His doctors found a donor with a gene mutation that confers natural resistance to HIV.
Dr. Gero Hutter, the German doctor who treated Brown, called the new case "great news" and "one piece in the HIV cure puzzle".
Both milestones resulted from bone-marrow transplants given to infected patients.
Gupta described his patient as "functionally cured" and "in remission", but cautioned: "It's too early to say he's cured".
It may have been 12 years since the famous 'Berlin patient' made history by becoming the first person to sustain HIV-1 remission without receiving anti-retroviral (ARV) drugs, but the newly announced case of an anonymous male British patient demonstrates the first result was not unique.
The man, who was not identified, was diagnosed with HIV - the virus that causes AIDS - in 2003, according to the findings published by the journal Nature.
To learn more about the factors that favor a cure, amfAR, the Foundation for AIDS Research, a New York City-based foundation, in 2014 began to fund a consortium of worldwide researchers who do transplants in HIV-infected people with blood cancers.
An HIV-positive man in Britain has become the second known adult worldwide to be cleared of the AIDS virus after he received a bone marrow transplant from an HIV resistant donor, his doctors said. The team also found that his white blood cells now can not be infected with CCR5-dependent HIV strains, indicating the donor's cells had engrafted.
"At the moment, the only way to treat HIV is with medications that suppress the virus, which people need to take for their entire lives", said Gupta.
He was placed in an induced coma at one point and almost died.
CCR5 is the most commonly used receptor by HIV-1.
He underwent a so-called haematopoietic stem cell transplant in 2016 from a donor with two copies of a CCR5 gene variant, a combination carried by about one percent of the world population.
The vast majority of people who express the CCR5 mutation live in Northern Europe, and there aren't many of them. He has now been in remission for 18 months, and regular testing has confirmed that his HIV viral load remains undetectable.
"Coming 10 years after the successful report of the Berlin Patient, this new case confirms that bone marrow transplantation from a CCR5-negative donor can eliminate residual virus and stop any traces of virus from rebounding". After two bone marrow transplants, Brown was considered cured of his HIV-1 infection.
"The second case strengthens the idea that a cure is feasible", Sharon R Lewin, director of the Peter Doherty Institute for Infection and Immunity and the University of Melbourne, told AFP. They also plan to present details in Seattle at the Conference on Retroviruses and Opportunistic Infections, which began Monday.
Compared to Brown, the London patient had a less punishing form of chemotherapy to get ready for the transplant, didn't have radiation and had only a mild reaction to the transplant.