registry’s adverse-event summary reports serious adverse events and other adverse events separately, with the number at risk and number affected for each listed group. For the initial dose groups, the serious-event counts were 2 among 29 for 0.25 mg, 6 among 30 for 0.75 mg, 2 among 31 for 2.25 mg, and 4 among 31 for DOR/3TC/TDF. The corresponding other-adverse-event counts were 22, 26, 23, and 22. The summary lists one death in the DOR/3TC/TDF group and zero in each initial islatravir group.

Later DOR/ISL continued and switch groups are also listed, with serious adverse-event counts of 2 among 67 and 1 among 22, and other adverse-event counts of 21 among 67 and 11 among 22. The record lists serious-event terms and percentages, including suicide attempt at 6.7%, COVID-19 at 4.5%, atrial fibrillation at 3.4%, Burkitt's lymphoma at 3.4%, lymphadenopathy at 3.3%, and appendicitis at 3.3%. The record does not specify the denominator and detailed timeframe for those term percentages in the information presented.

These are descriptive safety counts. They do not establish that an event was caused by a treatment, and the later groups are not equivalent to the original randomized comparison. Small group sizes and different follow-up periods also limit direct comparison. The registry record does not provide the information needed to make a causal or comprehensive safety assessment from these figures alone.

15. What the Result Does, and Does Not, Mean

The Week 24 results describe the proportion of participants in each group who had HIV-1 RNA below 50 copies/mL under the endpoint rule that counted missing values as failure. The observed percentages were high across all groups. The sponsor’s treatment-difference intervals include zero, and the unadjusted recalculated intervals also include zero for the contrasts they address. Together, these estimates show uncertainty about the magnitude and direction of between-group differences.

These results do not establish that the regimens are identical. Failure to demonstrate a difference is not the same as demonstrating equivalence. The registry record does not identify an equivalence or noninferiority margin or report that either was the primary objective. Nor do these data alone establish a treatment effect relative to no treatment: the study used an active comparator, and the reported endpoint is a Week 24 comparison among randomized groups.

The endpoint also has a specific scope. It is a viral-load threshold at a particular visit, not a measure of every aspect of HIV-1 disease, long-term clinical outcomes, quality of life, or sustained suppression throughout follow-up. The later outcomes in the record have different timeframes and, in some cases, describe open-label treatment. They should not be collapsed into the primary Week 24 result.

Precision is an important constraint. Group sizes were 29, 30, 31, and 31, and the confidence intervals permit a range of possible effects. The registry record does not provide the original sample-size justification or full statistical analysis plan, so it is not possible to assess the intended power or all prespecified analytical choices from the record alone. The posted figures support a careful description of the observed proportions and uncertainty, not a clinical recommendation or a definitive claim that one regimen is better, worse, or interchangeable with another.

16. Why This Trial Matters Statistically

This trial is statistically instructive because the primary outcome is a common binary endpoint, and the observed group percentages are high. When a large share of participants meet an endpoint, the absolute difference between groups may be small even when the observed percentages appear distinct. Interpretation therefore depends on the actual contrast and its uncertainty, not on comparing the percentages informally.

The record also illustrates why the comparator and estimand must be explicit. The sponsor’s primary analyses compare each islatravir dose with DOR/3TC/TDF, whereas the unadjusted recalculations compare with islatravir 0.25 mg. Those are different questions. Contrasts cannot be compared or substituted without attending to which group is the reference and what analysis produced the estimate.

Missing-data handling is another central issue. Counting missing Week 24 values as failures defines how the endpoint is calculated, but the absence of reported missingness details and sensitivity analyses limits assessment of how dependent the result is on that rule. Likewise, the record lists multiple secondary outcomes without reporting multiplicity procedures, so secondary signals need more cautious interpretation than a single prespecified primary comparison.

Finally, uncertainty intervals help distinguish an observed estimate from a precise conclusion. The posted intervals encompass zero and allow a range of effects. A p-value alone would not convey that range, and an observed percentage alone would not show comparative precision. Together, the trial’s results demonstrate why effect estimates, confidence intervals, analysis populations, missing-data rules, and the specific comparator all matter when reading clinical-trial statistics.

17. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
• Participant counts were reconstructed from posted percentages and arm sizes, so small rounding differences are possible.

The registry record does not report the statistical method used for the sponsor’s primary treatment-difference analyses, the complete statistical analysis plan, or the original sample-size justification. It also does not report whether interim analyses were conducted. These omissions make it difficult to evaluate prespecified modeling choices, the intended precision, or how the trial addressed repeated comparisons.

The primary endpoint is measured at Week 24, while treatment descriptions include possible regimen changes after that period and later open-label treatment. Long-term outcomes therefore arise in different treatment contexts from the initial randomized comparison. The registry record does not provide enough detail to assess the effects of those changes on every later analysis or to determine whether later groups remained comparable through follow-up.

The endpoint uses a missing-as-failure rule, but the record does not report the reasons for missing values or sensitivity analyses under different assumptions. In addition, the primary analysis population definition requires receipt of at least one dose and baseline data when needed; the record does not give a fuller account of the analysis population for each individual analysis.

The group sizes are limited, and the reported intervals are broad. This constrains the precision of treatment comparisons. The recalculated analyses are unadjusted and use a reference group that differs from the sponsor’s reported comparisons, so they should not be treated as reproductions of the sponsor’s method. Safety counts are descriptive, and the record does not provide enough detail to infer causation or make reliable comparisons across groups with different follow-up. These limitations apply to interpretation of the registry results and do not substitute for information not reported in the record.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Islatravir (MK-8591) With Doravirine and Lamivudine in Participants Infected With Human Immunodeficiency Virus Type 1 (MK-8591-011) — NCT03272347.
• Registry record last updated 2023-03-29; status last verified 2023-02.
• Results first posted 2022-04-27.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

21. Record Summary

NCT03272347 is a completed randomized, double-blind, active-comparator-controlled phase 2B trial in antiretroviral treatment-naïve adults with HIV-1 infection. The registry record lists enrollment of 123. Participants received one of three daily islatravir doses with doravirine and lamivudine, or the active comparator DOR/3TC/TDF.

The primary endpoint was the percentage with HIV-1 RNA below 50 copies/mL at Week 24, with missing values counted as failure. Posted group percentages ranged from 90.3% to 100.0%. Sponsor-reported treatment-difference confidence intervals included zero; unadjusted recalculations likewise show substantial uncertainty for their stated contrasts.

The registry also lists later viral-suppression, CD4+ T-cell, and adverse-event outcomes. Interpretation is limited by unreported details of the statistical analysis plan, sample-size justification, multiplicity handling, and missing-data sensitivity analyses.