Hi Aladin,
CRISPR is a gene editing technique. With it, you can change a part of your genome that is identified as causing problems ( see at
https://www.webmd.com/cancer/crispr-facts-overview#1 )
So, in order for it to be useful in POIS, or in any condition, you had to first identify a defective gene causing the condition. In the current state of POIS research, we are far from there.
CRISPR is, however, a real hope, in the long term, for those conditions like cystic fibrosis for which a responsible gene mutation had already been identified. The first conditions that will be successfully treated with CRISPR will probably be conditions that are linked to a single gene defect, like sickle cell disease (
https://en.wikipedia.org/wiki/Sickle_cell_disease ). If a condition is caused by a set of different defective genetic mutations, than to fix this with CRISPR will be a far more complicated process.
So, for POIS, first step is research of the possible cause(s).