A 27-year-old man diagnosed with both HIV/AIDS and leukemia in 2016 was treated with a new CRISPR-based therapy intended to cure both diseases, STAT reported. A team of scientists led by Deng Hongkui of Peking University treated the patient 19 months ago and detailed their findings in the New England Journal of Medicine on Wednesday. 

Why it matters: Although the treatment failed to eliminate HIV from the patient’s cells, his leukemia is in remission and he didn’t suffer from any side effects despite concerns that the therapy could trigger cancer or other genetic damage.   

  • Both the scientists involved in the study and outside observers see the results as an indication that CRISPR-based therapies are safe. 
  • According to Deng, the CRISPR did not go rogue and eliminate any unintended targets. 

“They attempted a moonshot, and while they did not land on the moon, they got back home safely… they highlighted how to get to the moon.”

—Fyodor Urnov of the Innovative Genomics Institute at the University of California, Berkeley to STAT

Details: Despite their patient having already received standard AIDS treatment and chemotherapy for his leukemia, Deng and his team saw an opportunity to test an experimental AIDS therapy that incorporates CRISPR-edited stem cells into a standard leukemia-treating bone marrow transplant. 

  • The treatment is based on a patient who was cured of both AIDS and leukemia after receiving a bone marrow transplant from a donor with a mutation in their CCR5 gene that blocks a common form of HIV from infecting cells. 
  • Deng’s team used CRISPR to disrupt the CCR5 genes of a healthy marrow donor, then proceeded with the transplant. 
  • Only about 17.8% of the targeted cells were successfully edited, and over time, only 5.2% to 8.28% of the new bone marrow cells generated by the patient showed the CCR5 edit. 
  • While the patient’s leukemia went into remission after the bone marrow transplant, his HIV persisted, indicating that the concentration of edited cells was not sufficient to successfully control the disease. 

Context: The multibillion-dollar CRISPR industry has exploded with big claims and controversial research in the first few years of its existence. While this is the first time CRISPR has been used in a combination treatment for HIV/AIDS and cancer, scientists have previously targeted the CCR5 gene as a potential path toward a HIV cure. 

  • Sangamo Therapeutics explored the potential of another genetic technology called zinc fingers to edit CCR5 and treat HIV but has since transitioned to study sickle cell disease.
  • Deng’s study follows up on an earlier one where his team injected mice with CCR5-edited human cells, making them resistant to HIV. 
  • He Jiankui’s controversial experiment involving CRISPR-edited human embryos was also intended to induce HIV resistance but sparked international condemnation due to the ethically questionable nature of the experiment. 

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