In the UK, the main therapy is called PrEP or Pre-Exposure Prophylaxis. It generally has two drugs Tenofovir and Emtricitabine. These act as a catalyst to help the body create antibodies and blocks an enzyme that the virus needs to replicate, allowing the immune system to destroy the virus. It must be started within two days of a high risk event, like drug injection or unprotected sex. It then carries on for up to 28 days after the last exposure. PrEP is one pill a day and has few side effects. Once PrEP is started it prevents infection to others. I don't know if ART does the same or not.