Safety and Efficacy of a Switch to MK-1439A in Human Immunodeficiency Virus (HIV-1)-Infected Participants Virologically Suppressed on an Anti-retroviral Regimen in Combination With Two Nucleoside Reverse Transcriptase Inhibitors (MK-1439A-024)

Inclusion Criteria:

- Receiving antiretroviral therapy with a ritonavir- or cobicistat-boosted protease
inhibitor (atazanavir, darunavir, or lopinavir) or cobicistat-boosted elvitegravir or
a NNRTI (specifically, efavirenz, nevirapine, or rilpivirine) in combination with 2
NRTIs (and no other antiretroviral therapy) continuously for >= 6 months

- Receiving first or second retroviral regimen (participants receiving a NNRTI at
Screening must be on their first retroviral regimen)

- No history of using an experimental NNRTI

- Not receiving lipid lowering therapy or on a stable dose of lipid lowering therapy at
the time of enrollment

- Male or female participant not of reproductive potential or, if of reproductive
potential, agrees to avoid becoming pregnant or impregnating a partner while
receiving study drug and for 14 days after the last dose of study drug by complying
with one of the following: 1) practice abstinence from heterosexual activity, or 2)
use acceptable contraception during heterosexual activity

- For inclusion in the Extension Study (optional): completed the Week 48 visit;
considered to have derived benefit from study participation up to Week 48; considered
to be a clinically appropriate candidate for an additional 2 years treatment with
study drug

Exclusion Criteria:

- Uses recreational or illicit drugs or has a recent history of drug or alcohol abuse
or dependence

- Received treatment for a viral infection other than HIV-1, such as hepatitis B, with
an agent that is active against HIV-1 such as adefovir, emtricitabine, lamivudine, or
tenofovir

- Has documented or known resistance to study drugs including MK-1439, lamivudine,
and/or tenofovir

- Participated in a study with an investigational compound or device within 30 days or
anticipates doing so during the course of this study

- Used systemic immunosuppressive therapy or immune modulators within 30 days or
anticipates needing them during the course of this study (short courses of
corticosteroids will be allowed)

- Current, active diagnosis of acute hepatitis due to any cause (participants with
chronic hepatitis B and C may enter the study as long as they fulfill all entry
criteria, have stable liver function tests, and have no significant impairment of
hepatic function)

- Has evidence of decompensated liver disease or has liver cirrhosis and a Child-Pugh
Class C score or Pugh-Turcotte score >9

- Pregnant, breastfeeding, or expecting to conceive at any time during the study

- Female and is expecting to donate eggs or male and is expecting to donate sperm
during the study