Filgrastim

證據等級: L5

預測適應症: 10 個

Filgrastim: From Chemotherapy-Induced Neutropenia to Primary Release Disorder of Platelets

One-Sentence Summary

Filgrastim is a recombinant human granulocyte colony-stimulating factor (G-CSF), widely used globally for the prevention and treatment of chemotherapy-induced neutropenia and as a hematopoietic stem cell (HSC) mobilizing agent — however, it is not currently registered in Singapore. The TxGNN model predicts it may be effective for Primary Release Disorder of Platelets, with 14 clinical trials and 1 publication currently identified; however, all existing evidence relates to HSCT support roles rather than direct intervention for platelet release disorders. The mechanistic rationale relies on an indirect pathway (G-CSF → HSC mobilization → allogeneic HSCT → hematopoietic reconstitution → correction of congenital platelet release defects), and no study has directly investigated this indication.

Quick Overview

Item	Content
Original Indication	Not registered in Singapore; globally indicated for chemotherapy-induced neutropenia and HSC mobilization
Predicted New Indication	Primary release disorder of platelets
TxGNN Prediction Score	99.998%
Evidence Level	L4
Singapore Market Status	Not marketed
Number of Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data is not available in this Evidence Pack. Based on known pharmacological information, Filgrastim is a recombinant form of human G-CSF that binds the CSF3 receptor (G-CSFR/CSF3R), activating JAK2/STAT3 and MAPK/ERK signaling to stimulate proliferation, differentiation, and survival of neutrophil precursors. It also mobilizes HSCs from bone marrow into peripheral blood, making it the backbone of stem cell collection protocols before transplantation.

Primary release disorder of platelets (also known as primary secretion disorders) involves dysfunction in the dense granule (δ-granule) or alpha granule (α-granule) release pathways — platelets fail to properly secrete their contents upon activation, impairing secondary aggregation and clot consolidation. The TxGNN model's predicted mechanistic link operates through two theoretical pathways: (1) G-CSF receptors are expressed at low levels on megakaryocyte (MK) progenitors, suggesting a theoretically possible minor direct effect on platelet progenitor biology; and (2) more importantly, G-CSF mobilizes HSCs for allogeneic HSCT, which reconstitutes the entire hematopoietic system — potentially replacing donor-derived megakaryocytes and correcting congenital platelet release defects from their root cause.

However, this mechanistic rationale is indirect and speculative. The G-CSF receptor signaling pathway (CSF3R → JAK2 → STAT3/ERK) has no established regulatory role over granule biogenesis or release mechanisms within mature platelets. All 14 identified clinical trials feature Filgrastim strictly in its conventional role as an HSCT support agent, and none are designed to study platelet release disorders. The near-perfect TxGNN score likely reflects the broad connectivity of the "platelet" and "hematopoietic stem cell" nodes in the knowledge graph rather than direct molecular pathway support.

Clinical Trial Evidence

Important caveat: All identified trials feature Filgrastim as an HSCT mobilization or chemotherapy-support agent. None are directly designed to treat primary release disorder of platelets. The trial list below represents the evidence landscape retrieved by the search pipeline, not direct indication-specific evidence.

Trial Number	Phase	Status	Enrollment	Key Findings
NCT04047628	Phase 3	Recruiting	156	Multi-center RCT comparing best available therapy vs. autologous HSCT for treatment-resistant relapsing multiple sclerosis; Filgrastim used as part of the mobilization regimen — the highest-quality trial retrieved, though with only indirect relevance
NCT00245037	Phase 1/2	Completed	147	Non-myeloablative allogeneic HSCT for hematologic malignancies using busulfan, fludarabine and TBI; Filgrastim serves as the HSC mobilizing agent — a completed trial providing safety and mobilization data
NCT00043979	Phase 2	Completed	60	Allogeneic/syngeneic blood stem cell transplantation for high-risk pediatric sarcomas; Filgrastim used as standard supportive therapy during HSC collection
NCT00923364	Phase 2	Completed	19	Reduced-intensity HSCT for patients with life-threatening GATA2 mutations (a hematologic disorder affecting hematopoiesis); Filgrastim as mobilizing agent — small sample but completed
NCT02646098	Phase 2	Completed	64	CD34+ selected vs. unselected autologous SCT in advanced mantle cell lymphoma and DLBCL; provides data on Filgrastim-mobilized graft composition
NCT01335932	Phase 2	Completed	160	Ganciclovir for CMV reactivation prevention in severe sepsis/trauma-associated respiratory failure (GRAIL study); Filgrastim used in post-transplant context, no platelet disorder relevance
NCT00076752	Phase 2	Completed	9	Intensified lymphodepletion followed by autologous HSCT in severe SLE; Filgrastim as HSC mobilization support — very small sample
NCT00281879	Phase 2	Terminated	200	Unrelated donor HSCT for hematological malignancies; trial terminated, limiting data value
NCT04540120	Phase 2	Terminated	49	Dapansutrile (NLRP3 inhibitor) for moderate COVID-19 and early cytokine release syndrome; terminated early, no relevant contribution
NCT05170828	Phase 1	Withdrawn	0	Cryopreserved HLA-mismatched unrelated donor bone marrow with PTCy for allogeneic transplantation; withdrawn before enrollment, no data

Literature Evidence

PMID	Year	Type	Journal	Key Findings
29770133	2018	Clinical Observational	Frontiers in Immunology	G-CSF mobilization of peripheral blood stem cells in healthy allogeneic donors causes preferential mobilization of specific lymphocyte subsets; relevant as background evidence for understanding G-CSF's broader immunological effects on graft cellular composition, though not directly addressing platelet release function

Singapore Market Information

Filgrastim is currently not registered with the Health Sciences Authority (HSA) of Singapore. There are no authorized products on record in the Singapore regulatory database.

Should a repurposing clinical program be considered, a new regulatory filing with HSA would be required from the outset.

Safety Considerations

Please refer to the package insert for safety information.

Conclusion and Next Steps

Decision: Hold

Rationale: Despite a near-perfect TxGNN prediction score (99.998%), the underlying evidence for Filgrastim in primary release disorder of platelets is entirely indirect. All 14 retrieved clinical trials use Filgrastim as an HSCT mobilization support agent — none target platelet release dysfunction as the primary endpoint. The sole literature piece addresses lymphocyte subset mobilization dynamics, not platelet biology. The proposed mechanistic pathway (G-CSF → allogeneic HSCT → donor hematopoietic reconstitution → correction of congenital platelet secretion defects) is biologically coherent in principle but has not been tested clinically, and the direct molecular link between CSF3R signaling and platelet granule release pathways remains unestablished.

To proceed, the following is needed:

MOA confirmation: Retrieve Filgrastim's full DrugBank pharmacology profile to confirm whether G-CSF receptor expression on megakaryocyte progenitors is sufficient to justify a direct (non-HSCT) therapeutic hypothesis
Focused literature search: Search specifically for G-CSF effects on megakaryopoiesis, platelet granulogenesis, and secretion function (dense granule release, α-granule release) in preclinical and clinical settings
Disease subtype clarification: Specify the molecular subtype of "primary release disorder of platelets" (e.g., Hermansky-Pudlak syndrome, Chediak-Higashi, isolated dense granule deficiency) — mechanistic feasibility varies substantially by subtype
Case report or registry review: Search hematology registries and published case series for any instances of Filgrastim use in patients with congenital platelet secretion disorders (e.g., in the context of HSCT donor mobilization where the recipient had platelet release disorder)
Singapore regulatory pathway scoping: If a hypothesis is confirmed at preclinical level, engage HSA for early scientific advice on first-in-indication clinical trial design
Safety data retrieval: Download and parse the Filgrastim package insert to complete the S1 safety screening that is currently blocked by missing warning and contraindication data
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.