Update on the biology and risk- adapted CLL management in 2013 and the prospect of novel therapies...

Update on the biology and risk-adapted CLL management in 2013 and the prospect of novel therapies

Sami N. Malek, MDAssociate Professor

Department of Internal MedicineDivision of Hematology and Oncology

University of MichiganAnn Arbor, Michigan

[email protected]

Disclosure InformationSami N. Malek, MD

• I have the following financial relationships to disclose:

• Speaker’s Bureau for Roche and Teva.

CLL: Introduction

• CLL is the most common leukemia in the western world. CLL is rare is Asia.

• CLL incidence is about 15,000 cases with about 4,400 deaths per year in the US.

• Mean age at diagnosis is 70 years.• Male to female ratio is ~2:1.• CLL can cluster in families (familial CLL).• Unaffected relatives of CLL patients demonstrate an

elevated frequency of Monoclonal B-cell Lymphocytosis (MBL) Rawstron, Blood 2002 and others.

CLL and MBL

• Essentially all CLL is preceded by MBL Landgren, NEJM 2009. • MBL is 100x more frequent than CLL.• CD5+ CLL-like MBL demonstrates clonal genomic

lesions (13q14, trisomy 12) similar to CLL Lanasa, Leukemia

2011, Fazi, Blood 2011 and others.• Clinical CD5+ CLL-like MBL demonstrates progression

to CLL at a frequency of 1%/year.• Low count CD5+ CLL-like MBL rarely progresses to

CLL and sometimes regresses.

Major biological phenomena underlying CLL pathogenesis

• Quality and strength of B-cell receptor signaling including self-aggregation and antigenic CLL cell stimulation.

• Non-malignant cell to CLL cell

signaling. Microenvironment

• Cytokine to CLL cell signaling.

• Survival dependence of CLL cells on the expression of Bcl2 family members (Mcl1, Bcl2).

• CLL transformation to aggressive NHL or HL (Richter’s transformation) Puente et al, Nature 2011, Rossi, Blood 2011 others.

Major genomic phenomena underlying CLL pathogenesis

• Recurrent acquired genomic copy number aberrations (aCNA; del17p, del11q, t12, del13q14) Dohner, NEJM 2000 and others.

• Genomic complexity.• Recurrent gene mutations (TP53, Notch1, SF3B1).• miRNA deregulations Calin, PNAS 2002 and others.• Epigenetic deregulation?

CLL disease progression/evolution

• Aberrant HSC (cell intrinsic?) Kikushige, Cancer Cell 2011

• Pro-B expansion and antigen encounter• CLL-like MBL• Early stage CLL• Progressive CLL• Treated CLL followed by relapsed CLL• Multi drug resistant CLL• Terminal CLL

Major phenomena underlying CLL clinical behavior

• CLL has a highly varied clinical course.• Phase 1: Diagnosis to need of first therapy (TTFT). • Short TTFT independently associates with expression of

ZAP70, IgVH-UM status, INSR expression/del11q, TP53 mutations/del17p and elevated genomic complexity.

• Phase 2: Time from first therapy to death (Survival).• Short survival is determined by TP53 mutations/del17p,

del11q status and most comprehensively SNP array-based elevated genomic complexity.

• Most CLL markers are unstable longitudinally necessitating outcome analysis from the dates of marker measurements.

Terminology

• Progressive CLL: Need of therapy within a few years from diagnosis.

• Aggressive CLL: Short OS.• Predictive markers: Predictive of response type

after therapy (CR, PR or PD).

• Prognostic markers: Predictive of OS.

CLL genomics: Recurrently mutated genes

• Gene mutation frequency at CLL diagnosis:• TP53 7-10%• SF3B1 6-9% • NOTCH1 4-6%• ATM 3-5%, few unbiased estimates.• POT1, BIRC3, MYD88, ZMYM3, CHD2, LRP1B,

BRAF all 2-5%.• 515 kinase genes in CLL: essentially unmutated


• TP53 mutations/aberrations anatomy:• Exon 4-10, majority are missense mutations in DBD.

Some are nonsense, frameshift or splice site mutations.

• Del17p plus TP53 mutated (most common).• TP53 mono-allelically mutated and the retained TP53

allele wt (2%).• Copy-neutral LOH at 17p plus TP53 mutated. • Very uncommon: Del17p and TP53 wt allele.

P53 exons 2-10 mutations and overall survival in CLL

Del17p in CLL summary (molecular)

• Del17p carries aberrant p53 (mutations or absent expression) (Gaidano 1991; El Rouby, 1993, Wattel, 1994; Dohner, 1995, Dohner, 2000; Saddler 2008, others)

• Copy neutral LOH (aUPD) at 17p exists in CLL and is associated with homozygous p53 mutations and is undetectable by FISH (Saddler, 2008).

• Sporadic p53 mutations in CLL exist without structural 17p abnormalities, although estimates of the true frequency need knowledge of aUPD (Zenz, 2008; Rossi, 2008 Dicker, 2009).

• The frequency of p53 mutations in fludarabine-refractory CLL is higher than in untreated CLL (Zenz, 2009).

Del17p in CLL summary (clinical)

• Early stage CLL with del17p can be non-progressive for years and should be observed (Best, 2009; Tam, 2009).

• PFS and OS of CLL patients with del17p is shortened relative to other FISH-defined CLL groups (estimated OS ~5-8 years) (Dohner, 2000; Shanfelt, 2006; Grever, 2007; Tam, 2009).

• Del17p patients should be enrolled into clinical trials using p53 status-insensitive drugs/ approaches and should be considered early for allo-RIT/MUD-RIT.

Approach to CLL patients with del17p/TP53 mutations

• Young and medically fit: Induction followed by RIC-SCT in first remission.

• Regimens: FCR, other CIT combinations, alemtuzumab, high dose methylprednisone plus rituximab, high dose methylprednisone plus alemtuzumab, induction on a clinical protocol.

• Ideal patient group for targeted clinical trials with novel agent acting through non-genotoxic pathways.


• SF3B1 mutation anatomy:• Always heterozygous missense mutations affecting

selected codons. • Presumed effects on 3’-mRNA splice site recognition

with activation of cryptic aberrant 3’- splice sites resulting in aberrant mRNA.

• Critical gene targets in CLL unknown.• Functional consequences unknown. • Quesada, Nature Genetics 2011, Wang, NEJM 2011, Rossi, Blood 2011.

• Associated with modest shortening of PFS (preliminary).


• NOTCH1 mutation anatomy: • Frameshift mutations are most common, non sense and

missense mutations are also found. Puente, Nature 2011, Rossi, JEM 2011

• Localized to exon 34 targeting the PEST domain.• Mutations result in NOTCH1 protein stabilization.• Mutated NOTCH1 likely remains Notch ligand- dependent

for activation. • Functional consequences are largely unknown.• NOTCH1 mutations almost always occur in ZAP70+/IgVH

UM CLL, often together with t12. Shedden, Leukemia 2011, Balatti, Blood 2011.

CLL genomics: Recurrently mutated genes and survival

• TP53: major negative effect, short OS.• ATM: Little or no effect on OS.• NOTCH1: conflicting data, additional prospective

evaluations are needed, association with Richter’s transformation.

• SF3B1: likely minor effects on PFS but further research is needed.

• Others: unknown.

Deletion 11q

SNP 6.0 profiling of 11q in ~255 CLL cases

11q deletions and overall survival in CLL

Del11q biology

• Associated with elevated genomic complexity indicative of defects in DNA ds break response and DNA maintenance.

• Associated with high insulin receptor levels.• Acquired over time indicative of a genomic driver

status.

• Almost all del11q are IgVH unmutated. Why?

CLL del11q interim summary

• The reason for relatively rapid disease progression in CLL with del11q pre therapy is not well understood.

• CLL del11q is associated with shortened OS relative to other genomically defined CLL groups (Fegan, 1995; Dohner, 1997, Neilson, 1997, Dohner, 2000, Shanafelt, 2006)

• Del11q exists with (~30%) and without (~70%), ATM mutations; thus, ATM defects alone are not sufficient to explain del11q biology or clinical features comprehensively (Bullrich, 1999; Schaffer, 1999; Stankovic, 1999; Austen, 2005, Austen, 2007).

Management of CLL patients with del11q

• Induction: FCR. Evidence from CLL8 trial and other trials suggest improvement in PFS using alkylators in 11q. Negative prognostic effect has been markedly reduced.

• Remission duration <2 years, re induction followed by RIC-SCT.

• Remission duration >2 years, individualized therapy for relapsed CLL.

Genomic complexity in CLL

Complex (aberrant) karyotypes /genomic complexity in CLL

• Chromosomal translocations in CLL are associated with aggressive disease (Mayr, 2006; Van Den Neste, 2007).

• Complex (aberrant) karyotypes in CLL are associated with aggressive disease (Juliusson, 1990, Fegan, 1995, Dicker, 2006, Haferlach, 2007, Dicker, 2009).

• Elevated SNP array-based acquired genomic complexity in CLL is associated with aggressive disease (Kujawski, 2008; Gunnarsson, 2009, Ouillette 2011).

• FISH with 2 or more findings is 90% sensitive and 50% specific for genomic complexity.

CLL genomics based on SNP 6.0 array profiling

• Prospective single institution (Univ. of Michigan) CLL cohort (since 2005).

• FACS sorted CD19+ and CD3+ cells.• Generated SNP 6.0 array data on 255 paired specimens

(255 CD19+ and 255 CD3+ DNA).• Refined software tools to analyze SNP 6.0 data: 64-bit

version of dChipSNP (Cheng Li, DFCI), PLUT (pre LOH tool unification tool) and the LOHtool version 2.

• Visual lesion scoring using dChipSNP heatmaps for paired copy number and LOH analysis (exclusion of CNVs).

Genomic complexity in CLL based on SNP 6.0 array data

• 0 subchromosomal aCNA 72/256~28%



• ≥3 subchromosomal aCNA 50/256~20% (range 3-22)

Results of multivariate analyses for overall survival risks in previously

untreated patients (N=190)

Risk factor Hazard ratio P-value

≥3 SNP 6.0 genomic lesions

3.96 0.02

P53 exon 2-10 mutations

2.07 0.26

ZAP70 positive 0.71 0.49

IgVH unmutated 2.27 0.1

Results of multivariate analyses for overall survival risks in previously

untreated patients (N=190)

Risk factor Hazard ratio P-value

≥3 SNP 6.0 genomic lesions

4.93 0.01

Deletion 17p/11q 1.39 0.62

ZAP70 positive 0.77 0.59

IgVH unmutated 2.24 0.12

Genomic complexity in CLL conclusions

• Genomic complexity is present in 20-35% of all CLL and identifies aggressive CLL (short OS).

• ~50% of all genomically complex CLL cases carry p53 exon 2-10 mutations.

• Work is in progress attempting to identify other genes with effects on genomic instability in CLL.

• Overall, genomic complexity identifies a larger high risk group of CLL than p53 mutations/ del17p.

• CLL with elevated genomic complexity is a prime target for non genotoxic therapy approaches.

Indications for RIC-allo-PBSCT

• Young (<65-70 years) and medically fit and• Del17p or• TP53 mutations or• Complex karyotype or even complex FISH or• Remission durations following chemoimmunotherapy

(FCR, FR, BR, PCR) of <2 years.

A few clinical perls

• Ignore the platelet count in CLL• Do not us the ALC as a basis for a treatment decision.• AIHA in CLL can be difficult to diagnose. Suspect in any

HGB drop or rise in MCV. If treating AIHA, taper steroids slowly.

• FCR is not for the elderly (>65-70).• Do not shorten life by attempting a CR in patient that

failed potent upfront CIT.• Define Rai stage 3 as HGB <11g/dl AND a packed

marrow.

A few more clinical perls

• Avoid single agent rituximab.• Campath sc can be given to elderly patients with del17p

and LN < 3 cm, monitor for CMV.• Chlorambucil (+ rituximab) likely is at least as good as

more potent therapies in the elderly patient with co-morbidities.

• There is no current indication for lenalidomide in CLL.• Use IVIG only as secondary prophylaxis and not lifelong.

The new era of non-genotoxic (targeted) therapies in CLL

Novel therapeutic approaches in CLL (non-genotoxic approaches)

• Targeting the B-cell antigen receptor and critical cell surface receptors involved in CLL cell – micro environment interaction (Ibrutinib, GS-1101, Syk-inhibitors).

• Targeting critical anti-apoptotic proteins like Bcl2, Bcl2-XL (ABT-199) and indirectly Mcl-1.

• Targeting T-cells to engage CLL B-cells for cell-mediated direct cell kill (chimeric antigen receptors or CARs).

• Activating wild type TP53 protein through use of MDM2 inhibitors.


• Selective inhibition of PI3K-delta:

• GS-1101 (CAL-101).• Inhibits multiple important CLL signaling pathways (BCR and

cytokine receptor and cell to cell interaction pathways). • Reduces protective effects of the micro environment on CLL

cells and results in egress of CLL cells from secondary lymphoid organs.


• ASH 2012 abstract #191: Phase 1 Study of GS-1101 in combination with rituximab, or bendamustine, or bendamustine/rituximab.

• Daily oral GS-1101 in various combinations.• Pre-treated CLL patient population with a median of 2,3

or 4 prior therapies (no therapy details provided).• Approximately 60% had LN > 5 cm at enrollment.• ≥ Grade 3 neutropenia was very common in the GS-

1101 + bendamustine treatment arms (70%)


• ASH 2012 abstract #191: Phase 1 Study of GS-1101 in combination with rituximab, or bendamustine, or bendamustine/rituximab.

• Overall response rate (ORR) 78%-87%.• Essentially all PRs.• LN size reductions median -75%• 1-year PFS was 74%-87%.


• Bruton’s tyrosine kinase (Btk) inhibitors (PCI-32765).• Btk is a critical mediator of BCR signaling as well as

signaling through multiple other CLL cell surface receptors.

• Tonic non antigen-driven BCR signaling is needed for B-lymphocyte survival.

• Irreversible inhibitor, oral, once daily. • Rapid reduction in LN size concomitant with

lymphocytosis (CLL mobilization).


• ASH 2012 abstract #189: Phase Ib/II study of Ibrutinib in treatment naïve and relapsed or refractory CLL…

• TN: all >65 years• RR: all ≥ 2 (median of 4) prior treatments incl. purine

analogues.• HR: relapse within 2 years from CIT or del17p.


• ASH 2012 abstract #189: Phase Ib/II study of Ibrutinib in treatment naïve and relapsed or refractory CLL….

• TN: ORR 71%, mostly PRs• RR: ORR 67%, mostly PRs• HR: ORR 50%, all PRs• In all arms there were additional PRs with lymphocytosis.• Response duration or PFS at 22 months f/u:• 76% for RR and HR• 94% for TN.


• ASH 2012 abstract #187: Study of Ibrutinib in combination with rituximab in high risk CLL patients….

• Patient population: del17p/TP53 mutated, response to CIT <36 months or relapsed CLL with del11q.

• Daily Ibrutinib plus weekly R x 4, followed by daily Ibrutinib plus monthly R x 5, followed by daily Ibrutinib.

• Toxicities: Mostly grade 2 or less: diarrhea, rash, fatigue, URIs, arthralgia.

• Some higher grade neutropenias.


• Inhibitors of Syk.• Activity as single agents in NHL and CLL.• Selective and less selective inhibitors.• Synergistic with fludarabine.• Currently not in an active CLL trial but may

resume after trials in RA or DLBCL are completed.


• The Mcl1 protein is critically involved in CLL cell survival.• Mcl1 protein has a short half life.• Mcl1 protein is a target for drugs that reduce mRNA

biosynthesis as the levels decline rapidly.• CDK9 inhibitors (SCH727965), flavopiridol, HHT, others. • Indirectly targeted through novel agents that reduce pro

survival cell surface receptor signal transduction.

Chimeric antigen receptors (CARs) in CLL

• Chimeric antigen receptors (CARs).• CD19-directed CARs (third generation).• Activity in pre clinical models and early-phase

trials in CLL with delayed TLS.• Unclear how scalable the approach is.• Other surface targets are being explored.• Promising in case studies despite toxicities.

Chimeric antigen receptors (CARs) in CLL

• ASH 2012 abstract #717: Chimeric antigen receptor T cells directed against CD19 induce durable responses and transient cytokine release in relapsed, refractory CLL and ALL.

• 10 patients, 9 RR CLL and one rALL.• Chemodepletion of lymphoid cells prior to CAR infusion.• Infusion of 7.5x108 CARs• 4/9 CR, 2/9 PR and 3/9 no response.• Substantial cytokine release and syndrome.• IL-6 antibody as supportive care.

BH3 mimetics in CLL

• Anti-apoptotic proteins including Bcl2, Bcl2-XL and Mcl1 control CLL cell survival.

• BH3-only proteins counteract these effects and liberate pro-apoptotic BAX and BAK.

• BH3 mimetics are novel drugs having similar effects as BH3-only proteins (pro-apoptotic).

• Navitoclax is in clinical development with substantial activity but limiting thrombocytopenia.

• ABT-199 with early phase promising activity against CLL.

Brief conclusion

• Tailor your therapy to CLL-type and patient characteristics.• Identify high-risk CLL early and the latest after short

remission durations following upfront CIT.• Understand the potential of many novel therapies and the

many unanswered questions that remain.• Avoid early or indiscriminate therapy of CLL.• Within years, CLL therapy will be devoid of traditional

chemotherapeutic drugs and will comprise of cocktails of targeted agents possibly in combination with antibodies.

• The future of patients with CLL is looking brighter than ever before.

Malek lab members and collaborators

• Peter Ouillette• Hongxiu Li• Brian Parkin• Kamlai Saiya-Cork• Mehmet Yildiz

• Cores: Microarray, FACS, DNA sequencing

• Kerby Shedden (Statistics)

Malek lab support

• NCI• LLSA • University of Michigan• Patient Donors

Update on the biology and risk- adapted CLL management in 2013 and the prospect of novel therapies...

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