Daily Trimethoprim-sulfamethoxazole or Weekly Chloroquine Among Adults on ART in Malawi

Overview

The purpose of this study is to determine if there is a benefit to taking trimethoprim-sulfamethoxazole (TS) as prophylaxis among HIV positive adults who have viral load suppression and a good clinical response on anti-retroviral therapy (ART). If there is a benefit, then is it due to antimalarial or antibacterial properties. The investigators hypothesize that there will be a long-term benefit on survival and disease control in the context of prophylaxis and that the benefit will largely be attributed to prevention of malaria. The main study hypothesis is that 1)TS and chloroquine (CQ) will decrease the rates of morbidity and mortality among adults after 6 or more months of ART and 2) CQ prophylaxis will be associated with more prolonged viral suppression and higher CD4 cell counts than TS prophylaxis or no prophylaxis.

This is a randomized, controlled, open-label, phase III trial of standard of care TS prophylaxis and CQ prophylaxis compared to no prophylaxis in adults receiving ART. Adults who have been receiving ART for at least six months with a good clinical response and provide informed consent and fulfill the eligibility criteria will be randomized to one of three arms: (1) to continue standard of care trimethoprim-sulfamethoxazole (TS) prophylaxis, (2) discontinue standard of care TS prophylaxis and begin weekly CQ prophylaxis or (3) discontinue standard of care TS prophylaxis. Participants will be asked to return to the research clinic every four weeks for the first 24 weeks then every 12 weeks thereafter, and any time they are ill to facilitate both active and passive follow-up of the study endpoints. Participation will last for 32 to approximately 66 months. Participants who develop a WHO clinical stage 3 or 4 illness, experience a sustained decline in their CD4 count below 200 cells/mm3, or who experience ART failure will be placed on standard of care TS prophylaxis. Those with confirmed ART failure will be evaluated for second-line therapy according to the Malawi Ministry of Health guidelines. The study population will include up to 1500 Malawian adults aged 18 years or older living with HIV in or near Blantyre or Zomba, Malawi, Central Africa who have been receiving antiretroviral therapy for at least 6 months with good clinical response to ART, have an undetectable HIV viral load and a CD4 count \>250/mm3.