Homogeneity of antibody-drug conjugates critically impacts the therapeutic efficacy in brain tumors

Click Chemistry-Generated Auristatin F–Linker–Benzylguanine for a SNAP-Tag-Based Recombinant Antibody–Drug Conjugate Demonstrating Selective Cytotoxicity toward EGFR-Overexpressing Tumor Cells

“…51 Homogeneous ADC products such as ours are highly efficient in payload delivery, resulting in improved antitumour effects compared to heterogeneous ADC species. 52 These earlystage preclinical studies also confirm that stochastic labeling of mAbs with payloads inhibits smooth targeting of tumors by the generated ADC products, underscoring the need for a more precise approach in the development of ADCs with improved pharmacokinetic profiles. Herein, we have demonstrated that a recombinant ADC generated by a novel click chemistry conjugation of a SNAP-tagbased scFv fusion protein to an antineoplastic payload, AuriF, by a synthetic chemical linker, is a potent ADC candidate for the therapy of EGFR-overexpressing tumor cells.…”

“…Among several expected properties, the ability of the linker to self-immolate to release the payload, in addition to cleavage and ease-of-synthesis, forms the backbone of an effective and stable ADC . Homogeneous ADC products such as ours are highly efficient in payload delivery, resulting in improved antitumour effects compared to heterogeneous ADC species . These early-stage preclinical studies also confirm that stochastic labeling of mAbs with payloads inhibits smooth targeting of tumors by the generated ADC products, underscoring the need for a more precise approach in the development of ADCs with improved pharmacokinetic profiles.…”

Site-Specific Radiohalogenation of a HER2-Targeted Single-Domain Antibody Fragment Using a Novel Residualizing Prosthetic Agent

“…The solvents from the pooled HPLC fractions containing the product were removed by lyophilization overnight to yield a white powder (4.9 mg, 30.0% yield): 1 H NMR (500 MHz, CDCl 3 ) δ: 9.90 (s, 1H), 9.50 (s, 1H), 7.99 (d, 2H, J = 8.8 Hz), 7.74 (m, 3H), 7.58 (s, 1H), 7.45 (s, 1H), 7.07 (s, 1H), 6.87 (s, 1H), 5.17 (s, 2H), 3.47−3.64 (m, 18H), 3.36 (q, 2H, J = 5.9 Hz), 2.66 (m, 2H), 2.57 (m, 2H), 1.90 (quint, 2H, J = 6.2 Hz), 1.74 (quint, 2H, J = 6.0 Hz), 1.48 (s, 9H), 1.36 (s, 9H), 0.27 (s, 9H). 13 Synthesis of Boc 2 -iso-GMIB-PODS. DIPEA (6.4 μL, 36.5 μmol, 3.0 equiv) was added to a solution of PODS (19.7 mg, 36.5 μmol, 3.0 equiv) in 1.0 mL of DMF.…”

“…The pooled HPLC fractions containing the product were lyophilized overnight to yield a white powder (4.0 mg, 87.1% yield; trifluoroacetate salt): 1 H NMR (500 MHz, DMSO-d 6 ) δ: 10.42 (s, 1H), 8.57 (t, 1H, J = 5.3 Hz), 8.12 (s, 1H), 8.03 (m, 3H), 7.86 (m, 3H), 7.79 (d, 2H, J = 7.8 Hz), 7.28 (s, 3H), 4.38 (d, 2H, J = 6.0 Hz), 3.69 (s, 3H), 3.25−3.54 (m, 14H), 3.07 (q, 2H, J = 6.3 Hz), 2.61 (t, 2H, J = 6.9 Hz), 2.41 (t, 2H, J = 7.0 Hz), 1.74 (quint, 2H, J = 6.6 Hz), 1.61 (quint, 2H, J = 6.6 Hz). 13 Syntheses and Validation of the Anti-HER2 sdAb Conjugates. The sdAb conjugate iso-GMIB-PODS-5F7GGC was synthesized by a slight modification of a previously reported method for thiol-maleimide conjugation.…”

“…The heterogeneity and irreproducibility inherent to random labeling are significant hurdles to the effective deployment of radioimmunoconjugates, particularly at the higher radioactivity levels required for clinical TRT. Indeed, both the site of conjugation and the number of modifications per molecule can have a profound impact on the pharmacokinetic profile, affinity, and therapeutic efficacy of an immunoconjugate. − This is especially true in the context of sdAbs given their small size.…”