received by the International Bureau on

12 December 2017 (12.12.2017)

What is claimed is:

1. A compound of formula III

Formula III

or a salt thereof, wherein

an A1 , A2, A3 and A4 are each covalently attached to a porphyrin ring and A1 , A2, A3, and A4 are independently selected from a substituted aromatic ring or a six membered heteroaromatic ring containing a single nitrogen atom at the 2, 3 or 4 position relative to the porphyrin ring;

B1 is selected from the group consisting of L9-L16 wherein n is selected from 1 -12; and Z1 is a cytotoxic agent selected from the group consisting of T1 b, T2b, T3b, T4b, 1 , T1 a, T3a, T4a, T8a, T10a, T14a, T15a, T18a, T19a, T21 a, T27a, T31 a, T32a, T33a, T4c, T5c, T9c, and Tl Oc and derivatives thereof and wherein there is one Z1 per porphyrin ring.

2. The compound of claim 1 or a salt thereof, further including a pharmaceutical acceptable carrier.

3. The compound of claim 2 or a salt thereof, wherein the pharmaceutically acceptable carrier is a liquid carrier selected from the group consisting of saline, glucose, alcohols, glycols, esters, amides, and any combination thereof.

4. The compound of claim 1 or a salt thereof, wherein the compound is in a dosage form and the dosage form is parenteral and the dosage form is selected from the group consisting of intradermal dosage form, a subcutaneous dosage form, an intramuscular dosage form, a subcutaneous dosage form, an intravenous dosage form, an intrathecal dosage form, and an epidural dosage form.

5. The compound of claim 1 or a salt thereof, wherein the compound is in a dosage form and the dosage form is nonparenteral and the dosage form is selected from the group consisting of oral dosage form, sublingual dosage form, topical dosage form, transdermal dosage form, ophthalmic dosage form, otic dosage form, nasal dosage form, rectal dosage form, and vaginal dosage form.

AMENDED SHEET (ARTICLE 19)

91

6. The compound of claim 1 or a salt thereof, wherein the substituted aromatic ring of the A1 comprises a carboxylic amide functional group at either an ortho, meta, or para position with respect to the porphyrin ring and wherein A2, A3 and A4 are each a substituted aromatic ring wherein each A2, A3, and A4 substituted aromatic ring has a substituent at either a ortho, meta or para position with respect to the porphyrin ring and the substituent is either a carboxylic acid or carboxylic methyl ester.

7. The compound of claim 1 or a salt thereof, wherein the substituted aromatic ring of the A2, A3, and A4 comprises a carboxylic methyl ester in a para position with respect to the porphyrin ring and the carboxylic amide of A1 is in the para position with respect to the porphyrin ring.

8. The compound of claim 1 or a salt thereof, wherein B1 is L1 1 or L13.

9. The compound of claim 1 or a salt thereof, wherein Z1 is selected from the group consisting of T1 b, 1 and T4c.

10. The compound of claim 1 or a salt thereof, wherein the substituted aromatic ring of A1 comprises an aromatic ether functional group at either an ortho, meta or para position with respect to the porphyrin ring, and wherein A2, A3 and A4 are each the substituted aromatic ring wherein each A2, A3, and A4 substituted aromatic ring has a substituent located at an ortho, meta or para position with respect to the porphyrin ring wherein the substituent on each A2, A3, and A4 substituted aromatic ring is independently selected from the group consisting of: lower alkyl, branched lower alkyl, cycloalkyl, halogens (F, CI, Br, I), cyano, amino or substituted amino, sulfonic acid or sulfonamide, aromatic ether, aromatic hydroxyl, carboxylic acid alkyl esters or carboxylic acid amide.

11 . The compound of claim 1 or a salt thereof, wherein B1 is selected from the group consisting of; L9, L10, L15, and L16.

12. The compound of claim 11 or a salt thereof, wherein a substituent of the substituted aromatic ring at position A2, A3 and A4 is a hydroxyl and may occupy the ortho, meta or para position with respect to the porphyrin ring and B1 is L9 or L15.

13. The compound of claim 1 or a salt thereof, wherein the substituted aromatic ring A1 comprises an aromatic ether functional group, where the position of the aromatic ether is meta with respect to the porphyrin ring, and wherein A2, A3 and A4 are each the substituted aromatic ring wherein the substituent on the substituted aromatic ring is an aromatic hydroxyl in the meta position with respect to the porphyrin ring, B1 is L9 or L15 and Z1 is selected from the group consisting of: T1 b, 1 and T4c.

AMENDED SHEET (ARTICLE 19)

92

14. The compound of claim 1 or a salt thereof, wherein the six membered heteroaromatic ring of A1 comprises a nitrogen atom where a position of the nitrogen atom on the six membered heteroaromatic ring may occupy one of a 2, 3 or 4 position with respect to the porphyrin ring, A2, A3 and A4 are each a pyridine ring where the position of a pyridine nitrogen on each pyridine ring of A2, A3 and A4 may independently occupy one of the 2, 3 or 4 position with respect to the porphyrin ring.

15. The compound of claim 14 or a salt thereof, wherein, B1 is selected from the group consisting of: L9, L10, L15, and L16.

16. The compound of claim 14 or a salt thereof, wherein the six membered heteroaromatic ring comprising the nitrogen atom at A1 is a pyridinium where the position of the nitrogen is in the 4 position with respect to the porphyrin ring, B1 is L9 or L15, and Z1 is selected from the group consisting of T1 b, 1 or T4c.

17. The compound of claim 16 or a salt thereof, wherein the B1 is L9.

18. A compound of claim 6 or a salt thereof, wherein the compound is selected from the group consisting of: OS002, OS007, OS009, OS0030, OS032 and OS035.

19. A compound of claim 10 or a salt thereof, wherein the compound is selected from the group consisting of: OS023 and OS024.

20. A compound of claim 14 or a salt thereof, wherein the compound is selected from the group consisting of: OS025, OS026, OS027, and OS029.

21 . The compound as in any one of claims 1 -20 wherein the salt is a pharmaceutically acceptable salt.

22. A compound as in any one of claims 1-20 or a pharmaceutically acceptable salt thereof, for use in the treatment of cancer.

23. A compound as in any one of claims 1-20 or a pharmaceutically acceptable salt thereof, for use in the treatment of cancer cells in vitro.

24. A composition comprising a compound of claim 1 and a cytotoxic agent wherein the cytotoxic agent is a formula that is the same or different than Z1 of the compound of claim 1 .

AMENDED SHEET (ARTICLE 19)

93

25. The composition of claim 24 wherein the different formula of the cytotoxic agent is selected from a class that is different as compared to Z1 of the compound of claim 1 .

26. A drug delivery device comprising the compound of claim 1 enmeshed with a biodegradable polymer.

27. The drug delivery device of claim 26 wherein the biodegradable polymer is selected from the group consisting of poly lactic co-glycolic acid, alginate, and polycaprolactone.

28. The drug delivery device of claim 27 wherein the compound is released over time when the drug delivery device is implanted into a patient.

29. A kit comprising a compound of claim 1 or a pharmaceutically acceptable salt thereof, and one or more pharmaceutically acceptable carriers.

30. A method of treating cancer in a patient in need thereof comprising the steps of:

administering to a patient in need thereof a therapeutically effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof.

31 . The method of claim 30 wherein the pharmaceutically acceptable carrier is a liquid carrier selected from the group consisting of saline, glucose, alcohols, glycols, esters, amides, and any combination thereof.

32. The method of claim 30 wherein the compound is in a dosage form and the dosage form is parenteral and the dosage form is selected from the group consisting of intradermal dosage form, a subcutaneous dosage form, an intramuscular dosage form, a subcutaneous dosage form, an intravenous dosage form, an intrathecal dosage form, and an epidural dosage form.

33. The method of claim 30 wherein the compound is in a dosage form and the dosage form is nonparenteral and the dosage form is selected from the group consisting of oral dosage form, sublingual dosage form, topical dosage form, transdermal dosage form, ophthalmic dosage form, otic dosage form, nasal dosage form, rectal dosage form, and vaginal dosage form.

34. The method of claim 30 wherein the substituted aromatic ring of the A1 of the compound comprises a carboxylic amide functional group at either an ortho, meta, or para position with respect to the porphyrin ring and wherein A2, A3 and A4 are each a substituted aromatic ring wherein each A2, A3,

AMENDED SHEET (ARTICLE 19)

94 and A4 substituted aromatic ring has a substituent at either a ortho, meta or para position with respect to the porphyrin ring and the substituent is either a carboxylic acid or carboxylic methyl ester.

35. The method of claim 34 wherein the substituted aromatic ring of the A2, A3, and A4 of the compound comprises a carboxylic methyl ester in a para position with respect to the porphyrin ring and the carboxylic amide of A1 is in the para position with respect to the porphyrin ring.

36. The method of claim 30 wherein the B1 of the compound is L1 1 or L13.

37. The method of claim 30 wherein Z1 of the compound is selected from the group consisting of T1 b, 1 or T4c.

38. The method of claim 37 wherein A2, A3 and A4 of the compound represent substituted aromatic rings wherein the substituent is a sulfonic acid or sulfonamide and may occupy the ortho, meta or para position with respect to the porphyrin ring.

39. The method of claim 30 wherein the substituted aromatic ring of A1 of the compound comprises an aromatic ether functional group at either an ortho, meta or para position with respect to the porphyrin ring, and wherein A2, A3 and A4 of the compound are each the substituted aromatic ring wherein each A2, A3, and A4 substituted aromatic ring has a substituent located at an ortho, meta or para position with respect to the porphyrin ring wherein the substituent on each A2, A3, and A4 substituted aromatic ring is independently selected from the group consisting of: lower alkyl, branched lower alkyl, cycloalkyl, halogens (F, CI, Br, I), cyano, hydroxyl, amino or substituted amino, sulfonic acid or sulfonamide, aromatic ether, aromatic hydroxyl, carboxylic acid alkyl esters or carboxylic acid amide.

40. The method of claim 30 wherein B1 of the compound may be independently selected from the group L9, L10, L15, L16.

41 . The method of claim 39 wherein the substituent of the substituted aromatic ring at position A2, A3 and A4 of the compound is a hydroxyl and may occupy either the ortho, meta or para position with respect to the porphyrin ring and B1 is L9 or L15.

42. The method of claim 30 wherein the substituted aromatic ring A1 of the compound comprises an aromatic ether functional group, where the position of the aromatic ether is meta with respect to the porphyrin ring, and wherein A2, A3 and A4 are each the substituted aromatic ring wherein the substituent on the substituted aromatic ring is an aromatic hydroxyl in the meta position with respect to the porphyrin ring, B1 is L9 or L15 and Z1 is selected from the group consisting of: T1 b, 1 and T4c.

AMENDED SHEET (ARTICLE 19)

95

43. The method of claim 30 wherein the six membered heteroaromatic ring of A1 of the compound comprises a nitrogen atom where a position of the nitrogen atom on the six membered heteroaromatic ring may occupy one of a 2, 3 or 4 position with respect to the porphyrin ring, A2, A3 and A4 of the compound are each a pyridine ring where the position of a pyridine nitrogen on each pyridine ring of A2, A3 and A4 may independently occupy one of the 2, 3 or 4 position with respect to the porphyrin ring.

44. The method of claim 43 wherein the six membered heteroaromatic ring comprising the nitrogen atom at A1 is a pyridinium where the position of the nitrogen is in the 4 position with respect to the porphyrin ring, B1 is L9 or L15, and Z1 is selected from the group consisting of T1 b, 1 or T4c.

45. The method of claim 34 wherein the compound is selected from the group consisting of: OS002, OS007, OS009, OS0030, OS032 and OS035.

46. The method of claim 39 wherein the compound is selected from the group consisting of: OS023 and OS024.

47. The method of claim 43 wherein the compound is selected from the group consisting of: OS025, OS026, OS027, and OS029.

AMENDED SHEET (ARTICLE 19)

96