Dose modifications and pharmacokinetics of adjuvant cisplatin monotherapy while on hemodialysis for patients with hepatoblastoma

Characteristics of patients with liver tumors deemed ineligible for enrollment on Children's Oncology Group trial AHEP1531: An opportunity to expand inclusion criteria and improve outcome

BACKGROUND

Specific patients with hepatoblastoma (HB) and hepatocellular carcinoma (HCC) do not meet eligibility criteria for Children's Oncology Group (COG) trials, limiting an understanding of how comorbidities affect the outcome. We define such a population for future-focused care improvements.

METHODS

A questionnaire was sent to COG institutional principal investigators to obtain anonymized data regarding patients with a liver tumor diagnosis not enrolled on AHEP1531 due to ineligibility by trial criteria or other reasons (excluding parent/patient preference).

RESULTS

Responses received for 55 patients (38 HB, 4 HCC, and 13 not reported) included 12 excluded from further analysis due to various factors, including lack of additional information. Five patients were eligible but not enrolled due to pandemic-related staffing issues (n = 1) or the best interest of the patient (physician preference, n = 1; risk for poor tolerance of chemotherapy, n = 1; not specified, n = 2). The remaining 38 patients included 1 ineligible due to a prior malignancy, 9 due to performance status, and 4 due to timing requirements. Thirty-five of 38 patients were ineligible due to organ function criteria (pulmonary/oxygen requirement, n = 25; renal, n = 10; liver, n = 4; cardiac, n = 3). Seven patients were ineligible due to two or more organ function criteria. Twenty-five of 38 patients were reported to have a preexisting condition including 4 patients with trisomy 18.

CONCLUSIONS

Patients with HB, and potentially HCC, who are ineligible for COG trials are primarily patients with an oxygen requirement and/or renal insufficiency, often associated with preexisting congenital conditions. Such patients would benefit from future studies to improve outcomes.

Cisplatin-induced ototoxicity: Updates on molecular mechanisms and otoprotective strategies

Cisplatin is a highly effective antitumor drug generally used in the treatment of solid malignant tumors. However, cisplatin causes severe side effects such as bone marrow depression, nephrotoxicity, and ototoxicity, thus limiting its clinical application. The incidence of ototoxicity induced by cisplatin ranges from 20% to 70%, and it usually manifests as a progressive, bilateral and irreversible hearing loss. Although the etiology of cisplatin-induced ototoxicity remains unclear, an increasing body of evidence suggests that the ototoxicity of cisplatin is mainly related to the production of reactive oxygen species and activation of apoptotic pathway in cochlear tissues. Many drugs have been well proved to protect cisplatin-induced hearing loss in vitro and in vivo. However, the anti-tumor effect of cisplatin is also weakened by systemic administration of those drugs for hearing protection, especially antioxidants. Therefore, establishing a local administration strategy contributes to the otoprotection without affecting the effect of cisplatin. This review introduces the pathology of ototoxicity caused by cisplatin, and focuses on recent developments in the mechanisms and protective strategies of cisplatin-induced ototoxicity.

Diversity of dose-individualization and therapeutic drug monitoring practices of platinum compounds: a review

Introduction: Platinum-derived drugs are commonly used for the treatment of solid tumors. The differences in chemical structures of these molecules lead to different pharmacological properties, in terms of indication, efficacy, and toxicity. Their pharmacokinetics (PK) differ according to their respective renal elimination and have led to many studies investigating their dose optimization. Area covered: This review attempts to summarize and compare PK and pharmacodynamics of cisplatin, carboplatin, and oxaliplatin, with an emphasis on differences of dose calculations and opportunities for therapeutic drug monitoring (TDM) in various patient populations. Expert opinion: Although cisplatin and carboplatin can be considered as analogs since they share the same DNA interacting properties, the slower hydrolysis of the latter results in a better safety profile. Carboplatin is the only drug in oncology to be administrated according to a target area under the curve of concentration versus time, considering that its PK variability is almost fully explained by renal function, not by body size. This enables individual dosing based on predicted carboplatin clearance (along with patients renal characteristics) or on actual clearance with TDM, especially in a high-dose protocol.

Cisplatin and carboplatin pharmacokinetics in a pediatric patient with hepatoblastoma receiving peritoneal dialysis

Purpose

Cisplatin and carboplatin are frequently used drugs in the treatment of pediatric hepatoblastoma. Dosing guidelines for these drugs in children requiring peritoneal dialysis are lacking. Here, we describe the case of a 3-year-old boy with pre-existing end-stage renal disease on peritoneal dialysis, requiring treatment with cisplatin and carboplatin for hepatoblastoma.

Methods

Pharmacokinetic data were generated to support clinical dosing decisions, with the aim of adequate exposure and minimal toxicity. In the first chemotherapy cycle, 25% of the standard cisplatin dose and 75% of the carboplatin dose, calculated using the pediatric Calvert formula, were administered. Free platinum concentrations were determined in plasma ultrafiltrate and dialysate samples drawn after administration of cis- and carboplatin.

Results

Cisplatin was well tolerated and the observed AUC of cisplatin were 15.3 and 14.3 mg/L h in cycles 1 and 3, respectively. The calculated AUC of carboplatin in cycle 1 (9.8 mg/mL min) exceeded target AUC of 6.5 mg/mL min and toxicity was observed; therefore, the dose was reduced in cycles 2 and 3. The observed AUC in cycles 2 and 3 was 5.4 and 5.7 mg/mL min respectively. Platinum concentrations in the dialysate showed that 3–4% of the total dose of cisplatin and 10–12% of the total dose of carboplatin were excreted via peritoneal dialysis. Chemotherapy enabled extended hemihepatectomy and complete remission was achieved.

Conclusion

This report shows that it is feasible to measure AUCs for both drugs and to individualize the dose of these drugs according to the PK results and clinical parameters. Our advice for future cases would be to calculate the starting dose of carboplatin using the (pediatric) Calvert formula, assuming a dialytic clearance of zero, and to adjust the dose if required, based on therapeutic drug monitoring.