Discovery of a Novel Macrocyclic Noncovalent CDK7 Inhibitor for Cancer Therapy

Area of Science:

• Oncology
• Medicinal Chemistry

Background:

• Cyclin-dependent kinase 7 (CDK7) is crucial for cell cycle regulation and transcription, making it a key cancer target.
• Existing CDK7 inhibitors face clinical development hurdles due to severe gastrointestinal and hematotoxic side effects.

Purpose of the Study:

• To develop novel, noncovalent macrocyclic CDK7 inhibitors with improved safety profiles.
• To optimize compounds for enhanced potency, oral bioavailability, and reduced intestinal distribution.

Main Methods:

• Utilized a macrocyclization platform to optimize SY-5609, a leading clinical asset, into novel hit compounds 2 and 3.
• Conducted extensive structure-activity relationship (SAR) studies to identify compound 13.
• Evaluated compound 13 for in vitro activity, ADME properties, and in vivo antitumor efficacy in xenograft models.

Main Results:

• Compound 13 demonstrated potent in vitro activity and robust in vivo antitumor effects as a monotherapy.
• Optimized compound 13 exhibited improved Caco-2 permeability and reduced intestinal distribution due to lower basicity.
• Reduced blood/plasma ratio and intestinal distribution in rats suggest mitigation of gastrointestinal and hematotoxic side effects.

Conclusions:

• Novel macrocyclic CDK7 inhibitors, exemplified by compound 13, offer a promising therapeutic strategy for cancer.
• Compound 13's improved pharmacokinetic properties and reduced toxicity profile address limitations of previous CDK7 inhibitors.
• Further development of compound 13 warrants investigation for its potential in cancer treatment.