Pharmacokinetic study of the oral fluorouracil antitumor agent S-1 in patients with impaired renal function

Prospective evaluation and refinement of an S-1 dosage formula based on renal function for clinical application

In patients with impaired renal function, S-1-related toxicities increase due to higher exposure of 5-fluorouracil (5-FU). Our previous pharmacokinetic study in 16 cancer patients with various renal functions developed an S-1 dosage formula based on individual creatinine clearance (CLcr) and body surface area (BSA). To evaluate and refine the formula, this prospective study was conducted. Thirty-three patients with various renal functions received S-1 for 4 weeks at doses determined by the nomogram derived from the previously developed formula. A series of blood samples were collected after the first dose to calculate the area under the concentration-time curve (AUC) of 5-FU. Thirty patients with BSA of 1.14-1.84 m² and CLcr of 23.8-96.4 mL/min were assessable for pharmacokinetics. The observed daily AUC ranged from 712.6 to 2868.7 ng·h/mL, and 18 patients achieved the target AUC (1447.8 ± 545.4 ng·h/mL). Three patients experienced S-1-related grade 3 adverse events during the first course. In the population pharmacokinetic analysis from the combined data of 46 patients in this study and the previous study, sex was identified as a statistically significant covariate for 5-FU clearance. Hence, the refined formula includes sex as an additional factor: Recommended daily dose = target AUC × (14.5 + 8.23 × SEX [0 for female and 1 for male] + 0.301 × CLcr) × BSA. Revised nomograms for recommended daily doses derived from the refined formula can be used in clinical practice to achieve the target AUC ensuring efficacy and safety of S-1.

Rapidly progressive glomerulonephritis caused by tegafur/gimeracil/oteracil resulted in diabetes nephropathy, in a patient with minor risk of diabetes nephropathy: a case report

A 79-year-old Japanese male with a history of type 2 diabetes mellitus (T2DM) for 16 years was admitted to evaluate possible renal disease. The T2DM was well controlled in this patient using nutrition therapy without the need for any diabetes medication, and both diabetes retinopathy and proteinuria were negative. At the age of 78 advanced colorectal cancer (stage IIIa) was diagnosed and laparoscopic-assisted colectomy was performed. Following this procedure, the patient began treatment with tegafur/gimeracil/oteracil (S-1), 80 mg twice daily for 28 days of 42-day cycle. The patient received S-1 for 6 months, during which time, serum albumin decreased from 3.0 g/dL to 1.1 g/dL, urinary protein increased from negative to 3.0 g/day, and serum creatinine increased from 0.9 mg/dL to 2.1 mg/dL. Treatment with S-1 was discontinued, and furosemide 180 mg and prednisolone 30 mg treatment was initiated; however, serum creatinine levels continued to increase to 7.2 mg/dL and proteinuria continued to increase reaching a nephrotic range. A disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity was decreased to 27.0%. Renal biopsy showed Kimmelstiel-Wilson nodules, while immunofluorescence intensity of IgG subclass was IgG1 dominant, which was not compatible with diabetic nephropathy (DN). Plasma exchange was not affected. However, hemodialysis was initiated.The results of this investigation suggest that when S-1 monotherapy is performed in the case with DN, rapidly progressive glomerulonephritis (RPGN) may develop due to a condition similar to thrombotic microangiopathy, even in patients with a minor risk factor of DN.

Single-Dose Pharmacokinetics, Safety, and Tolerability of Avadomide (CC-122) in Subjects With Mild, Moderate, or Severe Renal Impairment

CC-122 (Avadomide) is a nonphthalimide analogue of thalidomide that has multiple pharmacological activities including immune modulation of several immune cell subsets, antigrowth activity, antiproliferative activity, and antiangiogenic activity. CC-122 as monotherapy and in combination with other agents is being evaluated for multiple indications including hematologic malignancies and advanced solid tumors. Given that renal clearance is one of the major routes of elimination for CC-122 and its clearance/exposure could be affected by renal impairment, a total of 50 subjects with various degrees of renal function were enrolled in an open-label, single-dose study to evaluate the impact of renal impairment on CC-122 pharmacokinetic disposition. The study showed that following administration of a single oral dose of 3 mg CC-122, renal impairment reduced both the apparent total plasma clearance and renal clearance of CC-122, but it had less impact on CC-122 absorption, as demonstrated by similar T_max and C_max among groups with various degrees of renal function. Compared with exposure in subjects with normal renal function, total plasma exposure to CC-122 increased by ∼20%, ∼50%, and ∼120% in subjects with mild, moderate, and severe renal insufficiency, respectively. Results from this study combined with modeling/simulation suggest that dose adjustments are necessary in patients with moderate or severe but not with mild renal impairment. Finally, a single dose of 3 mg CC-122 was safe and well tolerated by healthy subjects and subjects with mild, moderate, and severe renal impairment.

Pharmacokinetic study of the oral fluorouracil antitumor agent S-1 in patients with impaired renal function

Although dose reduction of S-1 is recommended for patients with impaired renal function, dose modification for such patients has not been prospectively evaluated. The aim of the present study was to investigate the pharmacokinetic parameters of 5-fluorouracil, 5-chloro-2,4 dihydroxypyridine and oteracil potassium, and to review the recommended dose modification of S-1 in patients with renal impairment. We classified patients receiving S-1 into 4 groups according to their renal function, as measured using the Japanese estimated glomerular filtration rate (eGFR) equation. The daily S-1 dose was adjusted based on the patient's eGFR and body surface area. Blood samples were collected for pharmacokinetic analysis. A total of 33 patients were enrolled and classified into 4 groups as follows: 10 patients in cohort 1 (eGFR ≥ 80 mL/min/1.73 m² ), 10 patients in cohort 2 (eGFR = 50-79 mL/min/1.73 m² ), 10 patients in cohort 3 (eGFR = 30-49 mL/min/1.73 m² ), and 3 patients in cohort 4 (eGFR < 30 mL/min/1.73 m² ). Those in cohorts 3 and 4 treated with an adjusted dose of S-1 showed a similar area under the curve for 5-fluorouracil (941.9 ± 275.6 and 1043.5 ± 224.8 ng/mL, respectively) compared with cohort 2 (1034.9 ± 414.3 ng/mL). Notably, while there was a statistically significant difference between cohort 1 (689.6 ± 208.8 ng/mL) and 2 (P = 0.0474) treated with an equal dose of S-1, there was no significant difference observed in the toxicity profiles of the cohorts. In conclusion, dose adjustment of S-1 in patients with impaired renal function using eGFR is appropriate and safe.