A compound comprising the formula: wherein each of P 1 and P 2 individually is a protecting group or a hydrogen atom; wherein ------ is a double bond; wherein the double bonds at the 4, 16 and 19 positions are each of Z configuration and the double bond at the 10 position is of E configuration; wherein Z is -C OR d, -C NR c R c, -C H, -C NR c R c, -C H, -C OR d, -C NR c R c, or -CN; each R a, is independently selected from hydrogen, (C1-C6) alkyl, (C3-C8) cycloalkyl, cyclohexyl, (C4-C11) cycloalkylalkyl, (C5-C10) aryl, phenyl, (C6-C16) arylalkyl, benzyl, 2-6 membered heteroalkyl, 3-8 membered cycloheteroalkyl, morpholinyl, piperazinyl, homopiperazinyl, piperidinyl, 4-11 membered cycloheteroalkylalkyl, 5-10 membered heteroaryl or 6-16 membered heteroarylalkyl; each R c, is independently a protecting group or R a, or, alternatively, each R c is taken together with the nitrogen atom to which it is bonded to form a 5 to 8-membered cycloheteroalkyl or heteroaryl which may optionally include one or more of the same or different additional heteroatoms and which may optionally be substituted with one or more of the same or different R a or suitable R b groups; each R b is independently selected from =O, -OR d, (C1-C3) haloalkyloxy, -OCF 3, =S, -SR d, =NR d, =NOR d, -NR c R c, halogen, -CF 3, -CN, -NC, -OCN, -SCN, -NO, -NO 2, =N 2, -N 3, -S R d, -S 2 R d, -S 2 OR d, -S NR c R c, -S 2 NR c R c, -OS R d, -OS 2 R d, -OS 2 OR d, -OS 2 NR c R c, -C R d, -C OR d, -C NR c R c, -C NR c R c, -C(NR a)NR c R c, -C R a, -C NR c R c, -OC R d, -OC OR d, -OC NR c R c, -OC NR c R c, -OC(NR a)NR c R c, -[NHC] n R d, -[NR a C] n R d, -LNHC] n OR d, -LNR a C] n OR d, -[NHC] n NR c R c, -[NR a C] n NR c R c, -[NHC] n NR c R c or -[NR a C(NR a)] n NR c R c; each n, independently is an integer from 0 to 3; and each R d, independently is a protecting group or R a; wherein "alkyl" by itself or as part of another substituent refers to a saturated or unsaturated branched, straight-chain or cyclic monovalent hydrocarbon radical, having the stated number of carbon atoms, that is derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane, alkene or alkyne; or a pharmaceutically acceptable salt thereof, provided that: (i) the compound is purified; and/or (ii) when Z is -C OR d, then R d for Z is not a hydrogen. wherein each of P 1 and P 2 individually is a protecting group or a hydrogen atom; wherein ------ is a double bond; wherein the double bonds at the 4, 16 and 19 positions are each of Z configuration and the double bond at the 10 position is of E configuration; wherein Z is -C OR d, -C NR c R c, -C H, -C NR c R c, -C H, -C OR d, -C NR c R c, or -CN; each R a, is independently selected from hydrogen, (C1-C6) alkyl, (C3-C8) cycloalkyl, cyclohexyl, (C4-C11) cycloalkylalkyl, (C5-C10) aryl, phenyl, (C6-C16) arylalkyl, benzyl, 2-6 membered heteroalkyl, 3-8 membered cycloheteroalkyl, morpholinyl, piperazinyl, homopiperazinyl, piperidinyl, 4-11 membered cycloheteroalkylalkyl, 5-10 membered heteroaryl or 6-16 membered heteroarylalkyl; each R c, is independently a protecting group or R a, or, alternatively, each R c is taken together with the nitrogen atom to which it is bonded to form a 5 to 8-membered cycloheteroalkyl or heteroaryl which may optionally include one or more of the same or different additional heteroatoms and which may optionally be substituted with one or more of the same or different R a or suitable R b groups; each R b is independently selected from =O, -OR d, (C1-C3) haloalkyloxy, -OCF 3, =S, -SR d, =NR d, =NOR d, -NR c R c, halogen, -CF 3, -CN, -NC, -OCN, -SCN, -NO, -NO 2, =N 2, -N 3, -S R d, -S 2 R d, -S 2 OR d, -S NR c R c, -S 2 NR c R c, -OS R d, -OS 2 R d, -OS 2 OR d, -OS 2 NR c R c, -C R d, -C OR d, -C NR c R c, -C NR c R c, -C(NR a)NR c R c, -C R a, -C NR c R c, -OC R d, -OC OR d, -OC NR c R c, -OC NR c R c, -OC(NR a)NR c R c, -[NHC] n R d, -[NR a C] n R d, -LNHC] n OR d, -LNR a C] n OR d, -[NHC] n NR c R c, -[NR a C] n NR c R c, -[NHC] n NR c R c or -[NR a C(NR a)] n NR c R c; each n, independently is an integer from 0 to 3; and each R d, independently is a protecting group or R a; wherein "alkyl" by itself or as part of another substituent refers to a saturated or unsaturated branched, straight-chain or cyclic monovalent hydrocarbon radical, having the stated number of carbon atoms, that is derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane, alkene or alkyne; or a pharmaceutically acceptable salt thereof, provided that: (i) the compound is purified; and/or (ii) when Z is -C OR d, then R d for Z is not a hydrogen. (i) the compound is purified; and/or (ii) when Z is -C OR d, then R d for Z is not a hydrogen.