Supplementary Material for: Safe Administration of Fruquintinib in a Hemodialysis Patient with Metastatic Colorectal Cancer: A Case Report

**Background:** Fruquintinib is a selective vascular endothelial growth factor receptor (VEGFR) inhibitor approved for metastatic colorectal cancer (mCRC) that is refractory to standard therapies. While its efficacy and safety have been demonstrated in phase III trials, data on its use in patients undergoing hemodialysis for end-stage renal disease (ESRD) are lacking. We report the first known case of fruquintinib administration in a patient undergoing maintenance hemodialysis. **Case Presentation:** A 66-year-old woman with mCRC and ESRD undergoing thrice-weekly hemodialysis received multiple lines of chemotherapy, including FOLFOX, FOLFIRI, and regorafenib. Owing to progressive disease and limited treatment options, fruquintinib was initiated after informed consent was obtained. The starting dose was 3 mg/day, with escalation to 4 mg, and subsequently to 5 mg in later cycles. The drug was administered daily regardless of the dialysis schedule. Adverse events, graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, included Grade 1 fatigue and diarrhea and Grade 3 anemia requiring transfusion, which was attributed to underlying renal anemia rather than fruquintinib. Clinically significant hypertension, electrolyte disturbances, or other toxicities were not observed. Despite acceptable tolerability, computed tomography (CT) after three cycles indicated disease progression. **Conclusion:** This case suggests that fruquintinib may be administered safely to selected patients with mCRC on maintenance hemodialysis. Further data are needed to establish dosing strategies and monitor potential toxicities in this population.