The issue isn't necessarily the "associated side effects" but that the ZNF treatment that Sangamo has developed REQUIRES Cytoxan to produce a desired result. Therefore ZNF is not a standalone therapy. Many might not realize that Cytoxan seems to be a requirement that has it's own side effects, but that the dose that Sangamo is using in their trials is way more than Cancer patients receive if one has Cancer.
Sangamo has been suggesting that their therapy using ZFN could potentially be a "functional cure". But it might not be a "functional cure" as a standalone treatment. It is requiring the use of Cytoxan. This might mean for some that they would rather be on current therapy, rather than risking the side effects that Cancer patients do with Cytoxan. Why change a regiment that is working to keep HIV in check if one isn't switching to a functional cure that also wipes out the hidden HIV reservoirs?
The argument that many would like to be off medication and switch to something like this doesn't necessarily hold water. 1) cost. What would the cost be? Most likely higher than anything out on the market considering the necessity of using Cytoxan and ZFN at the same time. 2) Switching to something new, when what is already been proven successful in suppressing viral load might mean that a Cytoxan/ZFN approach might be a last resort, not first choice until there are hundreds of successful cases, 3) who makes the choice to switch and how do insurance companies deal with funding for such treatment when other less costly options are available?
The recent information provided by Sangamo concerning ZFN on HIV infected individuals indicates that they are using Cytoxan at various levels to determine what appropriate dose would work better than others in diminishing the T cell count in order to repopulate. The question I have is anyone concerned about the use of Cytoxan in that Cancer patients seem to usually get 40-50 mg/kg intravenously over 2-5 days in divided doses. Sangamo might be giving their 'higher' doses all at once. Although, Sangamo claims there is limited side effects from their approach, is this a concern that if Cytoxan is made a requirement in order for them to shortly there after provide the ZFN treatment, that many would opt not to take a drug associated with Cancer treatment, with the potential of chemo associated side effects?