A 35-year-old Brazilian man who participated in a trial in which he received an intensified antiretroviral regimen plus supplemental vitamin B3 for 48 weeks has joined the short list of patients who have experienced a period of remission from HIV in the absence of effective treatment.
Along with the Mississippi baby, a San Francisco man, a 24-year-old Thai man, a 9-year-old South African child, and the London and Berlin patients, the Brazilian man has an undetectable viral load and, more than a year after stopping treatment, his HIV antibody test is negative.
But as with the Berlin and London patients, it seems unlikely that – even if the man remains HIV free into the future – the circumstances of his remission will be broadly applicable to other people with HIV, said Carl Dieffenbach, PhD, director of the Division of AIDS at the National Institute of Allergy and Infectious Diseases, National Institutes of Health.
“I don’t think it’s replicable,” Dieffenbach told Medscape Medical News. Researchers should still try to confirm the finding, but they will probably learn more by studying the man’s unique genetic characteristics and immune system “than to go out and treat another 200 people with the same protocol.”
The man had been on treatment since his HIV diagnosis in 2012, and was one of 30 people to enroll in a Brazilian study – the Multi Interventional Study Exploring HIV-1 Residual Replication: A Step Toward HIV Eradication and Sterilizing Cure – in 2016. At that point, his regimen consisted of the combination of efavirenz, lamivudine, and tenofovir disoproxil fumarate (Symfi, Mylan Pharmaceuticals) and his viral load was undetectable.
He was one of five people in the study to be randomized to receive the integrase inhibitor dolutegravir (Tivicay, ViiV Healthcare), the CCR5 receptor inhibitor maraviroc (Selzentry, ViiV Healthcare), and twice-daily nicotinamide 500 mg, a form of vitamin B3, in addition to his regular regimen for 48 weeks.
Nicotinamide has been used for decades because of its anti-infective properties, particularly in tuberculosis. In vitro, it also works to reverse HIV latency, said study investigator Ricardo Diaz, MD, from the Federal University of São Paulo, who presented the data at a press conference for the International AIDS Conference (AIDS) 2020.
“This is a shock-and-kill strategy,” said Leila Giron, PhD, from the Wistar Institute in Philadelphia, who was one of the study investigators. “We did in vitro studies to make sure nicotinamide took HIV out of the cells.”
“The cell machinery changed a lot,” she told Medscape Medical News. “And because it’s a B vitamin, all five participants didn’t have any side effects.”
But the patient was the only person in his treatment group to experience viral load “blips” during treatment – at weeks 16 and 24. And viral DNA was present at low levels in his peripheral blood spots and rectal tissue at baseline and at 48 weeks, and his HIV antibodies dropped from 91.8 RLU at baseline to 58.0 RLU at week 48.
“He had a decline in cell activation, inflammation, and a very deep decline in antibody titers,” Diaz reported.
After 48 weeks of the intensified treatment, the patient returned to his usual regimen for 3 years. Then, in March 2019, he agreed to try an analytical treatment interruption and discontinued all HIV treatment.
“What’s interesting is right before the analytical treatment interruption, the HIV DNA sequences were completely negative,” said Diaz.
Every 3 weeks for the next 64.7 weeks, his viral load came back undetectable, and so did HIV DNA in blood spots. One thing did change, though: in February 2020, the man’s HIV antibody test came back negative.
The team checked that he wasn’t still taking his antiretroviral medication, which might have explained the undetectable viral load, and he wasn’t.