“It is the most solid demonstration in the scientific literature that a therapeutic vaccine is possible,” the team said in a statement.
According to their study, published Wednesday in Science Translation Medicine, the results of the vaccine were the best yet recorded for such a treatment.
Tested on 36 patients infected with the virus, the vaccine treats an existing disease rather than preventing it and is based on immune cells exposed to HIV that have been inactivated with heat. The study says the therapeutic vaccine was safe and led to a dramatic drop in the amount of HIV virus detected in some patients.
“What we did was give instructions to the immune system so it could learn to destroy the virus, which it does not do naturally,” said Felipe Garcia, one of the scientists in the team at Barcelona University’s Hospital Clinic.
With results similar to those achieved with a single anti-retroviral drug, the vaccine allowed patients to live temporarily without taking multiple medicines on a daily basis.
The AFP reports:
After 12 weeks of the trial, the HIV viral load dropped by more than 90 percent among 12 of the 22 patients who received the vaccine. Only one among the 11 patients who received a control injection without the vaccine experienced a similar result.
After 24 weeks, the effectiveness had begun to decline, however, with seven of the 20 remaining patients receiving the vaccine enjoying a similar 90-percent slump in viral load. No-one in the control group of 10 patients experienced such a decline in the virus.
The vaccine lost its effectiveness after a year, when the patients had to return to their regular combination therapy of anti-retroviral drugs.
“This investigation opens the path to additional studies with the final goal of achieving a functional cure — the control of HIV replication for long periods or an entire life without anti-retroviral treatment,” the researchers said in a statement. “Although we still have not got a functional cure, the results published today open the possibility of achieving an optimal therapeutic vaccine, or a combination of strategies that includes a therapeutic vaccine, and could help to reach that goal.”