A Study to Assess the Efficacy of Raltegravir, Administered in Combination With Other Antiretroviral Drugs as Treatment for Adults and Older Adults Infected With the Human Immunodeficiency Virus 1 (HIV-1)(MK-0518-145 AM1) (Wirksamkeit Von Isentress® Unter Praxisbedingungen) (WIP)

• The proportion of participants with an HIV-1 viral load < 50 copies/mL after 48 weeks of Raltegravir treatment [ Time Frame: 48 weeks ] [ Designated as safety issue: No ]
• The proportion of aging participants with an HIV-1 viral load < 50 copies/mL after 48 weeks of Raltegravir treatment [ Time Frame: 48 weeks ] [ Designated as safety issue: No ]

• The proportion of participants with an HIV-1 viral load < 50 copies/mL after 96 weeks of Raltegravir treatment [ Time Frame: 96 weeks ] [ Designated as safety issue: No ]
• HIV-1 viral load in participants over a period of 96 weeks [ Time Frame: 96 weeks ] [ Designated as safety issue: No ]
• Change from Baseline in CD4+ T-cell counts over a period of 96 weeks [ Time Frame: Baseline and 96 weeks ] [ Designated as safety issue: No ]
• HIV-1 viral load in aging participants over a period of 48 weeks [ Time Frame: 48 weeks ] [ Designated as safety issue: No ]
• Change from Baseline in CD4+ T-cell counts in aging participants over a period of 48 weeks [ Time Frame: 48 Weeks ] [ Designated as safety issue: No ]
• Framingham Risk Scores for cardiovascular disease in aging participants and changes from baseline [ Time Frame: Baseline and 48 weeks ] [ Designated as safety issue: No ]
• Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) Risk Scores for cardiovascular disease in aging participants and changes from baseline [ Time Frame: Baseline and 48 weeks ] [ Designated as safety issue: No ]
• Number of aging participants with a comorbidity [ Time Frame: 48 weeks ] [ Designated as safety issue: No ]
• Number of aging participants taking a concomitant medication [ Time Frame: 48 weeks ] [ Designated as safety issue: No ]

• The proportion of participants with an HIV-1 viral load < 50 copies/mL 96 weeks of Raltegravir treatment [ Time Frame: 96 weeks ] [ Designated as safety issue: No ]
  The proportion of participants with an HIV-1 viral load < 50 copies/mL after 48 weeks of Raltegravir treatment will be determined, to be evaluated against an expected response rate of 45%
• Immunologic data regarding viral load count [ Time Frame: 96 weeks ] [ Designated as safety issue: No ]
  Immunologic data regarding viral load count will be evaluated for the 96 week treatment period, changes over time will be described
• Immunologic data regarding lymphocyte count [ Time Frame: 96 weeks ] [ Designated as safety issue: No ]
  Immunologic data regarding viral load count will be evaluated for the 96 week treatment period, changes over time will be described

This is an observational, non-comparative, multicenter, open-label study. Participants will be treated with Raltegravir according to standard clinical practice, and monitored over a total period of 96 weeks. In an extension to the study (Amendment 1), a new cohort of aging participants (≥ 50 years) will be recruited and monitored over a total period of 48 weeks. Participants who stop taking Raltegravir before the end of the 96-week period or 48-week period, respectively, will be followed up for 3 months after discontinuing the drug. The primary objective is to determine the proportion of participants with a human immunodeficiency virus (HIV)-1 viral load < 50 copies/mL after 48 weeks of treatment with Raltegravir.

Adults with confirmed HIV-1 infection

• Drug: Raltegravir
  Raltegravir, 400 mg, per oral (p.o.) twice daily (b.i.d.) for 48 weeks
  Other Name: ISENTRESS®
• Drug: Raltegravir
  Raltegravir, 400 mg, per oral (p.o.) twice daily (b.i.d.) for 96 weeks
  Other Name: ISENTRESS®

• HIV-1 infected participants
  Adults ≥18 years with confirmed HIV-1 infection
  Intervention: Drug: Raltegravir
• HIV-1 infected aging participants

  Adults ≥50 years with confirmed HIV-1 infection

  Newly enrolled aging participants - Amendment 1, plus participants from Cohort 1, who were ≥ 50 years of age at time of recruitment and who completed 48 weeks of treatment.

  Intervention: Drug: Raltegravir

Inclusion Criteria

The prospective participant must meet, at least, all of the criteria below to be eligible for study participation. The participant:

• Is a minimum age of 18 years (adults) or 50 years (aging participants);
• Is male or female;
• Has confirmed infection with HIV-1 (positive HIV test according to appropriate standard practice;
• Has commenced antiretroviral treatment with Raltegravir according to the recommendations made in the Summary of Product Characteristics at the time of enrollment on the study, or a maximum 6 months prior to enrollment on the study;
• Has any cluster of differentiation (CD4) cell (specialized white blood cell) count upon enrollment on the study.

Exclusion criteria

If the prospective participant meets any of the criteria below (among others determined by the study staff) they will NOT be eligible for study participation. The participant:

• For which Raltegravir, or its ingredients, are contraindicated;
• Has intolerance to Raltegravir, or its ingredients;
• If female, is pregnant, breastfeeding, or are planning a pregnancy or egg donation during the study.