Panitumumab

Electrolyte Disturbance — representative incidence ~36%.

Hypomagnesemia is the signature renal-tubular toxicity and one of panitumumab's most frequent adverse effects. Any-grade rates cluster around 30-40% across RAS/KRAS wild-type mCRC trials, with grade 3-4 hypomagnesemia in roughly 3-7%; it is dose- and duration-related and deepens with cumulative exposure (Van Cutsem, J Clin Oncol 2007, established it as a frequent toxicity of the registration monotherapy trial). Rates are consistently HIGHER than with cetuximab: a pooled analysis put the relative risk of hypomagnesemia at ~12.6 for panitumumab versus ~3.9 for cetuximab (Petrelli, Expert Opin Drug Saf 2011), and in the head-to-head ASPECCT trial grade 3-4 hypomagnesemia was 7% with panitumumab versus 3% with cetuximab (Price, Lancet Oncol 2014).

Source: Van Cutsem, J Clin Oncol 2007

Reported injury signatures: Electrolyte Disturbance.

Subacute (~1–6 weeks) — Develops over weeks of therapy; cumulative, worsens with duration.

• Longer treatment duration / greater cumulative exposure
• Older age
• Concurrent cisplatin (additive distal tubular Mg wasting) or loop/thiazide diuretics
• Low or low-normal baseline serum magnesium
• Concurrent GI losses (diarrhea, dehydration) or poor oral intake
• Combination with chemotherapy rather than monotherapy

• Baseline and periodic serum magnesium, at least every 2 weeks (aligned with q2wk dosing)
• Co-monitor calcium and potassium alongside magnesium
• Proactive oral magnesium supplementation in at-risk patients
• Address concurrent GI losses and avoid unnecessary diuretics
• Continue monitoring magnesium for 6-8 weeks after the last dose, since hypomagnesemia can persist or worsen after stopping

• Serum magnesium at baseline and at least every 2 weeks during therapy, then periodically for 6-8 weeks after the last dose
• Co-monitor serum calcium and potassium (secondary hypocalcemia/hypokalemia)
• ECG if magnesium is severely low or the patient is symptomatic (QT/arrhythmia risk)
• Assess for tetany, cramps, weakness, and neuromuscular irritability
• Fractional excretion of magnesium (FEMg) when the renal-versus-GI source of hypomagnesemia is unclear

• Van Cutsem J Clin Oncol 2007 — panitumumab + best supportive care vs BSC in chemorefractory mCRC (PFS HR 0.54); registration trial that flagged hypomagnesemia as a frequent, duration-related toxicity.
• ASPECCT (Price, Lancet Oncol 2014) — head-to-head panitumumab vs cetuximab in KRAS wild-type chemorefractory mCRC; non-inferior overall survival, but grade 3-4 hypomagnesemia was higher with panitumumab (7% vs 3%).

• Panitumumab is the heavier magnesium-waster of the two anti-EGFR antibodies — pooled relative risk ~12.6 vs ~3.9 for cetuximab (Petrelli 2011) and grade 3-4 hypomagnesemia 7% vs 3% head-to-head in ASPECCT — so anticipate more, and more severe, hypomagnesemia than with cetuximab.
• The lesion is a functional distal-tubule electrolyte defect, not structural AKI: EGFR blockade removes tonic EGF stimulation of TRPM6 in the DCT, causing renal magnesium loss while creatinine and GFR stay normal.
• Always correct magnesium first — secondary hypocalcemia and hypokalemia are refractory to calcium/potassium repletion until the magnesium deficit is fixed.
• Hypomagnesemia is cumulative: it deepens with treatment duration and can persist or even transiently worsen for weeks after the last dose, so keep checking magnesium after stopping.
• Oral magnesium is often inadequate (diarrhea caps the dose) and the renal leak continues during therapy, so many patients need recurrent scheduled IV magnesium; check Mg together with Ca and K at least every 2 weeks.

• ADQI (2026) — The nephrotoxic effects of anti-cancer therapies: consensus report of the 34th Acute Disease Quality Initiative workgroupProvides expert-based statements (modified Delphi) on preventing and managing cisplatin/platinum-associated AKI, including isotonic IV hydration, attention to volume status and concomitant nephrotoxins, and incorporates evidence that IV magnesium supplementation may reduce cisplatin-associated AKI; emphasizes risk stratification and standardized AKI definitions.Nat Rev Nephrol · PMID 41361704
• SIRM (2022) — SIRM-SIN-AIOM: appropriateness criteria for evaluation and prevention of renal damage in the patient undergoing contrast medium examinations-consensus statements from Italian College of Radiology (SIRM), Italian College of Nephrology (SIN) and Italian Association of Medical Oncology (AIOM)Recommends eGFR-based renal risk assessment and pre/post-contrast isotonic saline or sodium bicarbonate hydration; advises maintaining a 5-7 day interval between iodinated contrast administration and cisplatin in cancer patients to reduce additive nephrotoxicity.Radiol Med · PMID 35303246
• KDIGO (2020) — KDIGO Controversies Conference on onco-nephrology: understanding kidney impairment and solid-organ malignancies, and managing kidney cancerIdentifies platinum compounds (especially cisplatin) as leading cytotoxic causes of acute tubular injury, AKI, and electrolyte/magnesium wasting; calls for interdisciplinary onco-nephrology care, accurate GFR estimation, and individualized drug dosing in patients with reduced kidney function.Kidney Int · PMID 33126977
• KDIGO (2020) — KDIGO Controversies Conference on onco-nephrology: kidney disease in hematological malignancies and the burden of cancer after kidney transplantationAddresses chemotherapy-associated AKI/CKD in hematologic cancer, GFR estimation and chemotherapy dosing in patients with reduced kidney function, and management priorities and research gaps for onco-nephrology care.Kidney Int · PMID 33276867
• ADDIKD (2025) — Integrating International Consensus Guidelines for Anticancer Drug Dosing in Kidney Dysfunction (ADDIKD) into everyday practiceProvides GRADE-based, drug-specific dose-adjustment recommendations for anticancer agents in kidney dysfunction (illustrated for methotrexate, cisplatin, carboplatin and nivolumab); the recommendations build on Part 1's standardised CKD-EPI eGFR assessment rather than Cockcroft-Gault creatinine clearance.EClinicalMedicine · PMID 40290844
• ADDIKD (2025) — Aligning kidney function assessment in patients with cancer to global practices in internal medicineThree consensus recommendations: assess kidney function by GFR (measured GFR or CKD-EPI eGFR), classify it using KDIGO categories, and use this uniform approach to dose anticancer drugs — moving cancer medicine away from Cockcroft-Gault estimated creatinine clearance.EClinicalMedicine · PMID 40290845
• ADDIKD (2025) — A methodology for determining dosing recommendations for anticancer drugs in patients with reduced kidney functionEstablishes that, where RCT evidence is lacking, anticancer drug dosing recommendations in kidney dysfunction should be derived by critically appraising observational literature via GRADE combined with structured international multidisciplinary consensus voting.EClinicalMedicine · PMID 40290846
• KDIGO (2013) — Diagnosis, evaluation, and management of acute kidney injury: a KDIGO summary (Part 1)Defines/stages AKI by serum creatinine and urine output; emphasizes avoiding nephrotoxins, maintaining euvolemia/perfusion, dose-adjusting drugs to kidney function, and monitoring high-risk patients — the framework applied to nephrotoxic anti-cancer agents.Crit Care · PMID 23394211
• KDIGO (2021) — Executive summary of the KDIGO 2021 Guideline for the Management of Glomerular DiseasesProvides the staging/treatment framework for drug-associated glomerular lesions (e.g., bisphosphonate- and interferon-related collapsing FSGS, VEGF-inhibitor podocytopathy/proteinuria), including immunosuppression and supportive RAAS-blockade strategies.Kidney Int · PMID 34556300
• KDIGO (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Management of ANCA-Associated VasculitisUpdates immunosuppressive induction (rituximab/cyclophosphamide), incorporates avacopan and lower-dose or glucocorticoid-sparing regimens — the management framework for drug- and checkpoint-inhibitor-associated ANCA/pauci-immune glomerulonephritis.Kidney Int · PMID 38388147
• KDIGO (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Management of Lupus NephritisUpdates first-line lupus nephritis therapy to combination immunosuppression with the addition of belimumab or a calcineurin inhibitor (voclosporin) — informs management of immune-complex/lupus-like glomerulonephritis encountered with immunotherapy.Kidney Int · PMID 38182299
• KDIGO (2025) — Executive summary of the KDIGO 2025 Clinical Practice Guideline for the Management of Immunoglobulin A Nephropathy (IgAN) and Immunoglobulin A Vasculitis (IgAV)Encourages liberal kidney biopsy and stricter proteinuria control (<0.5 g/d, ideally <0.3 g/d) with RAAS blockers, SGLT2 inhibitors, and targeted-release budesonide — the framework for IgA-dominant glomerular lesions, including those triggered by immune-modulating cancer therapy.Kidney Int · PMID 40975525