It very clearly prevents infection incredibly well, proof of that in the real world is exactly why there is excitement over this drug.
It also sounds as though you misunderstood the mechanism, it interferes in both an early and a late step in the viral process, there no theoretical reason to describe it as "not interfering with infection".
That implies that as long as the drug is present, the virus won’t be able to replicate, however as soon as the drug is no longer present the virus will start replicating. Because the cell has been infected.
Now, if replication is stopped, AND the body is able to destroy the first infected cell, then the patient is cured, but otherwise?
I guess that even if the body's immune system cannot get rid of that "patient cell zero", it is quite possible that a 6 month period is enough for the cell to die from the virus.
I do not have any medical training though, so please correct me if I am wrong.