Sitagliptin for Reducing Inflammation and Immune Activation

The purpose of the study is to evaluate whether sitagliptin (Januvia is the brand name for sitagliptin) reduces inflammation and immune activation markers in HIV-infected men and women when compared to a placebo (inactive medication like a dummy pill). The study evaluated whether taking 100 mg of sitagliptin by mouth daily for 16 weeks is safe and effective for HIV-infected persons on antiretroviral therapy (ART) who do not have diabetes. Sitagliptin is a medication that is used to treat people with diabetes (high blood sugar) but also may reduce inflammation in the body.

ACTG A5346 is a phase II, randomized, double-blinded, placebo-controlled, trial of sitagliptin 100 mg vs. placebo for 16 weeks followed by a 4-week post-intervention follow-up. A5346 studied whether sitagliptin reduced plasma concentrations of sCD14 in HIV-infected men and women ≥18 years of age who were on suppressive ART with HIV-1 RNA below the limit of quantification at screening and for at least the prior 48 weeks. Participants were randomized 1:1 to Sitagliptin arm vs. Placebo arm, and were stratified by screening CD4 count (100-350 vs. \>350 cells/mm\^3) and statin use (on statins vs. not on statins).

Eligibility Criteria:
Inclusion Criteria:

* Documented HIV-1 infection.
* Currently on an antiretroviral regimen consisting of at least 2 NRTIs and either a protease inhibitor boosted with low dose ritonavir, an integrase inhibitor, or an NNRTI. (Other ART regimens may be acceptable. Sites must consult the protocol team for approval)
* Currently on continuous ART for ≥48 weeks prior to study entry with no interruption longer than 7 consecutive days during that period.
* Plasma HIV-1 RNA levels below 75 copies/mL for at least 48 weeks prior to study entry. The participant must have a minimum of two values in the last 48 weeks obtained \>30 days apart, with the most recent value obtained within 90 days prior to entry. (Single determinations that are between the assay quantification limit and 500 copies/mL (i.e., "blips") are allowed as long as the preceding and subsequent determinations are below the level of quantification).
* CD4+ cell count ≥100 cells/mm\^3 obtained within 90 days prior to study entry.
* The following laboratory values obtained within 90 days prior to entry.

  * Absolute neutrophil count (ANC) ≥750/mm\^3
  * Hemoglobin ≥8.0 g/dL
  * Platelet count ≥50,000/mm\^3
  * Calculated creatinine clearance (CrCl) ≥60 mL/min as estimated by the Cockroft-Gault formula NOTE: Calculation for the Cockcroft-Gault equation is available at https://www.fstrf.org/apps/cfmx/apps/common/Portal/index.cfm
  * Aspartate aminotransferase (AST) (SGOT) ≤5 x upper limit of normal (ULN).
  * alanine aminotransferase (ALT) (SGPT) ≤5 x ULN.
  * alkaline phosphatase ≤5 x ULN.
  * Total bilirubin ≤2.5 x ULN (if the participant is receiving atazanavir, a total bilirubin of ≤5 x ULN is acceptable).
  * Hemoglobin A1C ≤6.5%
* For females of reproductive potential, adequate contraception.
* Karnofsky performance score ≥70 within 90 days prior to entry.
* Ability and willingness of participant or legal guardian/representative to provide informed consent.
* Participants on statin therapy must be stable on the same dose for at least the prior 12 weeks with no anticipated change in statin or dose during the intervention.

Exclusion Criteria:

* Change in the ART regimen within the 12 weeks prior to study entry, or anticipated/intended modification of ART during the study period.
* Two or more HIV-1 RNA determinations \>200 copies/mL within the 48 week period prior to study entry.
* History of clinical pancreatitis or diabetes mellitus diagnosed by a medical provider.
* Acute or chronic liver disease with evidence of cirrhosis or portal hypertension.
* Chronic hepatitis C (defined as HCV antibody positive and HCV RNA detectable).
* History of chronic hepatitis B (defined as surface antibody negative, surface antigen positive, and/or HBV DNA detectable).
* Use of any immunomodulator, HIV vaccine, investigational therapy, or anti-TNF therapies within 90 days prior to study entry.
* Active malignancy with expected need for systemic chemotherapy or radiation therapy during the study period.
* Use of human growth hormone, tesamorelin, testosterone or anabolic steroids within 90 days prior to study entry (except chronic, stable, replacement dosages in men with diagnosed hypogonadism is allowed).
* Pregnant or breastfeeding.
* Use of any anti-diabetic medication or GLP-1 analogues within the 12 weeks prior to study entry.
* Current diagnosis of congestive heart failure.
* Known allergy/sensitivity or any hypersensitivity to components of the study drug or its formulation.
* Active drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements.
* Acute or serious illness requiring systemic treatment and/or hospitalization within 90 days prior to entry.