Researchers have determined the dose of an injectable formulation of the integrase inhibitor cabotegravir (formerly GSK744) that will be taken into efficacy trials to see if it can be used for pre-exposure prophylaxis (PrEP). Studies in animals were presented earlier this year suggesting that drug levels stayed high enough in the body for it to be injected quarterly, and now studies of drug concentration in humans have confirmed that an 800mg intramuscular injection will be given once every twelve weeks in efficacy trials. Progress on an injectable formulation of another drug, rilpivirine, received a setback, however, when animal studies showed it lost its efficacy against viral challenge after only 18-21 days.
Would be easier to get somebody to visit their doctor for a quarterly injection than it would to get them to take a daily (or less frequent) pill at home? (Tipped by JMG reader Bill)