Balancing Properties with Carboxylates: A Lead Optimization Campaign for Selective and Orally Active CDK9 Inhibitors

Area of Science:

• Molecular Biology
• Pharmacology
• Oncology

Background:

• Cyclin-dependent kinase 9 (CDK9) regulates transcription elongation.
• CDK9 inhibition downregulates tumor survival proteins like MCL-1.
• Existing pan-CDK inhibitors present clinical dosing and toxicity issues.

Purpose of the Study:

• To develop selective CDK9 inhibitors for oral administration.
• To overcome promiscuity and cardiovascular toxicity associated with early inhibitors.
• To identify potent and safe CDK9 inhibitors for cancer therapy.

Main Methods:

• Lead optimization of azaindole-based compounds.
• Introduction of carboxylates into the pharmacophore to enhance selectivity and reduce toxicity.
• Pharmacokinetic and in vivo efficacy studies in mouse models.

Main Results:

• Development of selective CDK9 inhibitors, compounds 14 and 16.
• Demonstrated reduced toxicity and improved pharmacokinetic profiles.
• Achieved robust in vivo anti-tumor efficacy following oral administration in mice.

Conclusions:

• Selective CDK9 inhibition is a viable therapeutic strategy for cancer.
• Azaindole-based inhibitors with carboxylate modifications offer a promising approach for oral administration.
• These novel inhibitors warrant further clinical investigation for cancer treatment.