Adverse reactions to WELIREG are frequent, with decreased hemoglobin and fatigue being prominent across indications, alongside other specific side effects and laboratory abnormalities detailed for patients with VHL disease and advanced renal cell carcinoma.

Adverse Reaction Profile of WELIREG in Clinical Settings

The administration of WELIREG is associated with a range of adverse reactions, with hematological toxicities, particularly decreased hemoglobin (anemia), being very common. In patients with VHL disease (LITESPARK-004 study), the most frequent ($\ge2525\ge$25%) adverse reactions, including laboratory abnormalities, were decreased hemoglobin, fatigue, musculoskeletal pain, increased creatinine, decreased lymphocytes, increased alanine aminotransferase, decreased sodium, increased potassium, and increased aspartate aminotransferase. Serious adverse reactions, including hypoxia and severe anemia requiring intervention, have been reported in both populations. Dosage interruptions and reductions due to adverse events are also common. The specific incidence and severity of other effects like visual impairment, dyspnea, and gastrointestinal issues vary by indication and are detailed in the clinical trial data. Any parts not explicitly mentioned (e.g., precise percentage of a very rare side effect not listed among the most common) would be "not specified in the description" within this summary but are available in the full document.