Efficacy of Pazopanib for a Patient with FGFR1-Amplified Breast Cancer: A Case Report

Fibroblast growth factor receptor 1 (FGFR1) amplification is associated with endocrine therapy resistance and a poor prognosis in hormone receptor-positive breast cancer. However, effective therapeutic options for FGFR1 amplification remain limited. We report a patient with metastatic breast cancer who was treated with pazopanib for FGFR1 amplification in the BELIEVE trial.

A 71-year-old woman was diagnosed with bilateral luminal-HER2 type breast cancer (pT2N1M0) 18 years previously, and underwent bilateral mastectomy and axillary lymph nodes dissection followed by adjuvant therapy. She had no family history. She developed bone and liver metastases 4 years after the operation and her condition became worse, despite multiple lines of endocrine and cytotoxic therapies. She was treated with pazopanib under the trial because comprehensive genomic profiling showed FGFR1 amplification. After 3 months, computed tomography demonstrated necrosis and shrinkage of liver metastases, consistent with a partial response. Serum tumor markers (CEA and CA15-3) showed a sustained decline, reaching their lowest levels at approximately 5 months, consistent with radiologic response. Treatment was continued for 8 months until tumor markers increased and imaging revealed disease progression. Adverse events were manageable.

Pazopanib is likely to have a clinical benefit for patients with FGFR1-amplified breast cancer using genomic profiling in personalized oncology at the early stage of metastasis.