PIVOT: Complete Statistical Analysis of Protease Inhibitor Monotherapy in HIV Infection

Scope of this record

This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record.

1. Trial at a Glance

PIVOT was a randomized phase 4 parallel-group treatment trial comparing protease inhibitor monotherapy with ongoing triple-therapy in people with HIV infection or acquired immunodeficiency syndrome.

587Enrollment

2Arms

4Phase

5 yearsPrimary endpoint timeframe

Feature	PIVOT
NCT ID	NCT01230580
Title	Protease Inhibitor Monotherapy Versus Ongoing Triple-therapy in the Long Term Management of HIV Infection
Design	Randomized, parallel assignment, open-label
Primary purpose	Treatment
Enrollment	587
Sponsor	Medical Research Council

2. Clinical Question

Population

Individuals with HIV Infection or Acquired Immunodeficiency Syndrome.

Intervention

Protease inhibitor monotherapy.

Comparator

Standard-of-care antiretroviral therapy.

Primary question

Whether protease inhibitor monotherapy affects long-term loss of future drug options compared with ongoing triple-therapy.

3. Trial Design

Design element	Description
Allocation	Randomized
Masking	None
Model	Parallel assignment
Number of arms	2
Study start	2008-11
Primary completion	2013-11

4. Trial Arms

Protease inhibitor monotherapy

Randomized treatment strategy using a protease inhibitor drug.

Ongoing triple-therapy

Standard-of-care antiretroviral therapy comparator.

5. Primary Endpoint

Endpoint	Definition	Time frame
Loss of future drug options	The first occurrence of intermediate to high level resistance to any one or more of the standard antiretroviral drugs to which the patient's virus was considered sensitive at trial entry, excluding resistance known from previous testing.	Up to 5 years

6. Planned Analysis

The registry identifies loss of future drug options as the primary endpoint but does not report posted statistical analyses or endpoint estimates.

For a time-to-event endpoint such as loss of future drug options, analysis would typically involve methods that account for the timing of events and censoring, allowing comparison of event occurrence over follow-up between randomized groups.

Registry reporting: ClinicalTrials.gov does not report formal statistical analyses for the primary endpoint.

7. Statistical Methodology

Randomization

Randomization creates comparable groups at baseline in expectation and supports interpretation of differences between treatment strategies as treatment-assignment comparisons.

Time-to-event analysis

The primary endpoint is defined by the first occurrence of a resistance event over follow-up. Time-to-event methods are commonly used when patients may have different observation times.

Conceptual survival framework

S(t) = Probability of remaining event-free beyond time t

Patients without the event by the end of observation contribute information through their censoring time.

8. Statistical Methods Explained

Why is the endpoint defined as the first resistance event?

A first-event definition provides a consistent comparison point between randomized groups and avoids counting repeated resistance measurements as multiple primary outcomes.

Why does censoring matter?

Not every participant will necessarily experience the endpoint during follow-up. Statistical methods must distinguish observed event times from periods where event status is unknown after follow-up ends.

Why is randomization important?

Randomization is intended to balance known and unknown prognostic factors, allowing the treatment groups to be compared without relying on observational adjustment.

Why is the endpoint timeframe important?

The registry specifies a timeframe of up to 5 years, defining the period over which the primary endpoint is assessed.

9. Limitations

No posted analyses: ClinicalTrials.gov does not report endpoint estimates, confidence intervals, or p-values for this trial.
Endpoint complexity: Resistance-based endpoints depend on clinical assessment and definitions of resistance thresholds.
Follow-up dependence: Interpretation of time-to-event outcomes depends on duration and completeness of follow-up.
Open-label design: The registry reports no masking, which may affect some aspects of treatment management or assessment.

10. Why This Trial Matters Statistically

Concept	Application in PIVOT
Randomized trial design	Two-arm randomized comparison
Time-to-event outcomes	Primary endpoint measured over up to 5 years
Censoring	Important for long-term follow-up analyses
Clinical endpoint definition	Resistance-based composite event definition