Pegstim Special Precautions

Administration: Because rapidly dividing myeloid cells may be particularly sensitive to cytotoxic chemotherapy, Pegfilgrastim (Pegstim) should not be administered during the 14 days before or 24 hours after administration of cytotoxic chemotherapy. (See Dosage & Administration).
Potential Effect on Malignant Cells: The granulocyte-colony stimulating factor (G-CSF) receptor through which Pegfilgrastim and Filgrastim act has been found on tumor cell lines like those of myeloid, T-lymphoid, lung, head and neck, and bladder tumor cells), the possibility that Pegfilgrastim (Pegstim) could act as a growth factor for any tumor type cannot be excluded. Use of the drug in patients with myeloid malignancies or myelodysplastic syndrome (MDS) has not been studied.
Bone Pain: Bone pain was generally reported to be of mild-to-moderate severity. Among patients experiencing bone pain, most utilized non-narcotic analgesics and a few used narcotic analgesics. However no patient was withdrawn from the study due to bone pain.
Immunogenicity: As with all therapeutic proteins, there is a potential for immunogenicity. The incidence of antibody development in patients receiving Pegfilgrastim has been adequately determined using a BIAcore assay. The approximate limit for detection of this assay is 500 ng/ml. While available data suggest that a small proportion of patients developed binding antibodies to Pegfilgrastim, the nature and specificity of these antibodies has not been adequately studied. No neutralizing antibodies have been detected using a cell-based bioassay in patients who apparently developed binding antibodies.
Laboratory Monitoring: Leucocytosis (WBC counts >100 x 10⁹/L) was observed in less than 1% of 932 patients with non myeloid malignancies receiving Pegfilgrastim (Pegstim). Leukocytosis was not associated with any adverse effects. Reversible elevations in LDH, alkaline phosphatase, and uric acid, not requiring treatment were seen in pegfilgrastim and placebo-treated patients in similar rates.
Cytopenias resulting from an antibody response to exogenous growth factors have been reported on rare occasions in patients treated with other recombinant growth factors. Though there is a theoretical possibility that an antibody directed against Pegfilgrastim (Pegstim) may cross-react with endogenous G-CSF, resulting in immune-mediated neutropenia, this has not been observed in clinical studies.
Effects on ability to drive and use machines: No studies on the effects on the ability to drive and use machines have been performed.
Use in Children: Safety and efficacy of Pegfilgrastim (Pegstim) have not been established in pediatric patients. Hence the 6 mg fixed dose single-use syringe formulation should not be used in infants, children and adolescents weighing less than 45 kg.
Use in Elderly: No substantial differences in safety and efficacy between patients >65 years and younger adults were noted.