Crizotinib

Receptor Tyrosine Kinase Inhibition

Crizotinib functions as a multitargeted inhibitor of receptor tyrosine kinases. nih.govresearchgate.net By binding to the ATP-binding site, it prevents the phosphorylation of these kinases, which is essential for their activation and downstream signaling. drugbank.comresearchgate.netfrontiersin.org This competitive inhibition disrupts the aberrant signaling cascades that drive cancer cell growth and survival in tumors expressing activated forms of ALK, ROS1, or c-Met. nih.govdrugbank.combecarispublishing.com

Ligand Binding and Inhibitory Mechanisms

This compound exerts its inhibitory effects through specific interactions within the kinase structure, primarily involving the ATP binding site and, in some cases, allosteric sites.

Influence on Malignant Cell Biological Processes

The inhibition of key kinases by this compound translates into significant effects on the biological processes that drive malignant cell growth and survival.

Molecular Architecture and Key Interacting Moieties of Crizotinib

The chemical structure of this compound (C₂₁H₂₂Cl₂FN₅O) is characterized by the presence of several key functional groups, including pyrazole, pyridine, and piperidine rings frontiersin.orgmrc.ac.ukuni.lu. A critical component for target engagement is the 2-aminopyridine moiety, which forms essential bonds within the ATP-binding sites of ALK, ROS1, and c-Met mdpi.com. The piperidine ring is typically oriented towards the solvent-exposed surface of the protein, making it a potential point for chemical modification or conjugation strategies mdpi.com. This compound exists as a chiral compound, with the (R)-enantiomer demonstrating superior potency compared to the (S)-isomer or the racemic mixture guidetopharmacology.org.

Co-crystal Structure Analysis of this compound-Kinase Complexes (e.g., ALK, ROS1, c-Met)

Co-crystal structures of this compound in complex with the kinase domains of its primary targets – ALK, ROS1, and c-Met – have provided invaluable atomic-level details regarding its binding mode and the basis for its selectivity mdpi.comaacrjournals.orgacs.org. These structures consistently show this compound occupying the ATP-binding pocket in a conserved fashion across these kinases mdpi.com.

In the co-crystal structure of the ALK-crizotinib complex (PDB ID: 2XP2), the 2-aminopyridine group engages in crucial hydrogen bonding interactions with backbone atoms of residues in the hinge region, specifically with the oxygen atom of Glu1197 and the N-H group of Met1199 nih.gov. An additional hydrogen bond is formed between the N2 nitrogen of the pyrazole ring and a water molecule that is coordinated by Asp1203 nih.gov. This compound is observed to bind to ALK in an inactive conformational state aacrjournals.org.

The co-crystal structure of ROS1 bound to this compound (PDB ID: 3ZBF) reveals that this compound binds within the ATP-binding cleft situated between the N-terminal and C-terminal lobes of the kinase domain researchgate.net. Similar to its interaction with ALK, the 2-aminopyridine ring forms hydrogen bonds with backbone residues in the hinge region, specifically Glu2027 and Met2029 in ROS1 mdpi.com. This binding characteristic is consistent with a Type I inhibitor, which typically binds to the active conformation of the kinase pnas.orgnih.gov.

For c-Met, the co-crystal structure (PDB ID: 2WGJ) illustrates this compound's binding within the ATP pocket mdpi.comnih.gov. The 2-aminopyridine core is essential for interactions with hinge region residues Pro1158 and Met1160 mdpi.com. Furthermore, a significant π-stacking interaction is observed between the 2,6-dichloro-3-fluorophenyl ring of this compound and the Tyr1230 residue mdpi.com. This compound is categorized as a Type Ia inhibitor for c-Met, characterized by its interactions with both Tyr1230 and G1163 mdpi.com.

Despite the high degree of sequence homology, particularly within the ATP-binding sites of ALK and ROS1 (approximately 84% similarity) mdpi.com, and the generally similar binding mode of this compound, subtle structural differences contribute to the observed selectivity profile and can influence the emergence of resistance mutations pnas.org.

Computational Approaches in this compound Structural Biology

Computational methods have served as powerful tools to complement experimental structural data, offering deeper insights into the dynamic nature of protein-ligand interactions, conformational landscapes, and the thermodynamics of binding obmclab.com.

Rational Drug Design Principles Guiding this compound Development

The development of this compound is a prime example of the application of rational drug design principles, a strategy that leverages detailed structural and biochemical information about the target to design molecules with desired pharmacological properties scielo.org.mxbbau.ac.in. This compound's journey began with a first-generation c-Met inhibitor, PHA-66752. The co-crystal structure of PHA-66752 bound to c-Met provided crucial structural insights that guided subsequent optimization efforts aimed at improving binding within the active site aacrjournals.orgacs.org. The design strategy focused on creating a molecule that was less lipophilic and featured a small hinge-binding motif to enhance its interaction within the kinase pocket nih.gov.

This process involved iterative cycles of design, synthesis, and evaluation. A key step was the re-engineering of the central core rings to arrive at the 5-aryl-3-benzyloxy-2-aminopyridine scaffold. This specific arrangement allowed the 2-aminopyridine nitrogen and its attached amino group to form favorable hydrogen bonds with residues in the kinase hinge region acs.org. Further refinement of this lead series ultimately led to the identification of this compound, a potent dual inhibitor of both c-Met and ALK acs.org. The high structural similarity between the ATP-binding sites of ALK and ROS1 subsequently facilitated the expansion of this compound's inhibitory profile to include ROS1 mdpi.com.

Rational drug design also incorporates considerations beyond just binding affinity, such as ligand efficiency and the influence of molecular features on physicochemical properties like lipophilicity (represented by log D) acs.org. This systematic, structure-guided approach, coupled with rigorous biochemical and cellular evaluations, was fundamental to the successful development of this compound with its specific potency and selectivity profile acs.org.

On-Target Resistance Mechanisms

On-target resistance mechanisms involve alterations to the ALK or ROS1 kinase, the primary targets of crizotinib. These alterations can reduce the drug's binding affinity or increase the activity of the kinase, thereby overcoming the inhibitory effects of this compound. researchgate.netresearchgate.net

Off-Target Resistance Mechanisms (Bypass Signaling)

Off-target or bypass signaling mechanisms involve the activation of alternative signaling pathways that can compensate for the inhibition of ALK or ROS1 by this compound. These pathways can reactivate downstream signaling cascades crucial for tumor cell survival and proliferation, rendering the tumor resistant to the TKI. amegroups.orgresearchgate.netoaepublish.com

Examples of activated bypass signaling pathways in this compound resistance include:

EGFR Pathway Activation: Increased phosphorylation of EGFR and activation of downstream signaling have been observed in this compound-resistant cells and patient samples, even in the absence of EGFR mutations. nih.govamegroups.orgoaepublish.comkarger.comaacrjournals.org This can lead to the activation of downstream pathways like MAPK, bypassing the ALK inhibition. oaepublish.comnih.gov

KIT Amplification/Activation: Amplification and activation of the KIT receptor tyrosine kinase have been identified as a bypass mechanism in this compound-resistant tumors. nih.govamegroups.orgmdpi.comkarger.com

HER2/HER3 Activation: Activation of HER2 and HER3, other members of the ErbB family of receptor tyrosine kinases, can also contribute to bypass signaling and this compound resistance. oaepublish.comkarger.com

KRAS Mutations: Mutations in KRAS have been found in some patients who developed resistance to this compound. amegroups.orgkarger.com

MAPK Pathway Activation: Upregulation of the MAPK signaling pathway, potentially through alterations in genes like MAP2K1, has been implicated in this compound resistance. becarispublishing.commdpi.comcrsf.in

Other Pathways: Other pathways such as IGF-1R, SRC, and mTOR have also been suggested to play a role in bypass signaling in this compound resistance. researchgate.netuhod.orgkarger.com Epithelial-mesenchymal transition (EMT) is also associated with this compound resistance and involves the activation of specific signaling pathways. karger.comaacrjournals.orgfrontiersin.org

The activation of these bypass pathways can occur independently of ALK or ROS1 genetic alterations and can lead to resistance by reactivating downstream signaling despite effective inhibition of the primary target. amegroups.orgoaepublish.comcrsf.in In some cases, multiple resistance mechanisms, including both on-target mutations and bypass signaling, can be present in the same tumor. nih.govamegroups.org

Drug Efflux Pump Activity (e.g., P-glycoprotein/ABCB1)

Increased activity of drug efflux pumps, particularly P-glycoprotein (P-gp), encoded by the ABCB1 gene, can contribute to acquired resistance to this compound researchgate.netfrontiersin.org. P-gp is an ATP-binding cassette (ABC) transporter that actively pumps a wide variety of substrates, including many chemotherapeutic agents and targeted therapies like this compound, out of cancer cells mdpi.commdpi.com. Overexpression or increased activity of P-gp can lead to reduced intracellular concentrations of this compound, thus diminishing its effectiveness researchgate.netmdpi.com.

Studies have shown that this compound is a transport substrate of P-gp researchgate.netmdpi.com. Upregulation of P-gp expression or function after this compound administration has been identified as a mechanism of resistance researchgate.net. This is particularly relevant in certain anatomical sites, such as the central nervous system (CNS), where P-gp is present at the blood-brain barrier and can limit the penetration of this compound into brain tissue, potentially contributing to CNS progression as a site of resistance researchgate.net.

Research indicates that this compound can reverse multidrug resistance mediated by ABCB1 by inhibiting its transport function nih.gov. However, the development of resistance suggests that in some cases, the level of P-gp activity may be sufficient to reduce intracellular this compound concentrations below therapeutic levels, or other resistance mechanisms may be co-occurring researchgate.netfrontiersin.org.

Tumor Microenvironment Contributions to Resistance

The tumor microenvironment (TME), comprising various cell types, extracellular matrix components, and signaling molecules, plays a significant role in the development of acquired resistance to targeted therapies, including this compound frontiersin.orgnih.gov. Interactions between cancer cells and the surrounding stromal cells can provide survival signals that bypass the effects of ALK inhibition aacrjournals.orgfrontiersin.org.

Components of the TME, such as endothelial cells and fibroblasts, can secrete growth factors and cytokines that activate alternative signaling pathways in cancer cells aacrjournals.orgfrontiersin.org. For example, endothelial cells can produce EGFR ligands, while fibroblasts can secrete HGF, both of which can trigger bypass survival signals and reduce sensitivity to ALK inhibitors like this compound aacrjournals.org. This paracrine signaling from stromal cells can lead to the activation of pathways such as EGFR, c-Met, and others, contributing to resistance aacrjournals.orgfrontiersin.org.

Furthermore, the TME can influence resistance through mechanisms like inducing epithelial-mesenchymal transition (EMT), which is associated with increased invasiveness and drug resistance frontiersin.orgaacrjournals.org. Inflammatory cytokines secreted by senescent cells within the TME can also alter the microenvironment and contribute to resistance ersnet.org. Studies have shown that blocking signaling pathways activated by the TME, such as mTOR signaling, can help restore sensitivity to this compound frontiersin.org.

Efficacy in ROS1-Rearranged NSCLC

Crizotinib has demonstrated marked efficacy in patients with ROS1-rearranged advanced NSCLC and is a standard therapy for this molecular subgroup aacrjournals.orgnih.gov.

The PROFILE 1001 study, a phase 1 expansion cohort, evaluated this compound in patients with ROS1-rearranged NSCLC. Updated results showed an ORR of 72%, a median PFS of 19.3 months, and a median OS of 51.4 months nih.govnih.gov. These findings established a new benchmark for OS in this patient population nih.gov.

Other studies have corroborated these findings. The OO12-01 study in East Asian patients reported an ORR of 71.7% and a median PFS of 15.9 months nih.gov. The EUROS1 cohort, a retrospective study, observed an ORR of 80% and a median PFS of 9.1 months nih.gov. A multicenter retrospective analysis showed an ORR of 72%, a median PFS of 20.9 months, and a median OS of 52.7 months in real-world individuals with ROS1-rearranged NSCLC mdpi.com.

Data Table: Efficacy of this compound in ROS1-Rearranged NSCLC

Efficacy in c-Met-Amplified/Activated Cancers (e.g., Gastroesophageal Cancers)

This compound is a potent inhibitor of c-Met aacrjournals.org. Its efficacy in c-Met-altered cancers has been investigated, although its role is less established compared to ALK and ROS1 alterations aacrjournals.orgaacrjournals.org.

Data Table: Efficacy of this compound in c-Met-Altered Cancers

Research in Philadelphia Chromosome-Positive (Ph+) Leukemia

Research has explored the therapeutic potential of this compound in advanced and therapy-resistant Philadelphia chromosome-positive (Ph+) leukemia. This compound has been shown to inhibit the BCR-ABL1 kinase, which is a hallmark of Ph+ leukemia. Studies have indicated that this compound can efficiently suppress the growth of Ph+ cells without affecting the growth of Ph- cells. nih.govaku.edunih.gov Its activity has also been observed in Ph+ patient-derived long-term cultures, irrespective of their responsiveness or resistance to other TKIs. nih.govaku.edunih.gov

The efficacy of this compound in Ph+ leukemia has been supported by in vivo studies using syngeneic mouse models. These models included those driven by BCR-ABL1 or the BCR-ABL1T315I mutation in chronic myeloid leukemia (CML)-like disease, as well as BCR-ABL1-driven acute lymphoblastic leukemia (ALL). nih.govaku.edunih.gov Notably, this compound has shown activity against native BCR-ABL1 and its resistance and compound mutants, including BCR-ABL1 T315I and BCR-ABL1 T315I-E255K. nih.govnih.gov While this compound binds to the ATP-binding site, it also appears to allosterically affect the myristoylation binding pocket, a site targeted by other agents like GNF2 and asciminib. nih.govaku.edunih.gov These findings suggest a potentially unique dual mechanism of action for this compound in this context and strongly support its clinical evaluation for advanced and therapy-resistant Ph+ leukemia. nih.govaku.edunih.gov

Studies on Intracranial Efficacy and Central Nervous System (CNS) Progression

Central nervous system (CNS) metastases are a significant challenge in managing ALK-rearranged NSCLC, with a high frequency of CNS involvement observed in these tumors. amegroups.org The incidence of CNS disease approaches 25% in treatment-naïve patients and can rise to 50% in patients treated with this compound. amegroups.org this compound is considered to have poor penetration of the blood-brain barrier, which may contribute to the development of brain metastases during treatment. amegroups.orgoncotarget.com

However, studies have evaluated the intracranial efficacy of this compound. A subset analysis of the PROFILE 1005 and 1007 clinical trials reported that in ALK-rearranged advanced NSCLC patients treated with this compound, the intracranial disease control rate (DCR) at 12 weeks was 56% and 62% in patients with previously untreated and treated brain metastases, respectively. oncotarget.comascopubs.org The objective response rate (ORR) in these groups was 18% and 33%, respectively. oncotarget.comascopubs.org The median intracranial time to progression (TTP) was 7 months for patients with previously untreated brain metastases and 13.2 months for those with previously treated brain metastases. oncotarget.comascopubs.org

The PROFILE 1014 study, which compared this compound with platinum-pemetrexed chemotherapy in ALK-positive NSCLC, demonstrated a non-significant trend towards improved intracranial TTP with this compound compared to chemotherapy in the intention-to-treat population and in the subgroup with baseline treated and stable brain metastases. amegroups.org At 12 weeks, the intracranial DCR was significantly higher with this compound (85%) compared to chemotherapy (45%) in the subgroup with baseline treated and stable brain metastases. amegroups.orgcancernetwork.com At 24 weeks, the rates were 56% and 25%, respectively. cancernetwork.com this compound treatment was associated with significantly better intracranial disease control rate in patients with previously treated CNS metastases, confirming results from a combined analysis of PROFILE 1005 and PROFILE 1007 studies. amegroups.org

Despite demonstrating intracranial activity, progression of pre-existing or development of new intracranial lesions is a common manifestation of acquired resistance to this compound. ascopubs.org

Intracranial Efficacy Data from PROFILE 1005/1007 (Subset Analysis) oncotarget.comascopubs.org

Intracranial Efficacy Data from PROFILE 1014 (Treated and Stable Brain Metastases Subgroup) amegroups.orgcancernetwork.com

Real-World Evidence Studies of this compound Efficacy

Real-world evidence (RWE) studies provide valuable insights into the effectiveness of this compound in routine clinical practice, complementing data from controlled clinical trials. Studies in patients with ALK-positive NSCLC have indicated that outcomes for this compound recipients in real-world settings align with those observed in clinical trials. mdpi.com

Real-world data from Japan on ROS1-positive NSCLC patients treated with this compound also provided evidence of its effectiveness, with a median duration of treatment of 12.9 months regardless of the line of therapy. tandfonline.com Some patients in this study continued this compound treatment for over 33 months. tandfonline.com

Real-World Efficacy Data Examples

Real-World Study in ROS1-Rearranged NSCLC mdpi.com

Real-World Study in ALK-Positive NSCLC (North America) mdpi.com

Real-World Study in ALK-Positive NSCLC with Brain Metastases (Chinese Population) oncotarget.com

Pharmacodynamic Markers and Their Utility in Clinical Trials

Pharmacodynamic (PD) markers are crucial in clinical trials to assess the biological activity of a drug and its effect on target pathways. For crizotinib, PD research has focused on evaluating the inhibition of its target kinases, primarily ALK and MET. Studies have aimed to characterize the relationship between this compound systemic exposure, target inhibition, and clinical outcomes like tumor growth inhibition. nih.gov

Translational pharmacokinetic-pharmacodynamic modeling has been employed to predict the level of ALK or MET inhibition in patient tumors based on simulated plasma concentrations. nih.gov Research findings suggest that specific levels of ALK and MET inhibition are associated with significant tumor growth inhibition in nonclinical models. For instance, one study indicated that 50% ALK inhibition was required for over 50% tumor growth inhibition, while over 90% MET inhibition was necessary for the same effect. nih.gov Based on these models and clinically recommended dosing, it was projected that this compound could achieve over 75% ALK inhibition and over 95% MET inhibition in patient tumors. nih.gov These projections align with observed clinical responses. nih.gov

Biomarkers, including those assessing the phosphorylation status of target receptors like c-Met/HGFR in tumor samples, have been utilized in clinical trials to monitor the pharmacodynamic effects of this compound. fda.gov The detection of genetic aberrations, such as ALK rearrangements, using methods like fluorescence in situ hybridization (FISH), is also a critical component in identifying patients likely to respond to this compound, serving as a predictive biomarker. nih.govnih.govopenaccessjournals.com

Hepatic Metabolism Pathways (e.g., CYP3A4, CYP3A5)

This compound undergoes extensive metabolism primarily in the liver. nih.gov The major enzymes involved in the metabolic clearance of this compound are CYP3A4 and CYP3A5. nih.govdrugbank.compharmgkb.orgtga.gov.au The primary metabolic pathways in humans involve the oxidation of the piperidine ring, leading to the formation of this compound lactam, and O-dealkylation, followed by phase 2 conjugation of the O-dealkylated metabolites. drugbank.comtga.gov.au

This compound lactam (PF-06260182), a racemic mixture of two diastereomers (PF-06270079 and PF-06270080), has been identified as the only active metabolite in humans. drugbank.compharmgkb.org While active, these metabolites are less potent against ALK and MET compared to this compound itself, with approximately 3- to 8-fold lower potency against ALK and 2.5- to 4-fold lower potency against MET in in vitro studies. drugbank.compharmgkb.org The formation of this compound lactam likely involves a two-step process mediated by CYP3A4, CYP3A5, and AOX1. pharmgkb.org CYP3A4 and CYP3A5 are also involved in the further metabolism of this compound lactam. pharmgkb.org

Non-metabolic elimination, such as biliary excretion, may also contribute to this compound clearance. nih.govdrugbank.com Following a single radiolabeled dose, a significant portion of the administered dose is recovered in feces (63%) and urine (22%), with unchanged this compound representing a larger percentage in feces (approximately 53%) than in urine (approximately 2.3%). drugbank.comtga.gov.au

Influence of Drug-Drug Interactions on this compound Exposure

This compound's metabolism by CYP3A4 and CYP3A5 makes it susceptible to drug-drug interactions with agents that either inhibit or induce these enzymes. nih.govresearchgate.net

Strong inhibitors of CYP3A can increase this compound plasma concentrations. nih.goveuropa.eu For example, coadministration of a single 150 mg oral dose of this compound with ketoconazole, a strong CYP3A inhibitor, resulted in a substantial increase in this compound systemic exposure, with the AUC and Cmax increasing by approximately 3.2-fold and 1.4-fold, respectively, compared to this compound administered alone. europa.eupfizermedicalinformation.com Another study showed that coadministration with itraconazole, another strong CYP3A inhibitor, increased this compound steady-state AUC by 57% and Cmax by 33%. pfizermedicalinformation.com

Conversely, strong inducers of CYP3A can decrease this compound plasma concentrations. pharmgkb.orgeuropa.eu Coadministration of a single 250 mg this compound dose with rifampicin, a strong CYP3A inducer, led to significant decreases in this compound exposure, with AUCinf and Cmax decreasing by 82% and 69%, respectively. europa.eu The concurrent use of strong CYP3A inducers, including but not limited to carbamazepine, phenobarbital, phenytoin, rifabutin, rifampicin, and St. John's wort, should be avoided as they may decrease this compound plasma concentrations. nih.goveuropa.eu

The effect of CYP3A inducers or inhibitors on steady-state this compound exposure can be complex due to the time-dependent pharmacokinetics of this compound, including auto-inhibition of CYP3A. pharmgkb.orgfda.gov Studies evaluating these interactions at steady-state are important for predicting their full impact. fda.gov

The aqueous solubility of this compound is pH-dependent, with higher solubility at low (acidic) pH. nih.govtga.gov.au However, coadministration with agents that increase gastric pH, such as proton-pump inhibitors, H2 blockers, or antacids, resulted in only a small decrease in this compound total exposure (approximately 10% decrease in AUCinf with esomeprazole), which was not considered clinically meaningful. europa.eutga.gov.au Therefore, dose adjustments are generally not required when this compound is coadministered with these agents. europa.eutga.gov.au

Transport Protein Interactions (e.g., P-glycoprotein, OCT1, OCT2)

This compound interacts with various transport proteins, which can influence its absorption, distribution, and elimination, as well as potentially affect the pharmacokinetics of coadministered drugs.

In vitro studies suggest that this compound is a substrate for P-glycoprotein (P-gp). tga.gov.aunih.govtga.gov.au P-gp is an efflux transporter that can limit the absorption and tissue penetration of its substrates. nih.gov Mouse model studies have indicated that P-gp primarily restricts the oral availability and brain accumulation of this compound. nih.gov

This compound is also an inhibitor of P-gp in vitro. nih.goveuropa.eunih.govtga.gov.aupfizer.com This inhibition suggests that coadministration of this compound with medicinal products that are substrates of P-gp (e.g., digoxin, dabigatran, colchicine, pravastatin) may lead to increased plasma concentrations and potentially enhanced therapeutic effects or adverse reactions of these coadministered drugs. europa.eutga.gov.aupfizer.com Close clinical surveillance is recommended when this compound is administered with P-gp substrates. europa.eupfizer.com

Furthermore, this compound has been shown to inhibit organic cation transporter 1 (OCT1) and organic cation transporter 2 (OCT2) in vitro. nih.goveuropa.eunih.govtga.gov.aupfizer.comfda.gov OCT1 is a hepatic uptake transporter, while OCT2 is a renal uptake transporter. tga.gov.aufda.gov Inhibition of OCT1 and OCT2 by this compound may increase the plasma concentrations of coadministered drugs that are substrates of these transporters (e.g., metformin, procainamide). europa.eupfizer.comfda.gov However, in vitro studies indicated that this compound did not inhibit other uptake transporters like OATP1B1, OATP1B3, OAT1, or OAT3 at clinically relevant concentrations, suggesting that clinical drug-drug interactions mediated by the inhibition of hepatic or renal uptake by these transporters are unlikely. europa.eutga.gov.aupfizer.com

This compound is also an inhibitor of MATE1 and MATE2-K transporters in vitro, which are involved in renal excretion. nih.gov

Time-Dependent Pharmacokinetics and Auto-inhibition Phenomena

This compound exhibits time-dependent pharmacokinetics. pharmgkb.orgfda.govaacrjournals.org This phenomenon is characterized by a decrease in apparent oral clearance over time with repeated dosing. pharmgkb.orgtga.gov.auaacrjournals.org This reduction in clearance is likely attributable to the auto-inhibition of CYP3A enzymes by this compound. drugbank.comnih.govpharmgkb.orgtga.gov.auresearchgate.netfda.govaacrjournals.org

Following single doses, the mean apparent clearance (CL/F) of this compound was approximately 100 L/hr. drugbank.comtga.gov.autandfonline.com However, at steady-state after multiple doses (250 mg twice daily), the mean apparent clearance was lower, around 60 L/hr to 64 L/hr. drugbank.comtga.gov.aufda.gov This decrease in clearance at steady-state compared to a single dose is consistent with CYP3A auto-inhibition. drugbank.comtga.gov.aufda.gov

In vitro studies using human liver microsomes have demonstrated that this compound is a time-dependent inhibitor of CYP3A, as well as CYP2B6. tga.gov.autga.gov.au Furthermore, this compound may also act as a CYP3A inducer, as it has been shown to increase CYP3A4 mRNA levels in vitro, although without a corresponding increase in CYP3A enzyme activity in that specific context. fda.gov The net effect observed in vivo at steady-state is a reduction in clearance, indicative of dominant auto-inhibition of CYP3A. fda.gov

Steady-state plasma concentrations are typically reached within approximately 15 days of repeated administration with a twice-daily dosing regimen. nih.govtga.gov.aufda.govtga.gov.autandfonline.com The median accumulation ratio at steady-state is around 4.5 to 4.8. tga.gov.aupfizermedicalinformation.comfda.govtga.gov.autandfonline.com

The time-dependent pharmacokinetics and auto-inhibition of CYP3A by this compound have implications for drug-drug interaction studies and predicting the impact of CYP3A modulators on this compound exposure at steady-state. fda.gov

Data Tables

Predictive Biomarkers for Crizotinib Sensitivity

Predictive biomarkers are essential for identifying patients who are most likely to benefit from this compound treatment. The presence of ALK or ROS1 gene rearrangements are the primary predictive biomarkers for this compound sensitivity in NSCLC. nih.govhematologyandoncology.net

Prognostic Biomarkers in this compound-Treated Patient Populations

Prognostic biomarkers provide information about the likely course of the disease and patient outcome, independent of the specific treatment received. In the context of this compound treatment, certain factors have been explored for their prognostic value in ALK-positive NSCLC patients.

Studies have investigated the role of systemic inflammatory markers, such as the neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), platelet-to-lymphocyte ratio (PLR), and white blood cell (WBC) count, as potential prognostic indicators in ALK-positive NSCLC patients treated with this compound. nih.govjournalpulmonology.org

Here is a table summarizing potential prognostic biomarkers in this compound-treated patients:

Research Findings on Prognostic Biomarkers:

A retrospective study of 113 ALK-positive NSCLC patients treated with this compound found that elevated pre-treatment NLR, dNLR, and PLR, and decreased HGB were significantly associated with shorter PFS and OS. nih.gov The median PFS and OS in this cohort were 10.1 and 23.4 months, respectively. nih.gov

Methodological Considerations for Predictive Biomarker Development and Validation

The development and validation of predictive biomarkers for this compound response involve several crucial methodological considerations to ensure their clinical utility and reliability.

Assay Sensitivity and Specificity: The analytical sensitivity and specificity of the detection methods (FISH, IHC, RT-PCR, NGS) are paramount for accurate identification of eligible patients. mdpi.com False positives can lead to unnecessary treatment, while false negatives can result in missed opportunities for effective therapy.

Standardization of Assays: Variability in assay protocols, interpretation criteria, and technical expertise across different laboratories can impact the reliability of biomarker testing. Standardization of these methodologies is essential for consistent and reproducible results. nih.gov

Tissue Sample Quality and Availability: Obtaining sufficient and high-quality tumor tissue is sometimes challenging, especially in advanced NSCLC. oncotarget.com The suitability of different sample types (e.g., formalin-fixed, paraffin-embedded tissue, cytology samples, liquid biopsies) for various detection methods needs careful consideration and validation. turkjpath.orgsemanticscholar.org

Defining Positive and Negative Results: Establishing clear and validated cut-off values for positivity for each assay is critical for accurate patient selection. nih.govmdpi.com

Assessment of Tumor Heterogeneity: Tumors can exhibit spatial and temporal heterogeneity in their molecular profiles. aacrjournals.org This can impact biomarker detection and the development of resistance. Methodologies that can assess heterogeneity, such as NGS or liquid biopsies, may provide a more comprehensive picture. amegroups.orgdovepress.com

Identification of Resistance Mechanisms: Understanding the mechanisms of acquired resistance is crucial for developing strategies to overcome it. frontiersin.orgamegroups.org Biomarker research should include the profiling of post-progression samples to identify new genetic alterations or pathway activations driving resistance. frontiersin.orgamegroups.orgaacrjournals.org This often involves repeat biopsies and advanced molecular testing. frontiersin.orgamegroups.orgaacrjournals.org

The successful implementation of predictive biomarkers for this compound requires a multidisciplinary approach involving pathologists, molecular biologists, and oncologists, along with robust quality control measures and ongoing research to identify and validate new biomarkers and improve existing methodologies.

7.4. Role of Genotyping in Personalized Oncology Approaches

Genotyping plays a critical role in the personalized oncology approach for patients being considered for or treated with this compound. This compound is a tyrosine kinase inhibitor (TKI) that targets specific genomic alterations, primarily rearrangements in the Anaplastic Lymphoma Kinase (ALK) and ROS1 genes, as well as amplification and exon 14 skipping mutations in the MET gene. Identifying these alterations through genotyping is essential for selecting patients who are most likely to benefit from this compound therapy and for understanding mechanisms of acquired resistance. clinicaltrials.eunih.govnih.govdovepress.com

The presence of specific genetic alterations serves as predictive biomarkers for response to this compound. ALK gene rearrangements were the first identified target for this compound, and their detection is crucial for patient selection in non-small cell lung cancer (NSCLC). canceradvocacy.orgmedscape.comnih.govnih.gov These rearrangements, such as the EML4-ALK fusion, lead to constitutive activation of the ALK kinase, driving tumor growth. nih.gov ALK rearrangements are found in a subset of NSCLC patients, typically ranging from 2% to 7%, and are more frequently observed in younger patients and never-smokers with adenocarcinoma histology. nih.govnih.govjci.org

Similarly, rearrangements in the ROS1 gene are also targetable alterations for this compound. ROS1 fusions function as oncogenic drivers in NSCLC and occur in approximately 1% to 2% of cases. jci.orgfrontiersin.orgmdpi.com Clinical studies have demonstrated significant antitumor activity of this compound in patients with ROS1-rearranged NSCLC. jci.orgmdpi.comresearchgate.net

Genomic alterations in the MET gene, including MET amplification and MET exon 14 skipping mutations, represent another subset of alterations for which this compound has shown activity. nih.govnih.govdovepress.com While the response rates in MET-altered tumors might differ from those with ALK or ROS1 rearrangements, genotyping for MET alterations helps identify additional patients who may benefit from this compound. nih.govfrontiersin.orgaacrjournals.org

Various genotyping platforms and techniques are employed to detect these targetable alterations. Historically, fluorescence in situ hybridization (FISH) has been a standard method for detecting ALK rearrangements, and it was the basis for the companion diagnostic test approved concurrently with this compound by the FDA. nih.govnih.govtheoncologynurse.comoncotarget.com Other methods include reverse transcriptase PCR (RT-PCR) and immunohistochemistry (IHC) as potential pre-screening tools or complementary assays. nih.govoncotarget.comoncotarget.com

More advanced genotyping approaches, such as multiplex genotyping and Next-Generation Sequencing (NGS), are increasingly being implemented in clinical practice. nih.govmedscape.comnih.govoncotarget.com Comprehensive genomic profiling (CGP) using NGS allows for the simultaneous detection of a wide range of genomic alterations, including fusions, mutations, and amplifications in genes like ALK, ROS1, and MET, from a single tumor sample. nih.govoncotarget.comresearchgate.net This comprehensive approach facilitates the identification of patients with various targetable alterations and can provide insights into potential co-occurring mutations that might influence response or resistance. nih.govaacrjournals.org

The integration of genotyping results into clinical decision-making enables a personalized approach to cancer treatment. By identifying the specific oncogenic driver in a patient's tumor, clinicians can select targeted therapies like this compound for those whose tumors harbor ALK, ROS1, or MET alterations. medscape.comnih.govresearchgate.netjpccr.eu This genotype-directed therapy approach has significantly changed the management of NSCLC and improved outcomes in selected patient populations compared to traditional chemotherapy. medscape.comnih.govjpccr.eu

Furthermore, genotyping plays a crucial role in understanding and managing acquired resistance to this compound. Despite initial responses, most patients eventually develop resistance. mdpi.comoncotarget.com Genotyping of tumor samples collected at the time of progression can reveal the underlying resistance mechanisms. These mechanisms can include the development of secondary mutations within the kinase domain of the target gene (ALK or ROS1) that reduce the binding affinity of this compound, or the activation of alternative signaling pathways (bypass mechanisms) such as amplification of MET or alterations in other genes like EGFR or KRAS. mdpi.comfrontiersin.orgoncotarget.comnih.govamegroups.org Identifying these resistance mechanisms through repeat genotyping can inform subsequent treatment decisions, including switching to next-generation TKIs or exploring combination therapies. oncotarget.comnih.govnih.gov

Data on the prevalence of targetable alterations in NSCLC highlights the importance of routine genotyping:

Clinical trials have demonstrated varying response rates to this compound based on the specific genetic alteration:

Note: Response rates can vary between studies based on patient populations, prior treatments, and specific genetic contexts.

The continuous evolution of genotyping technologies, particularly NGS, is providing a more comprehensive understanding of the genomic landscape of tumors and its implications for targeted therapy with agents like this compound. nih.govmedscape.comoncotarget.com This allows for more precise patient stratification and the potential to identify novel biomarkers for response and resistance, further advancing personalized oncology. medscape.comnih.govresearchgate.net

Overcoming Acquired Resistance with Combination Regimens

Acquired resistance to targeted therapies like crizotinib is a major impediment to long-term treatment success. nih.govmdpi.comamegroups.org Resistance can arise through various mechanisms, including secondary mutations in the target kinase (e.g., ALK or ROS1), activation of bypass signaling pathways, or changes in the tumor microenvironment. nih.govmdpi.comamegroups.org Combination regimens are designed to simultaneously inhibit the primary target and these emergent resistance pathways.

Studies have shown that combining this compound with other chemotherapeutic agents can restore sensitivity in resistant tumors. nih.govmdpi.com For instance, the combination of this compound with topotecan and cyclophosphamide demonstrated improved tumor responses in neuroblastoma models, including those with ALK mutations associated with single-agent this compound resistance. nih.govaacrjournals.org This combination also showed synergistic cytotoxicity and increased caspase-dependent apoptosis in ALK-aberrant neuroblastoma cell lines. aacrjournals.org

In ovarian cancer, this compound has shown efficacy in restoring platinum chemosensitivity, particularly in cases where resistance is associated with elevated levels of hepatocyte growth factor (HGF) and IL-6, which activate the HGF/c-Met and IL-6/JAK signaling pathways, respectively. nih.gov High c-Met expression is linked to poor prognosis in ovarian cancer, and this compound, as a c-Met inhibitor, has demonstrated synergistic effects with platinum compounds in inhibiting ovarian cancer cell growth in preclinical models. nih.gov

The dynamic nature of tumors and the potential for multiple resistance mechanisms to emerge simultaneously underscore the need for combination therapies. amegroups.orgnih.gov Identifying the specific resistance mechanisms in individual patients is crucial for tailoring effective combination strategies. nih.gov

Synergistic Effects with DNA Repair Pathway Inhibitors (e.g., PARP Inhibitors)

This compound has shown synergistic effects when combined with poly (ADP-ribose) polymerase (PARP) inhibitors, particularly in cancers harboring BRCA gene mutations. nih.govmdpi.comresearchgate.net PARP inhibitors target DNA repair mechanisms, and combining them with this compound can enhance anti-tumor activity. nih.govaacrjournals.org

Preclinical studies in high-grade serous ovarian cancer (HGSOC) have demonstrated that the combination of this compound and PARP inhibitors like olaparib, niraparib, rucaparib, and talazoparib results in synergistic growth inhibition. aacrjournals.orgoncotarget.comresearchgate.net This combination has been shown to reduce cell viability and clonogenic growth in olaparib-resistant ovarian cancer cell lines and patient-derived organoids. nih.govaacrjournals.org

Mechanistically, the combination of this compound and PARP inhibitors can lead to increased levels of reactive oxygen species (ROS), induced DNA damage (indicated by elevated γH2AX levels), and decreased phosphorylation of key signaling molecules such as AKT, mTOR, and ULK-1. nih.govaacrjournals.orgoncotarget.com This contributes to increased autophagy and apoptosis. nih.govaacrjournals.orgoncotarget.com The combination has also been shown to activate the ATM/CHK2 pathway and inhibit the c-Met pathway, leading to a decrease in RAD51 levels and induction of caspase-3-dependent apoptotic cell death. nih.govmdpi.comoncotarget.comresearchgate.net

Synergistic effects between c-Met and PARP1 inhibitors have also been reported in breast cancer and lung cancer xenograft models. nih.govmdpi.com this compound enhanced the efficacy of PARP inhibitors in ovarian cancer cells and xenograft models by inducing autophagy. nih.govmdpi.comnih.govaacrjournals.org These findings suggest that combining this compound with PARP inhibitors is a promising strategy, potentially limiting resistance to PARP inhibitors. nih.govmdpi.com

Table 8.2: Synergistic Effects of this compound with PARP Inhibitors

Rational Combinations Targeting Bypass Signaling Pathways (e.g., MET/FAK, ERK5, NRG1)

Activation of alternative signaling pathways, or bypass tracts, is a common mechanism of acquired resistance to targeted therapies, including this compound. amegroups.orgnih.govnih.gov Rational combination strategies involve inhibiting both the primary oncogenic driver and the activated bypass pathway. nih.govdovepress.com

MET amplification and activation are well-documented mechanisms of resistance to ALK and EGFR inhibitors. amegroups.orgnih.govplos.org this compound, initially developed as a MET inhibitor, can be combined with other agents to overcome resistance mediated by MET signaling. amegroups.org Studies have shown that combining this compound with new generation EGFR-TKIs like afatinib or WZ4002 can overcome resistance in lung cancer cells with EGFR-T790M mutations, MET amplification, or HGF overexpression. plos.org This combination effectively inhibits the phosphorylation of both EGFR and MET, as well as downstream signaling molecules like Akt and ERK1/2. plos.org

The MET and FAK (Focal Adhesion Kinase) pathway has been implicated in resistance to CDK4/6 inhibitors by activating CDK2. oncology-central.comucl.ac.uk Combining this compound (a MET inhibitor) with CDK4/6 inhibitors like palbociclib has shown significantly greater effectiveness in inhibiting cancer cell division and inducing senescence in various cancer cell types, including breast and lung cancer, compared to either drug alone. oncology-central.comucl.ac.uk Research suggests that targeting FAK in combination with CDK4/6 inhibitors could also be a promising strategy. oncology-central.comucl.ac.uk

In neuroblastoma, ALK can stimulate the production of ERK5, which enhances the activity of the MYCN oncogene and promotes aggressive tumor growth. icr.ac.uk Targeting both ALK with this compound and ERK5 simultaneously has been shown to be more effective in reducing tumor growth in preclinical models than targeting either pathway alone. icr.ac.uk

The YAP-NRG1 pathway has been identified as a mechanism of adaptive resistance to BRAF inhibitors in BRAF-mutant thyroid cancer. mdpi.comencyclopedia.pubresearchgate.net While direct combinations with this compound in this specific context were not detailed in the provided results, the principle of targeting bypass pathways like those involving NRG1 remains relevant for rational combination design.

Combinations targeting other bypass pathways, such as EGFR, KRAS, and KIT, have also been explored to overcome this compound resistance. amegroups.orgnih.govnih.gov Preclinical data suggests that dual inhibition of ALK and these altered enzymes or their downstream effectors (e.g., PI3K/AKT/mTOR and MEK/ERK) represents potential therapeutic strategies. amegroups.org For instance, combining this compound with imatinib, a KIT inhibitor, was able to overcome resistance mediated by acquired KIT amplification in cell line models. nih.gov

Table 8.3: Rational Combinations Targeting Bypass Signaling Pathways

Combination with Cell Cycle Regulators (e.g., CDK4/6 Inhibitors)

Cell cycle dysregulation is a hallmark of cancer, and inhibitors targeting key cell cycle regulators like CDK4/6 have shown efficacy in various malignancies. Combining this compound with cell cycle regulators, particularly CDK4/6 inhibitors, is being investigated as a strategy to enhance anti-tumor activity and overcome resistance.

As mentioned in Section 8.3, the combination of this compound and the CDK4/6 inhibitor palbociclib has demonstrated synergistic effects in inhibiting cancer cell proliferation and inducing senescence. oncology-central.comucl.ac.uk This synergy is particularly relevant in the context of resistance to CDK4/6 inhibitors mediated by the activation of CDK2 through pathways involving MET and FAK. oncology-central.comucl.ac.uk Preclinical studies have shown that this combination is significantly more effective against various cancer cell types, including breast and lung cancer cells, both in vitro and in vivo. oncology-central.comucl.ac.uk

In high-grade serous ovarian cancer cells, while PARP inhibitors and carboplatin induced G2/M cell cycle arrest, this compound alone or in combination with PARP inhibitors led to an accumulation of cells in the sub-G1 phase, indicative of increased DNA fragmentation and apoptosis. oncotarget.comresearchgate.net

Studies in ALK-positive anaplastic large cell lymphoma (ALCL) cell lines have shown that the combination of this compound and everolimus, an mTOR inhibitor which can influence cell cycle progression, synergistically inhibited proliferation. nih.gov This combination increased G0/G1 cell-cycle arrest, DNA damage, and apoptosis compared to single agents. nih.gov this compound down-regulated aberrant AKT and ERK phosphorylation induced by everolimus and more effectively suppressed mTOR activity. nih.gov

Preclinical data also suggests that CDK4/6 inhibitors like ribociclib can act synergistically with this compound to inhibit the growth of ROS1-fusion-positive lung cancer cells, particularly in the context of MYC amplification, which can contribute to tyrosine kinase inhibitor resistance. researchgate.net

Table 8.4: Combination with Cell Cycle Regulators

Strategies Utilizing Heat Shock Protein 90 (Hsp90) Inhibitors

Heat Shock Protein 90 (Hsp90) is a molecular chaperone essential for the proper folding and stability of many oncogenic proteins, including ALK and MET. hematologyandoncology.netresearchgate.net Inhibition of Hsp90 leads to the degradation of its client proteins, disrupting downstream signaling and inducing apoptosis. amegroups.org Hsp90 inhibitors represent a promising strategy to overcome resistance to ALK and MET inhibitors, including this compound. amegroups.orghematologyandoncology.netoncotarget.comnih.gov

Preclinical studies have shown that this compound-resistant ALK-positive cell lines are highly sensitive to Hsp90 inhibitors. hematologyandoncology.net Hsp90 inhibition has demonstrated activity against various acquired ALK mutations and ALK amplification, mechanisms known to confer this compound resistance. amegroups.orghematologyandoncology.net Combining Hsp90 inhibitors with this compound has shown synergistic anti-tumor effects in preclinical models of ALK- and MET-driven cancers. hematologyandoncology.netoncotarget.comnih.gov

Clinical trials are investigating the combination of this compound with Hsp90 inhibitors in patients with ALK-positive NSCLC, both in this compound-naïve and this compound-resistant settings. hematologyandoncology.netresearchgate.netoncotarget.com For example, studies are evaluating the combination of this compound with ganetespib or AT13387. hematologyandoncology.netresearchgate.netoncotarget.com

Early clinical data from a Phase 1/2 study investigating AT13387 in combination with this compound in NSCLC patients receiving this compound showed that the combination was generally well tolerated and demonstrated anti-tumor activity, including objective responses and tumor shrinkage, even in some patients who had progressed on prior this compound. researchgate.net

Table 8.5: Strategies Utilizing Heat Shock Protein 90 (Hsp90) Inhibitors

Preclinical Research Models (e.g., In Vitro Cell Line Assays, In Vivo Xenograft Models)

Preclinical research models are fundamental in evaluating the efficacy and mechanisms of action of Crizotinib and its potential combinations before clinical trials. In vitro cell line assays are widely used to assess the inhibitory potential of this compound against its target kinases and to study its effects on cell proliferation, survival, and signaling pathways. For instance, this compound has demonstrated potent inhibition of cell proliferation in various cancer cell lines dependent on ALK or c-MET. hematologyandoncology.netnih.gov Studies have utilized ALK-positive anaplastic large-cell lymphoma (ALCL) cells to show that this compound inhibits cell proliferation, leading to G1-S phase cell cycle arrest and apoptosis. nih.gov In ovarian cancer cell lines, this compound inhibited growth in a dose-dependent manner, with IC₅₀ values ranging from 2.70 to 7.41 µM. nih.gov

In vivo xenograft models, particularly those derived from cell lines (CDX) or patients (PDX), are crucial for evaluating drug efficacy in a more complex tumor microenvironment. mdpi.com These models allow for the assessment of tumor growth inhibition, regression, and the impact of treatment on survival. For example, in murine xenografts harboring ALK mutations, including those associated with resistance, combining this compound with chemotherapy agents like topotecan and cyclophosphamide enhanced tumor responses and improved event-free survival. aacrjournals.orgnih.gov Complete tumor remission was observed in the NB-1643 xenograft model (harboring the ALK R1275Q mutation) when treated with this compound plus topotecan/cyclophosphamide for the duration of the treatment. nih.gov In another study using A2780 ovarian cancer xenograft models in nude mice, co-treatment with this compound and cisplatin significantly reduced tumor volume and weight compared to single-agent treatments. nih.gov The inhibition rates of tumor growth in the combined group were significantly higher (46.84%) than with cisplatin alone (2.55%) or this compound alone (22.04%). nih.gov PDX models are considered more reliable for predicting responses to systemic therapies, especially molecularly targeted agents, as they retain the original tumor's histopathology and genetic features. mdpi.com

Here is a table summarizing some preclinical findings:

Synthesis Methodologies and Optimization for Scalability

The synthesis of this compound involves complex chemical processes that require optimization for scalability to produce large quantities of the active pharmaceutical ingredient (API). A robust six-step process for this compound synthesis has been developed, capable of delivering over 100 kg of API. researchgate.netacs.org Key steps in this synthesis include a Mitsunobu reaction, a chemoselective reduction of an arylnitro group, and a Suzuki coupling. researchgate.netacs.orgresearchgate.net

Optimization of these steps is crucial for successful scale-up. For instance, conducting the Mitsunobu reaction in toluene followed by crystallization from ethanol was found to efficiently purge reaction byproducts. researchgate.netacs.org The chemoselective reduction of the arylnitro group was identified as a bottleneck in the synthesis. researchgate.netnih.gov Highly efficient catalytic hydrogenation in continuous flow has been explored as a method to achieve high yields (up to 99.8%) and selectivity for the aniline product under mild conditions, demonstrating the potential for improved efficiency and lower energy costs compared to batch reactors. researchgate.net A highly selective Suzuki reaction is also a critical step in completing the synthesis. researchgate.netresearchgate.net Continuous flow chemistry, in general, is being increasingly exploited in both academic and industrial settings for organic synthesis due to benefits such as improved heat and mass transfer, better process control and safety, and a smaller equipment footprint, all of which are relevant for scaling up this compound synthesis. researchgate.netnih.gov

Prodrug Development and Activation Mechanisms (e.g., ROS-Sensitive Prodrugs)

Prodrug strategies are explored to enhance the therapeutic profile of this compound, particularly to improve tumor selectivity and minimize systemic toxicity. mdpi.comfrontiersin.org This involves designing inactive derivatives that are converted into the active this compound molecule under specific conditions prevalent in the tumor microenvironment. mdpi.comfrontiersin.org

One approach focuses on exploiting the elevated levels of reactive oxygen species (ROS), such as hydrogen peroxide (H₂O₂), in malignant tissues compared to healthy tissues. mdpi.comnih.govresearchgate.net ROS-sensitive prodrugs of this compound have been designed, utilizing a phenylboronic acid residue as a trigger moiety. mdpi.comnih.govresearchgate.net In the presence of H₂O₂, the boronic acid is oxidized, leading to the generation of boric acid, which undergoes hydrolysis to release the parent drug, this compound, often via an electron-migration cascade. mdpi.comnih.gov The 2-aminopyridine functional group of this compound, essential for target kinase binding, has been identified as an ideal position for prodrug derivatization. mdpi.comnih.govnih.gov Prodrugs have been synthesized by attaching the ROS-sensitive trigger via carbamoylation or alkylation of this amino group. nih.gov Studies have shown that these prodrugs can be activated by H₂O₂ in vitro, releasing free this compound. nih.gov Hypoxia-activatable prodrugs based on a 2-nitroimidazole unit attached to the 2-aminopyridine moiety have also been developed and investigated, showing hypoxia-dependent activation in certain cell lines. nih.gov Molecular docking studies are used to assess the binding profiles of these prodrugs to target kinases like ALK and c-MET, aiming for reduced affinity compared to the parent drug. nih.govnih.gov

Advanced Imaging Techniques for Drug Distribution Research (e.g., PET with Labeled this compound)

Advanced imaging techniques, particularly Positron Emission Tomography (PET), are valuable tools for studying the in vivo distribution and pharmacokinetics of this compound. Radiolabeling this compound allows for non-invasive tracking of the drug in living organisms. mdpi.com

Fluorine-18 (¹⁸F) is a suitable radioisotope for labeling this compound due to its ideal half-life and decay properties, and the presence of a fluorine atom in the this compound structure allows for isotopic labeling without modifying the core chemical structure, thus preserving its biological properties. mdpi.com A spirocyclic hypervalent iodine precursor has been synthesized for the isotopic labeling of this compound with ¹⁸F. mdpi.com A two-step radiolabeling process has been optimized and automated to produce ¹⁸F-Crizotinib and the enantiomerically pure ¹⁸F-Crizotinib. mdpi.com

PET imaging with ¹⁸F-Crizotinib has been performed in non-human primates to demonstrate its feasibility for in vivo imaging. mdpi.com Whole-body PET imaging highlighted the elimination routes of this compound and showed negligible penetration into the brain. mdpi.com This type of imaging is a powerful tool for investigating strategies to enhance this compound distribution in sanctuary sites like the brain, which is relevant for treating conditions such as brain metastases. mdpi.com Beyond labeled this compound itself, PET imaging with tracers like ¹⁸F-FDG can also be used to assess metabolic tumor response in patients treated with this compound, showing good agreement with CT measurements and potentially earlier detection of disease progression. plos.org Furthermore, ¹⁸F-labeled this compound derivatives, such as [¹⁸F]FPC, have been developed and evaluated as potential PET imaging probes specifically targeting c-MET-positive tumors. researchgate.net

High-Throughput Screening for Novel Modulators

High-throughput screening (HTS) methodologies are employed to identify novel compounds that can modulate the activity of this compound's targets or pathways, potentially leading to the discovery of new therapeutic agents or combination strategies. HTS allows for the rapid screening of large libraries of small molecules against specific targets or cell lines. mdpi.comnih.govnih.gov

In the context of this compound, HTS can be used to identify compounds that inhibit ALK, c-MET, or ROS1 kinases, or that affect downstream signaling pathways. Kinase inhibitor libraries are commonly used in such screens. nih.gov HTS has been utilized to identify novel small-molecule kinase modulators with cytotoxic effects in cancer cell lines, including neuroblastoma, which can harbor ALK aberrations. nih.gov These screens can reveal compounds that affect various signaling pathways relevant to cancer cell survival and proliferation. nih.gov

Furthermore, HTS platforms can be designed to identify compounds that synergize with existing therapies like this compound. For example, HTS has been used to screen libraries of anti-cancer compounds to identify those that enhance T-cell-mediated cytotoxicity, which could be relevant for combination therapies. mdpi.com While this specific study did not focus on this compound, the methodology is applicable to finding modulators that enhance the effects of targeted therapies. HTS can also be applied to identify genes or pathways that, when modulated, affect sensitivity or resistance to this compound, often utilizing techniques like CRISPR screening. mdpi.comresearchgate.net This can help uncover mechanisms of resistance and identify potential targets for combination therapies to overcome such resistance. aacrjournals.orgmdpi.com

Here is a table illustrating the application of HTS:

Addressing Persistent and Emerging Resistance Mechanisms

Acquired resistance to crizotinib is a major challenge that limits the duration of clinical benefit. nih.govdovepress.comaacrjournals.org Mechanisms of resistance are complex and heterogeneous, often involving secondary mutations in the ALK or ROS1 kinase domains, as well as activation of alternative signaling pathways. aacrjournals.orgdovepress.comaacrjournals.org

Specific ALK resistance mutations identified in this compound-resistant patients include L1196M, G1269A, and G1202R, among others. aacrjournals.orgoaepublish.com The G1202R mutation, while uncommon in post-crizotinib samples (~2%), is a significant resistance mechanism to first and second-generation ALK TKIs. amegroups.org Beyond on-target mutations, bypass signaling pathways, such as those involving EGFR, HER2/3, and protein kinase C, have been implicated in resistance. oaepublish.com MET amplification is another reported mechanism of acquired resistance to this compound, particularly in patients with MET exon 14 skipping mutations or MET amplification. dovepress.comnih.gov

Future research is focused on identifying and characterizing the full spectrum of resistance mechanisms, including those that are ALK-independent. aacrjournals.orgnih.gov Understanding these mechanisms at the epigenetic, RNA, protein, and phospho-protein levels is crucial for developing strategies to overcome resistance. aacrjournals.orgnih.gov Liquid biopsies, such as analysis of circulating tumor DNA (ctDNA), are being explored to provide real-time information on the molecular evolution of resistance and guide subsequent treatment decisions. amegroups.org

Development and Optimal Sequencing of Next-Generation Tyrosine Kinase Inhibitors

The development of second and third-generation ALK inhibitors was driven by the need to overcome this compound resistance and improve efficacy, particularly in the CNS. researchgate.netnih.gov These newer TKIs, such as ceritinib, alectinib, brigatinib, and lorlatinib, have demonstrated superior efficacy compared to this compound in clinical trials and are now preferred first-line options for many patients. researchgate.netjpccr.eudovepress.commdpi.com

While next-generation TKIs are effective in this compound-resistant patients, the optimal sequencing of these agents remains an area of active investigation. amegroups.orgdovepress.commdpi.com The pattern of resistance mutations can differ depending on the prior ALK inhibitor used, which is relevant for selecting the most appropriate subsequent TKI. amegroups.orgmdpi.com For example, the G1202R mutation is more frequently observed after progression on second-generation ALK TKIs compared to this compound. amegroups.org

Studies are ongoing to determine the best sequence of ALK TKIs to maximize patient outcomes and prolong survival. amegroups.orgnih.gov Factors such as the specific acquired resistance mutations, CNS involvement, and patient comorbidities need to be considered when making sequencing decisions. oaepublish.commdpi.com

Enhancing this compound Efficacy in CNS Metastases

CNS metastases are common in patients with ALK-positive NSCLC, and this compound has limited penetration of the blood-brain barrier, which can lead to CNS progression despite systemic disease control. nih.govtandfonline.comdovepress.com This highlights a significant challenge in this compound therapy. While this compound showed some intracranial activity, newer generation ALK inhibitors have demonstrated superior CNS efficacy. nih.govmdpi.comtandfonline.comdovepress.com

Research efforts are aimed at improving the treatment of CNS metastases in ALK-positive patients. This includes the development of ALK inhibitors with enhanced CNS penetration and exploring strategies to increase the concentration of ALK inhibitors in the brain. nih.govtandfonline.com The superior CNS activity of next-generation ALK inhibitors may allow for the deferral of local CNS therapies like radiotherapy in some patients with baseline CNS disease. amegroups.org

Exploration of Novel Combinatorial Therapeutic Approaches

Combining this compound with other therapeutic agents is an area of ongoing research to potentially enhance efficacy and overcome resistance. nih.govjadpro.com This includes combinations with chemotherapy and other small molecule inhibitors. nih.govjadpro.comeuropeanjournalofrespiratorymedicine.com

Recent research suggests that TKIs like this compound may modulate the tumor microenvironment and enhance the effectiveness of immunotherapy. europeanjournalofrespiratorymedicine.com this compound has been shown to potentially increase immunogenic cell death and T-lymphocyte infiltration, which could synergize with immune checkpoint inhibitors. europeanjournalofrespiratorymedicine.com Case reports have described rapid resensitization to PD-1 blockade therapy when combined with this compound in a patient with acquired resistance and MET overexpression. europeanjournalofrespiratorymedicine.com Further research is needed to explore the mechanisms and clinical utility of combining this compound with immunotherapy and other targeted agents. europeanjournalofrespiratorymedicine.com

Refinement of Predictive Biomarker Identification and Clinical Implementation

Accurate identification of patients most likely to benefit from this compound is crucial for personalized therapy. nih.govnih.govhematologyandoncology.net While ALK and ROS1 rearrangements are established predictive biomarkers for this compound response, research continues to refine biomarker identification and implementation. nih.govnih.govhematologyandoncology.net

Challenges in biomarker testing include obtaining adequate specimens and choosing appropriate testing methods. nih.gov The use of next-generation sequencing (NGS) can provide a more comprehensive genetic profile, identifying different ALK fusion types and coexisting mutations that may influence response. amegroups.cnamegroups.org

Research is also exploring novel non-invasive biomarkers, such as circulating microRNAs, which may serve as diagnostic markers for ALK-positive NSCLC and predict response to this compound. oncotarget.com Further validation in larger studies is needed to confirm the utility of these potential biomarkers. oncotarget.com

Understanding the Role of Different ALK Fusion Variants in Response Heterogeneity

The ALK gene can fuse with various partner genes, leading to different ALK fusion variants. aacrjournals.org These variants may influence protein stability and sensitivity to ALK inhibitors, potentially contributing to the observed heterogeneity in clinical responses to this compound. amegroups.cnaacrjournals.orgnih.govresearchgate.net

Studies have investigated the correlation between specific ALK fusion variants and the efficacy of this compound, with some suggesting differential sensitivity based on the variant type. amegroups.cnamegroups.orgaacrjournals.orgnih.gov For example, some studies indicated that patients with EML4-ALK variant 1 may have a longer progression-free survival compared to those with non-variant 1 fusions when treated with this compound. nih.gov However, results across different studies have not always been consistent, and further research is needed to definitively establish the impact of specific ALK fusion variants on this compound response and resistance development. oaepublish.comamegroups.cnamegroups.orgresearchgate.net Understanding the functional significance of these different fusions is critical for advancing ALK-targeted therapies. aacrjournals.org

Note: Data from different studies may vary due to differences in patient populations and methodologies.

Translational Research for Broader Clinical Application

Translational research plays a vital role in translating laboratory findings into clinical applications and expanding the use of this compound and other targeted therapies to broader patient populations and different cancer types. researchgate.netvaluebasedcancer.comacs.org The initial success of this compound in ALK-positive NSCLC, which was based on early-phase trials, exemplifies the potential of translational research to expedite drug development and approval for specific molecular subsets of cancer. valuebasedcancer.comacs.org

Future translational research efforts include identifying other oncogenic drivers that may be sensitive to this compound or similar inhibitors. This compound also inhibits MET and ROS1, and its efficacy has been explored in ROS1-rearranged NSCLC and MET-amplified cancers. researchgate.netaacrjournals.orgnih.govoup.comaacrjournals.org

Translational research is also crucial for developing and validating new predictive biomarkers, understanding the mechanisms of drug resistance, and exploring novel combination strategies to improve patient outcomes across various malignancies where ALK, ROS1, or MET alterations may play a role. researchgate.netnih.govvaluebasedcancer.com The goal is to continue moving towards a more personalized approach to cancer treatment based on the molecular characteristics of each patient's tumor. researchgate.netnih.govdovepress.com