As a new wave of interest in HIV therapeutic vaccines hits the biotech world, a team of Spanish researchers claims to have developed such a vaccine that temporarily halts the growth of the HIV virus in patients.
The study, published in Science Translational Medicine, tested 36 individuals carrying the virus. After 12 weeks of the trial, the HIV viral load plummeted by more than 90% among 12 of the 22 patients who received the vaccine, the study says. But after 24 weeks, the effectiveness weakened, with only 7 of the 20 remaining patients receiving the vaccine showing that same 90% drop in viral load. The vaccine lost all effectiveness after a year.
Still, the drug proved promising against a control injection. And the researchers noted the results paralleled those achieved with a single antiretroviral drug--the standard form of care for HIV-positive 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," Felipe Garcia, one of the scientists in the team at Barcelona University's Hospital Clinic, said in a statement. The researchers spent about 7 years getting to this point, and will spend the next 3 to 4 years improving the vaccine.
Why pursue a therapeutic vaccine? A successful one would free patients from taking multiple antiretroviral drugs daily. Patients must take those drugs 95% of the time for them to work effectively, yet adherence rates hover around 70%. Several biotech companies, such as Argos Therapeutics and Bionor, are working on HIV therapeutic vaccines. Therapeutic vaccines aim to prevent the disease when a patient isn't on drugs by identifying and eliminating the HIV-infected cells that crop up and continue to do damage. And the ultimate goal always remains eliminating the virus entirely with a cure.
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