Stephen MulliganSenior Staff Haematologist, Royal North Shore Hospital;

Adjunct Associate Professor, The University of Sydney, Australia

Senior Staff Haematologist, Royal North Shore Hospital Sydney

Adjunct Associate Professor, University of Sydney

Director of Haematology, Symbion Pathology

Founder and Chairman, Chronic Lymphocytic Leukaemia Australian Research Consortium

Royal North Shore Hospital

CLL treatment today and tomorrow: the role of rituximab

Stephen MulliganRoyal North Shore Hospital,

Sydney, Australia

CLL: indications for primary treatment

Progressive lymphocytosis– lymphocyte increase >50% in 2 months– lymphocyte doubling time <6 months

At least one of the following systemic symptoms 10% weight loss over 6 months– extreme fatigue, persistent fevers, night sweats

Progressive marrow failure (anaemia or thrombocytopenia)

Massive or progressive splenomegaly

Massive or progressive lymphadenopathy

Autoimmune cytopenias

Cheson B, et al. Blood 1996;87:4990–7Hallek M, et al. Blood 2008. In pressCLL = chronic lymphocytic leukaemia

Treatment strategies for CLL

Treatment strategy decisions are influenced by disease, patient performance status and comorbidities

Palliative approach (traditional)

– goals: obtain maximum control of symptoms, prevent complications and maintain quality of life

– multiple intermittent treatment schedules

– no survival advantage for tested treatments

Response-orientated approach

– aim for complete remission (CR)

– minimal residual disease (MRD)

– improved response may improve survival

Prognostic factors independent of disease stage

Chromosomal aberrations: 11q-, 17p-

Unmutated IgVH status

Expression of cytoplasmic ZAP-70

Short lymphocyte doubling time

Elevated serum β2 microglobulin

Elevated serum levels of soluble CD23

Elevated serum thymidine kinase activity

Leukaemia cell surface expression of CD38

Binet JL, Blood 2006;107:859–61

First-line treatment for CLL: a brief historical perspective

Alkylating agents-treatment of choice until the 1990s– chlorambucil – introduced early 1950s – cyclophosphamide, adriamycin and prednisone

(CAP)– cyclophosphamide, doxorubicin, vincristine,

prednisone (CHOP)

Fludarabine superior to chlorambucil in randomised clinical trials

Johnson S, et al. Lancet 1996;347:1432–8 Rai K, et al. N Engl J Med 2000;343:1750–7 Leporrier M, et al. Blood 2001;98:2319–25

1Eichhorst B, et al. Blood 2005;107:885–912Flinn IW, et al. J Clin Oncol 2007;25:793–8

3Catovsky D, et al. Lancet 2007;370:230–9

FC versus F

Investigator Year n ORR (%) CR (%) PFS

Eichhorst1 2006 375 94 vs 83; p=0.001

24 vs 7; p<0.001

48 vs 20 months; p=0.001

Flinn2 2007 278 74.3 vs 59.5 p=0.013

23.4 vs 4.6; p<0.001

31.6 vs 19.2 months; p<0.0001

Catovsky3 2007 390* 94 vs 80; p<0.0001

38 vs 15; p<0.0001

36% vs 10%;†

p<0.00005

*A further 387 patients were randomly assigned to receive chlorambucil†PFS at 5 yearsORR = overall response ratePFS = progression-free survival

Fludarabine plus cyclophosphamide (FC versus F) in CLL

CLL4 trial: benefit of FC over F or chlorambucil in terms of PFS

777 patients with CLL requiring treatment were randomised fludarabine (n=196), chlorambucil (n=387) or FC (194)

Overall survival (OS) PFS

Catovsky D, et al. Lancet 2007;370:230–9

100

80

60

40

20

0

Su

rviv

al (

%)

0 1 2 3 4 5Time (years)

100

80

60

40

20

0

PF

S (

%)

0 1 2 3 4 5Time (years)

Chlorambucil

FludarabineFC

Chlorambucil

Fludarabine

FCPatients Events O/E

387 116 0.9

194 71 1.1

196 67 1.0

Patients Events O/E

387 311 1.3

194 149 1.1

196 102 0.5

CD20 structure and epitope recognition

B-cell tetraspan protein

33–37kDa non-glycosylated phosphoprotein

Rituximab epitope – conformationally-

dependent and discontinuous epitope

– steric proximity with disulphide bond

From: Binder M, et al. Blood 2006;108:1975–1978 (original article) Jensen-Jarolim E, et al. Blood 2006;108:1794–1795 (commentary)

(170) ANPS (173)(182) YCYS (185)

Rituximab binding rapidly redistributes CD20 within lipid rafts

Signal transduction platforms

– microdomains enriched in cholesterol and sphingolipid

– outer membrane

– complement defence proteins

– inner membrane

– Src-family kinases

Rituximab cross-linking

– induces rapid redistribution in the plasma membrane

– modifies cell function

Cragg MS, et al. Curr Dir Autoimmun 2005;8:140–74

CD20 multitimers

Rituximab

Raft domain

Rituximab in CLL: rationale

Mechanism of action– antibody-dependent cellular cytotoxicity (ADCC)1

– complement-dependent cytotoxicity2

– induction of apoptosis3,4

Good clinical activity in combination chemotherapy– synergistic with other cytotoxics3,5

Generally well tolerated – potential for maintenance therapy

1Lefebvre ML, et al. J Immunother 2006;29:388–97; 2Golay J, et al. Blood 2001;98:3383–93Byrd J, et al. Blood 2002;99:1038–43; 4Hussain S, et al. Clin Cancer Res 2007;13:2144–50

5Alas S, et al. Clin Cancer Res 2001;7:709–23

Synergy between rituximab and fludarabine

Rituximab Increases efficacy of fludarabine and other cytotoxics

– independent of mechanism of cytotoxic action

– occurs in CLL with incomplete antigen saturation1,2 Activation of caspases and apoptosis3 Downregulates Bcl-2 and Bcl-x(L) protein4 Increased propensity to ADCC and complement activation Altered cell signalling and calcium flux

Fludarabine Prevents DNA repair of alkylating agent cross links Induction of apoptosis Down-regulates CD46, CD55, CD59 (complement defence proteins)5

1Wierda W, et al. J Clin Oncol 2005;98:3383–9; 2Chow KU, et al. Haematologica 2002;87:33–43 3Byrd J, et al. Blood 2002;99:1038–43; 4Alas S, et al. Clin Cancer Res 2001;7:709–23

5Di Gaetano N, et al. Br J Haematol 2001;114:800–09

The evolution toward immunochemotherapy for CLL

Single-agent therapy– fludarabine

Combination chemotherapy– FC

Combination with immunotherapy– rituximab plus FC (R-FC)

Single-agent rituximab is active in CLL

1O’Brien S, et al. J Clin Oncol 2001;19:2165–702Byrd J, et al. J Clin Oncol 2001;19:2153–64

3Hainsworth J, et al. J Clin Oncol 2003;21:1746–534Thomas D, et al. Blood 2001;98:364a (Abstract 1533)

Investigator Year n

Prior rituximab treatment

ORR(%)

CR(%)

Rituximab(mg/m2/wk)

O’Brien1 2001 40Yes

and no22–75 –

375 x 1500–2,250 x 3

Byrd2 2001 33Yes

and no45 3

250–375t.i.w. x 4

Hainsworth3 2003 44 No 58 9375 x 4

+ 4 x every 6 months

Thomas4 2001 31 No 90 19 375 x 8

t.i.w. = three times weekly

Rituximab + fludarabine results in improved response rates

Induction regimenCR(%)

OR(%)

2-year PFS

2-year OS

Rituximab + fludarabine

(n=104)

CALGB 9712 38 84 67 93

Fludarabine (n=178)CALGB 9011 20 63 45 81

Byrd J, et al. Blood 2005;105:49–53

OR = overall response

Byrd J, et al. Blood 2005;105:49–53

PFS OS

Pro

bab

ilit

y

Time (months)

p<0.0001

Rituximab + fludarabine (CALGB 9712)

Fludarabine (CALGB 9011)

1.0

0.8

0.6

0.4

0.2

00 20 40 60 80 100 120 140

Rituximab + fludarabine results in prolonged PFS and increased OS

Time (months)

p=0.003

Rituximab + fludarabine (CALGB 9712)

Fludarabine(CALGB 9011)

1.0

0.8

0.6

0.4

0.2

00 20 40 60 80 100 120 140

Pro

bab

ilit

y

The R-FC study at MDACC, University of Texas

November 1999–January 2004

n=300

R-FC as first-line treatment

CR rate 72%; time-to-progression (TTP) 80 months

Treated every 4 weeks to six cycles of R-FC

– rituximab 375mg/m2 day 1 cycle 1 rituximab 500mg/m2 day 1 cycles 2–6

– fludarabine 25mg/m2 days 1–3

– cyclophosphamide 250mg/m2 days 1–3

Keating M, et al. J Clin Oncol 2005;23:4079–88Tam C, et al. J Clin Oncol 2007;25(Suppl. 18):359s (Abstract 7008)

MDACC = MD Anderson Cancer Center

R-FC results in the highest OR and CR rates reported to date

Tam C, et al. J Clin Oncol 2007;25(Suppl. 18):359s (Abstract 7008)

Response Patients (n) %

CR 217 72

nPR 30 11

PR 36 12

No response 12 4

Early death 2 1

95%

nPR = nodular partial responsePR = partial response

First-line R-FC is well tolerated

Most toxicities were similar to FC

Grade 3/4 infusion-related reactions occurred in 6%

The infection rate was similar to historical FC alone

IgVH mutation status

– no effect on the CR rate – most important determinate of remission duration

• >90% mutated patients remain in CR at 5 years• unmutated patients median CR duration 5 years

Keating M, et al. J Clin Oncol 2005;23:4079–88Lin KI, et al. Blood 2007;110:232a (Abstract 753)

Tam C, et al. J Clin Oncol 2007;25(Suppl. 18):359s (Abstract 7008)

Tam C, et al. J Clin Oncol 2007;25(Suppl.18):359s (Abstract 7008)

1.0

0.8

0.6

0.4

0.2

0

Pro

po

rtio

n

0 12 24 36 48 60 72 84 96

Months

R-FC

Patients Died Treatment

190 150 Fludarabine

140 81 FC/FM

300 68 R-FC

FC/FM

Fludarabine

} p=0.001

Improved OS with R-FC compared with historical MDACC

fludarabine-containing regimens

M = mitoxantrone

German CLL study group/international CLL8 study of FC versus R-FC

• CLL

• Binet B,C

• 18 years

• No priortherapy

• Centralhistologyreview

RANDOMISE

R-FC x 3 cycles(every 4 weeks)

FC x 3 cycles (every 4 weeks)

RESTAGING

R-FC x 3 cycles(every 4 weeks)

FC x 3 cycles (every 4 weeks)

SD, PD off study

SD = stable diseasePD = progressive disease

Recruitment closed March 2006 861 patients recruited Analysis anticipated 2008

Rituximab doseCycle 1: 375mg/m2

Cycles 2–6: 500mg/m2

Roche Media Release 25th January, 2008

Basel, 25 January 2008

http://www.roche.com/med-cor-2008-01-25

“MabThera increases the time patients with (CLL) live ... Pivotal Phase III study with MabThera reaches primary endpoint in first line treatment for patients with CLL

The pivotal CLL8 trial, initiated by the German CLL study group, successfully met its primary endpoint, by showing that patients treated with MabThera in combination with the current standard chemotherapy achieved a significant improvement in progression free survival, compared to patients treated with chemotherapy alone

  The CLL8 study is an international study ... included 817 patients … at 203 study sites across 11 countries ... The study aimed to show a 35% increase in progression free survival when the MabThera-based combination was used”  

Reduced dose R-FC: ‘R-FC-Lite’ 6 x 4-weekly cycles of

– fludarabine 20mg/m2 days 1–3

– cyclophosphamide 150mg/m2 days 1–3

Rituximab 500mg/m2 days 1 and 14

– rituximab-maintenance therapy 500mg/m2 every 3 months until progression

40 previously untreated patients evaluable for efficacy

– ORR 100%, CR 85%

– all CR patients CD5/19 flow negative in marrow

42 patients evaluable for safety/toxicity

– grade 3/4 neutropenia in 12% of courses

– grade 3/4 thrombocytopenia in 3% of courses

– grade 3/4 anaemia in 2.5% of courses

Tarhini T, et al. Blood 2006;108:805a (Abstract 2844)

Tumour lysis – allopurinol

HSV/CMV – valacyclovir/valganciclovir

PCP – SMX/TMP

Neutropenia – pegfilgrastim

Wierda WG, et al. Blood 2007;110:194a (Abstract 628)

*High risk CLL defined as 2M 4mg/LCFAR = cyclophosphamide, fludarabine, alemtuzumab, rituximab

CFAR frontline for high risk CLL*:doses and schedule

Drug Dose Day of course

Cyclophosphamide 200mg/m2 3–5

Fludarabine 20mg/m2 3–5

Alemtuzumab 30mg 1, 3, 5

Rituximab 375–500mg/m2 2

Response Patients (%)

CR 18 (69)

nPR 0 (0)

PR PR cytopenia PR disease

7 (27) 5 (19)

2 (8)

Non-responders 1 (4)

CFAR frontline for high risk CLL*: responses (NCI-WG) (n=26)

(96%)

Wierda WG, et al. Blood 2007;110:194a (Abstract 628)

*High risk CLL defined as 2M 4mg/LNCI-WG = National Cancer Institute – Working Group

Rituximab, pentostatin, cyclophosphamide achieves high response rates in CLL

Kay N, et al. Blood 2007;109:405–11Mena RR, et al. J Clin Oncol 2007;25 (Suppl. 18s):680s (Abstract 17508)

Study Eligibility criteria

No. of evaluable patients

CR/CRun (%)

ORn (%)

Kay et al. 2007

Previously untreated, ECOG PS 0–3

64 26 (41) 58 (91)

Mena et al. 2007

Previously treated/ treatment naïve, low-grade stage II–IV CLL

59 14 (24) 36 (61)

CRu = unconfirmed CRECOG PS = Eastern Cooperative Oncology Group performance status

International Scandinavian/Australian study in previously untreated CLL

Chlorambucil – 10mg2/day for 10 days orally

Fludarabine– 25mg2/day for 5 days i.v., or– 40mg2/day for 5 days orally

Cladribine– 5mg2/day for 5 days i.v./2 hours or sq, or– 10mg2/day for 5 days orally

All treatments repeated every 28 days x 6

n=221: chlorambucil 76, fludarabine 73, cladribine 72

Karlsson KA, et al. Blood 2007;110:194a (Abstract 630) i.v. = intravenously

TTP Time to start of second therapy

Longer response duration with cladribine versus fludarabine and high dose chlorambucil

Karlsson KA, et al. Blood 2007;110:194a (Abstract 630)

100

90

80

70

60

50

40

30

20

10

00 365 730 1,095 1,460 1,825 2,190 2,555

Days

Cu

mu

lati

ve p

rop

ort

ion

su

rviv

ing

(%

)

p=0.0003 p=0.005

Chlorambucil

Fludarabine Cladribine

Chlorambucil

Fludarabine Cladribine

0 365 730 1,095 1,460 1,825 2,190 2,555

Days

100

90

80

70

60

50

40

30

20

10

0

Cu

mu

lati

ve p

rop

ort

ion

su

rviv

ing

(%

)

6 x fludarabine phosphate:fludarabine 25mg/m², days 1–5 every 28 days

Chlorambucil(up to a maximum of 12 months):chlorambucil 0.4mg/kg body weight increasing 0.1mg up to 0.8mg/kg body weight every 15 days

Eichhorst BF, et al. Blood 2007;110:194a (Abstract 629)

DCLLSG CLL5 protocol for elderly patients with advanced CLL

CLL, >65 years, untreated, Binet stage C or symptomatic A/B

Median PFS: fludarabine 21.6 months; chlorambucil 16.2 months

Median OS: fludarabine 52.6months; chlorambucil not reached

0 12 24 36 48 60 72 84PFS in months

Cu

mu

lati

ve s

urv

ival

p=0.166

OS in months

p=0.071

Median observation time = 42.7months

Fludarabine versus chlorambucil in elderly patients: PFS and OS

Eichhorst BF, et al. Blood 2007;110:194a (Abstract 629)

1.0

0.8

0.6

0.4

0.2

0C

um

ula

tive

su

rviv

al

1.0

0.8

0.6

0.4

0.2

0

RandomChlorambucilFludarabineChlorambucil -censoredFludarabine -censored

0 12 24 36 48 60 72 84

RandomChlorambucilFludarabineChlorambucil -censoredFludarabine -censored

Chlorambucil + rituximab for patients with comorbidity (CLL208)

PI: Peter Hillmen, Andrew Pettitt

Trial outline Untreated CLL unfit for fludarabine-based therapy Chlorambucil (10mg/m2/day x 7) + rituximab (6 doses) Single arm, phase II, 50 patients in total

Trial objectives 1o: safety analysis 2o: assess response rate, MRD, PFS, OS

Timelines Investigator Meeting November 2007 – first patient recruited

Rituximab maintenance therapy: improved duration of response

Induction therapy with rituximab plus fludarabine (n=79) followed by rituximab-maintenance therapy (n=35) or not (n=13) in patients with bone marrow or peripheral blood MRD

After a median follow-up of 38 months duration of response was– significantly longer in MRD-positive patients receiving

rituximab-maintenance therapy compared with no further treatment (85% vs 20% at 5 years; p=0.0001)

– superior in the subset (n=30) of high-risk patients (CD38+, unmutated, ZAP-70+) treated with rituximab-maintenance therapy (64% [n=11] vs 13% [n=9] at 2 years; p=0.006)

4, monthly cycles of rituximab 375mg/m2 followed by 12, monthly low doses of rituximab at 150mg/m2

Del Poeta G, et al. Haematologica 2007;92 (Suppl. 1) (Abstract 0361)

Summary of rationale for rituximab in CLL

CD20 in lipid raft signal transduction platforms – Rituximab crosslinking leads to

• redistribution of CD20 in lipid rafts in plasma membrane • altered cell signalling • altered calcium flux • altered complement defence • increased propensity to ADCC and complement activation • increased apoptosis • synergistic mechanism of action with fludarabine and other

cytotoxics

Clinical evidence of synergism with fludarabine and other cytotoxics

Conclusions

Immunochemotherapy is becoming standard therapy for CLL– the CLL8 trial will provide further information – data analysis in progress, scheduled completion mid-2008

Rituximab is an eminently suitable combination partner for a variety of active agents in CLL – with purine analogues in patients with good

performance status– possibly with less aggressive cytotoxic regimens in elderly

or patients with comorbidity

Maintenance rituximab is a promising potential strategy in CLL