What is known and objective Augmented renal clearance (ARC; hyperfiltration with over 130 mL/min/1.73 m2 of creatinine clearance (CLcr)) commonly occurs in critically ill patients. Recent reports indicate that ARC also occurs in haematologic malignancies. However, the risk factors for ARC in haematologic malignancies remain unknown, and there is no established method to predict ARC in haematologic malignancies. Our objective was to explore the risk factors for ARC retrospectively and develop a scoring method to predict ARC. Methods A single‐centre, retrospective, observational cohort study was conducted at the Sendai Medical Center (Sendai, Japan); 133 patients (April 2017‐March 2019) and 41 patients (April‐November 2019) with haematopoietic tumours who were administered vancomycin were enrolled in the analysis and validation cohorts, respectively. To define ARC, we calculated the vancomycin serum concentration when CLcr = 130 mL/min/1.73 m2 using a one‐compartment model. Patients with ARC were defined as those whose actual concentration of vancomycin remained lower than the calculated concentration. Using the analysis cohort, we explored risk factors of ARC and developed a scoring method to predict ARC in haematologic malignancies. The reproducibility of the scoring system was demonstrated using the validation cohort. Results and discussion Through multivariate analysis, young age (P < .001), leukaemia (P = .001) and low serum creatinine (P < .001) were identified as risk factors. According to this result, we established the ARC detection method: age ≤ 50 years = 3 points, 50 years < age ≤65 years = 1 point, leukaemia = 2 points, low SCr = 2 points; patients scoring ≥ 5 points represent the ARC high‐risk group. Using this scoring system, we could detect ARC with a sensitivity and specificity of 60.0% and 89.7% in the analysis cohort and 90.0% and 90.9% in the validation cohort, respectively. What is new and conclusion Our scoring method could predict ARC in haematologic malignancies and is useful as a simple screening tool for ARC.

Background: Eribulin therapy has recently attracted attention from various viewpoints, including quality of life, and is considered a standard therapy for inoperable or recurrent breast cancer. Although a reduction in renal function reportedly decreases total eribulin clearance, its association with dose-limiting toxicity and the reduction of neutrophils remain unclear. Aim: This study was aimed at analyzing the association between decreased renal function prior to eribulin administration and the occurrence of neutrophil reduction and time to treatment failure in patients with breast cancer. Methods and Results: We retrospectively assessed patients with breast cancer, who underwent eribulin therapy between July 2011 and March 2018. Multivariate analysis revealed creatinine clearance <70 mL/min and serum albumin levels <3.9 mg/dL as predictive factors for neutrophil reduction. Even on increasing the relative dose intensity by these factors, no difference in time to treatment failure was observed, suggesting that treatment efficacy is potentially unaffected. Conclusions: For continuous eribulin therapy, eribulin may need to be administered to individual patients in accordance with renal function and albumin levels before treatment initiation.