Adebrelimab Plus Apatinib and Etoposide for the Treatment of HER2-Negative Breast Cancer Brain Metastasis

Some studies have shown that approximately 15% of patients with advanced hormone receptor (HR) positive breast cancer and 1/3 of triple negative breast cancer will develop brain metastasis. At present, there is no unified drug treatment standard for HER2-negative breast cancer brain metastasis (BCBM). The evidence of single traditional chemotherapy drug as the main treatment of brain metastasis is not sufficient. Some exploratory studies on HER2-negative BCBM have shown that the central nervous system objective response rate (CNS-ORR) of anti-angiogenic drugs combined with chemotherapy is around 55%-80%。 Adebrelimab (a humanized PD-L1 monoclonal antibody) specifically blocks the binding of PD-1 and PD-L1, terminates the immunosuppressive signal produced by T cells, and makes T cells re-recognize tumor cells and kill them, thereby inhibiting tumor growth. In China, Adebelizumab has been approved for using in combination with chemotherapy as a first-line treatment for extensive stage small cell lung cancer. Apatinib (a small molecule VEGFR tyrosine kinase inhibitor) mainly plays an anti-angiogenic effect in the treatment of malignant tumors by inhibiting VEGFR. Apatinib has been approved monotherapy for advanced gastric adenocarcinoma or gastroesophageal junction adenocarcinoma that has progressed or relapsed after at least two systematic chemotherapies, advanced liver cancer that has failed or is intolerable after at least first-line systematic treatment, and first-line treatment in patients with unresectable or metastatic hepatocellular carcinoma combined with camrelizumab.

Due to the lack of effective drug therapy for HER2-negative BCBM, a variety of treatment combinations are still being explored. We hypothesized that adebrelimab plus apatinib and etoposide is an explorable and effective treatment for HER2- negative BCBM.