[Creatinine clearance estimation in the extremely elderly subjects]

Population Pharmacokinetics Analysis of Amikacin Initial Dosing Regimen in Elderly Patients

There are limited data of amikacin pharmacokinetics (PK) in the elderly population. Hence, we aimed to describe the population PK of amikacin in elderly patients (>70 years old) and to establish optimized initial dosing regimens. We simulated individual maximum concentrations in plasma (Cmax) and minimal concentrations (Cmin) for several dosing regimens (200–2000 mg every 24, 48, and 72 h) for patients with creatinine clearance (CCr) of 10–90 mL/min and analyzed efficacy (Cmax/minimal inhibitory concentration (MIC) ≥ 8) for MICs of 4, 8, and 16 mg/L and safety (Cmin < 4 mg/L). A one-compartment model best described the data. CCr was the only covariate associated with amikacin clearance. The population PK parameter estimates were 2.25 L/h for clearance and 18.0 L for volume of distribution. Dosing simulations recommended the dosing regimens (1800 mg) with dosing intervals ranging 48–72 h for patients with CCr of 40–90 mL/min based on achievement of both efficacy for the MIC of 8 mg/L and safety. None of the dosing regimens achieved the targets for an MIC of 16 mg/L. We recommend the initial dosing regimen using a nomogram based on CCr for an MIC of ≤8 mg/L in elderly patients with CCr of 40–90 mL/min.

Clinical impact of baseline renal function on the safety of radiotherapy with concurrent docetaxel for esophageal cancer in elderly patients

BACKGROUND

We aimed to compare the safety of radiotherapy with concurrent docetaxel (DOC-RT) for esophageal cancer (EC) in elderly patients who were divided into a creatinine clearance (Ccr) < 60 mL/min (Ccr-L) group and a Ccr ≥ 60 mL/min (Ccr-H) group.

METHODS

Eligible patients included those aged ≥ 76 years who were diagnosed with esophageal squamous cell carcinoma. The patients received radiotherapy (60 Gy in 30 fractions) and concurrent docetaxel (10 mg/m² weekly for six cycles), after which toxicity and treatment completion rates were retrospectively evaluated.

RESULTS

The 73 elderly EC patients receiving DOC-RT were divided into two groups for evaluation: the Ccr-L group (49 patients) and the Ccr-H group (24 patients). The median survival time for patients in the Ccr-L and Ccr-H groups was 21 and 20 months, respectively (p = 0.2). The incidence of grade 1 acute kidney injury was 8% vs. 8% (p = 1) in the Ccr-L and Ccr-H groups, respectively. No other hematological or nonhematological toxicities differed between patients in the two groups. No grade 4 or 5 toxicities were observed in the two groups. No significant difference was observed in the treatment completion rates (88% vs. 92%, p = 1) between patients in the Ccr-L and Ccr-H groups.

CONCLUSIONS

Regardless of baseline renal function, DOC-RT is a safe regimen for elderly patients with EC.