NTRKinhibitors:whatwelearnedandwheretogoMichelaCasanova,FondazioneIRCCSIstitutoNazionaledeiTumoriMilano,Italy

TRKreceptorsmediateneurotrophinsignaling•  Neurotrophinsareimportantgrowthfactorsinvolvedinthegrowth,differentiation,andsurvivalofneurons

•  NeurotrophinsignalingoccursthroughactivationoftheTRKreceptorfamily

NeurotrophinFamilyofReceptors

TRKReceptor

Gene(Chromosomal

Location)

FunctionsNaturalLigandsDevelopmental Adult

TRKA NTRK1(1q23.1)

Cellulardifferentiation/sensoryneuronsubtypespecificationanddevelopmentofpainandthermoregulationmodalities

Painsignaling,thermoregulation

Nervegrowthfactor(NGF),neurotrophin-3(NT-3)

TRKB NTRK2(9q21.33)

Developmentofsensoryneuronsinthebrain

Regulationofmovement,memory,mood,appetite,bodyweight

Brain-derivedneurotrophicfactor(BDNF),neurotrophin-3/4/5(NT-3/4/5)

TRKC NTRK3(15q25.3)

Neuronaldifferentiation,axonoutgrowth/guidance,andsynapticplasticity

Proprioception NT-3

NeurotrophinSignaling1,3

Genefusions:animportantclassofoncogenes•  Associatedwithadiverserangeofsolidtumoursand

hematologicmalignancies

•  NTRKgenefusionsareassociatedwithmanyhumancancers•  Associatedwith≥19tumourtypes

•  Implicatedinupto1%ofallsolidtumours

TRKfusionproteinsareprimaryoncogenicdrivers

TRKfusioncanceroccursacrossawiderangeofchildhoodandadulttumourtypes

Paediatric/youngadult

InfantilefibrosarcomaThyroidcancer

Sarcoma(multiple)

Spitznevi

Adult

Thyroidcancer

IntrahepaticcholangiocarcinomaSecretorybreastcancer

SalivaryMASC

Braincancer(glioma,GBM,astrocytoma)

Lungcancer

Colon

Melanoma

Pancreatic

Sarcoma

Paediatric(infants)high-gradeglioma

Congenitalmesoblasticnephroma

•  RaretumourswithhighNTRKgenefusionfrequency

•  CommontumourswithlowNTRKgenefusionfrequency

GBM,glioblastomamultiforme;MASC,mammaryanaloguesecretorycarcinoma;NTRK,neurotrophictyrosinereceptorkinase;TRK,tropomyosinreceptorkinase.

Single-drivertumorsparticularlysuitable

forprecisionmedicine

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Highunmetneedbothintermsofchanceofrelapsebutalsocurrenttherapiescanleadtosignificanttreatmentburdenandlongtermsideeffects

Whatwearelearning:braintumors

Whatwelearned:rapidclinicaldevelopment

•  LarotrectinibisthefirstandonlyselectiveTRKinhibitor

•  HighlypotentagainstTRKA,TRKB,andTRKC

•  IC505–11nM•  Highlyselective

•  Limitedinhibitionofotherkinases

•  Noinhibitionof229otherkinasesat1000nM

•  DemonstrateactivityinCNSdisease

Larotrectinib

Larotrectinib

Larotrectinib

Larotrectinib

Whatwelearned:efficacy

Entrectinib

Entrectinib

28childrentreatedbetween5/2016-10/2018

Entrectinib

Entrectinib/Larotrectinib Entrectinib ORR Larotrectinib ORR

Extra-CNS NTRK+ 3/3 (3 PR) 100% (29-100%)

32/34 (11 CR, 21 PR)

94% (80-99%)

CNS NTRK + 3/4 (1 CR, 2 PR, 1ong)

75% (19-100%)

5/11 (2 CR, 3 PR) 45% (17-77%)

CNS ROS1 + 2/2 (1 PR, 1 uPR)

Extra-CNS ROS1 + 1/1 (1 PR)

Extra-CNS ALK + Fusion: 2/2 (2 CR) Mut: 1/1 (1CR)

•  Differenceresponseratetoextra-CNSandCNStumorrelatedtoCNSpenetrance?•  LarotrectinibwasdesignedtohavelimitedCNSpenetrationtoreducethepotential

foron-targettoxicityduetoinhibitionofnormalTRKreceptorsinthebrain•  EntrectinibwasfirstdevelopedasanALKinhibitor

Larotrectinib

Larotrectinib

Larotrectinib

PotentialNTRKinhibitorstoxicities

NodataonlateeffectsThephaseIadulttrialoflarotrectinibenrolledpatientstartinginMarch2015

Entrectinib

NTRKinhibitorsapprovedinNTRK-fusionpositivetumours

Larotrectinib

Approved: FDA 2018; Brazil, Canada, EMA 2019

Dose: 25-mg or 100-mg oral capsule or 20-mg/mL oral solution

•  Adults and children with BSA ≥1.0m2: 100 mg orally BID

•  Children with BSA ≤1.0m2 : 100 mg/m2 orally BID

Entrectinib

Approved: FDA and Japan 2019

Dose: 100-mg and 200-mg oral capsule

•  Adults: 600 mg orally once daily

•  Children: Recommended dose based on BSA

Indication: For the treatment of patients with solid tumours harbouring NTRK fusions in paediatric or adult patients

Indication: For the treatment of NTRK fusion-positive advanced or recurrent solid tumours in adult patients and paediatric patients aged ≥12 years old

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Wheretogo?

IdentificationofNTRKfusionsinpediatricpatients

Treatment:when?howlong?

Toxicityandlateeffects

ResistancesandsecondgenerationNTRKi

NointumorwithactivatingmutationmutuallyexclusivetoNTRK

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Needforspecific

recommendationsforchildren

Tumourtype Clinicalsummary Screening

methodology Rationale

Infantilefibrosarcoma

•  Mostcommonsofttissuesarcomainchildren<1year•  Morethanhalfofinfantshaveunresectableormetastaticdiseasethatrequiresneoadjuvanttreatment

IHC/FISH(ETV6and/orNTRK3)RT-PCR;NGSifnegative

HighfrequencyofETV6-NTRK3fusion;variantNTRK3andNTRK1fusionshavebeendescribed

Cellularcongenitalmesoblasticnephroma

•  Mostcommonkidneytumourinthefirstmonthoflife•  96%overallsurvivalrate•  Mostpatientstreatedwithnephrectomy;~20%treatedwithadjuvantchemotherapy

IHC/FISH(ETV6and/orNTRK3)RT-PCR;NGSifnegative

HighfrequencyofETV6-NTRK3fusion;variantNTRK3andNTRK1fusionshavebeendescribed

Secretorybreastcancer

•  Raresubtypeofbreastcancer(<0.02%ofpatients)•  Prognosisgenerallygoodwhendiseaseislocalised•  Standardtreatmentissurgerywith/withoutradiation•  Lymphnodemetastasescanoccur,somepatientswithmetastaticrecurrence

IHC/FISH(ETV6and/orNTRK3)RT-PCR;NGSifnegative

HighfrequencyofNTRK3fusions

MASCofthesalivarygland

•  Histologicallyresemblessecretorybreastcancer•  Primarilyoccursinadults;somecasesinadolescents•  AlmostalltumoursharbourETV6-NTRK3fusions

IHC/FISH(ETV6and/orNTRK3)RT-PCR;NGSifnegative

HighfrequencyofNTRK3fusions

Tumourswithhigh-frequencyTRKfusions(>75%)

Tumourswithmedium-frequencyTRKfusions(10%to40%)Tumourtype Clinicalsummary Screening

methodology Rationale

Spitzoidmelanomas

•  Raremelanocyticlesions(rangingfrombenigntomalignantspitzoidmelanoma)

•  90%ofpatientsdiagnosedare<30yearsold•  Childrenaged10–18yearsareatgreaterriskofmetastaticspreadanddeathvsyoungerchildren

•  Recently,recurrentkinasefusionshavebeendescribed

IHC/NGS

TRKfusionsoccurin15–25%ofpaediatricmelanocyticneoplasms

Papillarythyroidcancer

•  Thyroidcancersaccountfor~4%ofmalignanciesinchildren;>90%ofthesearePTCcases

•  Goodprognosis,with>95%overallsurvivalrateat5years•  Treatmentconsistsofthyroidectomyforlocalisedtumours,andradioactiveiodineformetastatictumours

•  TRKfusionsmaybeassociatedwithhigher-stagedisease

IHC/NGS

TRKfusions(NTRK1andNTRK3)occurinapproximately25%ofchildren,andBRAFactivatingmutationsoccurin~50%ofpatients

High-gradegliomas,especiallyinyoungchildren

•  Gliomasarethemostcommonbraintumoursinchildren•  Poorsurvivaloutcomesinchildrenwithhigh-gradegliomas(<25%3-yearoverallsurvivalrate)

•  NTRKfusionsshowntooccurin~40%ofhigh-gradegliomasinchildren<3yearsold

NGS

TRKfusionsoccur,especiallyintumoursofchildren<3yearsofage;patientshavepoorprognosis;IHChasnotbeenvalidatedingliomas,whichcanhavenormalphysiologicexpressionsofTRK

Tumourswithunknownorlow-frequencyTRKfusions(<5%)Tumourtype Clinicalsummary Screening

methodology Rationale

Undifferentiatedsarcoma

(withoutknowndefiningfusion)

•  LinkwithTRKfusionslargelyanecdotal,sofrequencyhasnotbeenestimated

•  Historically,treatmentofundifferentiatedsarcomahasbeenvariable,morerecentlyrisk-basedchemoradiotherapy

NGS

PrevalenceofTRKfusionsunknownbutdescribed;inadditiontoNTRK,othertargetablefusionshavebeendescribed

InflammatoryMyofibroblastic

Tumour

•  Locallyaggressiveneoplasms•  Medianageatdiagnosis:9years•  Metastasesarerare(<5%),andcompletesurgicalresectionisusuallycurative

•  PatientswithALKfusions(50–60%ofcases)haveagoodtreatmentresponsewithcrizotinib

NGS

TRKfusiontumoursmayshareinflammatorymyofibroblastictumour-likemorphology;mutuallyexclusivefusionsofALKandROS1alsooccur

ICH: sensitivityandspecificityishighinmesenchymaltumorsuselessinbraintumors

SIOPENTRKtestingworkshop

Molecularprofilingprogramsatrelapse

MYCKIDSTUDY:MOLECULARIDENTITYCARDFORKIDS,ADOLESCENTANDYOUNGADULT

WITHNONRHABDOMYOSARCOMASSOFTTISSUESARCOMA

EpSSGCountryA

EpSSGCountryB

Center1Localpathology

Center2Localpathology

Center3Localpathology

Center4Localpathology

Utrecht

Frozenmaterial(molecularcharacterization):-  Wholeexomesequencing(WES),RNAseqfor

fusiondetection,DNAmethylation-  Ancillarystudies(organoids,singlecellRNS

sequencing)

Lyon

FFPEmaterial(molecularcharacterization):-  RNAseq,CGH:CINSARC,GI-  Transcriptfusion,clustering:diagnosis

EpSSGCountryC

Diagnosispurpose Researchpurpose

Additionaldataarecominginthenextyearsinadultsandchildren

LarotrectinibinTreatingPatientsWithPreviouslyUntreatedTRKFusionSolidTumorsandTRKFusion

RelapsedAcuteLeukemia–COGADVL1823

•  PrimaryoutcomemeasureORRofchildrenwithinfantilefibrosarcoma(IFS)treatedwith

neoadjuvantlarotrectinibpriortolocalcontrol

•  SecondaryoutcomemeasuresEFS/OS/DoRinIFStreatedwithneoadjuvantlarotrectinibORR/EFS/OS/DoRinnewlydiagnosedTRKfusionsolidtumorsotherthanIFStreatedwithneoadjuvantlarotrectinibpriortolocalcontrol

IncidenceofadverseeventsPercentageofpatientswithTRKfusionsolidtumorswithdetectablectDNA

Chemotherapy Larotrectinib

EV(catheter) Oral

Effective(75%) Effective(>90%),rapidresponse

Acutetoxicity(VOD) Nosevereacutetoxicity

Durationoftherapy:median4months

Durationoftherapy?

Longtermtoxicityonlytosecondlinetherapy(alkylatingagents,anthracycline)

Longtermeffects?

Costs:cheap Cost:veryexpensive

Available Currentavailabilityonlywithintrials

ChemotherapyversusLarotrectinibasfirst-linetherapyinIFS

DOXO,doxorubicin;ETV6,translocation-Ets-leukaemiavirus;IFS,infantilefibrosarcoma;IFO,ifosfamide;NTRK,neurotrophictyrosinereceptorkinase;VA,vincristine-actinomycin-D1.InfantileFibrosarcomaConsensusRecommendations.ExPO-r-NetProject.2017;2.MarchiòC,etal.AnnOncol.2019;30:1417–27

Newtargetedtherapies

TheuseofTRKinhibitordrugsshouldbecertainlyconsideredwhenconventionalchemotherapyfails

VAregimenrecommendedinitially

IfresponsetoVAisnotsufficienttopermitconservativesurgery,ifosfamideand/orcyclophosphamideand/ordoxorubicinshouldbeadded

IfnoresponsetoVA,theIFO-DOXOregimenshouldbeadopted

TumourassessmentResectabilitywithoutanyfunctionalormutilatingconsequenceswith

ROintent

Yes:Surgeryfirst

No:Neoadjuvantchemotherapyuntilmaximumtumourshrinkage

IRSI–II:nofurthertherapy

IRSIII:chemotherapy Conservativesurgery

RO,R1margins,completenecrosis:nofurthertherapy

R2:post-operativechemotherapy

EpSSG/EXPeRTguidelinesforIFSrecommendconservativesurgeryorneoadjuvantchemotherapyas

first-linetherapy

ToxicityandlateaffectsNeurocognitiveoutcome

-Veryyoungchildren-Patientswhoremainontreatmentforyears

DiscussionwithparentsonthistopicisessentialMultipleinitiativeBrussels5thFeb:Readdressingtheneedforlong-termfollowupAccelerategroup:DanielleHortonTaylor/MarkKieran

Acquiredresistancemechanisms

ResistancetoNTRKinhibitionbylarotrectinibandentrectinibismediatedbyrecurrentmutationstothekinasedomainofNTRKgeneatthreedifferentlocations(solvent-frontmutations,gatekeeperandxDFG)Thekinasesolvent-frontmutationismediatedtroughG595RsubstitutionintheTRKAproteinandG623RsubstitutionintheTRKCproteinThegatekeepermutationisfoundatF589LsubstitutionintheTRKAThexDFGmotifmutationisfoundatG667CsubstitutionintheTRKAproteinandG696SsubstitutionintheTRKCprotein

SecondgenerationNTRKinhibitorsarebeingdevelopedtoovercomeacquiredresistance

michela.casanova@istitutotumori.mi.it

Thankyou