The present invention relates to compounds of formula (I): ##STR1## as well as the salts or solvates thereof, to pharmaceutical compositions containing them, to a process for preparing them and to synthetic intermediates in this process.

Drug and multidrug resistant modulators of the formula: ##STR1## where R.sup.1 and R.sup.2 are independently hydrogen or halo; A is --CH.sub.2 --CH.sub.2 --, --CH.sub.2 --CHR.sup.4 --CH.sub.2 --, or --CH.sub.2 --CHR.sup.5 --CHR.sup.6 --CH.sub.2 --, where R.sup.4 is --H, --OH, or acyloxy; one of R.sup.5 or R.sup.6 is --H, --OH, or acyloxy, and the other is --H; R.sup.3 is a polyaryl; and pharmaceutically acceptable salts and solvates thereof, are described and claimed. Use of the new compounds in the preparation of pharmaceutical compositions is described and claimed. In addition, methods for treating drug and multidrug resistance in various diseases using a compound, or pharmaceutically acceptable salt or solvate thereof, of this invention are described and claimed. Also, methods of enhancing oral bioavailability of a drug and methods of enhancing bioavailability of a drug to the brain using a compound, or pharmaceutically acceptable salt or solvate thereof, of this invention are described and claimed.

Drug and multidrug resistant modulators of the formula: ##STR1## where R.sup.1 and R.sup.2 are independently hydrogen or halo; A is --CH.sub.2 --CH.sub.2 --, --CH.sub.2 --CHR.sup.4 --CH.sub.2 --, or --CH.sub.2 --CHR.sup.5 --CHR.sup.6 --CH.sub.2 --, where R.sup.4 is --H, --OH, or acyloxy; one of R.sup.5 or R.sup.6 is --H, --OH, or acyloxy, and the other is --H; R.sup.3 is a polyaryl; and pharmaceutically acceptable salts and solvates thereof, are described and claimed. Use of the new compounds in the preparation of pharmaceutical compositions is described and claimed. In addition, methods for treating drug and multidrug resistance in various diseases using a compound, or pharmaceutically acceptable salt or solvate thereof, of this invention are described and claimed. Also, methods of enhancing oral bioavailability of a drug and methods of enhancing bioavailability of a drug to the brain using a compound, or pharmaceutically acceptable salt or solvate thereof, of this invention are described and claimed.

Drug and multidrug resistant modulators of the formula: ##STR1## where R.sup.1 and R.sup.2 are independently hydrogen or halo; A is --CH.sub.2 --CH.sub.2 --, --CH.sub.2 --CHR.sup.4 --CH.sub.2 --, or --CH.sub.2 --CHR.sup.5 --CHR.sup.6 --CH.sub.2 --, where R.sup.4 is --H, --OH, or acyloxy; one of R.sup.5 or R.sup.6 is --H, --OH, or acyloxy, and the other is --H; R.sup.3 is a polyaryl; and pharmaceutically acceptable salts and solvates thereof, are described and claimed. Use of the new compounds in the preparation of pharmaceutical compositions is described and claimed. In addition, methods for treating drug and multidrug resistance in various diseases using a compound, or pharmaceutically acceptable salt or solvate thereof, of this invention are described and claimed. Also, methods of enhancing oral bioavailability of a drug and methods of enhancing bioavailability of a drug to the brain using a compound, or pharmaceutically acceptable salt or solvate thereof, of this invention are described and claimed.

Taxane antineoplastic agents which have heretofore exhibited poor or non-existent oral bioavailability are administered orally to human patients suffering from taxane-responsive disease conditions and made sufficiently bioavailable to achieve therapeutic blood levels. In a preferred embodiment, the taxane, preferably paclitaxel, is co-administered to the patient with an oral cyclosporin enhancing agent, preferably cyclosporin A. By one preferred method, a dose of oral enhancer is administered about 0.5-72 hours before the taxane and a second dose of the enhancer and administered immediately before, together with or immediately after the taxane. A method of treating human patients suffering from taxane-responsive disease conditions is also provided, as well as a method for providing such treatment while preventing or reducing hypersensitivity and allergic reactions without the need for pre-medication.