clinical trial: Immunotherapy With NK Cell, Rituximab and Rhu-GMCSF in mini SCT

[Guest guest]

This clinical trial description is unique in that it provides a very

technical study rationale. ~ Karl

==

Official Title: Immunotherapy With NK Cell, Rituximab and Rhu-GMCSF in

Non-Myeloablative Allogeneic Stem Cell Transplantation

Further study details as provided by M.D. Cancer Center:

Patients with previous diagnosis of CD20+ B-cell CLL and non-Hodgkin's

lymphoma who have failed standard conventional chemotherapy, and who had

persistent disease at 3 months, or progressive disease after non-

myeloablative allogeneic transplantation. Donor willingness to donate

peripheral blood (same donor of the original transplant).

=2.1 Graft versus Leukemia/Lymphoma

Over the past 2 decades, a number of different immune-based strategies aimed

at eradication or suppression of residual malignant disease have been

proposed for the clearance of malignant cells.

T-cell-mediated graft-versus-leukemia/lymphoma (GVL) has been shown to be

the most efficacious following allogeneic hematopoietic stem cell

transplantation and donor lymphocyte infusions1,2. Although specific

anti-malignancy responses have been documented, most T-cell-mediated

alloreactions are thought to be direct against minor or major

histocompatibility antigens shared by both malignant and normal cells with

potential for widespread host tissue damage.

Successful T-cell-based immunotherapy will, therefore, ultimately require

better definition of tumor-specific antigens that will allow the direction

of the immune response to the tumor cells3.

Unfortunately, tumor-specific antigens have only been identified on a

minority of cancers4.

=2.2 Targeted therapy with Rituximab in allogeneic stem cell transplantation

Rituximab (IDEC-C2B8) has significant activity as a single agent in patients

with relapsed B-cell lymphoid malignancies5. Various mechanisms of action

been described: direct apoptosis; complement-mediated and antibody-dependent

cellular cytotoxicity (ADCC). Golay et al demonstrated ADCC in four

different follicular lymphoma cell lines exposed to Rituximab6.

No significant direct apoptosis was observed in that study. B-cell depletion

in vitro was observed with Rituximab therapy in the presence of mononuclear

cells, but not complement, suggesting that cell-mediated mechanisms (ADCC)

may be dominant7.

The expression of complement inhibitors on tumor cells did not predict

clinical outcome after in vivo treatment with Rituximab in a recent clinical

trial8 . In a recent study from M. D. , an increased ADCC activity

correlated with response in patients with recurrent indolent lymphoma

treated with Rituximab in combination with rhu-GMCSF9.

There are several reasons to consider using Rituximab in the allogeneic

transplantation setting. We and others, have reported a lower incidence of

acute and chronic GVHD when we combined this anti-CD20 chimeric molecule

with the chemo-conditioning regimen10,11.

We have also demonstrated an improved GVL in patients with persistent or

recurrent disease after non-myeloablative stem cell transplantation when

Rituximab was added to the schema of immunomanipulation after transplant11.

Some of these responses occured in patients having both, a progressive

disease and graft-versus-host disease, suggesting a non-T cell mediated

response but rather an alternative mechanisms of response such as the

antibody-dependent cellular cytotoxicity which is mediated mainly by NK

cells.

=2.3 Human NK Cells

NK cells are the major mediator of ADCC. Human NK cells comprise

approximately 10% of all blood lymphocytes and are identified by the

expression of the CD56 surface antigen and lack of CD3.

Functionally, NK cells have direct or natural cytotoxic activity against

some virus-infected, leukemic, and other tumor cells, and they also mediate

antibody-dependent cellular cytotoxicity ADCC of targets through FcyRIII

(CD16), a receptor that binds the Fc portion of antibody12-15.

It has been postulated that rhu-GM-CSF may enhance the ADCC response to

Rituximab by increasing cellular expression of CD20 and by upregulating CD16

prior to the infusion of effector cells.

It has also been suggested that ADCC may be enhanced by various cytokines,

such as IL-2, IL-12 and Interferon which could also be stimulated by

rhu-GM-CSF. These different mechanisms16-18 may result in a higher tumor

kill without an increased risk of GVHD10,11.

Two distinct subsets of human NK cells are identified according to cell

surface density of CD56 expression19. The majority (90%) of human NK cells

are CD56dim and express high level of CD16, whereas a minority (10%) is

CD56bright and CD16dim/neg.

Unlike T and B lymphocytes, NK cells do not rearrange genes encoding

receptors for antigen recognition, but they have developed the ability to

recognize self-MHC class I or class I-like molecules through a unique class

of receptors, NK cells receptors (NKRs), that can inhibit or activate NK

cell killing.

In humans, receptors termed killer Ig-like receptors (KIRs) recognize groups

of HLA class I alleles20. Although KIRs and other class-I inhibitory

receptors may be coexpressed NK cells, in any given individual's NK

repertoire there are cells that express a single KIR and are blocked only by

a specific class I allele group21.

Missing expression of the KIR ligand on mismatched allogeneic cells can

therefore trigger NK cell alloreactivity22.

Another level of alloreactivity is provided by mismatches at the KIR

epitopes expressed by HLA class I alleles. Conversely, if class I group

mismatch is not present, despite the haplotype-mismatch, donor NK cells will

be inhibited by their inhibitory KIR ligands and no alloreactivity is

expected.

A remarkable GVL effect was observed in patients with acute myeloid leukemia

at high risk of relapse (15% of patients were in second complete remission,

and 85% were in third or more complete remission or in relapse)22. Patients

were conditioned with total body irradiation (800 cGy), thiotepa,

antithymocyte globulin, and fludarabine (or cyclophosphamide) and were

transplanted with T-cell-depleted granulocyte colony-stimulating

factor-mobilized peripheral blood cells (15 + 5 x 106 CD34+ cells/kg and < 4

104 CD3+ cells/kg). No post transplantation GVHD prophylaxis was

administered.

When KIR epitope-mismatch in the GvH direction was not present, the

probability or relapse at 5 years was 75% in the face of intensive

pretransplantation conditioning regimen, compared with 0% when KIR

epitope-mismatch in the GvH direction was present22.

In addition, whereas rejection and grade II or greater acute GVHD rates were

15.5% and 13.7%, respectively, in the first group, they were 0% for both in

the second. Thus, in AML the probability of survival at 5 years was 5%

without KIR ligand incompatibility in the GvH direction and 60% with it. The

latter is considerably better than survival reported by the National Marrow

Donor Program after matched unrelated-donor transplant in adult patients in

the same risk category (27% in second complete remission; 7% in third or

more complete remission or in relapse).

However important, KIR mismatching is not the only determinant of NK cell

activity. The response of NK cells depends on the balance between triggering

and inhibited signals mediated through corresponding activating and

inhibited receptors. One such activating receptor is CD16, a receptor that

finds the FC receptor of Rituximab.

Published reports of NK-DLI in the haploidentical transplant setting,

demonstrated that the infusion of a starting dose of 1 x 107 /kg was

feasible without any significant infusion-related toxicity. No other

immediate or late side effects were observed23-25.

2.4 Hypothesis of the current study

Based upon our clinical observation of GVL augmentation in the presence of

Rituximab, we believe that this activity is mediated by NK cells and ADCC,

which could occur independently of the KIR mismatching.

Eligibility

Genders Eligible for Study: Both

Criteria

Inclusion Criteria:

Patients with previous diagnosis of CD20+ B-cell CLL and non-Hodgkin's

lymphoma who have failed standard conventional chemotherapy, and who had

persistent disease at 3 months, or progressive disease after non-

myeloablative allogeneic transplantation.

Donor willingness to donate peripheral blood (same donor of the original

transplant).

Negative Beta HCG in a woman with child bearing potential defined as not

post-menopausal for 12 months or no previous surgical sterilization.

Exclusion Criteria:

Pregnancy or lactation.

HIV or HTLV-I positivity, or with hepatitis.

Active infection (s) >/= grade 3.

Severe active concomitant medical or psychiatric illness.

Concurrent active GVHD needing the use of tacrolimus.

Location and Contact Information

Please refer to this study by ClinicalTrials.gov identifier NCT00383994

Celina Ledesma, BS 713-794-1058 celsaenz@...

Texas

MD Cancer Center, Houston, Texas, 77030, United States;

Recruiting

Issa Khouri, MD, Principal Investigator

Study chairs or principal investigators

Issa Khouri, MD, Principal Investigator, M.D. Cancer Center

[Guest guest]

Several things jump out at me when I read this interesting clinical

trial description. As Karl wrote, it is unusual to have what almost

amounts to an medical journal abstract in the body of the

justification for the trial.

First, someone cannot appropriately use commas.

More importantly, the authors state that in their opinion, research

shows that complement is the most important path involved in the

cell-killing ability of rituximab, but antibody-dependent cellular

cytotoxicity (ADCC) is.

Natural Killer cells are the major mediator of ADCC. These cells

make up about 10% of the lymphocytes.

Recombinant human GM-CSF may boost the ability of Natural Killer

cells to attack cancer cells, thus enhancing the ability of

rituximab to kill CLL cells.

Survival after allogenic transplant may be greatly enhanced by

eliminating serious graft versus host disease. This may be mediated

by killer Ig-like receptors.

>

> This clinical trial description is unique in that it provides a

very

> technical study rationale. ~ Karl

>

> ==

> Official Title: Immunotherapy With NK Cell, Rituximab and Rhu-

GMCSF in

> Non-Myeloablative Allogeneic Stem Cell Transplantation

> Further study details as provided by M.D. Cancer Center:

>

> Patients with previous diagnosis of CD20+ B-cell CLL and non-

Hodgkin's

> lymphoma who have failed standard conventional chemotherapy, and

who had

> persistent disease at 3 months, or progressive disease after non-

> myeloablative allogeneic transplantation. Donor willingness to

donate

> peripheral blood (same donor of the original transplant).

>

> =2.1 Graft versus Leukemia/Lymphoma

>

> Over the past 2 decades, a number of different immune-based

strategies aimed

> at eradication or suppression of residual malignant disease have

been

> proposed for the clearance of malignant cells.

>

> T-cell-mediated graft-versus-leukemia/lymphoma (GVL) has been

shown to be

> the most efficacious following allogeneic hematopoietic stem cell

> transplantation and donor lymphocyte infusions1,2. Although

specific

> anti-malignancy responses have been documented, most T-cell-

mediated

> alloreactions are thought to be direct against minor or major

> histocompatibility antigens shared by both malignant and normal

cells with

> potential for widespread host tissue damage.

>

> Successful T-cell-based immunotherapy will, therefore, ultimately

require

> better definition of tumor-specific antigens that will allow the

direction

> of the immune response to the tumor cells3.

>

> Unfortunately, tumor-specific antigens have only been identified

on a

> minority of cancers4.

>

> =2.2 Targeted therapy with Rituximab in allogeneic stem cell

transplantation

>

> Rituximab (IDEC-C2B8) has significant activity as a single agent

in patients

> with relapsed B-cell lymphoid malignancies5. Various mechanisms of

action

> been described: direct apoptosis; complement-mediated and antibody-

dependent

> cellular cytotoxicity (ADCC). Golay et al demonstrated ADCC in

four

> different follicular lymphoma cell lines exposed to Rituximab6.

>

> No significant direct apoptosis was observed in that study. B-cell

depletion

> in vitro was observed with Rituximab therapy in the presence of

mononuclear

> cells, but not complement, suggesting that cell-mediated

mechanisms (ADCC)

> may be dominant7.

>

> The expression of complement inhibitors on tumor cells did not

predict

> clinical outcome after in vivo treatment with Rituximab in a

recent clinical

> trial8 . In a recent study from M. D. , an increased ADCC

activity

> correlated with response in patients with recurrent indolent

lymphoma

> treated with Rituximab in combination with rhu-GMCSF9.

>

> There are several reasons to consider using Rituximab in the

allogeneic

> transplantation setting. We and others, have reported a lower

incidence of

> acute and chronic GVHD when we combined this anti-CD20 chimeric

molecule

> with the chemo-conditioning regimen10,11.

>

> We have also demonstrated an improved GVL in patients with

persistent or

> recurrent disease after non-myeloablative stem cell

transplantation when

> Rituximab was added to the schema of immunomanipulation after

transplant11.

>

> Some of these responses occured in patients having both, a

progressive

> disease and graft-versus-host disease, suggesting a non-T cell

mediated

> response but rather an alternative mechanisms of response such as

the

> antibody-dependent cellular cytotoxicity which is mediated mainly

by Natural Killer

> cells.

>

> =2.3 Human NK Cells

>

> NK cells are the major mediator of ADCC. Human NK cells comprise

> approximately 10% of all blood lymphocytes and are identified by

the

> expression of the CD56 surface antigen and lack of CD3.

>

> Functionally, NK cells have direct or natural cytotoxic activity

against

> some virus-infected, leukemic, and other tumor cells, and they

also mediate

> antibody-dependent cellular cytotoxicity ADCC of targets through

FcyRIII

> (CD16), a receptor that binds the Fc portion of antibody12-15.

>

> It has been postulated that rhu-GM-CSF may enhance the ADCC

response to

> Rituximab by increasing cellular expression of CD20 and by

upregulating CD16

> prior to the infusion of effector cells.

>

> It has also been suggested that ADCC may be enhanced by various

cytokines,

> such as IL-2, IL-12 and Interferon which could also be stimulated

by

> rhu-GM-CSF. These different mechanisms16-18 may result in a higher

tumor

> kill without an increased risk of GVHD10,11.

>

> Two distinct subsets of human NK cells are identified according to

cell

> surface density of CD56 expression19. The majority (90%) of human

NK cells

> are CD56dim and express high level of CD16, whereas a minority

(10%) is

> CD56bright and CD16dim/neg.

>

> Unlike T and B lymphocytes, NK cells do not rearrange genes

encoding

> receptors for antigen recognition, but they have developed the

ability to

> recognize self-MHC class I or class I-like molecules through a

unique class

> of receptors, NK cells receptors (NKRs), that can inhibit or

activate NK

> cell killing.

>

> In humans, receptors termed killer Ig-like receptors (KIRs)

recognize groups

> of HLA class I alleles20. Although KIRs and other class-I

inhibitory

> receptors may be coexpressed NK cells, in any given individual's

NK

> repertoire there are cells that express a single KIR and are

blocked only by

> a specific class I allele group21.

>

> Missing expression of the KIR ligand on mismatched allogeneic

cells can

> therefore trigger NK cell alloreactivity22.

>

> Another level of alloreactivity is provided by mismatches at the

KIR

> epitopes expressed by HLA class I alleles. Conversely, if class I

group

> mismatch is not present, despite the haplotype-mismatch, donor NK

cells will

> be inhibited by their inhibitory KIR ligands and no alloreactivity

is

> expected.

>

> A remarkable GVL effect was observed in patients with acute

myeloid leukemia

> at high risk of relapse (15% of patients were in second complete

remission,

> and 85% were in third or more complete remission or in relapse)22.

Patients

> were conditioned with total body irradiation (800 cGy), thiotepa,

> antithymocyte globulin, and fludarabine (or cyclophosphamide) and

were

> transplanted with T-cell-depleted granulocyte colony-stimulating

> factor-mobilized peripheral blood cells (15 + 5 x 106 CD34+

cells/kg and < 4

> 104 CD3+ cells/kg). No post transplantation GVHD prophylaxis was

> administered.

>

> When KIR epitope-mismatch in the GvH direction was not present,

the

> probability or relapse at 5 years was 75% in the face of intensive

> pretransplantation conditioning regimen, compared with 0% when KIR

> epitope-mismatch in the GvH direction was present22.

>

> In addition, whereas rejection and grade II or greater acute GVHD

rates were

> 15.5% and 13.7%, respectively, in the first group, they were 0%

for both in

> the second. Thus, in AML the probability of survival at 5 years

was 5%

> without KIR ligand incompatibility in the GvH direction and 60%

with it. The

> latter is considerably better than survival reported by the

National Marrow

> Donor Program after matched unrelated-donor transplant in adult

patients in

> the same risk category (27% in second complete remission; 7% in

third or

> more complete remission or in relapse).

>

> However important, KIR mismatching is not the only determinant of

NK cell

> activity. The response of NK cells depends on the balance between

triggering

> and inhibited signals mediated through corresponding activating

and

> inhibited receptors. One such activating receptor is CD16, a

receptor that

> finds the FC receptor of Rituximab.

>

> Published reports of NK-DLI in the haploidentical transplant

setting,

> demonstrated that the infusion of a starting dose of 1 x 107 /kg

was

> feasible without any significant infusion-related toxicity. No

other

> immediate or late side effects were observed23-25.

>

> 2.4 Hypothesis of the current study

>

> Based upon our clinical observation of GVL augmentation in the

presence of

> Rituximab, we believe that this activity is mediated by NK cells

and ADCC,

> which could occur independently of the KIR mismatching.