Method for preparing cell targeting conjugates, and the complexes obtained
A first aspect of the disclosure relates to a method for preparing cell-targeting conjugates by coupling at least one functional moiety, such as a therapeutic compound, diagnostic compound or chelating agent to a targeting moiety. A second aspect of this disclosure relates to the cell-targeting conjugates obtainable with this method. A third aspect of the disclosure described herein relates to pharmaceutical compositions comprising the cell-targeting conjugates.
1. A method for preparing a cell-targeting conjugate by coupling erlotinib or an auristatin to a targeting moiety, the method comprising:
i. providing a platinum(II)ethlyenediamine compound, either as Pt(en)Cl 2 or as Pt(en)(NO 3 ) 2 , having a first reactive group and a second reactive group, wherein the first reactive group and the second reactive group are NO 3 or Cl of the platinum(II)ethlyenediamine compound;
ii. providing at least one functional moiety, which is erlotinib or an auristatin;
iii. mixing said platinum(II)ethlyenediamine compound with the functional moiety, wherein the first reactive group reacts with said functional moiety, thereby forming a functional metal ion construct,
iv. mixing functional metal ion construct(s) with a targeting moiety selected from the group consisting of adalimumab, bevacizumab, catumaxomab, cetuximab, gemtuzumab, golimumab, infliximab, panitumumab, rituximab, and trastuzumab, such that the second reactive group forms a coordination bond with the targeting moiety such that a conjugate is formed and wherein the immunoreactivity of the targeting moiety of said conjugate remains substantially the same as the immunoreactivity of the unbound targeting moiety; and
v. separating the resulting conjugate from the mixture.
2. The method according to claim 1 , wherein functional metal ion constructs are mixed with the targeting moiety or moieties for from 10 to 240 minutes.
3. The method according to claim 1 , wherein the mixing is carried out at a temperature of from 20 to 50° C.
4. The method according to claim 1 , wherein before or during mixing, the pH of the mixture of the functional metal ion constructs and the targeting moiety or moieties is adjusted to from 4 to 12.
5. The method according to claim 1 , wherein at least one functional metal ion construct is bound via a coordination bond with one targeting moiety.
6. The method according to claim 1 , wherein 1-30 functional metal ion constructs are bound via a coordination bond with one targeting moiety.
7. A method of preparing a conjugate, the method comprising:
(a) mixing platinum complex platinum(II)ethylenediamine Pt(en)(NO 3 ) 2 , with a functional moiety selected from the group consisting of erlotinib and an auristatin, so as to form a metal ion construct;
(b) mixing the thus formed metal ion construct with a targeting moiety selected from the group consisting of adalimumab, bevacizumab, catumaxomab, cetuximab, gemtuzumab, golimumab, infliximab, panitumumab, rituximab, and trastuzumab to form a conjugate; and
(c) separating the conjugate from the mixture.