Eur J Cancer: Efficacy and safety of the combination of pabocinil, pembrolizumab and letrozole in the treatment of HR+ metastatic breast cancer

CDK4/6 inhibitors (CDK4/6i) can prevent the transition of the cell cycle from G1 to S phase and show promise in overcoming endocrine resistance

CDK4/6 inhibitors can regulate the immune response of breast cancer

Patients with stage IV HR+HER2-metastatic breast cancer were recruited and treated with pabocinil, pembrolizumab, and letrozole

From November 2016 to July 2020, a total of 23 patients were recruited, of which 20 were available for reactivity assessment, of which 4 were in cohort 1 and 16 were in cohort 2

Grade 3-4 adverse reactions are neutropenia (83%), leukopenia (65%), thrombocytopenia (17%) and elevated liver enzymes (17%)

PFS and OS in 2 cohorts

In cohort 1, 50% of patients achieved partial remission (PR), and 50% of patients had stable disease (SD)

In summary, the combination of Pabocinib , pembrolizumab, and letrozole is well tolerated in patients with HR+ metastatic breast cancer, and the complete remission rate can be as high as 31%

Yuan Yuan,Lee Jin Sun,Yost Susan E et al.