A regimen that includes CRISPR gene editing has eliminated HIV from the bodies of mice infected with the virus.

Antiretroviral drugs, which slow replication of HIV, have revolutionized AIDS treatment. But the drugs do not eliminate the virus from the body, and people who are infected must take the treatment for the rest of their lives.

Kamel Khalili at Temple University in Philadelphia, Pennsylvania, Howard Gendelman at the University of Nebraska Medical Center in Omaha and their colleagues treated HIV-infected mice with beefed-up antiretrovirals that suppress the virus longer than previous formulations. Special formulation meant that the drugs were released slowly into areas where HIV is known to lie latent. This dramatically reduced viral levels.

The scientists then injected 23 of the treated mice with a version of the CRISPR–Cas9 gene-editing system that was designed to snip HIV out of the genome. The virus eventually rebounded in 14 of the 23 mice, but remained undetectable in the other 9 even 8 weeks after treatment ended. Gene editing was able to eliminate HIV only after the drugs had suppressed the virus.