China's BD111 Is the Most Advanced Gene-Editing Therapy for Herpes in Humans

Chinese biotech company BDgene Therapeutics, based in Shanghai, has developed BD111, a gene-editing therapy using CRISPR-Cas9 technology to target and remove latent herpes simplex virus type 1 (HSV-1) DNA from infected nerve cells. The therapy employs a proprietary lentivirus-based mRNA delivery system designed to reach the trigeminal ganglion, where HSV-1 establishes lifelong latency.

In the first human study, published in 2023, three patients with severe, recurring herpes keratitis (an HSV-1 infection of the cornea) received a single injection. None had a recurrence during roughly 18 months of follow-up, and no off-target edits were found.

Three patients is a very small number, and the eye is easier to reach than the nerve ganglia where genital herpes hides. A 40-patient randomized trial is due to finish in December 2026.

BD111 delivers CRISPR in virus-like particles to cut viral DNA

BD111’s delivery system, based on virus-like particles carrying Cas9 mRNA and guide RNAs (called HELP, for HSV-1-erasing lentiviral particles),, enables retrograde transport from the cornea to the trigeminal ganglion. This allows the CRISPR-Cas9 components to excise the viral genome hidden within nerve cells, directly targeting the root cause of HSV-1 persistence and recurrence.

Unlike conventional antiviral drugs that only inhibit viral replication, BD111 aims to remove the latent virus by cutting its DNA. The therapy delivers Cas9 mRNA transiently, minimizing immune response and reducing the risk of off-target gene editing. To date, no significant off-target effects on the human genome have been detected.

It has US orphan drug status but no US trial

In June 2022, BD111 received orphan drug designation from the U.S. Food and Drug Administration (FDA), which facilitates accelerated development and review. As of mid-2026, however, BD111 remains in trials in China only, and no BDgene-sponsored trial has yet opened in the United States. The orphan drug designation still stands, but it has not yet translated into an active U.S. clinical program.

While several Western companies are developing gene-editing therapies for HSV, most remain in preclinical or early clinical stages. BD111 currently is the most advanced gene-editing treatment targeting HSV in humans.

A 40-patient Phase 2a trial completes in December 2026

Two BD111 trials are now running in China. A Phase I safety and preliminary efficacy study (NCT06474416) began in September 2023 and has an estimated completion date of March 2026. A larger, randomized, single-blind Phase IIa trial (NCT06474442), which began in April 2025, is enrolling 40 patients aged 18-70 with HSV-1 stromal keratitis and following them for 12 months; it targets primary completion in December 2026, with full study completion expected in March 2027.

Experts caution that further large-scale clinical trials are necessary to confirm long-term safety and efficacy, and formal Phase IIa efficacy results are not expected before late 2026 at the earliest. Additional challenges remain around manufacturing scalability and expanding treatment to HSV-2, responsible for genital herpes.

BDgene is actively expanding its research pipeline to include gene-editing therapies targeting HSV-2, although these efforts are still in early stages.

Eye infections are a stepping stone, not a genital herpes cure

Herpes keratitis is a good first target. The cornea can be injected directly, the virus there is HSV-1, and recurrences are easy to see and measure. It is also a leading infectious cause of blindness, so even a partial benefit matters.

Curing genital or oral herpes is harder. The editor would need to reach the sacral or trigeminal ganglia throughout the body and cut the virus in most infected neurons without harming them. Fred Hutchinson Cancer Center's meganuclease approach, which removed 90% or more of latent virus in mice, is designed for that problem but has not reached human trials.

If BD111's Phase 2a confirms fewer recurrences than the control group with no safety problems, it will be the first controlled evidence that gene editing can reduce herpes reactivation in people. For a wider view, see our herpes cure research update.