Design and Characterization of a Pyridone-Containing EZH2 Inhibitor Phosphate Prodrug

Area of Science:

• Medicinal Chemistry
• Pharmacology
• Oncology

Background:

• Enhancer of zeste homolog 2 (EZH2) is a key epigenetic regulator implicated in various cancers.
• Poor aqueous solubility of pyridone-containing EZH2 inhibitors limits their therapeutic potential.
• Prodrug strategies can overcome pharmacokinetic limitations of drug candidates.

Purpose of the Study:

• To design and synthesize a novel pyridone-derived phosphate prodrug of an EZH2 inhibitor.
• To evaluate the in vivo pharmacokinetic properties and anti-tumor efficacy of the prodrug.
• To assess the general applicability of this prodrug strategy for poorly soluble EZH2 inhibitors.

Main Methods:

• Synthesis of a pyridone-derived phosphate prodrug (compound 5).
• Pharmacokinetic studies in animals following oral administration to assess conversion to the parent compound (compound 2).
• In vivo efficacy evaluation using a diffuse large B-cell lymphoma Karpas-422 cell line-derived xenograft model.

Main Results:

• The prodrug (compound 5) was successfully synthesized.
• In vivo studies demonstrated efficient conversion of the prodrug to its parent compound (compound 2) after oral administration.
• The prodrug exhibited significant in vivo tumor growth inhibition in the diffuse large B-cell lymphoma xenograft model.

Conclusions:

• The developed phosphate prodrug strategy effectively improves the in vivo delivery and anti-tumor activity of EZH2 inhibitors.
• This approach offers a viable solution for enhancing the therapeutic potential of poorly soluble pyridone-containing EZH2 inhibitors.
• The prodrug strategy is potentially applicable to a broader range of pyridone-based EZH2 inhibitors, enabling sufficient in vivo exposures.