Stem Cell MobilizationStandards of Care for HSCT

Novel ApplicationsRichard Champlin, M.D.

Why is the bone marrow in the bone marrow?

Hematopoietic stem cells home to a “niche” in the marrow

Marrow microenvironment provides critical interactions controlling the growth and differentiation of hematopoietic cells

Maturing cells naturally egress the bone marrow into the blood and later into the tissues

Stem cells traffic into and out of the bone marrow physiologically

HSC

Stem Cell Niche

VLA-4VCAM-1

Bone Marrow Stromal Microenvironment

CXCR4

Osteoblasts

SDF1

Pamela S, et al. ASH 2008. Abstract #: 858;

Shivtiel et al. J Exp Med. 2008;205:2381.

Mechanisms Governing Stem Cell Mobilization with G-CSF

Adhesive Adhesive interactions interactions between HSC and between HSC and matrix components matrix components in the BMin the BM

G-CSF MobilizationG-CSF Mobilization

Cathepsin G (CG), chemokine receptor-4 (CXCR4), hematopoieic stem cell (HSC), hyaluronic acid (HA), interleukin 8 (IL-8), kit ligand (KL), matrix metalloproteinase-9 (MMP-9), neutrophil elastase (NE), stromal cell derived factor-1 (SDF-1), vascular cell adhesion molecule-1 (VCAM-1), very lateantigen-4 (VLA-4), P-selectin glycoprotein ligand-1 (PSGL). Source: Nervi B, et al. J Cell Biochem. 2006;99:690-705

Considerations for Mobilization Regimen

• Reliable• Collect sufficient number of HSCs and progenitors

• Predictable• Able to predict day of collection

• Low failure rate

• Limited toxicity

• Cost Effective • Limited number of days of apheresis required• Low resource utilization

• Low tumor contamination

HSC

Agents for Stem Cell Mobilization

VLA-4VCAM-1

G-CSFG-CSF

SDF1

Bone Marrow Stromal Microenvironment

Fibronectin

CXCR4

Osteoblasts

D11-5908

Plerixafor

SDF1

MM9

G-CSFG-CSF

Scr kinase

PP2 scr inhibitor

Pamela S, et al. ASH 2008. Abstract #: 858;

Shivtiel et al. J Exp Med. 2008;205:2381.

CD34+ Cells Are Heterogenous

CD34CD34++

CD34+/CD38-

CD34CD34++//CD133CD133++

CD34CD34++//CD133CD133--

CD34CD34++/HLA-/HLA-DRDR++

CD34CD34++/HLA-/HLA-DRDR--

CD34+/CD61-

CD34+/CD61+

CD34CD34++/CD38/CD38- - = Most Primitive Stem Cells= Most Primitive Stem CellsHock H. J Exp Med. 2010;207:1127-1130

When to Collect?

Armitage S, et al. Bone Marrow Transplant. 1997;20:587-591.

Correlation between PB CD34+ cells/Correlation between PB CD34+ cells/µLµL and CD34+ cells/kg and CD34+ cells/kg collectioncollection

How Many HSCT do you need for AutoSCT?Richard Champlin, MD

Platelet Engraftment Kinetics As A Function Of CD34+ Cell Dose

Glaspy JA, et al. Blood. 1997;90(8):2939-2951.

CD34+ Cells x 106/kg

1.02.05.010.0

7 14 28 28

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0

Days

N = 212

Importance of CD34+ Cell Dose

Stiff PJ, et al. Blood. 2008;112:758-759. Abstract 2175.

Percent Patient Platelet Count > 150,000/L

Defining a Target?

Generally accepted that ≥ 2 x 106 CD34+ cells/kg is ensures a threshold effect for a rapid hematopoietic engraftment1-2

95% of patients receiving > 2.5 x 106 CD34+ cells/kg experience durable neutrophil engraftment by day 18

5 x 106/kg may be threshold for rapid platelet engraftment3-4

Unclear if > 5 x 106/kg will result in any better engraftment, may be associated with improved outcome5

1To LB, et al. Blood. 1997;89:2233-58; 2Schiller G, et al. Blood. 1995;86:390-7; 3Kiss JE, et al.  Bone Marrow Transplant. 1997;19:303–10;4Weaver CH, et al. Blood 1995;86:3961–9; 5Dercksen MW, et al. J Clin Oncol. 1995;13:1922–32.

Higher Cell Dose: Impact on Cost

Costs of transplant-related care in patients who experience “good” versus “poor” mobilization Retrospective analysis of 172 NHL patients treated

with HDT and autologous PBSC transplantation Mobilizations categorized as “poor” (<2 ×106 CD34+

cells/kg) or “good” (≥2 ×106 CD34+ cells/kg) Cyclophosphamide + G-CSF used for mobilization Cost data in a subset of patients (n=57)

Stockerl-Goldstein KE, et al. Biol Blood Marrow Transplant. 2000;6(5):506-512.a Includes cost of apheresis and bone marrow harvest, if performed.

How to collect HSCT

Chemo-Mobilization Integrates collection

into disease management

Improves CD34 yield

Cost, complications, can’t predict date of collection

We use this for aggressive lymphoma

Growth Factor Mobilization Simple Efficient, can schedule Provides adequate

CD34 yield in many categories of patients

Less Costly, few complications, can predict date of collection

May interrupt/delay chemotherapy

We use this for myeloma

Factors Affecting CD34+ Cell Yield

Patient-related Age

Mobilization regimen chosen Generally higher CD34 yields with chemo-

based mobilization

Amount and type of prior therapy Alkylators, lenalidomide, radiation

Platelet count at the time of mobilization

G-CSF vs Chemotherapy + G-CSF

Chemo = various chemotherapeutic agents; Cy = cyclophosphamide; HD = Hodgkin's disease; MM = multiple myeloma; NHL = non-Hodgkin's lymphoma; NR = not reported.

1Alegre A, et al. Bone Marrow Transplant. 1997;20:211–217; 2Desikan KR, et al. J Clin Oncol. 1998;16:1547–1553; 3Dazzi C, et al. Leuk Lymphoma. 2000;39:301–310; 4Narayanasami U, et al. Blood. 2001;98:2059–2064; 5Pusic I, et al. Biol Blood Marrow Transplant 2008;14:1045–1056.

Rituximab and HSC Mobilization- MDACC Experience

Rituximab reduces circulating lymphoma cells

No impact on HSC mobilization, particularly with chemomobilization

Improvement in results of autoSCT using Rituximab in mobilization and transplant.

ASCT for Aggressive NHLImpact of Rituximab on DFS

0 3 6 9 12 15 18 21 24 27 30

Months Post Transplant

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Cu

mu

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ve P

rop

ort

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Su

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Rituximab (N=67)

No Rituximab (N=30)

p = 0.004

Adhesion Molecules And HSC Mobilization

NatalizumabBIO5192

Plerixafor

MobilizationMobilization

Nervi B, et al. J Cell Biochem. 2006;99:690-705.

20

Plerixafor

A sustained elevation of peripheral blood CD34+ cell levels was noted between 4 and 18 hours1

G-CSF, granulocyte-colony stimulating factor.1. Mozobil™ [prescribing information]. Cambridge, MA: Genzyme Corp; 2008. 2. Adapted from Liles WC, et al. Transfusion. 2005;45:295-300.

250

200

150

100

50

00 5 10 15 20

n = 3 healthy volunteers

Time (hours) calculated after 4 days of G-CSF therapy and addition of G-CSF + Mozobil™ (plerixafor injection) on day 5

Mobilization Using G-CSF With Plerixafor

Efficacy as single agent

Synergistic with G-CSF

Increases likelihood of successful CD34+ cell mobilization

QUESTIONS: Are there important functional differences in the grafts

collected? Are the improvements in CD34 yield worth the added

cost? Effect on mobilization of malignant cells?

Gene Expression of Mobilized CD34+ Cells and Leukocytes

Donahue RE, et al. Blood. 2009;114:2530-2541.

Gene expression differs among CD34 cells mobilized plerixafor, G-CSF, and plerixafor + G-CSF1. Composition of mobilized

CD34+ cells is dependent on the mobilization protocol

2. Composition of CD34+ cells mobilized by the combination is not simply a mixture of cells mobilized by each agent separately

Functional Differences Noted With Plerixafor vs G-CSF-Mobilized HSPCs

Higher proportion of cells in G1 phase of the cell cycle

Higher proportion of more ‘primitive’ CD34+CD38- cells

More cells expressing CXCR4 and VLA-4 on the cell surface

Grafts contain more T, B and NK cells

Larochelle A, et al. Blood. 2006; 107:3772–3778; Hess DA, et al. Biol Blood Marrow Transplant. 2007; 13:398–411;Fruehauf S, et al. Cytotherapy. 2009; 11:992–1001; Donahue RE, et al. Blood. 2009; 114:2530–2541;

Plerixafor vs G-CSF-Based Stem Cell Mobilization in HLA-Identical Donors: Allograft Composition

*Mean.†Median.‡Includes 8 donors mobilized by both plerixafor and G-CSF.

Devine S, et al. Blood. 2008;112(4):990-998.

Cancer Cell Mobilization in Autologous Donors???

CXCR4 / SDF-1

? Release of Tumor Cells

CXCR4 CXCR4 AntagonistAntagonist

Gazitt Y. Leukemia. 2004;18;1-10.

Apheresis Costs

Treatment Phase Cost

Pre-apheresis Clinic visit

Lab evaluation

Insertion of CVC

Chest –x-ray

$1,800

Apheresis Apheresis procedure (2)

G-CSF treatment (2)

CD34+ analysis

$5,161

($2,580.7 per day)

Post-apheresis Cryopreservation

Supplies

Storage

Sterility testing

$2,493

($1,246 per bag)

Total Cost* $9,454

Cost Savings of Eliminating One Day of Apheresis*,#

$3,826

Hosing et al

MDACC Policy PBPC Collection

For autos and allos- goal 5 million, accept minimum 2 million CD34/kg,

Day 1 or 2 stop >4M

Day 3 stop >3M

Day >4 stop >2M

Collect If CD34 > 10/mcl

If collection is ≤ 0.3 million/kg/d x 2 consecutive days despite use of plerixafor or stop apheresis

Myeloma- plan for 2 transplants

Target doses: Goal 6-8 million/kg for 2 transplants (minimum acceptable 4 million/kg)

If after 1 or 2 collections CD34 collected is > 8 million/kg stop

If after 3 collections CD34 collected is > 6 million/kg stop

If after 4 collections CD34 collected > 4 million/kg stop

If after 5 collections CD34 collected > 2 million/kg stop, do one transplant

Just In Time Strategy for Cost Effectiveness

G-CSF alone successfully mobilizes many patients

Plerixafor is synergistic with G-CSF for stem cell mobilization

An approach to improving cost effectiveness is reserving plerixafor for patients with suboptimal mobilization

Use circulating CD34 on day 4 or first day’s collection to determine who needs addition of plerixafor.

Factors Associated With Poor Mobilization

Increasing cycles / duration of prior chemotherapy

Female gender

Prior radiation to bone marrow

Low pre-mobilization platelet count

Bone marrow positivity

Indolent lymphoma histology

Exposure to fludarabine, platinum-based chemotherapy, alkylating agents, lenalidomide

Low PB CD34 count during mobilization

Outcome of Mobilization by Disease

2727%%

3333%%

1414%%

Gertz M, et al. Bone Marrow Transplant. 2010 Jan 11. epub.

Percent ≥ 2 Million CD34+ Cells/kg

Phase III NHL Study

Plerixafor +G-CSFPlerixafor +G-CSF

Placebo + G-CSFPlacebo + G-CSF

HR=2.50, 95%CI (1.86, 3.36), p<0.0001 HR=2.50, 95%CI (1.86, 3.36), p<0.0001

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DiPersio JF, et al. J Clin Oncol. 2009;27:4767-4773.

Conclusions

Hematopoietic stem and progenitor cells are mobilized by G-CSF and plerixafor a CXCR4 inhibitor

Plerixafor mobilizes PBPC by inhibition of SDF-1 and CXCR4 interaction

Plerixafor and G-CSF are synergistic

The combination of Plerixafor and G-CSF will reduce the number of aphereses required for PBPC collection and enhance to ability to perform autologous HSCT in “hard to mobilize” patients

Chemotherapy plus growth factor enhances mobilization and is warranted when the chemotherapy is indicated for treatment of the malignancy