Method for radiolabeling antibodies with yttrium-90
View Patent ↗Methods and kits for radiolabeling proteins, peptides and ligands with radiolytic isotopes, particularly yttrium-90, are disclosed, whereby sufficient purity, specific activity and binding affinity are achieved such that the radiolabeled protein may be directly administered to a patient without further column purification. Such kits and methods will be particularly useful in bringing radioimmunotherapy to the hospital and outpatient setting for the treatment of cancer.
1. A method for radiolabeling a chelator-conjugated antibody or antibody fragment with 90 Y for administration to a patient comprising:
(i) mixing the chelator-conjugated antibody or antibody fragment with a solution comprising 90 Y or a salt thereof, and
(ii) incubating the mixture for a sufficient amount of time under amiable conditions such that a 90 Y-labeled antibody or antibody fragment is produced having sufficient radioincorporation, immunoreactivity of at least 50%, and a specific activity of at least about 5 mCi/mg, such that the 90 Y-labeled antibody or antibody fragment may be administered directly to the patient without further purification of the 90 Y-labeled radiolabeled antibody or antibody fragment from unincorporated 90 Y;
wherein said chelator is a bifunctional chelator selected from the group consisting of MX-DTPA, phenyl-DTPA, benzyl-DTPA, CHX-DTPA, DOTA and derivatives thereof.
2. The method of claim 1 , wherein said amiable conditions refer to acceptable temperature, pH and buffer conditions.
3. The method of claim 2 , wherein said acceptable temperature ranges from about 25° C. to about 50° C.
4. The method of claim 2 , wherein said acceptable pH ranges from about 3 to about 6.
5. The method of claim 2 , wherein said acceptable buffer is an acetate buffer and is at a concentration of between about 10 and about 1000 mM.
6. The method of claim 1 , wherein said sufficient incubation time is less than about eight minutes.
7. The method of claim 6 , wherein said sufficient incubation time is between about 30 seconds to about five minutes.
8. The method of claim 1 , wherein the specific activity of the 90 Y-labeled antibody or antibody fragment is greater than 10 mCi/mg.
9. The method of claim 8 , wherein the specific activity of the 90 Y-labeled antibody or antibody fragment is at least 15 mCimg.
10. The method of claim 1 , wherein a level of radioincorporation of greater than 95% is achieved.
11. The method of claim 1 , wherein a level of radioincorporation of greater than 96% is achieved.
12. The method of claim 1 , wherein the immunoreactivity is at least 70%.
13. The method of claim 1 , wherein the immunoreactivity is at least 80%.
14. The method of claim 1 , wherein the chelator is MX-DTPA.
15. The method of claim 1 , wherein the ratio of chelator to antibody or antibody fragment ranges from 1½ to 1.
16. The method of claim 1 , wherein the antibody or antibody fragment binds specifically to CD20.
17. The method of claim 16 , wherein the antibody is 2B8.
18. The method of claim 17 , wherein the chelator is MX-DTPA.
19. The method of claim 1 , wherein the antibody fragment is selected from the group consisting of Fab, F(ab′) 2 , and Fv fragments.
20. A method for radiolabeling a MX-DTPA-conjugated 2B8 antibody or antibody fragment with 90 Y for administration to a patient comprising:
(i) mixing the MX-DTPA-conjugated antibody or antibody fragment with a solution comprising 90 Y or a salt thereof, and
(ii) incubating the mixture for a sufficient amount of time under acceptable temperature, pH and buffer conditions such that a 90 Y-labeled antibody or antibody fragment is produced having sufficient radioincorporation, immunoreactivity of at least 50% , and a specific activity of at least about 5 mCi/mg, such that the 90 Y-labeled antibody or antibody fragment may be administered directly to the patient without further purification of the 90 Y-labeled 2B8 antibody or antibody fragment from unincorporated 90 Y.