Skip to content
Back to full profile

HER2 bispecific antibody

Zanidatamab

Ziihera · ZANI

HER2 bispecific antibody · approved 2024 · 5 references

A biparatopic HER2 bispecific that clamps two HER2 epitopes at once — with a kidney signal that is, so far, mostly indirect.

Signature injury
Prerenal / Hemodynamic AKI
Severity
Mild
Reversibility
Reversible
Onset
Variable; tied to GI/volume events during treatment cycles rather than a fixed latency.

Signature kidney injury & incidence

Prerenal / Hemodynamic AKI.

No drug-specific nephrotoxicity rate is established. In HERIZON-BTC-01 the dominant toxicities were diarrhea and infusion reactions; any AKI is expected to be largely prerenal/volume-mediated (diarrhea, reduced intake) or related to the underlying biliary obstruction, rather than a direct tubular effect.

Source: Harding et al., Lancet Oncol 2023

Reported injury signatures: Prerenal / Hemodynamic AKI, Electrolyte Disturbance.

Renal toxicity profile

  1. Prerenal / Hemodynamic AKIPrimary
  2. Electrolyte DisturbanceSecondary

Onset timing & rechallenge

Variable / unpredictable — Tied to GI/volume events during treatment cycles rather than a fixed latency.

Mechanism of kidney injury

No established direct nephron injury. HER2 is not a major renal tubular antigen, so antibody-mediated tubular toxicity is not expected. The plausible pathway is prerenal/hemodynamic: GI losses from diarrhea and infusion-related volume shifts reducing effective renal perfusion. In cholangiocarcinoma/gallbladder cancer, post-renal obstructive AKI from biliary/ureteric compression and sepsis-associated ischemic injury are competing, often dominant, causes.

Clinical presentation

When present, a modest reversible creatinine rise in the setting of diarrhea/volume depletion; bland urinalysis; electrolyte derangements (hypokalemia, hypomagnesemia) tracking GI losses rather than a primary tubulopathy.

Management

Largely supportive: rehydrate, control diarrhea, replace electrolytes, and hold for severe volume-mediated AKI. True intrinsic renal injury has not been characterized; evaluate for alternative causes (obstruction, sepsis, contrast, concomitant chemotherapy) before drug attribution.

Risk factors

  • Treatment-related diarrhea and poor oral intake
  • Baseline CKD or volume depletion
  • Concurrent nephrotoxins or diuretics
  • Biliary/ureteric obstruction and sepsis in cholangiocarcinoma

Prevention

  • Aggressive antidiarrheal management and hydration
  • Correct volume status and exclude obstruction before attributing AKI to the drug

Renal dose adjustment

No dedicated renal dose adjustment is specified; as a ~150 kDa monoclonal-type bispecific, clearance is not renal and exposure is not expected to change meaningfully with reduced GFR. No data in dialysis. Manage by holding/resuming for toxicity rather than CrCl-based reduction.

Dialyzability & ESKD dosing

Not dialyzable — large bispecific antibody cleared by reticuloendothelial proteolysis, not removed by hemodialysis or peritoneal dialysis. No ESKD-specific dosing guidance exists; standard dosing is reasonable with attention to volume status during infusion.

Differential diagnosis

Distinguish prerenal/diarrhea-driven AKI (low FeNa, responds to volume) from post-renal obstruction (hydronephrosis on ultrasound — common in biliary cancer) and from sepsis-associated ATN. The drug itself is rarely the primary cause.

Monitoring

  • Stool frequency/volume and weight as surrogates for volume status
  • Imaging review for biliary/ureteric obstruction if creatinine rises
  • LVEF per label (HER2-directed cardiac monitoring)

Key trials & series

  • HERIZON-BTC-01 (Harding, Lancet Oncol 2023) — pivotal phase 2b carrying the safety signal
  • Real-world biliary-tract cohort (Smolenschi, Eur J Cancer 2025)

Clinical pearls

  • In biliary-tract cancer, think obstruction and sepsis first — antibody-mediated tubular injury is not an expected mechanism.
  • Electrolyte loss here is GI, not tubular: replace and treat the diarrhea.

Anticancer mechanism

Humanized bispecific antibody binding two non-overlapping (biparatopic) epitopes of the HER2 ectodomain (ECD2 and ECD4), driving receptor clustering, internalization and downregulation, plus complement-dependent and antibody-dependent cellular cytotoxicity. Approved for HER2-amplified (IHC 3+) previously treated unresectable/metastatic biliary-tract cancer.

Note

2024 approval with essentially no renal-specific literature. The prerenal/vascular signature is inferred from the GI-dominant toxicity profile and class reasoning, not from published nephrology data. Treat all renal claims as provisional.

Guidelines & consensus

Each recommendation below is this atlas's faithful summary of the source, not a quotation from it — follow the PubMed link for the wording the society published. Summaries may be superseded; consult the current full text and individualize to the patient.

  • 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 (2024) — Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease: known knowns and known unknownsEvaluate and risk-stratify CKD, manage to delay progression and its complications, and practise explicit medication management and drug stewardship — the framework the atlas's G1–G5 eGFR banding and every renal dose-adjustment recommendation sit inside. Because the guideline excludes dialysis and transplant recipients by its own statement of scope, its recommendations do not carry to those settings, where this atlas's dialyzability and post-transplant guidance rests on other sources.Kidney Int · PMID 38519239
  • 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

References

5 peer-reviewed references. Citation metadata via PubMed / NLM.

  1. 1.Zanidatamab for HER2-amplified, unresectable, locally advanced or metastatic biliary tract cancer (HERIZON-BTC-01): a multicentre, single-arm, phase 2b study.Harding JJ et al. · Lancet Oncol · 2023 · PMID 37276871
  2. 2.Real-world efficacy of zanidatamab in patients with HER2 positive advanced biliary tract cancers.Smolenschi C et al. · Eur J Cancer · 2025 · PMID 40319675
  3. 3.Onconephrology: mitigation of renal injury in chemotherapy administration.Selamet U et al. · Curr Opin Nephrol Hypertens · 2024 · PMID 38095483
  4. 4.New drug toxicities in the onco-nephrology world.Perazella MA et al. · Kidney Int · 2015 · PMID 25671763
  5. 5.Acute Kidney Injury in Patients With Cancer: A Review of Onconephrology.Gudsoorkar P et al. · Adv Chronic Kidney Dis · 2021 · PMID 35190106
Educational monograph from NephTox (nephtox.com). Not medical advice — verify against current guidelines before any clinical decision.