Pharmacovigilance Analysis of the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) Events for Belzutifan

Background: Belzutifan is an anti-cancer medication used for the treatment of on Von Hippel–Lindau (VHL) disease-associated renal cell carcinoma. Belzutifan is a hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor. The adverse effects reported with belzutifan use include, but not limited to, fatigue, anemia, dyspnea and acute kidney injury (AKI). Methods: We explored belzutifan's reported adverse events using the FDA Adverse Reporting System (FAERS). We analyzed data that was used in the initial study to approve belzutifan from late 2021 until May 2024. Results: A total of 731 adverse events were reviewed. The most common side effect reported was anemia in 115 cases (14.9%). The second most common side effect were respiratory problems (both hypoxia and dyspnea) reported in over 92 cases (12.6%). The third most common side effect was fatigue, which was present in over 50 cases (6.8%). Among all adverse effects, over 543 (24.3%) were classified as severe cases that required hospitalization. Of those 543 cases, over 62 (8.5%) resulted in death. Conclusion: The side effects of belzutifan that were commonly reported in FAERS include fatigue, anemia and respiratory complaints. According to the LiteSpark study (1), the most common side effect was anemia,reported in over 25 percent of the patient cohort. According to our results that was also present amongst the most common side effects as well. With the new approval of this drug for the treatment of advanced RCC in the setting of VHL disease, it is crucial that there is ongoing monitoring and reporting of adverse events and safety monitoring as it is used to treat patients.Adverse event profile distrubution by cases of FAERS