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Last updated 4/28/2020

Some individuals who initiate antiretroviral therapy (ART) experience limited recovery of CD4 T cell numbers despite suppression of HIV viral load to undetectable levels. The most common risk factors for this type of discordant response to ART are low CD4 T cell count at the time of starting and older age. Individuals in this situation still experience a benefit from ART in terms of a greatly reduced risk of opportunistic infections, illness and death, but their risk of these outcomes is higher than among people with greater CD4 T cell gains (for additional background see the webinar hosted by TAG on November 29, 2017 and our March 2018 Issue Brief).

A number of clinical trials are investigating approaches that might boost CD4 T cell recovery in individuals whose CD4 T cell counts remain relatively low despite viral load suppression. The purpose of this page is to provide a resource listing of these clinical trials, which will be updated on an ongoing basis.

Complete information on the trials is available from by clicking on the study title link.

COVID-19 Update: The clinical research featured in this listing is being significantly affected by the COVID-19 crisis. Trials that have yet to begin recruiting are likely to be delayed, and enrollment in many ongoing studies is being temporarily suspended. Research sponsors are typically making efforts to continue following current study participants by the safest means possible (e.g. remote contact) but in some cases administration of investigational interventions may be stopped or interrupted.

Probiotic Supplementation for Those Immune Non-responders With HIV-1 Infection
Peking Union Medical College Hospital, Beijing, China
ART for >2 years, CD4 cell count <350 for past 2 years, undetectable viral load for past 2 years

A Single Dose of Pembrolizumab in HIV-Infected People
National Institutes of Health Clinical Center, Bethesda, Maryland, United States
ART for >/= 12 months, CD4 cell count 100-350, viral load <40 copies/mL for >/= 12 month (single blip >40 copies/mL but <500 copies/mL allowed)

Rice Bran Supplementation in Treated HIV Infection (BRM4)
(closed to enrollment)

Rand Schrader Health and Research Clinic, Los Angeles, California, United States
ART for >24 weeks, CD4 cell count 100-350, viral load <50 copies/mL

Pyridostigmine as Immunomodulator in People Living With HIV
(suspended – due to COVID-19, effective 3/19/2020 recruitment is halted until further notice)
Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán
Tlalpan, Ciudad de México, Mexico
Stable ART for at least six months, at least two undetectable viral load determinations in the previous six months

Probiotic VSL#3 for Inflammation and Translocation in HIV II (PROOV IT II)
Maple Leaf Medical Clinic & Toronto General Hospital, Toronto, Ontario, Canada
ART for >2 years, CD4 T cell count <350 for last 2 years, viral load <50 copies/mL for the past 2 years (1 viral blip over 500 copies/ml permitted in the past year)

Blood Markers of Inflammation, Blood Clotting and Blood Vessel Function in HIV-infected Adults
National Institutes of Health Clinical Center, Bethesda, Maryland, United States
Observational study including a cohort with CD4 T cell count <300 cells after 2 years of effective combination ART with documentation of viral suppression

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