Efbemalenograstim alfa

Summary

Efbemalenograstim alfa (Ryzneuta®, also known as F‑627) is a recombinant, Fc‑fusion granulocyte colony‑stimulating factor (G‑CSF) approved in China for preventing chemotherapy‑induced neutropenia in adults with non‑myeloid malignancies. By providing a single, long‑acting subcutaneous dose each chemotherapy cycle, it aims to reduce the duration and severity of neutropenia and the associated risk of infection.

Mechanism of Action

Efbemalenograstim alfa consists of two human G‑CSF molecules linked to an IgG2 Fc fragment, creating a non‑PEGylated fusion protein with prolonged plasma half‑life. It binds the G‑CSF receptor on myeloid progenitor cells, activating the JAK/STAT signaling cascade, which drives proliferation, differentiation, and survival of neutrophil precursors, thereby increasing circulating absolute neutrophil counts after myelosuppressive chemotherapy.

What the Research Shows

Phase II dose‑finding data in 138 breast‑cancer patients receiving epirubicin/cyclophosphamide showed that a 20 mg dose of efbemalenograstim alfa produced a shorter duration of moderate‑to‑severe neutropenia and higher ANC nadirs than 10 mg and was comparable to daily filgrastim, with lower rates of bone pain. A subsequent phase III trial (239 patients) demonstrated non‑inferiority of a single 20 mg subcutaneous dose per cycle versus daily filgrastim, with similar safety and a trend toward fewer neutropenic episodes. Two independent systematic reviews and meta‑analyses of five randomized trials (≈800 patients) concluded that efbemalenograstim alfa has efficacy and safety comparable to standard G‑CSFs, improving ANC nadir and showing no increase in serious adverse events. The drug received its first regulatory approval in China in May 2023 for reducing febrile neutropenia in adults receiving myelosuppressive chemotherapy.

Reported Benefits

Clinical trials indicate that a single fixed 20 mg subcutaneous dose each chemotherapy cycle is as effective as daily filgrastim in shortening the duration of grade 3‑4 neutropenia and raising ANC nadirs, simplifying dosing schedules. Reported bone‑pain rates were lower than with filgrastim, and no febrile neutropenia occurred in the studied cohorts, suggesting a convenient and well‑tolerated alternative for patients undergoing myelosuppressive regimens.

Limitations of the Evidence

Evidence to date is confined mainly to breast‑cancer patients receiving epirubicin/cyclophosphamide, limiting generalisability to other tumour types or chemotherapy protocols. Long‑term outcomes, real‑world effectiveness, and head‑to‑head comparisons with pegylated G‑CSFs (e.g., pegfilgrastim) remain unstudied. The meta‑analyses included a modest number of trials, and heterogeneity was noted when placebo‑controlled data were incorporated.

Safety Considerations

Across phase II, phase III, and pooled analyses, efbemalenograstim alfa displayed a safety profile similar to filgrastim, with most adverse events being mild bone or back pain. The incidence of these pains was lower than with filgrastim. No increase in serious adverse events or treatment discontinuations was observed, and no cases of febrile neutropenia were reported. Caution is advised in patients with known hypersensitivity to G‑CSF products or the Fc component.

How It Is Administered

Efbemalenograstim alfa is administered by subcutaneous injection. Clinical studies used a single fixed dose of 20 mg given on day 3 of each chemotherapy cycle, replacing the daily filgrastim regimen. The formulation is a recombinant Fc‑fusion protein supplied in prefilled syringes for single‑use administration.

Routes of Administration

Goals & Uses

• Prevention of febrile neutropeniaInfection PreventionHigh
• Maintenance of chemotherapy dose intensityOncologyModerate
• Reduction in chemotherapy-induced neutropenia durationHematologyHigh

Contraindications

• Hypersensitivity to efbemalenograstim alfa or any excipientAllergy/ImmunologyHigh
• Use in patients with myeloid malignanciesOncologyHigh

Adverse Effects

• Acute respiratory distress syndrome (ARDS)PulmonaryRare
• Injection site reactionsLocalCommon
• LeukocytosisHematologicCommon
• Splenic ruptureGastrointestinal/HematologicRare
• Bone pain / musculoskeletal painMusculoskeletalCommon
• GlomerulonephritisRenalRare

Drug Interactions

• Topoisomerase II inhibitors / other chemotherapy agentsHigh
• LithiumLow

Population Constraints

• PregnancyReproductive SafetyRelative
• Pediatric patientsAgeRelative
• LactationReproductiveRelative
• Sickle cell diseaseHematologicRelative

Regulatory Status

• European UnionUnknownNo EMA approval identified as of knowledge cutoff; not listed as an authorized medicinal product in the EU.
• United StatesApprovedApproved: To decrease the incidence of infection, as manifested by febrile neutropenia, in adults with non-myeloid malignancies receiving myelosuppressive anti-cancer drugs associated with a clinically significant incidence of febrile neutropeniaFDA approved September 9, 2022 under the brand name ROLVEDON. Marketed by Spectrum Pharmaceuticals.
• United KingdomUnknownNo MHRA authorization identified as of knowledge cutoff.

Approved by the FDA in September 2022 for prevention of chemotherapy-induced febrile neutropenia. Not yet approved by EMA or MHRA as a distinct product. Biosimilar considerations do not apply as it is a novel molecular entity.

Evidence & Sources

• A randomized, multicenter phase III Study of once-per-cycle administration of efbemalenograstim alfa (F-627), a novel long-acting rhG-CSF, for prophylaxis of chemotherapy-induced neutropenia in patients with breast cancer
  Journal ArticleModerateZhang Q, et al.2024-01-01T00:00:00.000000Z
• Efbemalenograstim Alfa, an Fc Fusion Protein, Long‑Acting Granulocyte Colony-Stimulating Factor for Reducing the Risk of Chemotherapy-Induced Neutropenia: Results of a Phase II Randomized, Multicenter, Open‑Label Trial
  Journal ArticleModerateJi D, et al.2025-01-01T00:00:00.000000Z
• Safety and efficacy of Efbemalenograstim alfa for patients at risk for chemotherapy-induced neutropenia: A Systematic review and Meta-analysis
  Journal ArticleHighDas P, et al.2026-01-01T00:00:00.000000Z
• Safety and efficacy of efbemalenograstim alfa for chemotherapy-induced neutropenia: A systematic review and meta-analysis of randomized controlled trials
  Journal ArticleModerateShaikh S, et al.2026-01-01T00:00:00.000000Z
• Efbemalenograstim Alfa: First Approval
  Journal ArticleModerateBlair HA2023-01-01T00:00:00.000000Z

Frequently Asked Questions