Managing Amivantamab Infusion Reactions: A Clinical Guide for International Practice

　　Amivantamab,a humanized bispecific antibody administered via intravenous infusion,requires careful monitoring for Infusion-Related Reactions(IRRs).These acute adverse events,driven by cytokine release(e.g.,IL-6,TNF-α),predominantly occur during the first or second cycles of treatment.Clinical data indicate that over half of patients experience some degree of reaction during their initial infusion,presenting a significant challenge for patient safety.

　　Symptoms range from mild to severe.Mild-to-moderate manifestations include pyrexia,chills,flushing,headache,mild dyspnea,chest tightness,nausea,dizziness,or rash.Severe reactions,though less common,can be life-threatening,presenting as severe hypotension,bronchospasm,laryngeal edema,tachycardia,or altered mental status.Symptoms typically emerge within 30 minutes to 2 hours after the start of infusion and correlate with the infusion rate.

　　To mitigate these risks,standardized premedication is mandatory before every infusion.Patients should receive a combination of an antihistamine(e.g.,diphenhydramine),a corticosteroid(e.g.,dexamethasone),and an antipyretic(e.g.,acetaminophen).This regimen helps suppress histamine release,modulate inflammatory pathways,and manage fever,thereby reducing the severity of cytokine release syndrome.

　　Graduated infusion rate escalation is critical for preventing severe toxicity.The initial infusion must follow a step-up dosing schedule:starting at a low rate(e.g.,25 mL/h)and increasing incrementally at intervals(e.g.,every 30 minutes)based on patient tolerance.This approach allows physiological adaptation and significantly lowers the risk of sudden,severe reactions.Subsequent infusions may be administered at a faster rate if prior cycles were well-tolerated,but vigilance remains essential.

　　In the event of a mild-to-moderate reaction,the infusion should be slowed or temporarily interrupted.Symptomatic relief can be provided with additional antihistamines,corticosteroids,or antipyretics.Once symptoms have completely resolved,the infusion may resume at a slower rate.Most mild reactions are manageable without compromising the overall treatment course.

　　Severe reactions necessitate immediate and permanent discontinuation of the infusion.Emergency interventions include administering epinephrine,high-flow oxygen,intravenous fluids,bronchodilators,and high-dose systemic corticosteroids.Transfer to an intensive care unit for close monitoring may be required.Permanent discontinuation of Amivantamab is generally recommended following Grade 3 or 4 infusion reactions.

　　Despite a lower incidence in subsequent cycles,vigilance must be maintained throughout all treatments.Patients require continuous monitoring of vital signs—blood pressure,heart rate,respiratory rate,and oxygen saturation—during the infusion and for at least one hour afterward.Medical observation should continue until it is certain no delayed reactions will occur,ensuring patient safety upon discharge.