Avacopan: Key Points on Dosing and Safety Monitoring for ANCA-Associated Vasculitis

Avacopan is an oral selective complement C5a receptor inhibitor indicated for use in combination with immunosuppressants for the treatment of adult anti-neutrophil cytoplasmic antibody-associated vasculitis. The standard recommended dose is 30 mg taken orally twice daily (morning and evening), for a total daily dose of 60 mg. The capsules can be taken with or without food, but it is advised to take them at the same times each day to maintain stable plasma levels. Patients should avoid missing or doubling doses.

Dose adjustments are required in specific clinical situations. Hepatotoxicity is a key focus for monitoring and intervention. Treatment should be permanently discontinued if alanine aminotransferase or aspartate aminotransferase levels increase to more than 5 times the upper limit of normal. For increases between 3 to 5 times the upper limit, treatment should be interrupted until levels normalize, after which the original dose may be re-attempted. If elevation recurs, treatment should be stopped. Elevations in bilirubin or prolonged prothrombin time are also indications for discontinuation. Furthermore, if the neutrophil count falls below 1.0×10⁹/L, treatment should be paused and the cause investigated. Upon recovery, the original dose may be re-initiated; if the decrease recurs, the dose should be reduced to 30 mg once daily.

For patients with renal impairment, no dose adjustment is typically needed for mild to moderate impairment. For patients with end-stage renal disease on dialysis, clinical data are limited. Use with caution under therapeutic drug monitoring, with close attention to liver function. Regarding drug interactions, co-administration with strong CYP3A4 enzyme inducers (e.g., rifampin, carbamazepine) should be avoided. If co-administration is unavoidable, an increase in the avacopan dose with close monitoring may be considered, although this is not routinely recommended per the prescribing information.

Special population use requires individualized assessment. For patients aged 65 and older, no initial dose adjustment is usually necessary, but more frequent monitoring of liver function is recommended due to a potentially increased risk of hepatotoxicity. The safety and efficacy in pediatric patients have not been established. For pregnant individuals, the decision to continue therapy should be made by a physician following a strict assessment of treatment benefits versus potential risks.