The present invention pertains to certain N.sup.8,N.sup.13-disubstituted quino[4,3,2-kl]acridinium salts of formula (Q.sup.-) which inhibit telomerase wherein: p is an integer from 0 to 4; q is an integer from 0 to 3; r is an integer from 0 to 4; each R.sup.A is --H or a ring substituent; each R.sup.B is --H or a ring substituent; each R.sup.C is --H or a ring substituent; R.sup.N8 is a nitrogen substituent; R.sup.N13 is a nitrogen substituent; and, Q is an anion. The present invention also pertains to pharmaceutical compositions comprising such compounds, and the use of such compounds and compositions, both in vitro and in vivo, to inhibit telomerase, to regulate cell proliferation, and in the treatment of proliferative conditions, such as cancer.