フィルグラスチム
Filgrastim
Granulocyte Colony Stimulating Factor; GCSF; recombinant methionyl human GCS-F
別名: Neupogen · Filgen · Granulen · Granulokine · Neulasta · Neutromax · granulocyte colony-stimulating factor · GCSF · recombinant methionyl human GCS-F · r-metHuG-CSF · rhG-CSF
VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
動物種別用量
🌎 NA — North America🌍 EU — Europe
犬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Adjunctive therapy of neutropenia (secondary to drug induced aplastic pancytopenia) | 5 micrograms/kg SC daily | SC | daily | Pulse therapy of no more than 5 days | 🌎 NA |
| Neutropenia | 1-5 micrograms/kg SC daily | SC | daily | Pulse therapy of no more than 5 days | 🌎 NA |
| Neutropenia | 100,000-500,000 IU (1-5 micrograms)/kg | SC | q24h | 3-5 days | 🌍 EU |
- Adjunctive therapy of neutropenia (secondary to drug induced aplastic pancytopenia): To avoid autoantibody formation, pulse therapy is recommended.
- Neutropenia: To avoid autoantibody formation, pulse therapy is recommended.
- Neutropenia: Neutrophil counts typically rise within 24 hours.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Neutropenia secondary to drug toxicity, infectious diseases, FeLV associated cyclic neutropenia or idiopathic causes | 5 micrograms/kg SC twice daily | SC | twice daily | Pulse therapy of no more than 5 days | 🌎 NA |
| Neutropenia | 1-5 micrograms/kg SC daily | SC | daily | Pulse therapy of no more than 5 days | 🌎 NA |
| Adjunctive therapy of neutropenia | 5 micrograms/kg SC daily until neutrophil count exceeds 3,000/mcl for 2 days | SC | daily | Until neutrophil count exceeds 3,000/mcl for 2 days (ideally ≤ 5 days) | 🌎 NA |
| Neutropenia | 100,000-500,000 IU (1-5 micrograms)/kg | SC | q24h | 3-5 days | 🌍 EU |
- Neutropenia secondary to drug toxicity, infectious diseases, FeLV associated cyclic neutropenia or idiopathic causes: Cost and/or development of antibodies usually limit usefulness to a few weeks, but often it is effective for acute or lifethreatening neutropenia.
- Neutropenia: To avoid autoantibody formation, pulse therapy is recommended.
- Adjunctive therapy of neutropenia: To avoid autoantibody formation, pulse therapy is recommended.
- Neutropenia: Neutrophil counts typically rise within 24 hours.
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
概要
フィルグラスチムは、獣医療において骨髄を刺激して好中球を産生させるために使用される遺伝子組換えヒト顆粒球コロニー刺激因子（G-CSF）です。
重要な臨床的ポイント：
- 主な適応： 重度で生命を脅かす好中球減少症（例：パルボウイルス感染症、化学療法による骨髄抑制、猫白血病ウイルス関連の周期性好中球減少症など）に使用されます。
- 免疫原性のリスク： ヒトDNA由来であるため、犬や猫に対して高い免疫原性を示す可能性があります。患者は外因性の薬剤だけでなく、自己のG-CSFに対する中和抗体を産生する可能性があり、その結果、重度で長期にわたる致命的な好中球減少症を引き起こす恐れがあります。
- 臨床戦略： 抗体産生を最小限に抑えるため、通常は好中球減少の最も危険な時期にのみ、短期間の「パルス」療法（3〜5日間）として投与されます。
- コスト： 治療費が非常に高額であるため、一般的な獣医療での使用は制限されることが多いです。
作用機序
Filgrastim acts as a hematopoietic growth factor.
- It binds specifically to G-CSF receptors located on the surface of myeloid progenitor cells in the bone marrow.
- Receptor activation triggers intracellular signaling pathways (such as the JAK/STAT pathway) → stimulates the proliferation, differentiation, and activation of progenitor cells exclusively within the neutrophil-granulocyte lineage.
- Clinical Pearl: In addition to increasing the absolute number of circulating mature neutrophils, filgrastim also enhances the functional capacity of these cells, including their phagocytic and bactericidal activities, thereby improving the patient's ability to fight off bacterial infections during periods of severe immunosuppression.
安全性・警告
禁忌
- Hypersensitivity to filgrastim
- Patients that have previously developed antibodies to filgrastim with resultant neutropenia
有害事象
- Severe neutropenia (due to autoantibody formation against G-CSF)
- Myelofibrosis (theoretical/reported concern)
- Medullary histiocytosis (theoretical/reported concern)
- Injection site irritation
- Bone pain
- Splenomegaly
- Hypotension
注意事項
High Risk of Immunogenicity: The development of neutralizing antibodies can cause severe, prolonged neutropenia. Use should generally be restricted to short pulse therapy (≤ 5 days).
- Pregnancy: FDA Category C. High doses have shown adverse effects in pregnant laboratory animals. Use only when benefits clearly outweigh risks.
- Nursing: Unknown if excreted in milk, but unlikely to pose significant risk to nursing offspring.
- Efficacy vs. Risk: Use is controversial due to cost, antibody potential, and lack of definitive evidence showing reduced mortality compared to aggressive broad-spectrum antibiotic therapy alone.
医薬品相互作用
Avoid using filgrastim within 24 hours of administering antineoplastic agents that target rapidly proliferating cells, as it may exacerbate toxicity to the newly stimulated myeloid cells.
May potentiate the release of neutrophils during G-CSF therapy.
May potentiate the release of neutrophils during G-CSF therapy.
Concurrent administration may increase the incidence of adverse effects. The stimulatory effects of G-CSF on haemopoietic precursors render them more susceptible to the effects of chemotherapy.
監視
- CBC with platelets, routinely (to monitor neutrophil response and detect potential antibody-induced neutropenia)
薬物動態
吸収
Rapidly absorbed after subcutaneous injection.
分布
Highest concentrations found in the bone marrow, liver, kidneys, and adrenal glands. It is unknown if it crosses the blood-brain barrier, placenta, or enters maternal milk.
代謝
Pathways are still under investigation.
消失
Elimination pathways are still under investigation.
過剰投与
Limited information is available regarding acute toxicity. Because of the high expense of the drug and its apparent limited acute toxic potential, clinically significant overdoses are considered unlikely. If an overdose occurs, monitor CBC closely and provide supportive care.
製品
製剤
- Injection
ヒト用医薬品
- Filgrastim Injection: 300 micrograms/mL preservative free in 1 mL and 1.6 mL single dose vials
- Filgrastim Injection: 300 micrograms/0.5 mL preservative free in 0.5 mL and 0.8 mL prefilled syringes; Neupogen (Amgen)
規制ステータス
Human POM (Prescription Only Medicine) used off-label under the cascade.
Human POM used off-label under the cascade.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Store in the refrigerator (2-8°C). Do not freeze or shake the vial. Never dilute with saline as a precipitate may form. If necessary, it may be diluted into 5% dextrose for injection. If diluted to concentrations between 5 and 15 micrograms/mL, it is recommended to add albumin to a concentration of 2 mg/mL to reduce adsorption to plastic IV tubing. Do not dilute to a concentration of less than 5 micrograms/mL.
飼主向け情報
獣医師は、ペットの骨髄が重篤な感染症と戦うために不可欠な白血球（特に好中球）をより多く産生するのを助けるために、フィルグラスチムを処方しました。
- 費用： この薬はヒトの遺伝子組換え製剤であり、非常に高価です。
- 重要なリスク： これはヒトのタンパク質であるため、ペットの免疫系が異物と認識し、抗体を作り出す可能性があります。これが起こると、免疫系が薬だけでなくペット自身の白血球も破壊してしまい、生命を脅かす免疫力低下を招く恐れがあります。
- 短期使用： このリスクを最小限に抑えるため、フィルグラスチムは通常、病気の最も危険な時期を乗り切るためのごく短期間（3〜5日間）のみ投与されます。
- モニタリング： 薬が効いているかを確認し、有害な免疫反応が起きていないかを監視するために、頻繁な血液検査が必要になります。
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