Doctors in Barcelona, Spain, announced earlier this month that they believe they’ve found a cure for HIV, according to the Latin Post. But don’t hold your breath, it’s not going to be available overnight.

Similar to the report published by Harvard researchers, the Spanish research team hypothesize that a blood transplant from a donor with a genetic mutation could prevent HIV from entering cells and replicating.

The announcement is based on results of an experimental treatment given to a 37-year-old man who contracted HIV in 2009. The “Barcelona Patient” developed lymphoma in 2012. He received chemotherapy and a transplant of blood from an umbilical cord of a donor who had a genetic mutation that gave the donor a heightened resistance to HIV.

“We suggested a transplant of blood from an umbilical cord but from someone who had the mutation because we knew from ‘the Berlin patient’ that as well as [ending] the cancer, we could also eradicate HIV,” Rafael Duarte, the director of the Haematopoietic Transplant Programme at the Catalan Oncology Institute in Barcelona, explained to Spanish news site The Local.

People with the CCR5 Delta 35 genetic mutation that leaves them without CCR5 cellular receptors, which act like doorways to the cell. HIV uses CCR5 receptors to enter white cells for replication. This heightened resistance to HIV occurs in about 1 percent of the population.

The Spanish medical team sought to replicate the results of Timothy Brown, an HIV-positive man dubbed “the Berlin Patient,” who received an experimental bone marrow transplant from a donor with the mutation. Brown had leukemia and HIV but six years later shows no signs of the virus.

The treatment seemed to work, as the Barcelona Patient was HIV free after three months, but unfortunately died due to cancer. The development spurred Spain’s National Transplant Organization to back the world’s first clinical trials of umbilical cord blood transplants for HIV patients with blood cancers, according to the Latin Post. Javier Martínez, a virologist from the research foundation Irsicaixa, is quoted as saying that while their trials are aimed at helping HIV-positive cancer patients but it could “allow us to speculate about a cure for HIV.”