Compositions and methods for treating cancer

1. A protected anti-neoplastic agent, in which the anti-neoplastic agent is an alkylating agent, and includes one or more protectable hydroxyl groups or amine groups, and wherein one or more of the protectable hydroxyl groups or amine groups is substituted with a group selected from Hyp-L- or Hyp-, wherein Hyp is a hypoxic activator having the formula

wherein R 1 is substituted or unsubstituted C 1 -C 6 alkyl or substituted or unsubstituted C 1 -C 6 alkoxy;

R 2 is hydrogen;

R 3 is —H or C 1 -C 6 alkyl; and

R 4 is —H, substituted or unsubstituted C 1 -C 6 alkyl, or substituted or unsubstituted C 1 -C 6 alkoxy;

wherein the R 1 and R 4 substituted alkyl and substituted alkoxy are independently substituted with one or more heteroatom-containing groups selected from ether (—OR 20 ), amino (—NH 2 ), mono-substituted amino (—NR 20 H), di-substituted amino (—NR 21 R 22 ), cyclic C 1-5 alkylamino, imidazolyl, C 1-6 alkylpiperazinyl, morpholino, thiol (—SH), thioether —(SR 20 ), tetrazole, carboxylic acid (—COOH), ester (—COOR 20 ), amide (—CONH 2 ), mono-substituted amide (—CONHR 20 ), disubstituted amide (—CONR 21 R 22 ), N-connected amide (—NH 2 —C(═O)—R 20 ), mono-substituted N-connected amide (—NHR 21 —C(═O)—R 20 ), disubstituted N-connected amide (—NR 21 R 22 —S(═O) 2 —R 20 ), N-connected sulfonamide (—NH 2 —S(═O) 2 —R 20 ), mono-substituted N-connected sulfonamide (—NHR 21 —S(═O) 2 —R 20 ), disubstituted N-connected sulfonamide (—NR 21 R 22 —S(═O) 2 —R 20 ), sulphoxy (—S(═O) 2 OH), sulphonate (S(═O) 2 OR 20 ), sulphonyl (S(═O) 2 R 20 ), sulphixy (S(═O)OH), sulphinate (S(═O)OR 20 ), sulphinyl (S(═O)R 20 ), phosphonooxy (OP(═O)(OH) 2 ), phosphate (OP(═O)(OR 20 ) 2 ), and sulfonamide (—S(═O) 2 NH 2 , —S(═O) 2 NHR 21 , or —S(═O) 2 NR 21 R 22 ), where R 20 , R 21 , and R 22 are independently selected from a C 1 -C 6 alkyl group; and

L is a linking group of the formula

 where X is selected from

wherein R 6 is unsubstituted alkyl or alkyl substituted with one or more heteroatom containing groups;

R 7 is hydrogen, unsubstituted alkyl or alkyl substituted with one or more heteroatom containing groups; and

Y is a spacer group selected from a substituted or unsubstituted —(CH 2 ) n — chain with n=1-4; a substituted or unsubstituted —(CH 2 ) n — chain with n=1-4 in which one of the carbon backbone chain atoms is substituted by a heteroatom containing group; or a delayed release group comprising an aromatic group.

2. The protected anti-neoplastic agent of claim 1 , wherein

R 6 is unsubstituted C1-C3 alkyl or C1-C3 alkyl substituted with one or more heteroatom containing groups selected from hydroxyl, ether, thiol, thioether, sulfinic ester, sulfoxide, sulfone, sulfonic acid, sulfonic acid ester, sulfenamide, sulfonamide, carboxylic acid, carboxylic acid salt, ester, amide, aldehydo, keto, amino, halo, and cyano;

R7 is hydrogen, unsubstituted C1-C3 alkyl, or C1-C3 alkyl substituted with one or more heteroatom containing groups selected from hydroxyl, ether, thiol, thioether, sulfinic ester, sulfoxide, sulfone, sulfonic acid, sulfonic acid ester, sulfenamide, sulfonamide, carboxylic acid, carboxylic acid salt, ester, amide, aldehydo, keto, amino, halo, and cyano; and

the spacer group Y is an unsubstituted —(CH 2 ) n — chain with n=1-4, or a —(CH 2 ) n — chain with n=1-4 substituted with one or more heteroatom containing groups selected from hydroxyl, ether, thiol, thioether, sulfinic ester, sulfoxide, sulfone, sulfonic acid, sulfonic acid ester, sulfenamide, sulfonamide, carboxylic acid, carboxylic acid salt, ester, amide, aldehydo, keto, amino, halo, and cyano; or

the spacer group Y is the delayed release group and has the formula

 where R10 is a bond; R11 is an unsubstituted or substituted aryl or substituted or unsubstituted heteroaryl group; and R12 has the formula —(CR 40 R 41 )—R 42 — or —(CR 40 R 41 )—CR 43 ═CR 44 —R 42 —, where R 42 is a bond or —OC(═O)—, and R 40 , R 41 , R 42 , and R 43 are independently selected from —H, unsubstituted C 1 -C 10 alkyl, and C 1 -C 10 alkyl substituted with one or more heteroatom containing groups selected from hydroxyl, ether, thiol, thioether, sulfinic ester, sulfoxide, sulfone, sulfonic acid, sulfonic acid ester, sulfenamide, sulfonamide, carboxylic acid, carboxylic acid salt, ester, amide, aldehydo, keto, amino, halo, and cyano.

3. A method for treating cancer comprising administering to a subject a therapeutically effective amount of a protected anti-neoplastic agent according to claim 1 , wherein the cancer is selected from the group consisting of colon cancer, prostate cancer, lung cancer, non-small cell lung cancer, liver cancer, skin cancer, sarcomas, pancreatic cancer, breast cancer, head and neck cancer, and myeloma.

4. A protected anti-neoplastic agent of formula Hyp-L-N or Hyp-N,

wherein Hyp is a hypoxic activator moiety of formula

wherein R 1 is unsubstituted C 1 -C 6 alkyl, C 1 -C 6 alkyl substituted with one or more heteroatom-containing groups, unsubstituted C 1 -C 6 alkoxy, or C 1 -C 6 alkoxy substituted with one or more heteroatom-containing groups;

R 2 is hydrogen;

R 3 is hydrogen or C 1 -C 6 alkyl; and

R 4 is hydrogen, unsubstituted C 1 -C 6 alkyl, C 1 -C 6 alkyl substituted with one or more heteroatom-containing groups, unsubstituted C 1 -C 6 alkoxy, or C 1 -C 6 alkoxy substituted with one or more heteroatom-containing groups;

L is a linking group of the formula

 wherein X is selected from

wherein R 6 is unsubstituted alkyl or alkyl substituted with one or more heteroatom containing groups;

R 7 is hydrogen, unsubstituted alkyl or alkyl substituted with one or more heteroatom containing groups; and

Y is a spacer group selected from a substituted or unsubstituted —(CH 2 ) n — chain with n=1-4; a substituted or unsubstituted —(CH 2 ) p -HAC-(CH 2 ) q — chain wherein each p and q independently is 1-3 and p+q is less than or equal to 3 and HAC is a heteroatom containing group; and a delayed release group comprising an aromatic group; and

N is an anti-neoplastic alkylating agent.

5. The protected anti-neoplastic agent of claim 4 wherein Hyp is of the formula

wherein R 1 and R 4 are each independently hydrogen or alkyl selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, t-butyl, cyclohexyl, cyclopentyl, and isopropyl, wherein the alkyl is optionally substituted with one or more heteroatom-containing groups; with the proviso that R 1 is not hydrogen.

6. The protected anti-neoplastic agent of claim 5 wherein the alkylating agent is selected from the group consisting of cyclophosphamide, ifosfamide, melphalan, chlorambucil, thiotepa.

7. The protected anti-neoplastic agent of claim 4 of formula

wherein R 3 is hydrogen or C 1 -C 6 alkyl.

8. The protected anti-neoplastic agent of claim 2 , wherein the alkylating agent is selected from the group consisting of cyclophosphamide, ifosfamide, melphalan, chlorambucil, thiotepa.

9. The protected anti-neoplastic agent of claim 1 , wherein the one or more protectable hydroxyl groups or amine groups is substituted with Hyp-.

10. The protected anti-neoplastic agent of claim 1 , wherein only one of the one or more protectable hydroxyl groups or amine groups is substituted with Hyp- or Hyp-L-.

11. The protected anti-neoplastic agent of claim 10 , wherein the one protectable hydroxyl group or one protectable amine group is substituted with Hyp-.

12. The protected anti-neoplastic agent of claim 11 , wherein a hydroxyl group is substituted with Hyp-.

13. The method of claim 3 , wherein the one or more protectable hydroxyl groups or amine groups of the anti-neoplastic agent is substituted with Hyp-.

14. The method of claim 3 , wherein only one of the one or more protectable hydroxyl groups or amine groups is substituted with Hyp- or Hyp-L-.

15. The method of claim 14 , wherein the one protectable hydroxyl group or one protectable amine group is substituted with Hyp-.

16. The method of claim 15 , wherein a protectable hydroxyl group of the anti-neoplastic is substituted with Hyp-.

17. The protected anti-neoplastic agent of claim 4 of formula Hyp-N.

18. The protected anti-neoplastic agent of claim 5 of formula Hyp-N.