I think ( and I believe JL said this also) the FDA didn't buy into the CCR5 immunomodulatory pathway being legitimate at the time, maybe still doesnt. This tends to a limitation of gov bureaucrats and why there is always this debate about innovation coming from the private sector and how much should the gov regulate. Being a no name biotech run by a guy like NP where there are no future job prospects for said FDA officials probably didnt help. With very sick patients, they also don't want to be blamed by the public for excess deaths by an unproven drug (ie. making a bad problem like severe covid worse) so they probably capped at 2 saying we should see improvement by then if it works. All bad decisions in hindsight.

Just my thoughts.