BALTIMORE — HIV patients who received a CRISPR-based gene editing treatment developed by Excision BioTherapeutics saw the virus rebound, and now the company is going back to the lab to develop the experimental treatment with a new vector.
In Excision’s Phase 1 study, five patients received a gene editing therapy for HIV. Three patients were taken off their standard antiretroviral therapy, but then had to return to standard treatments, according to clinical trial results shared Friday at the American Society of Gene & Cell Therapy’s annual meeting in Baltimore.
Two of the three patients saw no meaningful suppression of the virus, rebounding at three and four weeks. The third patient saw delayed viral rebound for 16 weeks before returning to standard antiviral treatment. The company said that’s a signal of the treatment’s potential.
Antiretroviral therapy can stop HIV from actively reproducing, but it can’t get rid of the viral DNA that has integrated into a person’s cells, making the disease difficult to cure. Excision’s gene editing treatment was an attempt to cure the disease by using CRISPR to slice out HIV DNA that has interspersed itself across a patient’s cells.
So far, the HIV field has seen very little success with attempts to cure the disease. Researchers believe that a very long-acting therapy could act like a functional cure, especially when compared to current treatments that have to be taken regularly.
“It’s really hard,” said lead investigator Rachel Presti of the Washington University School of Medicine in St. Louis. “But there’s a lot more movement in the field now.”
In the five patients treated, Excision’s therapy appeared safe with no serious side effects.
One patient did not meet the criteria to be taken off their antiretroviral therapy, and the researchers are awaiting efficacy results from another patient in the second treatment cohort, after which the trial will be completed.
Excision is pivoting to a next-generation vector that it hopes will be more effective. CEO Daniel Dornbusch did not provide a timeline for when the company would put the next iteration of the therapy into human trials, saying it depended on several factors, including discussions with the FDA.