Haematological toxicity associated with antineoplastic drugs: a pharmacovigilance analysis based on the FDA adverse event reporting system database.

Background: Antineoplastic drugs are effective for malignant tumours, but they frequently cause severe adverse drug reactions (ADRs), which seriously affect treatment continuity and patient prognosis. Post - marketing real - world safety monitoring is therefore critical. Methods: We conducted a retrospective pharmacovigilance study using FAERS (FDA Adverse Event Reporting System) data covering the period from 2004 Q1 to 2025 Q4. Safety signals were detected via disproportionate analysis, and associations were identified through LASSO and multivariable logistic regression, followed by an analysis of time to onset (TTO) for haematotoxicity. Results: A total of 347, 248 reports involving 367 antitumour drugs were analysed. Female patients (46.51%) outnumbered males (38.73%), with a median age of 59 years; patients aged 18 - 64.9 years represented 34.79% of the cohort. Fatal or life - threatening events were recorded in 78, 824 cases (22.70%). The leading drugs by report frequency were lenalidomide (ROR (Reporting Odds Ratio) = 1.51), methotrexate (ROR = 2.98), and rituximab (ROR = 3.69). Most events (61.65%) emerged within the first month, and median TTO differ significantly by sex. Furthermore, WSP analysis revealed that 26 of the top 30 drugs followed an early failure pattern. Conclusions: Our findings reveal a strong signal of haematological toxicity associated with antitumour agents, supporting enhanced routine monitoring to mitigate clinical risks. Nevertheless, confirmation through pharmacoepidemiological studies with rigorous causality assessment is required, owing to the inherent limitations of the FAERS spontaneous reporting system.