OBR OncologyPfizer Pushes Forward In Drug-Resistant Breast Cancer

Pfizer is lagging behind its peers with Ibrance, but the pharma giant is attempting to unveil the potential of CDK2 inhibitors to overcome CDK4/6 resistance.

At the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, Pfizer and Blueprint gave presentations on posters about their respective agents, and Incyte, Cyclacel, and a few private biotechs also had clinical trials going on. Although there are some positive signs, the research is still in its very early stages, and it is not apparent whether CDK2 inhibition is a workable monotherapy method.

• Pfizer, among others, is researching CDK2 inhibitors to overcome resistance to CDK4/6 inhibitors in ER-positive/HER2-negative breast cancer.
• CDK2 inhibition is being explored due to its potential role in resistance, with cyclin E1 upregulation and CDK2 activation promoting resistance to CDK4/6 inhibitors.
• Several trials are recruiting patients with CCNE1-amplified tumours, which are particularly prevalent in ovarian and breast cancers.
• Pfizer’s PF-07104091, a CDK2 inhibitor, showed promising early results in a study with CDK4/6 inhibitor-resistant metastatic breast cancer patients.
• Pfizer has initiated a combination trial of PF-07104091 with its selective CDK4 inhibitor PF-07220060, suggesting a potential strategy for overcoming resistance.