Clofarabine

證據等級: L5

預測適應症: 10 個

Clofarabine: From Pediatric Acute Lymphoblastic Leukemia to Myeloid Leukemia

One-Sentence Summary

Clofarabine is a purine nucleoside analog originally developed and approved (FDA, 2004) for relapsed/refractory acute lymphoblastic leukemia (ALL) in pediatric patients who failed at least two prior regimens. The TxGNN model predicts it may also be effective for Myeloid Leukemia (AML), with 44 clinical trials and 20 publications currently supporting this direction — though it is not yet marketed in Norway and key safety documentation is still missing.

Quick Overview

Item	Content
Original Indication	Not licensed in Norway (0 authorizations); internationally approved for relapsed/refractory pediatric ALL (ages 1–21, ≥2 prior regimens)
Predicted New Indication	Myeloid Leukemia (AML)
TxGNN Prediction Score	99.88%
Evidence Level	L2
Norway Market Status	✗ Not Marketed
Number of Authorizations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism-of-action data from DrugBank is currently unavailable for clofarabine (data gap), and the drug holds no market authorization in Norway. However, the clinical trial and literature evidence collected consistently describes clofarabine as a second-generation deoxyadenosine (purine) nucleoside analog that inhibits ribonucleotide reductase and DNA polymerase, and disrupts mitochondrial membrane integrity to trigger apoptosis — a mechanism specifically targeting rapidly dividing cells. It was originally approved for relapsed/refractory pediatric ALL after other regimens failed.

ALL and AML both originate from the hematopoietic stem/progenitor compartment and share the defining biological feature that clofarabine is designed to exploit: rapidly proliferating leukemic blasts with high DNA synthesis activity. This mechanistic overlap is the biological rationale for the TxGNN prediction, and it is not merely theoretical — clofarabine has already been extensively studied "off-label" in AML, myelodysplastic syndrome (MDS), and CML blast phase, both as monotherapy and in combination regimens (with cytarabine, idarubicin, busulfan, mitoxantrone, etc.).

The depth of existing investigation reinforces this plausibility: 44 clinical trials and 20 publications specifically address clofarabine in myeloid leukemia populations, including multiple completed Phase 2 studies and a large completed Phase 2/3 programme (NCT00454480, n=2000) in AML/high-risk MDS. This indicates an area of substantial existing clinical practice rather than a purely graph-derived association.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT00454480	Phase 2/3	Completed	2000	Large treatment-development programme for older AML/high-risk MDS patients, including gemtuzumab ozogamicin and tipifarnib comparator arms
NCT00932412	Phase 2	Completed	735	Randomized CLARA (clofarabine/intermediate-dose cytarabine) vs HDAC as consolidation in newly-diagnosed younger AML
NCT02665065	Phase 3	Active, not recruiting	153	Iomab-B + RIC transplant vs conventional care in active/relapsed/refractory AML
NCT00373529	Phase 2	Completed	116	Single-agent clofarabine in previously untreated older AML unlikely to benefit from intensive chemotherapy
NCT00067028	Phase 1/2	Completed	116	Clofarabine/AraC vs Clofarabine/Idarubicin vs triple combo in relapsed AML, high-grade MDS, and CML myeloid blast phase
NCT01295307	Phase 2	Completed	86	Clofarabine salvage therapy in relapsed/refractory AML as bridge to allogeneic HCT
NCT01101880	Phase 2	Completed	50	Clofarabine + high-dose cytarabine + G-CSF priming in newly diagnosed AML/advanced MDS/MPN
NCT02686593	Phase 2	Completed	50	CLAM regimen (clofarabine/cytarabine/mitoxantrone) as first salvage for relapsed/refractory AML
NCT00044889	Phase 2	Completed	40	Early open-label study of clofarabine in adult refractory/relapsed AML
NCT01090167	Phase 1	Completed	14	Safety, tolerability and PK of clofarabine in Japanese AML patients

Literature Evidence

PMID	Year	Type	Journal	Key Findings
31246522	2019	Phase III RCT	J Clin Oncol	AML08 trial: clofarabine can replace anthracyclines/etoposide in remission induction for childhood AML
18565853	2008	RCT	Blood	Randomized study of clofarabine vs clofarabine+low-dose cytarabine as front-line therapy in older AML/high-risk MDS
31905904	2019	Cohort	Cancers	Clofarabine-based consolidation (CLARA) improves relapse-free survival in AML with micro-complex karyotype
32187883	2020	Phase 2	Cancer Medicine	CLAM (clofarabine/cytarabine/mitoxantrone) shows high response rates, effective bridge to allo-HSCT in refractory/relapsed AML
29773602	2018	Phase IB	Haematologica	Clofarabine + HDAC + liposomal daunorubicin in pediatric relapsed/refractory AML
39078289	2024	Cohort	Clin Cancer Res	Pharmacogenomic (ACS10) score personalizes AML induction regimen selection
25457773	2015	Review	Crit Rev Oncol Hematol	Comprehensive review of clofarabine's role in adult AML, monotherapy and combination strategies
22957815	2013	Review	Leukemia & Lymphoma	Review of clofarabine's role in AML treatment
21182488	2011	Review	Curr Med Chem	Novel and emerging drugs for AML, including clofarabine pharmacology
17852710	2007	Review	Leukemia & Lymphoma	"Clofarabine: past, present, and future" — mechanism and combination rationale

Norway Market Information

Clofarabine is currently not marketed in Norway (0 authorizations on record).

Cytotoxicity

Clofarabine is a conventional cytotoxic antineoplastic agent (purine nucleoside antimetabolite), so this section applies.

Item	Content
Cytotoxicity Classification	Conventional cytotoxic (purine/deoxyadenosine nucleoside analog, antimetabolite class)
Myelosuppression Risk	High — as a DNA synthesis inhibitor targeting rapidly dividing cells, bone marrow suppression (neutropenia, thrombocytopenia, anemia) is expected; trial literature reports Grade >3 hematological toxicity as a common event (e.g., PMID 22431002)
Emetogenicity Classification	Moderate to High (consistent with intravenous purine analog chemotherapy)
Monitoring Items	CBC with differential, liver function tests, renal function/creatinine, fluid balance and blood pressure (capillary leak/hypotension risk reported with nucleoside analogs), signs of infection
Handling Protection	Requires standard cytotoxic/hazardous drug handling precautions (PPE, closed-system transfer devices) per antineoplastic handling regulations

Safety Considerations

Please refer to the package insert for safety information.

Conclusion and Next Steps

Decision: Hold

Rationale: The myeloid leukemia indication is well supported mechanistically and by a substantial body of clinical evidence (44 trials, 20 publications, including a completed Phase III pediatric AML RCT). However, clofarabine has no current market authorization in Norway, and a Blocking-severity data gap (missing TFDA-equivalent label warnings/contraindications) prevents entry into the Stage 1 (S1) safety evaluation. Until this is resolved, neither "Go" nor "Proceed with Guardrails" can be responsibly recommended.

To proceed, the following is needed:

Official prescribing information / SmPC with warnings, contraindications, and drug-drug interaction data (resolves the Blocking gap)
Detailed mechanism-of-action and DrugBank pharmacological classification data (resolves the High-severity gap)
Confirmation of Norway/EU marketing authorization status or applicable off-label/named-patient access pathways for AML
Systematic relevance grading of the 44 myeloid leukemia trials and 20 publications (currently unclassified/"pending")
Route-of-administration and dosing feasibility assessment for the AML population (currently unassessed)
Disclaimer

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