Doctors are saying that a third person’s HIV has been effectively cured, and there might be more soon.

Dr. Annemarie Wensing of the University Medical Center Utrecht, Netherlands, said that biopsies of the “Dusseldorf patient” show no signs of the virus after three months off HIV medication.

Twelve years ago, Timothy Ray Brown, also known as the Berlin patient, received a bone marrow transplant as treatment for leukemia and doctors later found that he was rid of the virus.

He had received bone marrow from a donor with a mutated gene for the CCR5 protein, which is found on white blood cells. HIV uses the protein to enter the cell, but it cannot attach to the mutated version.

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Earlier this week, researchers announced that they were able to cure the another person’s HIV. The “London patient” received a bone marrow transplant to treat his Hodgkin disease and was virus-free over a year after he stopped taking HIV medication.

The Dusseldorf patient also received a bone marrow transplant from a donor with the CCR5 mutation.

Around 22,000 people are known have the CCR5 mutation, and they are mostly northern European. Thirty-eight people living with HIV worldwide have received bone marrow from these donors and their progress is being tracked.

Bone marrow transplants cannot be used as a widespread cure for HIV because of the risk involved with the procedure, which can only be used as a last resort to treat cancer.

Still, researchers say that what they are learning from these patients is invaluable and could eventually provide gene therapy treatments for HIV.

“This will inspire people that cure is not a dream,” Wensing said. “It’s reachable.”