A single infusion of genetically modified immune cells may be enough to suppress HIV below the detection threshold for years. In a clinical trial, two participants remained HIV-free for 92 and 104 weeks after stopping daily medication following one infusion. Caring Cross presented these findings at the American Society of Gene and Cell Therapy annual meeting in Boston in May 2026.
38 million people take daily HIV pills
Since antiretroviral combination therapy was introduced in 1996, HIV is no longer an immediate death sentence. About 38 million people worldwide live with HIV according to UNAIDS. Modern antiretroviral therapy (ART) suppresses viral load below the detection threshold and protects the immune system. Life expectancy for HIV-positive people treated early now approximates the general population.
The central problem: ART must be taken daily, for life. Missing doses lets the virus return. For millions in low-income countries, this means not just logistical challenges but ongoing stigma. A therapy controlling HIV long-term without daily pills would be paradigm-shifting.
CAR-T cells originated in cancer therapy. The principle: T cells are taken from the patient, genetically modified in the lab to recognize specific target structures, then reinfused. The FDA approved the first CAR-T therapy in 2017 against certain leukemias. Today it is standard for several blood cancers. Caring Cross applies this principle to HIV.
Two patients: Virus undetectable beyond one year
Caring Cross's duoCAR-T variant carries two different receptors designed to recognize HIV-infected cells. The dual approach aims to prevent HIV from escaping via mutation of a single receptor.
In the Phase I/IIa trial with nine participants, three cohorts were tested. The first cohort, receiving no preparatory conditioning, showed no sustained benefit: all three experienced rapid viral rebound. In cohorts two and three, who received mild immune conditioning before CAR-T infusion, outcomes were markedly better.
According to Caring Cross, two patients remained undetectable for 92 and 104 weeks after stopping antiretroviral therapy. A third participant showed partial viral suppression for twelve weeks before rebound. No serious adverse events attributable to the CAR-T therapy occurred in any of the nine participants.
A shared characteristic of successful cases: all three patients had detected their HIV infection early and started ART immediately. This suggests a small HIV reservoir is prerequisite for therapy success. Those diagnosed and treated late have accumulated more dormant infected immune cells, harder for CAR-T cells to reach.
What the Berlin Patient and London Patient demonstrated
HIV is exceptionally difficult to cure because the virus hides as latent reservoir in dormant immune cells. The only complete cures so far came from allogeneic stem cell transplants for leukemia. Timothy Ray Brown, known as the Berlin Patient, became HIV-free after such a transplant in 2009. His donor carried a rare CCR5-gene mutation conferring natural HIV resistance. Similar cases followed: Adam Castillejo, the London Patient (2019) and a patient in Düsseldorf (2023).
These cures are real but not scalable. Stem cell transplant requires a life-threatening underlying disease, carries high risk, and demands a genetically matched donor with the rare CCR5-Delta32 mutation. The cases prove HIV is theoretically eliminable. They do not show the path for the 38 million HIV-positive people without leukemia.
CAR-T therapy is conceptually less invasive: the patient's own cells are extracted and reinfused. Caring Cross takes a different route. Whether it leads to durable remission requires longer observation. The Mississippi Baby, apparently cured in 2013, experienced viral rebound after three years. Viral suppression is not synonymous with cure.
Hundreds of thousands per patient: What future trials must clarify
A nine-person trial is very small. Rigorous claims about safety and efficacy demand Phase II and Phase III studies with far more participants. It remains unclear how long remission lasts in successful patients. Whether the virus returns after three or five years is presently unknown.
Manufacturing is a second issue. Individually crafted CAR-T products cost hundreds of thousands of dollars per patient for cancer indications. Such costs are scarcely bearable for global HIV use. Caring Cross is exploring whether standardized allogeneic CAR-T cells from healthy donors could be made more cheaply long-term.
Third, early diagnosis remains critical. Prior successes require early HIV detection and prompt therapy initiation. In sub-Saharan Africa, where need is greatest, early detection remains a gap. Advances in HIV testing infrastructure would be prerequisite for CAR-T therapies to reach full potential.