imatinib Cancer Research Results

IMA, imatinib: Click to Expand ⟱
Features:

Imatinib — a synthetic, orally active small-molecule protein tyrosine kinase inhibitor used as targeted anticancer therapy. It is most strongly defined by inhibition of the BCR::ABL1 fusion kinase, but it also inhibits KIT and platelet-derived growth factor receptors PDGFRA and PDGFRB. Imatinib is a first-generation BCR::ABL1 tyrosine kinase inhibitor and is commonly abbreviated IM; the Nestronics abbreviation is IMA. Imatinib mesylate is marketed as Gleevec/Glivec and was originally developed as STI571. Its antitumor activity is highly genotype-dependent: BCR::ABL1-driven leukemias and susceptible KIT- or PDGFRA-driven tumors can be exceptionally sensitive, whereas particular kinase-domain mutations produce profound primary or acquired resistance.

Primary mechanisms (ranked):

  1. Direct inhibition of BCR::ABL1 tyrosine kinase, suppressing the constitutive oncogenic signaling that drives Philadelphia-chromosome-positive chronic myeloid leukemia and other BCR::ABL1-positive malignancies.
  2. Direct inhibition of activating KIT kinase signaling, particularly in susceptible KIT-mutant gastrointestinal stromal tumors.
  3. Direct inhibition of PDGFRA and PDGFRB signaling, including PDGFR-rearranged myeloid neoplasms and FIP1L1-PDGFRA-driven hypereosinophilic syndrome/chronic eosinophilic leukemia.
  4. Secondary suppression of kinase-dependent PI3K/AKT, STAT5 and RAS/RAF/MEK/ERK survival and proliferative signaling.
  5. Suppression of proliferation with induction of apoptosis in oncogene-dependent malignant cells.
  6. Chemosensitization in selected BCR::ABL1-positive leukemias through removal of kinase-mediated survival signaling; imatinib is clinically combined with chemotherapy in Philadelphia-chromosome-positive ALL.

Bioavailability / PK relevance: Oral bioavailability is approximately 98%, with peak plasma concentration approximately 2–4 hours after dosing and an imatinib elimination half-life of approximately 18 hours. Plasma protein binding is approximately 95%. CYP3A4 is the principal metabolic enzyme and generates the active N-desmethyl metabolite CGP74588, whose plasma exposure is approximately 15% of parent-drug exposure. Strong CYP3A4 inducers can markedly reduce exposure, while strong CYP3A4 inhibitors can increase exposure. Renal or severe hepatic impairment can also substantially increase systemic exposure. The drug has poor penetration into cerebrospinal fluid, limiting usefulness against sanctuary-site CNS disease.

In-vitro vs systemic exposure relevance: Concentration-driven and clinically exposure-relevant. Standard oral dosing produces total plasma concentrations in the low-micromolar range, overlapping concentrations required for inhibition of susceptible BCR::ABL1, KIT and PDGFR kinases. However, because approximately 95% of circulating drug is protein-bound, experiments using several micromolar free imatinib can substantially exceed clinically achievable unbound exposure. Effects reported only at high multi-micromolar concentrations should therefore be interpreted cautiously, especially when they involve targets other than BCR::ABL1, KIT or PDGFR.

Clinical evidence status: Established targeted anticancer drug with extensive randomized, prospective and long-term human evidence. Imatinib is an approved therapy for Philadelphia-chromosome-positive CML, selected Ph-positive ALL, PDGFR-rearranged myeloid disorders, selected systemic mastocytosis, HES/CEL, dermatofibrosarcoma protuberans and KIT-positive GIST, including adjuvant GIST treatment. Long-term CML studies demonstrate durable disease control and survival, while randomized GIST trials demonstrate substantial benefit from prolonged adjuvant therapy. Clinical effectiveness is strongly mutation-dependent: BCR::ABL1 T315I, KIT D816V, PDGFRA D842V and numerous acquired KIT kinase-domain mutations confer substantial or complete resistance.

Imatinib Cancer-Relevant Mechanisms

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 BCR::ABL1 oncogenic kinase ↓ BCR::ABL1 kinase activity and substrate phosphorylation ↔ BCR::ABL1 absent; physiological ABL signaling may be ↓ P/R Loss of the dominant proliferative and survival driver Core mechanism in Philadelphia-chromosome-positive CML and Ph-positive ALL. Selectivity results largely from malignant-cell dependence on constitutive BCR::ABL1 signaling.
2 KIT and SCF signaling ↓ KIT phosphorylation and downstream signaling ↓ physiological KIT signaling in KIT-dependent cell populations P/R ↓ proliferation and survival of susceptible KIT-driven tumors Core mechanism in KIT-mutant GIST. Activity is highly mutation-dependent. KIT D816V and several secondary kinase-domain mutations are poorly inhibited or resistant.
3 PDGFRA and PDGFRB signaling ↓ receptor kinase activity and downstream signaling ↓ physiological PDGFR signaling P/R Suppression of PDGFR-driven proliferation Important in PDGFR-rearranged myeloid neoplasms, FIP1L1-PDGFRA disease, selected GIST and PDGFB-driven dermatofibrosarcoma protuberans. PDGFRA D842V is strongly imatinib-resistant.
4 PI3K AKT survival signaling ↓ p-AKT and survival signaling (context-dependent) ↔ to ↓ (target-dependent) R Reduced prosurvival signaling Primarily a downstream consequence of BCR::ABL1, KIT or PDGFR inhibition rather than a direct PI3K or AKT inhibitory action. Reactivation can contribute to resistance.
5 STAT5 signaling ↓ STAT5 phosphorylation and transcriptional signaling (BCR::ABL1-dependent) ↔ to ↓ (context-dependent) R ↓ transcription of survival and proliferation programs Particularly relevant to BCR::ABL1-driven hematologic malignancies. STAT5 suppression follows inhibition of the upstream oncogenic kinase.
6 RAS RAF MEK ERK signaling ↓ pathway activation (context-dependent) ↔ to ↓ (target-dependent) R ↓ mitogenic signaling and proliferation Secondary downstream effect. BCR::ABL1-independent or alternative ERK activation can permit survival despite continued imatinib exposure.
7 Apoptosis and proliferative dependence ↑ apoptosis; ↓ proliferation and colony formation Smaller effect in cells lacking imatinib-sensitive oncogenic kinase dependence R/G Selective elimination or growth arrest of kinase-addicted cells Documented in BCR::ABL1-positive leukemia and susceptible KIT-mutant GIST. This is the integrated phenotypic consequence of upstream kinase blockade.
8 Chemosensitization ↑ susceptibility to cytotoxic therapy (context-dependent) Variable R/G Reduction of oncogene-mediated survival and checkpoint protection Clinically established combination treatment is particularly relevant to Ph-positive ALL. The precise degree of sensitization depends on disease, schedule and resistance genotype.
9 Clinical Translation Constraint ↑ resistance with BCR::ABL1 T315I, KIT D816V, PDGFRA D842V, secondary KIT mutations and bypass signaling Systemic toxicity limits dose escalation G Genotype and exposure determine therapeutic effectiveness Acquired kinase-domain mutations are a major resistance mechanism. Additional constraints include CYP3A4 interactions, interpatient PK variability, poor CNS penetration, fluid retention, cytopenias, hepatotoxicity, renal toxicity and other treatment-related adverse effects.

TSF: P: 0–30 min    R: 30 min–3 hr    G: >3 hr
Scientific Papers found: Click to Expand⟱
7578- IMA,    Long-Term Outcomes of Imatinib Treatment for Chronic Myeloid Leukemia
- Trial, CML, NA
OS↑, toxicity↓, BCR-ABL↓,
7579- IMA,    One vs three years of adjuvant imatinib for operable gastrointestinal stromal tumor: a randomized trial
- Trial, GC, NA
RFS↑, OS↑,

Showing Research Papers: 1 to 2 of 2

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 2

Pathway results for Effect on Cancer / Diseased Cells:


NA, unassigned(tgid=0) ⓘ

RFS↑, 1,  

Mitochondria & Bioenergetics(tgid=3) ⓘ

BCR-ABL↓, 1,  

Functional Outcomes(tgid=23) ⓘ

OS↑, 2,   toxicity↓, 1,  
Total Targets: 4

Pathway results for Effect on Normal Cells:


Total Targets: 0

Query results interpretion may depend on "conditions" listed in the research papers.
Such Conditions may include : 
  -low or high Dose
  -format for product, such as nano of lipid formations
  -different cell line effects
  -synergies with other products 
  -if effect was for normal or cancerous cells

Filter Conditions: Pro/AntiFlg:%  IllCat:%  CanType:%  Cells:%  prod#:9  Target#:%  State#:%  Dir#:%
  wNotes=0  sortOrder:rid,rpid

 

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