B. Calciphylaxis
Cholangiocarcinoma is a rare malignant neoplasm that arises from intrahepatic and/or extrahepatic bile ducts. Treatment options include targeted systemic therapy, localized radiation therapy, and surgery. Treatments are based on tumor stage and location within the biliary tract. Standard-of-care first-line therapy for either locally advanced or metastatic cholangiocarcinoma is gemcitabine and cisplatin.1 In the era of next-generation sequencing, targetable alterations have been identified in cholangiocarcinoma. One such alteration is FGFR2 fusions, which is identified in 15% of patients with intrahepatic cholangiocarcinoma.2,3 In April 2020, the US Food and Drug Administration granted accelerated approval for pemigatinib, an oral inhibitor of FGFR1, FGFR2, and FGFR3. Common adverse effects affecting more than 30% of patients receiving oral therapy include alopecia, dysgeusia, diarrhea, and fatigue.4 Overall, the most common adverse effect of pemigatinib is hyperphosphatemia, which develops in approximately 60% of patients.2