Naxitamab

The kidney is an innocent bystander of the on-target infusion reaction rather than the site of a primary drug lesion. GD2 engagement triggers intense, largely complement-driven acute inflammation during each infusion, producing an infusion-related reaction spectrum that includes vasodilation, increased vascular permeability with capillary leak/third-spacing, bronchospasm, urticaria, and — most importantly for the kidney — abrupt hypotension. Effective circulating volume falls (from vasodilation, capillary leak, and any accompanying vomiting/diarrhea), renal perfusion pressure and glomerular filtration drop, and a hemodynamic/prerenal pattern of azotemia can result. Superimposed on this are swings toward hypertension: acute on-treatment hypertension is an expected naxitamab toxicity (partly pain- and catecholamine-mediated, partly from fluid resuscitation), so patients oscillate between hypo- and hypertension during and after the infusion. There is no evidence of direct tubular, interstitial, or glomerular immune injury; sustained or severe hypotension is what could tip a prerenal picture toward ischemic acute tubular necrosis.

Manifestations cluster around the infusion (given on Days 1, 3, and 5 of each 4-week cycle). Patients develop pain, urticaria/rash, bronchospasm, cough, nausea/vomiting, tachycardia, and hypotension, sometimes with a compensatory or subsequent hypertensive phase. The renal correlate is a transient rise in serum creatinine and reduced urine output tracking the hypotensive episode, typically recovering as perfusion is restored. Overt capillary-leak syndrome (edema, hypoalbuminemia, hypoxia) is uncommon with the short outpatient infusions used for naxitamab but is the severe end of the spectrum. Electrolyte disturbances are generally minor and secondary to fluid shifts and resuscitation.

Manage the hemodynamics, not the kidney per se. For infusion-related hypotension, follow established stepwise algorithms: slow or interrupt the infusion, give an IV isotonic fluid bolus, position supine/Trendelenburg, and escalate to vasopressors for refractory or severe drops; resume at a reduced rate once stable. Treat acute hypertension with monitoring and antihypertensives per protocol, avoiding overcorrection given the coexisting hypotension risk. Bronchospasm/allergic features are treated with bronchodilators, antihistamines, and steroids. Restoring renal perfusion promptly is the key renal intervention; a transient creatinine bump usually resolves with hemodynamic stabilization. Most events are managed in the outpatient setting; dose is often reduced or a day's dose halved for significant reactions, with full dosing typically resumed at the next infusion. Persistent, severe, or life-threatening reactions warrant treatment interruption or discontinuation.Lesion-level management framework

No pharmacokinetic renal dose adjustment is defined: as a ~150 kDa IgG1 monoclonal antibody, naxitamab is cleared by reticuloendothelial catabolism, not renal excretion, so creatinine clearance does not drive dosing. Dose modifications are triggered by infusion reactions and hemodynamic toxicity — slowing the rate, interrupting, reducing the dose, or giving a half-dose for a given day (as has been done for infusion-associated hypotension), with subsequent full doses usually tolerated. There is no established creatinine- or eGFR-based dose reduction.

Not dialyzable. Naxitamab is a large (~150 kDa) IgG1 monoclonal antibody with a large-molecule volume of distribution and reticuloendothelial clearance; it is not removed by hemodialysis or peritoneal dialysis, and dialysis has no role in enhancing its elimination.

The transient creatinine rise should be read as hemodynamic/prerenal from the infusion reaction, but consider: (1) volume depletion from concurrent vomiting/diarrhea or poor intake; (2) prolonged or severe hypotension tipping into ischemic acute tubular necrosis; (3) full anti-GD2 capillary-leak syndrome (well documented in the class — e.g., fatal capillary leak with dinutuximab beta plus IL-2), which causes intravascular volume loss and hypoperfusion; (4) nephrotoxicity from co-administered agents or supportive drugs (though partner cytotoxics like irinotecan/temozolomide are not classically nephrotoxic); (5) contrast- or sepsis-associated AKI in a heavily pretreated child; and (6) hypertension-related processes (e.g., PRES), which are uncommon with short outpatient naxitamab infusions.