Insights on specialty building blocks, conjugation chemistry, process questions, and material selection
57 articles in total

The Nature Chemical Biology paper reports a de novo cyclic-peptide screening strategy for intracellular protein-protein interaction targets. The authors screened 15,360 fully random cyclic peptides and identified inhibitors of the Keap1/Nrf2 interaction, then used rapid design-build-test cycles to produce a membrane-permeable compound active in live cells.

The paper title, "GD2-directed NAMPT inhibition using antibody-drug conjugates in neuroblastoma," supports a narrow evidence boundary: this is a reported preclinical ADC design built around GD2 targeting and NAMPT inhibition. It should not be presented as a clinical-stage therapy, a regulatory-stage asset, or proof that metabolic payloads broadly outperform established ADC payload classes.

A therapeutic radiopharmaceutical normally brings together a targeting vector, a radionuclide, and a linker or chelator system that keeps the radioactive payload associated with the targeting molecule. The targeting vector can be a small molecule, peptide, antibody, antibody fragment, or other binding element. The radionuclide provides the radiation source. The chelator or conjugation chemistry sits between them and has to preserve both radiochemical stability and target-binding behavior.

Traditional ADC conjugation through reduced interchain cysteines or surface lysines produces heterogeneous mixtures. Each batch contains species with different drug-to-antibody ratios, different attachment sites, and potentially different pharmacokinetic profiles. Site-specific enzymatic methods aim to place the payload at a single, defined position on every antibody molecule.

The most important boundary in this case is the counting basis. The reported 37-step first-generation sequence and 14-step third-generation sequence refer to a key northern fragment of MK-0616, not to the full molecule. The broader synthesis of enlicitide decanoate is a separate route-level subject, and a full-molecule step count should not be inferred from the fragment comparison.

Nucleoside and nucleotide analogs form a major class of anticancer agents, but their phosphorylated active forms carry a negative charge that prevents passive membrane crossing. Conventional small-molecule formulations rely on nucleoside transporters and intracellular phosphorylation — a multi-step process that introduces pharmacokinetic and resistance variables.