The Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) to Spectrum Pharmaceuticals regarding the Biologics License Application (BLA) for eflapegrastim (Rolontis®) for the treatment of neutropenia in patients receiving myelosuppressive anticancer drugs.

Eflapegrastim is a novel, long-acting granulocyte colony-stimulating factor (G-CSF) comprised of 2 protein components, an analogue of G-CSF and an Fc antibody fragment. In the CRL, the FDA noted that the application could not be approved due to deficiencies related to manufacturing.

The BLA is supported by data from 2 identical phase 3 studies, ADVANCE ( Identifier: NCT02643420) and RECOVER ( Identifier: NCT02953340), which evaluated the efficacy and safety of eflapegrastim in 643 early-stage breast cancer patients for the treatment of neutropenia due to myelosuppressive chemotherapy.

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Findings from both trials showed that the primary endpoint of noninferiority in the duration of severe neutropenia between eflapegrastim and pegfilgrastim was met. No statistically significant differences in adverse events were observed between the treatment arms.

“We are disappointed with this outcome and look forward to fully understanding the remediation timelines for the program,” said Joe Turgeon, President and CEO of Spectrum Pharmaceuticals. “We continue to believe in Rolontis and plan to diligently complete the regulatory process to bring Rolontis to market.”


  1. Spectrum Pharmaceuticals receives Complete Response Letter from FDA for Rolontis® (eflapegrastim). News release. Spectrum Pharmaceuticals. August 6, 2021. Accessed August 9, 2021.
  2. Development Pipeline: Rolontis. Spectrum Pharmaceuticals. Accessed August 9, 2021.

This article originally appeared on MPR