Cetuximab & Panitumumab
Erbitux · Vectibix · Anti-EGFR antibody
TRPM6 magnesium wasting.
LYTE
MildOpen →
Oral fluoropyrimidine + TP inhibitor
Trifluridine/tipiracil
Lonsurf · FTD-TPI
An oral fluoropyrimidine combo whose tipiracil component accumulates as the kidney fails — driving cytopenias.
ModerateOral fluoropyrimidine / thymidine-phosphorylase inhibitor · approved 2015
Refractory metastatic colorectal cancerPreviously treated metastatic gastric/gastroesophageal adenocarcinoma
Signature kidney injury
Electrolyte Wasting
Direct intrinsic nephrotoxicity is not a prominent feature; the renal relevance is pharmacokinetic. The tipiracil component is mainly renally excreted, so its exposure rises with declining GFR: a phase I study found tipiracil AUC increased significantly with renal-impairment severity and required a dose reduction (to 20 mg/m2 twice daily) in severe impairment, while grade >= 3 adverse events — chiefly hematologic (anemia, neutropenia) — were more frequent across the impaired cohorts. Real-world data confirm more early severe neutropenia in patients with reduced creatinine clearance.
Source: Saif et al., Cancer Chemother Pharmacol 2021 (renal-impairment phase I); Saito et al., Sci Rep 2024
Mechanism of kidney injury
The kidney is the route of elimination rather than the primary target. Tipiracil is predominantly renally cleared; as GFR falls its plasma exposure climbs, prolonging trifluridine's effective exposure and amplifying systemic, principally myelosuppressive, toxicity (neutropenia, anemia). This accumulation can secondarily contribute to volume depletion (mucositis, GI losses) and prerenal/tubular stress. Hematologic and constitutional toxicity dominate; there is no well-characterized direct tubular lesion. The renal management priority is dose reduction to prevent exposure-driven cytopenias.
Clinical presentation
Predominantly hematologic toxicity (neutropenia in roughly a third, leukopenia, anemia, occasional febrile neutropenia) and GI effects, amplified in renal impairment. Electrolyte disturbances and a creatinine rise can accompany severe GI losses; a discrete intrinsic renal lesion is not characteristic.
Onset
Within the first one to two cycles, especially early severe neutropenia in patients with reduced creatinine clearance.
Reversibility
Reversible
Anticancer mechanism
Oral combination of trifluridine (FTD), a thymidine-based nucleoside analog incorporated into DNA to cause dysfunction, and tipiracil (TPI), a thymidine-phosphorylase inhibitor that blocks FTD degradation and raises its systemic exposure. Approved for refractory metastatic colorectal cancer and for previously treated metastatic gastric/gastroesophageal cancer.
Management
Manage toxicity by dose interruption and reduction; supportive care for cytopenias (growth factors, transfusion) and hydration for GI losses. In severe renal impairment use the reduced starting dose; reassess renal function and counts each cycle.
Risk factors
- Moderate-to-severe renal impairment (CrCl < 60 mL/min)
- Low baseline blood counts
- Older age and low body surface area
- Volume depletion from diarrhea/poor intake
Prevention
- Assess creatinine clearance before starting and reduce dose for severe renal impairment per label
- Closely monitor counts (especially during the first cycles) in renal impairment
- Maintain hydration; manage GI losses
- Hold/dose-modify for grade >= 3 hematologic toxicity
Note · The renal signal is exposure/accumulation (tipiracil is renally cleared), not a primary tubular toxin. The actionable issue is reduced starting dose and intensified count monitoring in renal impairment; no dosing data exist for end-stage renal disease.
Clinical depth
Renal dose adjustment
No adjustment for mild renal impairment (CrCl 60-89 mL/min); for moderate impairment (CrCl 30-59) reduce the starting dose per current label; for severe impairment (CrCl 15-29) use a further-reduced dose (20 mg/m2 twice daily in the PK study). Not studied in ESKD/dialysis — avoid or use with extreme caution.
Dialyzability & ESKD dosing
Tipiracil is renally cleared and its dialyzability is not well characterized; no established dosing in dialysis-dependent patients. Use is generally avoided in ESKD.
Differential diagnosis
Distinguish exposure-driven cytopenias plus prerenal AKI (GI losses) from an intrinsic nephropathy; a creatinine rise here usually reflects volume depletion or unrecognized CKD increasing tipiracil exposure rather than a direct renal lesion.
Monitoring
- Creatinine clearance/eGFR before initiation and periodically
- Complete blood count before each cycle and at nadir (more often early in renal impairment)
- Volume status with diarrhea/mucositis
- Electrolytes if GI losses are significant
Key trials & series
- RECOURSE (Mayer NEJM 2015) pivotal colorectal trial
- Saif Cancer Chemother Pharmacol 2021 renal-impairment phase I PK/dosing study
- Saito Sci Rep 2024 real-world early-neutropenia analysis
Clinical pearls
- Tipiracil is renally cleared — reduce the starting dose and watch counts closely once CrCl drops below 60 mL/min.
- Early severe neutropenia in the first cycle is the tell-tale of overexposure in a patient with reduced kidney function.
- The kidney is the elimination route, not the primary target — there is no signature tubular lesion.
- No ESKD dosing exists; avoid in dialysis-dependent patients.
Where it strikes
Nephron segments
Proximal Tubule
Bulk reabsorption + drug uptake (OCT2, OATs)
Injury signatures
Electrolyte Wasting
Beyond the kidney
Class-level context for the major non-renal toxicities of oral fluoropyrimidine + tp inhibitors.
Gastrointestinal
Diarrhea, colitis, mucositis, perforation
- Mucositis and diarrhea
Hepatic / Liver
Transaminitis, hepatitis, VOD/SOS
- Transaminitis (methotrexate)
Hematologic
Cytopenias, thrombosis, TMA
- Myelosuppression
Pulmonary
Pneumonitis, ILD, effusions, hypertension
- Methotrexate / gemcitabine pneumonitis
Evidence
4 peer-reviewed references. Citation metadata via PubMed / NLM.
LandmarkA phase I, open-label study evaluating the safety and pharmacokinetics of trifluridine/tipiracil in patients with advanced solid tumors and varying degrees of renal impairment.Saif MW et al. · Cancer Chemother Pharmacol 2021 · PMID 34097100Defines renal dosing: tipiracil AUC rises with renal-impairment severity, grade >= 3 (mainly hematologic) AEs more frequent, with a reduced 20 mg/m2 dose for severe impairment.PMIDImpact of renal impairment on early development of severe neutropenia with trifluridine/tipiracil treatment for metastatic colorectal cancer.Saito Y et al. · Sci Rep 2024 · PMID 39506021Real-world cohort: renal impairment was an independent risk factor for early severe neutropenia, confirming the exposure-toxicity relationship.PMIDRandomized trial of TAS-102 for refractory metastatic colorectal cancer.Mayer RJ et al. · N Engl J Med 2015 · PMID 25970050Pivotal RECOURSE trial establishing efficacy and the dominant hematologic safety profile (neutropenia 38%).PMIDConventional Chemotherapy Nephrotoxicity.Gupta S et al. · Adv Chronic Kidney Dis 2021 · PMID 35190107Onconephrology reference for fluoropyrimidine/antimetabolite renal handling and dose-modification principles.