Phosphorodiamidate morpholino oligomers (PMOs) and peptide-conjugated PMOs (PPMOs) are emerging oligonucleotide therapeutic modalities that offer unique opportunities for targeted treatment approaches. 

PMOs contain a charge-neutral morpholino backbone that provides increased nuclease stability, while PPMOs are designed by conjugating a cell-penetrating peptide to a PMO to enhance cellular uptake and tissue delivery.