Antisense medicines make use of the "BASE PAIRING"rule :
among the four bases which form the backbone of nucleic acids (DNA & RNA), adenine has an affinity for thymine (or uracil), & guanine for cytosine.
Antisense medicines, of which only one (cidofovir) was commercialized (for cytomegalovirus ocular infection in immunosuppressed patients), are mostly developed in oncology
