Maraviroc, the only therapeutic approved to block

Maraviroc, the only therapeutic approved to block CCR five as a treatment for HIV is a small molecule that has black box boards for liver, etc..

When the drug was first approved in the HIV community was excited that we now had a novel entry inhibitor that blocked CCR5 preventing HIV from entering and hijacking T cells. But HIV mutate at an extremely high rate and CCR5 is not the only receptor that HIV can use to enter a cell. It uses. Gp120 as a co-receptor with cCR5 to enter the cell which then hijacked the replicate itself into many more, virions and then those new viruses can move on to attack more T cells, which harm the immune system and eventually can lead to the death of the patient

But HIV also can use a receptor called CXCR4 and the limitation spoken about pro-140 and maraviroc are that when you block CCR5 HIV virus can mutate and the dominant form of HIV then becomes the one that uses CXCR4 not CCR5. This means that when you use pro 140 or Maraviroc you are only blocking CCR5 and HIV is not affected because it’s using CXCR4 to enter T cells and replicate

That’s a pretty wordy explanation, but hopefully it helps