Chronotherapy as a Potential Strategy to Reduce Ifosfamide-Induced Encephalopathy: A Preclinical Study in a Murine Model

Abstract

PurposeNearly five decades after its introduction into clinical oncology, ifosfamide (IFO) remains a widely used alkylating chemotherapeutic agent for the treatment of sarcomas, germ-cell tumors and selected hematological malignancies in both adult and pediatric oncology. Its use is limited by severe toxicities, particularly hemorrhagic cystitis and central nervous system complications. Recent studies have highlighted the persistence and complexity of IFO-related neurotoxicity (Idle & Beyo[g]lu, 2023 [1]), including an increased risk of encephalopathy associated with certain formulations in pediatric populations (Hillaire-Buys et al., 2019 [2]) and differences between originator and generic formulations (Chambord et al., 2023 [3]), these concerns prompted a regulatory safety review by the European Medicines Agency [4]. Circadian rhythms are increasingly recognized as key regulators of drug metabolism and toxicity. In a previous chronotolerance study, we demonstrated a marked time-of-day-dependent variation in lethal IFO toxicity at the LD50 dose (Chennoufi & Boughattas, 2025 [5]). This study aimed to determine whether sublethal IFO exposure (LD30) also exhibits circadian variation in multi-organ toxicity. MethodsOne hundred male Swiss albino mice synchronized under a 12:12 h light-dark cycle received IFO LD30 at four circadian times (1, 7, 13 and 19 hours after light onset, HALO). Hematological parameters, hepatic enzymes, histopathology and neurobehavioral performance were evaluated. ResultsToxicity varied significantly according to dosing time. Administration at 7 HALO produced the most pronounced injury, whereas dosing at 13 HALO was associated with reduced hepatic, renal and bladder damage. Encephalopathy-related lesions were predominantly observed at 19 HALO. ConclusionSublethal IFO toxicity exhibits clear circadian variation. Administration at 13 HALO corresponded to the previously identified peak of LD50 tolerance, supporting further exploration of time-adjusted ifosfamide administration strategies to improve treatment tolerability.