Peptide vectors

1. A compound according to formula (I):

X—B 1 —B 2 —B 3 —B 4 -Z  (I)

wherein:

X is a cytotoxic or cytostatic agent;

each of B 1 , B 2 , B 3 , and B 4 is, independently for each occurrence, (Doc) m , (Aepa) n , —(C(O)-A1-A2-A3-A4-A5-C(O)) s — or (amino acid) p , provided that at least one of B 1 , B 2 , B 3 , and B 4 is —(C(O)-A1-A2-A3-A4-A5-C(O)) s —, and that at least one of B 1 , B 2 , B 3 , and B 4 is (Doc) m or (Aepa) n wherein at least one of m and n is not 0;

each of A1 and A5 is, independently for each occurrence, CR 1 R 2 ;

each of R 1 and R 2 is, independently for each occurrence, H, F, Br, Cl, I, C( 1-30 )alkyl, C( 2-30 )alkenyl, substituted C( 1-30 )alkyl, substituted C( 2-30 )alkenyl, SR 3 , S(O)R 4 , or S(O) 2 R 5 , or R 1 and R 2 together can form a C( 3-30 )cycloalkyl, C( 3-30 )heterocycle, or C( 5-30 )aryl ring;

each of R 3 , R 4 , and R 5 is, independently for each occurrence, C( 1-30 )alkyl, C( 2-30 )alkenyl, substituted C( 1-30 )alkyl, or substituted C( 2-30 )alkenyl;

each of A2, A3 and A4 is, independently for each occurrence, CR 6 R 7 , O, S, (CH 2 ) t or absent;

each of R 6 and R 7 is, independently for each occurrence, H, F, Br, Cl, I, C( 1-30 )alkyl, C( 2-30 )alkenyl, substituted C( 1-30 )alkyl, substituted C( 2-30 )alkenyl, SR 3 , S(O)R 4 , or S(O) 2 R 5 ; or R 6 and R 7 together may form a ring system;

m is, independently for each occurrence, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10;

n is, independently for each occurrence, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10;

p is, independently for each occurrence, 0, 1, or 2;

s is, independently for each occurrence, 1, 2, 3, 4, or 5;

t is, independently for each occurrence, 0, 1, 2, or 3; and

Z is selected from the group consisting of somatostatin, a somatostatin analog, luteinizing hormone-releasing hormone (LHRH), an LHRH analog, bombesin, and a bombesin analog;

provided that:

when X is doxorubicin or a doxorubicin derivative, at least one of m and n is not 0; and

when X is paclitaxel or a paclitaxel derivative, then B 1 is (amino acid) p and

p is 1 or 2;

or a pharmaceutically acceptable salt thereof.

2. The compound according to claim 1 , wherein X is a cytotoxic moiety; or a pharmaceutically acceptable salt thereof.

3. The compound according to claim 2 , wherein X is an anthracycline; or a pharmaceutically acceptable salt thereof.

4. The compound according to claim 3 , wherein X is doxorubicin, or a doxorubicin derivative; or a pharmaceutically acceptable salt thereof.

5. The compound according to claim 2 , wherein X is camptothecin, a camptothecin derivative, paclitaxel, or a paclitaxel derivative.

6. The compound according to claim 5 , wherein said camptothecin derivative is:

or a pharmaceutically acceptable salt thereof.

7. The compound according to claim 5 , wherein X is paclitaxel or a paclitaxel derivative, wherein said paclitaxel derivative is:

or a pharmaceutically acceptable salt thereof.

8. The compound according to claim 4 , wherein X is doxorubicin or a doxorubicin derivative, wherein said doxorubicin derivative is:

or a pharmaceutically acceptable salt thereof.

9. The compound according to claim 1 , wherein Z is a somatostatin analog according to the formula:

-DPhe-cyclo(Cys-Tyr-DTrp-Lys-Abu-Cys)-Thr-NH 2 ;

-DPhe-cyclo(Cys-3ITyr-DTrp-Lys-Val-Cys)-Thr-NH 2 ;

-DPhe-cyclo(Cys-3ITyr-DTrp-Lys-Abu-Cys)-Thr-NH 2 ;

-DPhe-cyclo(Cys-3ITyr-DTrp-Lys-Thr-Cys)-Thr-NH 2 ;

-Lys-DTyr-DTyr-cyclo(Cys-Tyr-DTrp-Lys-Abu-Cys)-Thr-NH 2 ;

-Caeg-cyclo(DCys-Pal-DTrp-Lys-DCys)-Thr(Bzl)-Tyr-NH 2 ;

-D2Nal-cyclo[Cys-Tyr-DTrp-Lys-Val-Cys]-Thr-NH 2 ;

-DPhe-cyclo [Cys-Phe-DTrp-Lys-Thr-Cys]-Thr-ol;

-cyclo({4-(—NH—C2H4—NH—CO—O)Pro}-Phg-DTrp-Lys-Tyr(4-Bzl)-Phe); or

-DPhe-cyclo[Cys-Tyr-DTrp-Lys-Val-Cys]-Trp-NH 2 ;

or a pharmaceutically acceptable salt thereof.

10. The compound according to claim 1 , wherein Z is an LHRH analog according to the formula:

Glp-His-Trp-Ser-Tyr-DLys(−)-Leu-Arg-Pro-Gly-NH 2 ;

Glp-His-Trp-Ser-Tyr-DOrn(−)-Leu-Arg-Pro-Gly-NH 2 ;

Glp-His-Trp-Ser-Tyr-DDab(−)-Leu-Arg-Pro-Gly-NH 2 ;

Glp-His-Trp-Ser-Tyr-DDap(−)-Leu-Arg-Pro-Gly-NH 2 ;

Glp-His-Trp-Ser-Tyr-DApa(−)-Leu-Arg-Pro-Gly-NH 2 ;

Glp-His-Trp-Ser-Tyr-DLys(−)-Leu-Arg-Pro-NHEt;

Glp-His-Trp-Ser-Tyr-DOrn(−)-Leu-Arg-Pro-NHEt;

Glp-His-Trp-Ser-Tyr-DDab(−)-Leu-Arg-Pro-NHEt;

Glp-His-Trp-Ser-Tyr-DDap(−)-Leu-Arg-Pro-NHEt;

Glp-His-Trp-Ser-His-DLys(−)-Trp-Tyr-Pro-Gly-NH 2 ;

Glp-His-Trp-Ser-His-DOrn(−)-Trp-Tyr-Pro-Gly-NH 2 ;

Glp-His-Trp-Ser-His-DDab(−)-Trp-Tyr-Pro-Gly-NH 2 ; or

Glp-His-Trp-Ser-His-DDap(−)-Trp-Tyr-Pro-Gly-NH 2 ;

or a pharmaceutically acceptable salt thereof.

11. The compound according to claim 1 , wherein Z is a bombesin analog according to the formula:

-Gln-Trp-Ala-Ala-βAla-His-Phe-Nle-NH 2 ; (SEQ ID NO: 8)

-Gln-Trp-Ala-Val-Gly-His-Leu-Ψ(CH 2 —NH)-Leu-NH 2 ; (SEQ ID NO: 9)

-Gln-Trp-Ala-Val-Gly-His-Leu-Ψ(CH 2 —NH)-Phe-NH 2 ; (SEQ ID NO: 10)

-Gln-Trp-Ala-Val-βAla-His-Leu-Leu-NH 2 ; (SEQ ID NO: 11)

-Gln-Trp-Ala-Val-βAla-His-Leu-Nle-NH 2 ; (SEQ ID NO: 12)

-Gln-Trp-Ala-Val-βAla-His-Phe-Nle-NH 2 ; (SEQ ID NO: 13)

-Gln-Trp-Ala-Val-βAla-His-Ala-Nle-NH 2 ; (SEQ ID NO: 14)

-Gln-Trp-Ala-Val-βAla-Ala-Phe-Nle-NH 2 ; (SEQ ID NO: 15)

-Gln-Trp-Ala-Val-Gly-His-Leu-Leu-NH 2 ; (SEQ ID NO: 1)

-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH 2 ; (SEQ ID NO: 2)

-Gln-Trp-Ala-Val-Gly-His-Phe-Met-NH 2 ; (SEQ ID NO: 3)

-DAla-Gln-Trp-Ala-Val-βAla-His-Phe-Nle-NH 2 ;

-DPhe-Gln-Trp-Ala-Ala-βAla-His-Phe-Nle-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-βAla-Ala-Phe-Nle-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-βAla-His-Phe-Nle-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-βAla-His-Phe-Nle-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-βAla-His-Ala-Nle-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-βAla-His-Leu-Leu-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-βAla-His-Leu-Nle-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-Gly-His-Leu-Ψ(CH 2 —NH)-Leu-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-Gly-His-Leu-Ψ(CH 2 —NH)-Phe-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-Gly-His-Phe-Met-NH 2 ;

-DPhe-Gln-Trp-Ala-Val-Gly-His-Leu-Leu-NH 2 ; or

or a pharmaceutically acceptable salt thereof.

12. The compound according to claim 1 , wherein said compound is:

Or a pharmaceutically acceptable salt thereof.

13. The compound according to claim 1 , wherein said compound is:

a pharmaceutically acceptable salt thereof.

14. The compound according to claim 12 , wherein said compound is

a pharmaceutically acceptable salt thereof.

15. The compound according to claim 12 , wherein said compound is

a pharmaceutically acceptable salt thereof.

16. A pharmaceutical composition comprising an effective amount of a compound according to claim 1 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.

17. A method of treating a disease in a subject in need thereof, said method comprising administering to said subject a therapeutically effective amount of a compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein said disease is selected from the group consisting of fibrosis, benign prostatic hyperplasia, atherosclerosis, restenosis, breast cancer, colon cancer, pancreas cancer, prostate cancer, lung cancer, small cell lung cancer, ovarian cancer, epidermal cancer, and hematopoietic cancer.

18. A method of treating a disease in a subject in need thereof, said method comprising administering to said subject a therapeutically effective amount of a compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein said disease is selected from the group consisting of benign prostatic hyperplasia, restenosis, breast cancer, colon cancer, pancreas cancer, prostate cancer, lung cancer, small cell lung carcinoma, ovarian cancer, epidermal cancer, and hematopoietic cancer.

19. A method of treating a disease in a subject in need thereof, said method comprising administering to said subject a therapeutically effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein said disease is characterized by undesired proliferation of cells that express one or more somatostatin-type receptors.

20. A method of treating a disease in a subject in need thereof, said method comprising administering to said subject a therapeutically effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein said disease is characterized by undesired proliferation of cells that express one or more of bombesin-type receptors.

21. A method of treating a disease in a subject in need thereof, said method comprising administering to said subject a therapeutically effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein said disease is characterized by undesired proliferation of cells that express one or more LHRH-type receptors.