Compositions and methods for imaging cancer
Somatostatin derivative compounds of general formula (I) that may be readily labelled with the isotope fluorine-18 and that have affinity and selectivity for cellular somatostatin receptors are provided. The labelled compounds are useful clinically as radioactive tracers in various in vivo imaging applications (for example, using positron emission tomography (PET) and related techniques) to detect somatostatin-expressing cells and tissues, including tumors, or as therapeutic agents.
1. A fluorinated somatostatin derivative having general formula (I):
B − F 3 —(CH 2 ) n —N + R 1 R 2 -L-X (I)
wherein:
B is boron;
R 1 and R 2 are each independently H, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl, or C 3 -C 6 aryl;
L is a linking group;
X is a somatostatin analogue conjugated via an N-terminal amino group to L, and
n is 1 or 2,
and wherein the somatostatin analogue is octreotide, octreotate, [Tyr 3 ]octreotate (TATE), JR-11, JR-10, LM3, [Tyr 3 ]octreotide (TOC) or [Nal 3 ]octreotide (NOC).
2. The fluorinated somatostatin derivative according to claim 1 , wherein n is 1.
3. The fluorinated somatostatin derivative according to claim 1 , wherein R 1 and R 2 are each independently C 1 -C 6 alkyl, or wherein the fluorinated somatostatin derivative has general formula (IV):
B − F 3 —CH 2 —N + (Me) 2 -L-X (IV),
wherein L and X are as defined for formula (I).
4. The fluorinated somatostatin derivative according to claim 1 , wherein:
L comprises a 1,2,3-triazole moiety
5. The fluorinated somatostatin derivative according to claim 1 , wherein:
the fluorinated somatostatin derivative has general formula (V)
wherein m and p are each independently 1 to 8, and wherein n and X are as defined for formula I; or
the fluorinated somatostatin derivative has general formula (VI)
wherein X is as defined for formula I.
6. The fluorinated somatostatin derivative according to claim 1 , wherein the somatostatin analogue is TATE, JR-11, LM3 or TOC.
7. The fluorinated somatostatin derivative according to claim 1 , selected from: AMBF 3 -TATE (compound 2), AMBF 3 -JR11 (compound 7), AMBF 3 -LM3 (compound 3) and AMBF 3 -TOC (compound 6).
8. The fluorinated somatostatin derivative according to claim 1 , wherein each F is 19 F or at least one F is 18 F.
9. A method of preparing a 18 F-labelled somatostatin derivative comprising contacting a fluorinated somatostatin derivative according to claim 1 , wherein each F is 19 F, with 18 F-fluoride under conditions suitable for isotope exchange.
10. The method according to claim 9 , wherein the 18 F-fluoride is a no carrier added 18 F-fluoride.
11. A method of imaging cells or tissues expressing somatostatin receptors, the method comprising:
administering a fluorinated somatostatin derivative according to claim 1 to a subject, wherein at least one F is 18 F; and
imaging the subject for the presence of the fluorinated somatostatin derivative.
12. The method of claim 11 , wherein the imaging is positron emission tomography (PET).
13. A method of imaging a cancer that expresses somatostatin receptors, the method comprising:
administering a fluorinated somatostatin derivative according to claim 1 to a subject, wherein at least one F is 18 F; and
imaging the subject for the presence of the fluorinated somatostatin derivative;
wherein the cancer is a neuroendocrine tumour, breast cancer, small cell lung cancer, lymphoma, meningioma, pituitary adenoma or pancreatic cancer.
14. A method of treating a disease or disorder, the method comprising administering the fluorinated somatostatin derivative of claim 8 to a subject, wherein the disease or disorder is a neuroendocrine tumour, breast cancer, small cell lung cancer, lymphoma, meningioma, pituitary adenoma or pancreatic cancer.
15. A kit for the preparation of a 18 F-labelled imaging agent comprising the fluorinated somatostatin derivative according to claim 1 , wherein each F is 19 F, and optionally instructions for use.
16. The kit according to claim 15 , wherein the kit comprises one or more containers and the somatostatin derivative is provided in the one or more containers in an effective amount to provide a single dose of the 18 F-labelled imaging agent or multiple doses of the 18 F-labelled imaging agent.
17. The fluorinated somatostatin derivative according to claim 1 , wherein:
L comprises formula (II)
wherein m is 1 to 15.
18. The fluorinated somatostatin derivative according to claim 1 , wherein:
L is a linking group of formula (III)
wherein m and p are each independently 1 to 8.
19. The method of claim 14 , wherein each F in the somatostatin derivative is 19 F.