Challenges and Considerations in Challenges and Considerations in Linking Adult and PediatricLinking Adult and Pediatric

LeukemiasLeukemias

David G. Poplack M.D.David G. Poplack M.D.

Texas Children’s Cancer CenterTexas Children’s Cancer Center

Baylor College of MedicineBaylor College of Medicine

• Explore the relationship between Explore the relationship between pediatric and adult leukemiaspediatric and adult leukemias

• Compelling biological evidence of Compelling biological evidence of similarities or differences useful in similarities or differences useful in guiding the drug development processguiding the drug development process

Are there defined subsets of adult and Are there defined subsets of adult and pediatric leukemias that share biologically pediatric leukemias that share biologically relevant features that would mandate they relevant features that would mandate they

be commonly studied?be commonly studied?

• Brief overviewBrief overview

• Discuss rationale and promiseDiscuss rationale and promise

• Highlight ChallengesHighlight Challenges

Linking Adult and Pediatric LeukemiasLinking Adult and Pediatric Leukemias

Adult and Pediatric LeukemiasAdult and Pediatric Leukemias

ADULTS ADULTS CHILDRENCHILDREN

Acute LymphocyticAcute Lymphocytic 11%11% 75-80% 75-80%

Acute MyeloidAcute Myeloid 32%32% 20%20%

Chronic MyeloidChronic Myeloid 15%15% <5%<5%

Chronic LymphocyticChronic Lymphocytic 26%26% N/AN/A

Adults have a worse prognosis!Adults have a worse prognosis!

Survival in Acute Leukemias Survival in Acute Leukemias

AdultsAdults ChildrenChildren

Acute LymphoidAcute Lymphoid 50-60%50-60% 80-85%80-85%

Acute MyeloidAcute Myeloid 10-20%10-20% 40-50%40-50%

ACUTE LEUKEMIASACUTE LEUKEMIAS

A heterogeneous group of disorders!A heterogeneous group of disorders!

Survival of Children withAcute Lymphoblastic Leukemia

8080

6060

4040

2020

100100 Years of Years of Number of Number of

1972-751972-751972-751972-75

00 22 44 8866 1010

Years from DiagnosisYears from Diagnosis

%%

SSuurrvvIIVVaall

1989-931989-93

1983-891983-891978-831978-83

1970-721970-72

1968-701968-70

3,0803,080

3,7123,7122,9792,9791,3131,313

936936

499499

402402

DIagnosisDIagnosis ChildrenChildren

12,92112,921Total Number ofTotal Number ofPatients Treated:Patients Treated:

C C GC C GBleyerBleyer

Evidence for Heterogeneity in ALLEvidence for Heterogeneity in ALL

• Clinical BehaviorClinical Behavior

• MorphologyMorphology

• CytochemistryCytochemistry

• ImmunophenotypeImmunophenotype

• CytogeneticsCytogenetics

• Molecular PhenotypingMolecular Phenotyping

Impact of Heterogeneity on ALL TherapyImpact of Heterogeneity on ALL Therapy

• ““Staging” of patients according to risk; therapy Staging” of patients according to risk; therapy “tailored” accordingly“tailored” accordingly

• Low risk patients -effective, less toxic therapiesLow risk patients -effective, less toxic therapies

• High risk patients - more intensive treatment High risk patients - more intensive treatment

• Successful strategySuccessful strategy

• Many prognostic criteria provided little biological Many prognostic criteria provided little biological insightsinsights

Technologic AdvancesTechnologic Advances

• Improvements in molecular cytogenetics and Improvements in molecular cytogenetics and genomics genomics

• A new paradigmA new paradigm

• More biologically relevant basis for classificationMore biologically relevant basis for classification

• Identifying molecular targets for therapyIdentifying molecular targets for therapy

CytogeneticsCytogenetics

• Giemsa bandingGiemsa banding

• FISHFISH

• Molecular cytogenetics (PCR/RTPCR) Molecular cytogenetics (PCR/RTPCR)

• Spectral karyotyping (SKY)Spectral karyotyping (SKY)

• Comparative genomic hybridization (CGH)Comparative genomic hybridization (CGH)

Case 169Pseudo-tetraploid

with two 12-15 translocations

Molecular Geno- and PhenotypingMolecular Geno- and Phenotyping

• Southern, Northern, and Western BlotsSouthern, Northern, and Western Blots

• PCR technology (single, multiplex, real-time)PCR technology (single, multiplex, real-time)

• Differential RNA expression technologies (cDNA Differential RNA expression technologies (cDNA microarray, SSH)microarray, SSH)

• CGH and SKY on arraysCGH and SKY on arrays

• Single Nucleotide Polymorphism (SNPs) chipsSingle Nucleotide Polymorphism (SNPs) chips

• ProteomicsProteomics

Genome-wide analysis of gene expression Genome-wide analysis of gene expression using cDNA microarray technologyusing cDNA microarray technology

CDNA Array in ALLCDNA Array in ALL

CD34 (7.4)CD34 (7.4)

FL Cytokine receptor (5.6)FL Cytokine receptor (5.6)

CD72 (4.6)CD72 (4.6)

NADH ubiquinone oxidoreduct.15kDA protein(4.2)NADH ubiquinone oxidoreduct.15kDA protein(4.2)

C-Fos (3.5)C-Fos (3.5)

Multiple ESTs (3-4)Multiple ESTs (3-4)

Insulin-like growth factor (2.3)Insulin-like growth factor (2.3)

Elevated in t(4:11)

cDNA Array in ALLcDNA Array in ALL

Membrane metallo-endopeptidase (enkephalinase/CALLA Membrane metallo-endopeptidase (enkephalinase/CALLA CD10) (18.6)CD10) (18.6)

Arachidonate 5-lipoxygenase (8.5)Arachidonate 5-lipoxygenase (8.5)

CGD gene (8.0)CGD gene (8.0)

CD20 (7.0)CD20 (7.0)

Hemoglobin beta (5.7)Hemoglobin beta (5.7)

CD1c antigen (5.7)CD1c antigen (5.7)

Human cerebellar degeneration associated protein (4.1)Human cerebellar degeneration associated protein (4.1)

Elevated in pre-B ALLElevated in pre-B ALL

What subsets of adult and What subsets of adult and pediatric leukemias might be pediatric leukemias might be

appropriate for common appropriate for common therapeutic studies?therapeutic studies?

Acute Lymphoblastic LeukemiaAcute Lymphoblastic Leukemia

• t (9;22)/Ph+ - BCR-ABLt (9;22)/Ph+ - BCR-ABL

• t (4;11) - MLL-AF4 - and other 11q23 abnormalitiest (4;11) - MLL-AF4 - and other 11q23 abnormalities

• t (8;14) - B-cellt (8;14) - B-cell

• Hypodiploidy (<45 chromosomes)Hypodiploidy (<45 chromosomes)

• Hyperdiploidy (>50 chromosomes)Hyperdiploidy (>50 chromosomes)

• t (12;21) - TEL-AML1t (12;21) - TEL-AML1

Acute Myeloblastic LeukemiaAcute Myeloblastic Leukemia

• True True De novoDe novo AML AML

- t (15;17) and other APL variants- t (15;17) and other APL variants

- t (8;21), inversion 16, trisomy 8- t (8;21), inversion 16, trisomy 8

• Therapy related AMLTherapy related AML

- Monosomy 7, 5q- , and 11q23- Monosomy 7, 5q- , and 11q23

• MDSMDS

The Era of Molecular Targeting The Era of Molecular Targeting

• BCR-ABL t(9;22) - target for treatment of PhBCR-ABL t(9;22) - target for treatment of Ph1 1

positive disease - e.g. STI 571positive disease - e.g. STI 571

• t(15;17) - APL treatment with ATRAt(15;17) - APL treatment with ATRA

• Provide compelling arguments:Provide compelling arguments:

- confirm validity of targeting relevant - confirm validity of targeting relevant molecular lesions molecular lesions

- testing targeted agents in all of the relevant - testing targeted agents in all of the relevant populationspopulations

Can we develop a general principle that Can we develop a general principle that might guide the identification of biological might guide the identification of biological

subsets that would be suitable for study subsets that would be suitable for study both in adults and children? both in adults and children?

Should be based on characteristics believed to be Should be based on characteristics believed to be associated with the establishment , maintenance associated with the establishment , maintenance

or progression of the malignant phenotype or or progression of the malignant phenotype or linked to its development of resistance to specific linked to its development of resistance to specific

treatments.treatments.

Examples of Biological Features that may Examples of Biological Features that may be Shared by Adult and Pediatric leukemiasbe Shared by Adult and Pediatric leukemias

Cytogenetic abnormalitiesCytogenetic abnormalities

Fusion proteins - downstream eventsFusion proteins - downstream events

Gene expression patternsGene expression patterns

Receptors - e.g. growth, anti-apoptosisReceptors - e.g. growth, anti-apoptosis

Drug resistance genesDrug resistance genes

Tumor suppressor genesTumor suppressor genes

Challenges to the Design of Common Adult Challenges to the Design of Common Adult and Pediatric Leukemia Trialsand Pediatric Leukemia Trials

• Biologic basis for selecting grouping may turn Biologic basis for selecting grouping may turn out to be incorrectout to be incorrect

• Toxicity Issues Toxicity Issues

• Small Patient Numbers (geographical accrual Small Patient Numbers (geographical accrual problems)problems)

• Impact of TransplantationImpact of Transplantation

• Requires extraordinary cooperationRequires extraordinary cooperation

• Heterogeniety in location of actual fusions Heterogeniety in location of actual fusions leads to heterogeneity in resulting proteins:leads to heterogeneity in resulting proteins:

t (9;22) resulting in p190 and p210 kinasest (9;22) resulting in p190 and p210 kinases

• Heterogeneity in mRNA expression:Heterogeneity in mRNA expression:

t (1;19) +/- RNA expressiont (1;19) +/- RNA expression

• Impact of other genetic changes: Impact of other genetic changes: Concomitant aneuploidyConcomitant aneuploidy

Beyond the BreakpointBeyond the Breakpoint

Benefits of Designing and Benefits of Designing and Implementing Common Adult and Implementing Common Adult and

Pediatric Leukemia TrialsPediatric Leukemia Trials

• New and improved therapies for our patientsNew and improved therapies for our patients

• Better understanding of the underlying Better understanding of the underlying biology of these diseasesbiology of these diseases

• Development of common,comprehensive Development of common,comprehensive prospective biological studies should be prospective biological studies should be encouragedencouraged

• It is important to study both poor and good It is important to study both poor and good prognostic groups.prognostic groups.

SummarySummary

• Using current classification techniques there are Using current classification techniques there are adult and pediatric leukemia subsets in which joint adult and pediatric leukemia subsets in which joint biology and treatment protocols are justifiedbiology and treatment protocols are justified

• Significant caveats to this strategy existSignificant caveats to this strategy exist

• Development of coordinated, prospective biological Development of coordinated, prospective biological and classification studies of adult and pediatric and classification studies of adult and pediatric leukemias, using the latest genomic technologies, leukemias, using the latest genomic technologies, is of critical importance.is of critical importance.

Cytogenetics in Adult and Pediatric ALLCytogenetics in Adult and Pediatric ALL

• B Cell B Cell t(8:14)t(8:14)

• B Cell precursorB Cell precursor

Hyperdiploidy (>50)Hyperdiploidy (>50)

TEL-AML1 t(12;21)TEL-AML1 t(12;21)

E2A-PBX1 t(1;19)E2A-PBX1 t(1;19)

BCR-ABL t(9;22)BCR-ABL t(9;22)

MLL-AF4 t(4;11)MLL-AF4 t(4;11)

Hypodiploidy (<45)Hypodiploidy (<45)

• T CellT Cell

30-50@ 3 yr30-50@ 3 yr 80-90@ 5 yr80-90@ 5 yr

UnknownUnknown 85-90@ 5 yr85-90@ 5 yr

20-40@ 3 yr20-40@ 3 yr 70-80@ 5 yr70-80@ 5 yr

<10@ 3 yr<10@ 3 yr 20-40@ 5 yr20-40@ 5 yr

10-20@ 3 yr10-20@ 3 yr 10-35@ 5 yr10-35@ 5 yr

10@ 3 yr10@ 3 yr 25-40@ 3 yr25-40@ 3 yr

50@ 3yr50@ 3yr 65-75@ 5yr65-75@ 5yr

ADULTSADULTS CHILDRENCHILDREN

50-55@ 4 yr50-55@ 4 yr 75-85@ 5 yr75-85@ 5 yr

Cytogenetics in Adult & Pediatric AMLCytogenetics in Adult & Pediatric AML

• t(8;21)t(8;21)

• t(15;17)t(15;17)

• 11q2311q23

• Inv (16)Inv (16)

• -7 or del(7q)-7 or del(7q)

• -5 or del(5q)-5 or del(5q)

• AML1-ETOAML1-ETO

• PML-RARalpha,etc.PML-RARalpha,etc.

• MLL fusionsMLL fusions

• CBFbetaMYH11CBFbetaMYH11

AbnormalityAbnormality Molecular LesionMolecular Lesion