Safety and Pharmacokinetics (PK) of Raltegravir in HIV (Human Immunodeficiency Virus)-Infected Children and Adolescents
Condition: HIV Infections
MeSH terms: HIV Infections
Study type: Interventional
Phase: Phase 1/Phase 2

Summary: 
      Integrase is 1 of 3 HIV (Human Immunodeficiency Virus)-1 enzymes required for viral
      replication. Raltegravir is a drug that prevents integrase from working properly. This drug
      has been tested for safety and efficacy in adults, but this is the first study to examine
      raltegravir in children and adolescents. The purpose of this study was to determine the
      appropriate dose for raltegravir across the pediatric age range from 4 weeks to 18 years of
      age, by acquiring short and long term safety data, intensive and population pharmacokinetic
      (PK) data, and efficacy experience with raltegravir in HIV-infected children and adolescents.
    

Detailed description: 
      Integrase is one of three enzymes necessary for HIV replication. Integrase allows for the
      integration of HIV DNA (deoxyribonucleic acid) into the human genome. Raltegravir is a strong
      and selective inhibitor of HIV integrase. In adults, raltegravir has shown significant
      antiretroviral activity in clinical trials and is well tolerated. The purpose of this study
      was to determine the appropriate dose for raltegravir across the pediatric age range from 4
      weeks (30 days) to 18 years of age, by acquiring short and long term safety data, intensive
      and population PK data, and efficacy experience with raltegravir in treatment-experienced,
      HIV-infected children and adolescents.

      The study consisted of two sequential Stages: I and II. The dose finding period of Stage I
      was intended to examine the pharmacokinetics and short term tolerability and safety of
      raltegravir in a limited number of participants to permit dose selection for further study in
      Stage II. The dose finding algorithm required a preliminary assessment of data from the first
      4 patients of each cohort (termed a "mini-cohort"). Failure to meet PK targets required dose
      adjustments, contingent upon the mini-cohort's dose having met safety criteria, followed by
      reassessment of safety and PK data from the new mini-cohort dose. When a mini-cohort dose had
      passed both safety and PK criteria, further accrual to and an assessment of results from the
      full cohort could occur. Again, failure to meet PK targets required dose adjustments
      contingent upon the full cohort's dose having met safety criteria with subsequent PK and
      safety evaluation of data from a new cohort taking the new dose.

      Chronic dosing, which includes Stage I extension (the period after Stage I dose finding) and
      Stage II (additional participants enrolled), was intended to provide longer term safety and
      antiviral activity data in a larger sample of participants. Participants accrued into Stage I
      and treated only at the dose ultimately selected for their cohorts were combined with those
      accrued into Stage II, where all patients received only the final selected doses for their
      respective cohorts. This group is denoted as the Final Dose Population, and results from this
      group are considered primary, since they reflect only the age-specific doses proposed for
      commercial use. The group with all participants exposed to raltegravir (at any dose) is
      denoted as the All Treated Population.

      Stage I lasted for a minimum of 48 weeks, Stage II was for 48 weeks, and a long-term
      follow-up period lasted for 5 years from initial exposure (i.e., 48 weeks of treatment plus 4
      years of follow-up). Participants were stratified by age and assigned to one of six cohorts.
      Participants in Cohort I were between the ages of 12 and 18 years and received poloxamer film
      coated raltegravir tablets. Participants in Cohort IIA were between the ages of 6 and 11
      years, weighed at least 25 kg, and received poloxamer film coated raltegravir tablets.
      Participants in Cohort IIB were between the ages of 6 and 11 years and received chewable
      raltegravir tablets. Participants in Cohort III were between the ages of 2 and 5 years and
      received chewable raltegravir tablets. Participants in Cohort IV were between the ages of 6
      months (defined as 180 days) and 23 months and received oral granules for suspension.
      Participants in Cohort V were between the ages of 4 weeks (defined as 30 days) and 5 months
      and received oral granules for suspension.

      Enrollment for Stage I of this study began with Cohort I and progressed to the other cohorts
      once preliminary dosage had been determined and safety data were reviewed. When this
      information had been determined for Cohort I, Cohorts IIA and IIB began enrollment. Once
      safety and dose data for these cohorts were reviewed, enrollment into Cohort III began. Once
      safety and dose data for Cohort III were reviewed, enrollment into Cohort IV began and once
      safety and dose data for Cohort IV were reviewed, enrollment into Cohort V began.

      During Stage II of this study, participants took raltegravir at the dosage determined as safe
      and reaching PK targets based on the the Stage I data. The purpose of Stage II was to
      determine long-term safety of raltegravir once a safe dose meeting PK targets has been
      determined.

      Participants whose Stage I dose was different from the dose determined for Stage II and who
      had not had individual dose adjustments because of extreme PK values had their raltegravir
      dose changed to the selected Stage II dose once it was determined. If individualizing the
      dose for participants in this manner resulted in a dose increase, these participants had an
      additional safety visit 4 weeks after the dose modification, and then continued on study
      visits with no further changes in the visit schedule.

      There were at least 9 study visits for participants in this study, occurring during the
      48-week raltegravir treatment period. For participants who completed 48 weeks of study and
      appeared to have benefited from receiving study drug, raltegravir was provided until five
      years after initial raltegravir exposure. For participants who opted to continue on
      study-provided raltegravir, extended provision of drug was implemented as part of a protocol
      extension involving visits every 4 months for five years after initial raltegravir exposure.
      Participants who did not continue on study-provided raltegravir were followed with annual
      visits for five years after initial raltegravir exposure (i.e. 48 weeks of raltegravir
      treatment plus 4 years follow-up). At each visit, a physical exam, blood collection, and
      determination of treatment adherence occurred. At some visits, urine collection and Tanner
      staging occurred. Selected cohorts underwent a taste evaluation at 1 of 2 visits.
      Participants aged 2 to less than 6 years of age were asked to participate in an additional PK
      substudy in which blood was collected two times over a 12-hour visit (or, if more convenient,
      this assessment may have been completed in 2 separate visits) in order to collect additional
      Cmin PK data. Participants were re-registered into the same cohort if a dose change was
      recommended.

      Current pediatric Food and Drug Administration approval and dosing recommendations are based
      upon evaluations in 122 Final Dose participants aged ≥4 weeks to 18 years enrolled in this
      study.

      The results present safety and efficacy results of the complete 5 year follow up data
      (primary and key secondary endpoints) of the participants from IMPAACT P1066, the Final Dose
      Population. By the date on which most of the data were frozen, 24 July 2017, all participants
      enrolled had Week 24 data (i.e., had either completed the Week 24 visit, or, for those who
      discontinued before Week 24, had the potential to have experienced the Week 24 visit), had
      also completed (or had the potential to have experienced) the Week 48 visit, and had either
      completed 240 weeks of study and were subsequently taken off study, or had prematurely
      discontinued study and were no longer in follow up.
    

Intervention name(s): Raltegravir poloxamer film coated tablet; Raltegravir chewable tablet; Raltegravir oral granules for suspension (20 mg/mL); Raltegravir poloxamer film coated tablet
Intervention type(s): Drug; Drug; Drug; Drug
Intervention description(s): Final Selected Dose: 400-mg tablet taken orally twice daily.; Final Selected Dose: Weight based dose of ~6 mg/kg according to the dosing table, to a maximum dose of 300 mg, taken orally twice daily.; Weight based dose of ~6 mg/kg orally every 12 hours according to dosing table in protocol or the dose determined by review of all available data.; Final Selected Dose: 400-mg tablet taken orally twice daily for participants weighing at least 25 kg. Participants < 25 kg were switched to a weight-based dose of the chewable tablet.
Other intervention name(s): Isentress; Isentress; Isentress; Isentress
Intervention MeSH terms: Raltegravir Potassium
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment