Ivosidenib

證據等級: L5

預測適應症: 10 個

Ivosidenib: From IDH1-Mutated AML to Myelodysplastic/Myeloproliferative Disease

One-Sentence Summary

Ivosidenib (Tibsovo) is an oral, first-in-class inhibitor of mutant IDH1, approved by the FDA for IDH1-mutated relapsed/refractory AML and cholangiocarcinoma, but not currently approved in Taiwan. The TxGNN model’s highest-evidence prediction suggests it may benefit patients with Myelodysplastic/Myeloproliferative Disease (MDS/MPN overlap syndromes), supported by 5 clinical trials at an L2 evidence level.

Note on ranking: The TxGNN #1 prediction (bulbar polio, 99.31%) is assessed as a knowledge graph proximity artifact with no plausible IDH1 mechanistic basis. The MDS/MPN prediction (rank 7, 98.56%) carries the strongest clinical evidence in this evidence pack and is the primary subject of this report.

Quick Overview

Item	Content
Original Indication	IDH1-mutated AML / cholangiocarcinoma (FDA-approved globally; no Taiwan authorization)
Predicted New Indication	Myelodysplastic/Myeloproliferative Disease
TxGNN Prediction Score	98.56%
Evidence Level	L2
Taiwan Market Status	✗ Not marketed
Number of Authorizations	0
Recommended Decision	Proceed with Guardrails

Why is This Prediction Reasonable?

Ivosidenib selectively inhibits the neomorphic IDH1 R132 mutant enzyme. Under normal conditions, IDH1 catalyzes the conversion of isocitrate to α-ketoglutarate (α-KG). The R132 gain-of-function mutation redirects this reaction to produce the oncometabolite 2-hydroxyglutarate (2-HG), which competitively inhibits α-KG-dependent dioxygenases—most importantly TET2 and histone demethylases—causing widespread epigenetic hypermethylation, blocked hematopoietic differentiation, and clonal expansion. Ivosidenib suppresses 2-HG production, restores TET2-dependent DNA demethylation, and allows leukemic progenitors to resume differentiation.

MDS/MPN overlap syndromes (chronic myelomonocytic leukemia [CMML], atypical CML, MDS/MPN-unclassifiable) share the same core pathobiology as IDH1-mutated AML: epigenetically driven differentiation arrest in clonal myeloid progenitors. IDH1 R132 mutations occur in approximately 5–8% of MDS/MPN cases. In this IDH1-mutated subset, the 2-HG–driven epigenetic silencing that arrests blast maturation in AML is mechanistically identical to the differentiation block seen in MDS/MPN progenitors—making ivosidenib’s mechanism directly applicable.

Clinical practice further supports this rationale: the standard-of-care backbone for MDS/MPN (hypomethylating agents such as azacitidine) is precisely the combination arm being investigated in the pivotal Phase 1b/2 basket trial NCT03471260. The convergence of mechanism, mutation prevalence, and ongoing clinical investigation makes this one of the most biologically credible repurposing directions for ivosidenib beyond its approved indications.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT03471260	Phase 1b/2	Recruiting	96	Ivosidenib + venetoclax ± azacitidine in IDH1-mutated hematologic malignancies; basket design includes MDS/MPN subtypes; evaluates safety, optimal dose, and efficacy of the triplet combination
NCT02074839	Phase 1	Recruiting	291	Large dose-escalation and dose-expansion study of ivosidenib across advanced IDH1-mutated hematologic malignancies; four expansion cohorts expected to include MDS/MPN subgroups
NCT04493164	Phase 2	Recruiting	30	CPX-351 liposomal chemotherapy + ivosidenib in IDH1-mutated AML or high-risk MDS; directly co-enrolls high-risk MDS patients alongside AML
NCT04250051	Phase 1	Active, not recruiting	2	Ivosidenib + FLAG chemotherapy in relapsed/refractory IDH1+ AML; very limited enrollment (n=2); indirect reference value only
NCT04603001	Phase 1	Active, not recruiting	260	LY3410738, a covalent IDH1/2 inhibitor (distinct from ivosidenib), across IDH1/2-mutated hematologic malignancies; provides class-level mechanistic support for IDH1 inhibition in MDS/MPN

Literature Evidence

Currently no related literature directly linking ivosidenib to MDS/MPN overlap syndromes is available in this evidence pack.

Taiwan Market Information

Ivosidenib currently holds no marketing authorization in Taiwan (market status: 未上市). There are no Taiwan FDA (TFDA) licenses on record. Patients in Taiwan seeking access would require enrollment in a clinical trial or application for compassionate use / expanded access through TFDA.

Cytotoxicity

Item	Content
Cytotoxicity Classification	Targeted therapy — selective mutant IDH1 inhibitor (not conventional cytotoxic)
Myelosuppression Risk	Low to moderate; classic myelosuppression is not the primary concern—differentiation syndrome (febrile illness, respiratory distress, hypoxia during blast maturation) is the hallmark toxicity requiring vigilant monitoring
Emetogenicity Classification	Low (oral targeted agent, once-daily dosing)
Monitoring Items	CBC with differential, LFTs, serum bilirubin, ECG (QTc interval), coagulation panel; 2-HG plasma levels if available; daily clinical assessment for differentiation syndrome signs during the first 8 weeks
Handling Protection	Standard oral antineoplastic precautions apply; full cytotoxic IV handling protocols are not required

Safety Considerations

Formal TFDA prescribing information is not available as the drug is not approved in Taiwan. Based on the FDA-approved label and EMA scientific opinion, the following are the key safety signals:

Differentiation Syndrome: The most important drug-specific risk; may be life-threatening. Manifests as fever, dyspnea, hypoxia, pulmonary infiltrates, or multi-organ dysfunction during the first weeks of treatment. Requires prompt corticosteroid treatment and temporary dose interruption.
QTc Prolongation: ECG monitoring required at baseline, during the first month, and periodically thereafter. Risk is amplified with concomitant QTc-prolonging drugs.
Guillain-Barré Syndrome: Rare but reported; neurological symptoms (ascending weakness, areflexia) warrant immediate evaluation and drug discontinuation.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: The IDH1 inhibition mechanism is directly applicable to the ~5–8% of MDS/MPN patients carrying IDH1 R132 mutations, and two Phase 1b/2 basket trials (NCT03471260, NCT04493164) are actively co-enrolling MDS patients, providing L2-level evidence that the clinical hypothesis is already being tested.

To proceed, the following is needed:

Resolve blocking data gap: Obtain TFDA prescribing information (SmPC equivalent) via official PDF download and parsing to enable formal S1 safety assessment
Patient selection strategy: Establish IDH1 R132 mutation testing protocol for MDS/MPN patients (NGS or ddPCR); this is a prerequisite for any biomarker-enriched trial design
Regulatory pathway: Define Taiwan access route—NDA submission, compassionate use, or co-enrollment in an international basket trial (e.g., NCT03471260)
Sub-group data extraction: Request IDH1-mutated MDS/MPN sub-group outcomes from NCT02074839 investigators to quantify response rate and durability in this subset
Safety management plan: Formalize differentiation syndrome surveillance protocol and QTc monitoring plan prior to any expanded use in Taiwan
Disclaimer

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