FDA Approves Ziextenzo (pegfilgrastim-bmez) for Febrile Neutropenia and Acute Radiation Syndrome

Not reported in label.

Ziextenzo is indicated to decrease the incidence of infection, as manifested by febrile neutropenia, in patients with non-myeloid malignancies receiving myelosuppressive anti-cancer drugs associated with a clinically significant incidence of febrile neutropenia. It is also indicated to increase survival in patients acutely exposed to myelosuppressive doses of radiation (hematopoietic subsyndrome of acute radiation syndrome). Limitations of use: not indicated for mobilization of peripheral blood progenitor cells for hematopoietic stem cell transplantation.

For patients with cancer receiving myelosuppressive chemotherapy: 6 mg subcutaneously once per chemotherapy cycle. Do not administer between 14 days before and 24 hours after cytotoxic chemotherapy. For pediatric patients weighing less than 45 kg, weight-based dosing is recommended (see Table 1 in label). For patients acutely exposed to myelosuppressive doses of radiation: two doses of 6 mg each subcutaneously one week apart. Administer first dose as soon as possible after suspected or confirmed exposure to radiation >2 Gy. Obtain baseline CBC but do not delay administration if CBC not available. For pediatric patients <45 kg, use weight-based dosing. Allow prefilled syringe to reach room temperature for 15-30 minutes before use. Discard if left at room temperature >120 hours. Inspect for particulate matter and discoloration; do not use if observed. The syringe is not designed for doses <0.6 mL (6 mg); direct administration for doses <6 mg is not recommended due to dosing errors.

Pegfilgrastim was evaluated in three randomized, double-blind, controlled studies. Studies 1 and 2 were active-controlled studies in patients with metastatic breast cancer receiving doxorubicin 60 mg/m2 and docetaxel 75 mg/m2 every 21 days for up to 4 cycles. Study 1 used a fixed dose of pegfilgrastim; Study 2 used a weight-adjusted dose. Similar chemotherapy regimens without growth factor support have been reported to result in 100% incidence of severe neutropenia (ANC <0.5 x 10^9/L) with mean duration 5-7 days and 30-40% incidence of febrile neutropenia. Duration of severe neutropenia was the primary endpoint. Specific efficacy results for Ziextenzo are not reported in the label.

Not reported in label.

Ziextenzo is a biosimilar to pegfilgrastim, providing an alternative for prophylaxis of febrile neutropenia in patients with non-myeloid malignancies receiving myelosuppressive chemotherapy. It also has a unique indication for acute radiation syndrome. It is not indicated for stem cell mobilization.