Evaluation of efficacy and safety of pegfilgrastim when given less than two weeks from dose-dense chemotherapy regimens.

INTRODUCTION: In clinical practice, waiting 14 days between the administration of pegfilgrastim and subsequent chemotherapy cycle (as recommended by the prescribing information) is sometimes not feasible with multi-cycle dose-dense regimens. This study evaluated the practice related to the use of pegfilgrastim in oncology patients at a multi-hospital health system. METHODS: Patients who received pegfilgrastim as primary prophylaxis following dose-dense chemotherapy scheduled every 14 days were included. The primary endpoint was the impact of <14 elapsed days between pegfilgrastim administration and next chemotherapy cycle on the change in mean absolute neutrophil counts (ANC). A generalized linear mixed-effects model with fixed effects for pegfilgrastim delivery method, elapsed days between pegfilgrastim and chemotherapy (fixed categorical effect for 12, 13, 14 days), and ANC at subsequent cycle was fitted to the change in ANC between chemotherapy cycles. RESULTS: One hundred and sixty four patients with breast cancer who received pegfilgrastim support for dose dense doxorubicin and cyclophosphamide (ddAC) qualified for the model. The mean age was 52 ± 12 years. Eighty-eight percent received pegfilgrastim on-body injector while 13% received pegfilgrastim injection. The mean number of elapsed days between pegfilgrastim and subsequent chemotherapy was 13 ± 0.5 days. The method of pegfilgrastim delivery and elapsed days between pegfilgrastim and chemotherapy administration had no significant effect on the change in ANC (p = 0.8663 and p = 0.8434 respectively); however, patient's age (p = 0.0125) had a significant effect on the change in ANC. CONCLUSION: The study findings suggest safety and efficacy when chemotherapy is administered 12-14 days from pegfilgrastim.

A Case Report of Neurotoxicity After Prolonged Doses of Acyclovir in a Patient With Renal Dysfunction.

Renal dysfunction is a significant risk factor for acyclovir-induced neurotoxicity and altered mentation and myoclonic movements are the most common clinical symptoms observed. In majority of reported cases, neurological sequelae associated with acyclovir-induced neurotoxicity often mimic viral infections of the central nervous system and makes diagnosis of the former challenging. Although plasma concentrations of the drug may not always correlate with neurotoxic symptoms, obtaining serum levels of acyclovir may be helpful in confirming drug-induced neurotoxicity. Hemodialysis has been shown to significantly improve altered mentation in patients with suspected or confirmed acyclovir-induced neurotoxicity. Here, we report a definite case of acyclovir-induced neurotoxicity in a patient with end-stage renal disease. Clinical improvements in neurologic symptoms were observed following discontinuation of the drug and hemodialysis.