It's one of two things. It could be SUW133 is not sufficiently flushing out the HIV reservoirs which is less likely given that simply the addition of NKT cells doubled the effectiveness. Much more likely that the combination of HAART and NKT is not killing off all of the HIV virus leading to continued infection and the establishment of new reservoirs.

With SUW133, NKT cells and leronlimab you'd have the flushing of reservoirs, increased virus death from the NKT cells and blockade of CCR5 stopping reinfection. From what I've read a high CCR5 blockade can also heighten immune response and help kill off the virus.