EATG » CROI 2019: London patient in long-term HIV remission after stem cell transplant

CROI 2019: London patient in long-term HIV remission after stem cell transplant

A London man has no remaining detectable HIV a year and a half after undergoing a bone marrow stem cell transplant to treat lymphoma, researchers are reporting this week at the Conference on Retroviruses and Opportunistic Infections (CROI 2019) in Seattle.

Ravindra Gupta, now at the University of Cambridge, will present the case on Tuesday, but after a premature embargo break many media outlets reported the findings in advance, with some suggesting that the case represents a second HIV cure, similar to that of Timothy Ray Brown, known as the ‘Berlin patient’.

Brown – the first and so far only person known to have been cured of HIV – received two stem cell transplants to treat leukaemia in 2006. The donor had double copies of an uncommon gene mutation known as CCR5-delta-32 that results in missing CCR5 co-receptors on T cells, the gateway most types of HIV use to infect cells. He underwent intensive conditioning chemotherapy and whole-body radiation to kill off his cancerous immune cells, allowing the donor stem cells to rebuild a new HIV-resistant immune system.

As described at the 2007 CROI, Brown stopped antiretroviral therapy at the time of his first transplant but his viral load did not rebound. Researchers extensively tested his blood, gut, brain and other tissues, finding no evidence of replication-competent HIV anywhere in his body. This week Brown celebrated 12 years free of HIV at a community cure workshop prior to the conference.

Other attempts to discontinue antiretroviral therapy in HIV-positive bone marrow transplant recipients have been less successful. Timothy Henrich, now at the University of California at San Francisco, and colleagues attempted to reproduce Brown’s cure in two cancer patients in Boston, but in those cases the donors had normal or ‘wild-type’ stem cells that remained susceptible to HIV, they received less intensive chemotherapy and they stayed on antiretroviral therapy.

After no HIV could be detected in their blood and tissues for years, the men underwent closely monitored treatment interruptions. Although their HIV remained in remission longer than expected – for three and eight months – eventually their virus returned, showing that the stem cell transplant process itself is not enough to eradicate HIV. More recently, researchers reported that a bone marrow transplant recipient in Minnesota had viral remission lasting nearly 10 months after an analytic treatment interruption, but he too ultimately experienced viral rebound.

The so-called ‘London patient’, who remains anonymous, underwent stem cell transplantation to treat Hodgkin lymphoma in May 2016. Like Brown, his donor had a double CCR5-delta-32 mutation.

The man continued on his antiretroviral regimen of dolutegravir (Tivicay), rilpivirine (Edurant) and lamivudine. He also received less aggressive conditioning chemotherapy (lomustine, cyclophosphamide, cytarabine and etoposide), alemtuzumab (Campath, a monoclonal antibody that targets CD52 on malignant B and T cells), and cyclosporine-A and methotrexate, immunosuppressive drugs used to prevent graft-versus-host disease (when transplanted immune cells attack the recipient’s body).

The transplant led to complete lymphoma remission and testing showed that the man’s CD4 T cells now lack CCR5 receptors. Extensive testing of blood plasma and T cells revealed undetectable HIV and his HIV-specific antibody level also dropped. About 10 weeks post-transplant he developed mild graft-versus-host disease, which resolved on its own. He also experienced reactivation of pre-existing Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection, which were treated.

The man stopped antiretroviral therapy in an analytic treatment interruption 17 months after the transplant. His blood viral load remains undetectable 18 months later, no HIV DNA can be found in peripheral CD4 cells using a sensitive assay with a 1 copy/ml limit and tests showed no “reactivatable” virus in 24 million resting T cells. One blood sample revealed bits of viral genetic material, which may reflect laboratory contamination or defective virus that is unable to replicate. Unlike Brown, the London patient has not yet undergone testing for residual HIV in his gut and other tissues.

These findings demonstrate that “the Berlin patient was not an anomaly,” the researchers said. What’s more, this current case shows that remission can happen without harsh conditioning chemotherapy or radiation. While this appears to be the second longest adult HIV remission yet observed, they acknowledge that “it is premature to conclude that this patient has been cured.”

A poster presented at CROI described another case of long-term HIV remission after a stem cell transplant from a donor with a double CCR5-delta-32 mutation. This patient, treated in Dusseldorf, underwent the procedure in February 2013 to treat acute myeloid leukemia. The man remained on antiretroviral therapy with undetectable viral load until November 2018. Extensive testing showed no viral DNA in his bone marrow, gut tissue samples rectal tissue samples or lymph nodes. The Dusseldorf patient stopped antiretroviral therapy in November 2018, still has undetectable HIV and is undergoing continued monitoring.

Experts caution that even if CCR5-delta-32 stem cell transplantation can lead to a functional cure of HIV, this high-risk procedure will not be an option for most people. Stem cell transplantation is life-threatening – Brown nearly died during the process and was left with lasting side-effects. However, this new case adds to the evidence that using gene therapy to delete CCR5 receptors from T cells may be a feasible approach.

“This is not a treatment appropriate for people with HIV who do not have cancer,” the Treatment Action Group said in a statement. “The hope is that lessons can be learned to help develop more widely applicable therapeutic approaches for attaining HIV remissions or cures.”

By Liz Highleyman

References

Gupta RK et al. Sustained HIV-1 remission following homozygous CCR5 delt32 allogeneic HSCT. Conference on Retroviruses and Opportunistic Infections, Seattle, abstract 29 LB, 2019.

Gupta RK et al. HIV-1 remission following CCr5Δ32/Δ32 haematopoietic stem-cell transplantation. Nature, 2019.

Jensen BO et al. Analytic treatment interruption (ATI) after allogeneic CCR-D32 HSCT for AML in 2013. Conference on Retroviruses and Opportunistic Infections, Seattle, abstract 394 LB, 2019.

 

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News categories: Cure, CROI 2019