TITLE:
Prolonged Pemetrexed Maintenance (42 Cycles over 34 Months) in Metastatic Lung Adenocarcinoma: Durable Disease Control and Progressive Renal Impairment—A Case Report
AUTHORS:
Maryem Agaraoui, Mounir Belcadi Abbassi, Lamyae Amaadour, Karima Oualla, Zineb Benbrahim, Samia Arifi, Nawfel Mellas
KEYWORDS:
Lung Adenocarcinoma, Pemetrexed, Maintenance Chemotherapy, Nephrotoxicity, Zoledronic Acid, Case Report
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.17 No.11,
November
5,
2026
ABSTRACT: Continuation maintenance with pemetrexed after platinum-pemetrexed induction is a standard of care in non-squamous non-small cell lung cancer, but very prolonged exposure and its renal consequences are rarely documented in detail. We report the case of a 55-year-old woman with stage IV lung adenocarcinoma (EGFR wild-type, ALK not rearranged; nodal, bone and brain metastases) and an ECOG performance status of 1. She received six cycles of cisplatin-pemetrexed, followed by 42 cycles of pemetrexed maintenance over approximately 34 months (M6 - M40; M0 = start of chemotherapy), with zoledronic acid from M17; the disease remained stable on every quarterly CT scan. After a nine-month break at her own request, progression occurred at M49. Rechallenge with platinum-pemetrexed (four cycles planned, incomplete because of supply shortages) was followed by approximately 19 months of stability from its start, including approximately 12 months without any treatment after M57, which may reflect indolent tumour behaviour rather than a treatment effect. A second pemetrexed maintenance could not be started because of impaired renal function: only dose-adjusted zoledronic acid was given. Cockcroft-Gault clearance fell from 85 - 130 mL/min during induction to 45 mL/min at M40 and 24 mL/min at M58. No dose of pemetrexed was given with a clearance below 45 mL/min; it was postponed from M54 and then permanently discontinued at M58. The only value available at M71 is 54 mL/min, suggesting partial and uncertain recovery after pemetrexed discontinuation. Cisplatin, carboplatin, zoledronic acid and repeated exposure to contrast media may have contributed to the renal injury, and no kidney biopsy was performed. This single case cannot establish the efficacy of prolonged maintenance or of rechallenge; it illustrates the need for renal monitoring with a single estimator before each cycle, hydration, review of nephrotoxic medications, and shared decisions with nephrology when clearance approaches 45 mL/min.