Re: PCI-32765 pushes the cells out of the lymph nodes

[Guest guest]

Dr. Furman,

Is this specific to CLL or has it been observed in other

lymphomas as well?

Might this effect also be exploited to measure for minimal

residual disease status? - one rap being that PCR can only

detect disease in the compartment tested?

Best,

Karl

[Guest guest]

At 08:39 PM 6/2/2011, Rick Furman, MD wrote:

>The PCI-32765 pushes the cells out of the lymph nodes into

the >peripheral blood.

At 12:10 PM 6/3/2011, karlamonyc wrote: >Might this effect

also be exploited to measure for minimal residual >disease

status?

Achieving minimal residual disease (MRD) may not be a

necessary objective, or even the best objective, for all CLL

patients.

For example, Dr. Byrd & coworkers reported (Woyach et al.,

Feb/2011), in a study of FR treatment of symptomatic,

previously untreated CLL patients, that only partial disease

elimination was necessary for long-term progression-free

survival (PFS) and long-term overall survival (OS) of " low-

risk " (i.e. IgVH-mutated) patients, whereas higher-risk

(e.g. positive for 11q del) patients did not respond well to

FR The paper's abstract is at:

http://jco.ascopubs.org/content/early/2011/02/14/JCO.2010.31.1811

In a March 3 press release, the paper's first author (Dr.

Woyach) elaborated, saying:

http://www.sciencedaily.com/releases/2011/02/110225094938.htm

" ....we show that it is possible to achieve long-term

remission without completely eliminating the disease, which

challenges the existing belief that it is necessary to

completely eradicate the disease for long-term remission in

low-risk patients. " and " We learned from this study that

many patients with low-risk disease will have excellent

outcomes with the two-drug combination, so they can be

spared the toxicity that comes with the addition of

cyclophosphamide. "

and

" .....unlike the three-drug combination (FCR), fludarabine

plus rituximab does not increase the risk of therapy-related

acute leukemias in CLL patients. "

The above latter comment identifies less risk of acute

leukemias as just one advantage of treating such low-risk

patients with a primary objective of long-term PFS & OS,

rather than assuming MRD is necessary for that objective,

which usually requires harsher treatments, which can hasten

development of more aggressive disease.

Long-term PFS & OS in these low-risk patients may be

achievable with treatments that are even less toxic than FR

treatment.

For example, monotherapy with low-toxicity agents (like

PCI-32765 or CAL-101) that push CLL cells out of nodes may

be sufficient therapy for long-term PFS & OS in low-risk

patients. The lower toxicity of these agents may also aid

in prolonging PFS & OS beyond what was observed for FR.

As I've explained in previous posts, the definition of " low-

risk " previously untreated CLL patients may include any

patient, regardless of mutation status, who only slowly

progresses (e.g. arbitrarily >5yrs after diagnosis) to

becoming symptomatic enough to require treatment.

Specifically, biochemical indicators (e.g. mutation status,

genetic abnormalities status) are only indicators of

probabilities for PFS & OS for a population of patients.

Whereas the progression rate of disease for a given patient

is an actual clinical outcome of all factors (identified and

unidentified) affecting that patient's disease.

A theory I've suggested for slow progression of CLL disease

is that proliferation centers (like lymph nodes) are more

dominated by less-aggressive CLLcell clones than more-

aggressive CLLcell clones. Given that theory, if agents

like PCI-32765 or CAL-101 push out different CLLcell clones

from nodes differentially, it is possible that treatment

with these agents could alter which CLLcell clone dominates

a proliferation center after treatment. However, both of

these agents are thought to overcome the protective effects

of stromal cells in proliferation centers, which may infer

that different CLLcell clones may not be differentially

pushed out of nodes.

Al Janski

[Guest guest]

Al,

Thank you for your post. The question we all have is when

clinical trials might be initiated for the slowly

progressing patients? There must be many in our situation

who be more than willing to participate.

[Guest guest]

re: > Achieving minimal residual disease (MRD) may not be a

necessary objective, or even the best objective, for all CLL

patients.

Thanks, Al.

I agree that MRD negative status may not be the ideal goal

for low risk CLL/SLL/indolent NHL (given the toxicities of

current therapies having the potential to achieve this) ...

My thought is that MDR negative status could be a compelling

endpoint for new treatments of high risk disease when a

durable remission is the goal.

Noting that HIV viral load was used as a clinical surrogate

for clinical benefit, which was the primary reason for rapid

development and assessment of effective HIV protocols.

The alternative as you know is to compare PFS and hope that

improvements in PFS translate into improved survival ...

sometimes it does, somtimes not, depending on offsetting

toxicities and impact on response to subsequent therapies,

so we still can have uncertainty following a very long study

with very long follow up.

Once validated as a clinically meaningful endpoint, MRD -

could be assessed in a month? ... but this endpoint would

have to be validated prospectively, which would take also

years. But once done we could compare MDR status to rapidly

evaluate future protocols.

One issue with MRD testing is that it can't detect cells

that may be sequestered in lymph system or nodes. Hence my

question if PC1-32765 might be applied to solving this

problem? PCR tests for molecular markers on blood prior to

and then after PC1-32765??

Just a thought.

Karl

[Guest guest]

At 09:41 AM 6/4/2011, Breeland wrote:

> The question we all have is when clinical trials might

> be initiated for the slowly progressing patients?

I do not know whether there has ever been a clinical study

of untreated CLL patients, with any therapeutic agent, in

which the study was initially designed specifically to

compare responses in patients who slowly-progressed to

needing treatment with patients who rapidly progressed to

needing treatment. However, I would very much like to see

such studies conducted, especially studies of low-toxicity

agents like PCI-32765 and CAL-101.

It is possible that retrospective analyses of past clinical

studies of untreated CLL patients might provide some useful

insights, if patients are re-grouped for analyses to compare

patients who slowly progressed with patients who rapidly

progressed.

For example, the FR study by Dr.Byrd & co-workers (Woyach et

al.,Feb/2011), was a retrospective analysis, as a long-term

follow-up, of a study of symptomatic untreated patients that

was initially reported in 2003. This 2011 re-analysis

included comparing responses of low-risk (i.e. IgVH-mutated)

patients with higher-risk (e.g. positive for 11q del)

patients.

http://jco.ascopubs.org/content/early/2011/02/14/JCO.2010.31.1811

It would seem one might be able re-group the patients from

this past FR study into slowly-progressed and rapidly-

progressed sub-groups, possibly using an arbitrary cut-off

point, for example patients who were treated with FR in the

study who were at more than 5yrs after CLL diagnosis vs.

patients who were treated less than 5yrs after their

diagnosis. Clearly, one would want to try to normalize

other factors in addition to simply time after diagnosis;

for example the stage of the disease at the time of

diagnosis would seem important to normalize in defining

slowly- vs. rapidly- progressed sub-groups.

One might expect to observe similarities in comparisons

between low-risk vs. high-risk groups and in the comparisons

between slowly-progressed and rapidly-progressed groups,

because the same known factors (e.g. status of IgVH) that

'define' risk are probably at least partially responsible

for the relative rate of progression.

However, it would be interesting to know whether pre-

treatment progression rate is a 'better' predictor than risk

(e.g. defined by mutation status) in how well patients

responded to FR in their PFS and OS. Because exceptions

exist, with some low-risk untreated patients progressing

rapidly and some high-risk patients progressing slowly to

becoming symptomatic and needing treatment, important

factors must exist that are not yet known and affect

progression.

How well progression rate predicts response to a given

therapy probably will be different for different therapies.

For example, PCI-32765 or CAL-101 may be better, or at least

different, than FR as a therapy for such comparisons of

responses of patients with different progression rates. For

example, PCI-32765 and CAL-101 seem to be effective in

patients who are 17p(del) or 11q(del) positive, whereas FR

(i.e. Fludarabine) is not very effective in 17p(del)

patients.

Until assessments are performed of progression rates as

indicators of responses to a given therapy for untreated

patients, not much can be concluded.

Al Janski

[Guest guest]

At 11:29 AM 6/4/2011, " karlamonyc " wrote:

>MDR negative status could be a compelling endpoint for new

>treatments of high risk disease when a durable remission is the goal.

>One issue with MRD testing is that it can't detect cells that may be

>sequestered in lymph system or nodes. Hence my question if PC1-32765

>might be applied to solving this problem? PCR tests for molecular

>markers on blood prior to and then after PC1-32765??

Given its low toxicity, PCI-32765 would seem preferable to

alternative, more toxic, agents for clearing nodes, for the objective

of obtaining more accurate MRD assessment. However, it would also

depend on whether PCI-32765 has sufficient effectiveness in clearing

nodes, spleen, marrow, etc. to achieve MRD negativity. I'm not sure

whether that is known yet.

At 11:29 AM 6/4/2011, " karlamonyc " wrote:

>The alternative as you know is to compare PFS and hope that

>improvements in PFS translate into improved survival ... sometimes

>it does, somtimes not, depending on offsetting toxicities and impact

>on response to subsequent therapies, so we still can have

>uncertainty following a very long study with very long follow up.

I realize MRD negativity would be intended for clinical approval

studies of agents tested in high-risk CLL patients, however, after

approval, those agents would also be used to treat symptomatic

previously untreated low-risk patients.

If a treatment of a given patient group provides long-term PFS and OS

(or if OS is yet to be determined), it seems that it may be necessary

to wait for the OS data, or at least do nothing that negatively

affects the long-term benefit of that treatment for that patient group.

For example, in the case of low-risk CLL patients, their low-risk

status may be harmed by exposing them to agents that will eliminate

their disease to the point of MRD negativity.

Consequently, design of clinical studies for approval of new agents,

which usually focus on high-risk, refractory patients, need to take

into account possible negative impacts of those designs on the use of

similar protocols in treating low-risk patients.

For example, the discussion in the study of Byrd & coworkers (Woyach

et al., Feb/2011) came to a related conclusion. They demonstrated

that only partial disease elimination was necessary for long-term PFS

& OS when low-risk (i.e. IgVH-mutated) untreated patients were

treated with FR, concluding that initial treatment of low-risk

patients should not be FCR, which achieves MRD negativity, because of

the greater risk for therapy-related acute leukemias with FCR and

likely reduction in OS of the low-risk sub-group.

http://jco.ascopubs.org/content/early/2011/02/14/JCO.2010.31.1811

In the existing analyses thus far of the previous studies of FCR vs.

FR, which demonstrated greater benefit of FCR, presumably no analyses

were performed to compare PFS & OS responses of low-risk vs.

high-risk untreated patients, but the discussion of Woyach et al.

implied, rather than a benefit, they expect FCR (compared with FR)

lowers PFS & OS in low-risk untreated patients.

Al Janski

[Guest guest]

Hi,

If the cells are being pushed out of the lymph nodes,

would that cause an increase in the lymphocyte #s

seen in the CBC?

Hal

[Guest guest]

Yes, Hal. As the CLL cells are pushed into the blood stream,

the WBC and ALC climb. Tom was told that his white blood

count would likely triple within the first month of

treatment with PCI-32765. That is to be expected and then

the hope is that the CLL cells will die while in the

bloodstream because they have lost their stromal link. I

think of it as nursing CLL babies who have lost their Mother

and cannot find a wet nurse.

JLOU

Hal wrote:

If the cells are being pushed out of the lymph nodes,

would that cause an increase in the lymphocyte #s

seen in the CBC?

[Guest guest]

At 09:16 PM 6/5/2011, lou Park wrote:

>......CLL cells will die while in the bloodstream because they have

>lost their stromal link. I think of it as nursing CLL babies who

>have lost their Mother and cannot find a wet nurse.

Nice analogy...... :-)

One caveat is that the host for the CLL cells is an

unwilling, and harmed, organism from the relationship,

whereas human Mothers and their babies (usually) have

mutually beneficial relationships.

Maybe CLL cells in humans are more like the result of a cow

bird laying it's egg in a warbler's nest, with the resultant

hatched cow bird feeding from an unsuspecting mother

warbler, and indirectly killing it's weaker warbler chicks

by out-competing them for that food or directly killing them

by pushing them out of the warbler's next.

Al Janski

[Guest guest]

Hi Jlou,

My wife is enrolled in phase 1 Estbon for her CLL (she also

has MDS from 2 bouts of treatment with FCR). After 2 weeks

on trial her Lymphs were down 66%. The docs. and us were

cautiously optimistic that drug was working on her CLL.

After 4th cycle her lymphs had doubled off their lows but

were still in line to meet protocol guidelines to continue

treatment. She'll have CBC early Wed. and if it shows an

improvement in lymph counts of 25% from her 1st test then

she'll start another round of 4 infusions. If counts are too

high, we'll have to wait for results of BM to be taken Wed.

to determine the % of CLL cells in BM. I am hoping that this

sudden increase in the counts is due to the cells leaving her

abdominal nodes and we can continue using the Estybon. The

66% decrease after two rounds of infusions were an exciting

and encouraging development.

I'll let the board know the results of tests at the end of

the week.

Hal

----- Original Message -----

From: " lou Park " <jlpark@...>

/message/15263

[Guest guest]

Re: More from Dr. Byrd on PCI-32765

At 10:44 AM 6/6/2011, S wrote:

>http://www.eurekalert.org/pub_releases/2011-06/osum-nea060311.php

>SNIP (quote from above press release):

> " The ongoing phase II clinical trial involves 78 patients with

>previously untreated or relapsed and refractory CLL or small

>lymphocytic leukemia. "

Dr. Byrd expressed agreement in an off-list reply (see below) to my

initial post (also below), which discussed the importance of a

difference in therapy responses of low-risk (IgVH mutated) vs.

high-risk (e.g. 11q del positive) untreated patients, and which used

Dr. Byrd's FR study as an example of that importance.

However, Dr. Byrd believes that both low-risk and high-risk CLL

patients will respond similarly ( " the same " ) to PCI-32765 or to CAL-101.

Athough I can think of biochemical reasons why patients with

different risk status might respond differently to either of these

two agents, I can also think of biochemical reasons why those

differences would not prevent the agents from being effective for

both risk groups. Read on........

>>>>>> quote <<<<<<<<

From: " Byrd, "

" Al Janski "

Date: Sat, 4 Jun 2011 00:37

Subject: RE: PCI-32765 pushes the cells out of the lymph nodes

Al, I agree with you and believe these drugs may also have the same

properties for high risk disease. Come to our ASCO presentation on

Monday if you are at this meeting

JB

C. Byrd M.D.

=====

From: Al Janski

Date: Sat, 04 Jun 2011 00:27

Subject: [] Re: PCI-32765 pushes the cells out of the lymph nodes

SNIP.......

Achieving minimal residual disease (MRD) may not be a necessary

objective, or even the best objective, for all CLL patients.

For example, Dr. Byrd & coworkers reported (Woyach et al., Feb/2011),

............

http://jco.ascopubs.org/content/early/2011/02/14/JCO.2010.31.1811

SNIP.........

..........monotherapy with low-toxicity agents (like PCI-32765 or

CAL-101) that push CLL cells out of nodes may be sufficient therapy

for long-term PFS & OS in low-risk patients.

SNIP......

..........the definition of " low-risk " previously untreated CLL

patients may include any patient, regardless of mutation status, who

only slowly progresses (e.g. arbitrarily >5yrs after diagnosis) to

becoming symptomatic enough to require treatment.

SNIP......

A theory I've suggested for slow progression of CLL disease is that

proliferation centers (like lymph nodes) are more dominated by

less-aggressive CLLcell clones than more-aggressive CLLcell clones.

>>>>>>> end of quote <<<<<<<<

I do not know whether Dr. Byrd was indicating he agreed with all of

the above SNIPs, but he did not take issue with any of them.

I have been proposing that both less-aggressive and more-aggressive

CLLcell clones exist in most (all?) CLL patients and the rate of

progression of the disease is at least partially related to which

type of clone is competing most effectively for space in

proliferation centers (nodes, spleen, marrow).

One possible importance of this clonal competition situation (if it

exists) is that disruption of the relative ability of less-aggressive

clones to out-compete more -aggressive clones could cause a

slowly-progressive disease to evolve into a rapidly progressive disease.

For example, a patient may be positive for 17p del, yet, because the

CLL clones dominating proliferation centers in that patient are

negative for 17p del, these patients may progress slowly. However,

if the patient were treated with a fludarbine therapy (e.g. FCR),

which could greatly reduce the population of the CLL cell clones

negative for 17p del, to a level at which the fludarabine-resistant

clones (17p del positive) become the dominant clones in those

proliferation centers, it could permit an acceleration of the

proliferation of those resistant CLL cells and, thus, an acceleration

of the progression of the disease.

This clonal competition theory in general, as well as the above

specific example of fludarabine altering the mix of different

populations of CLL cells, are supported by research reported in

Nov/2010 (reference below). In that report, E. Gross et al. observed

that treatment with fludarabine, bendamustin or rituximab resulted in

emergence of chemoresistant " side-populations " of CLL cells as the

dominant cells.

Consequently, Gross concluded that the treatment goal should be to

eliminate both the resistant side-populations and the non-resistant

populations of CLL cells, which indeed may be the best strategy for

many high-risk (rapidly-progressing patients).

However, the best strategy to achieve the longest-term PFS & OS for

low-risk (slowly-progressing) patients may be to only partially

reduce the population of total CLL cells in proliferation centers,

sufficiently to eliminate CLL-related symptoms, yet maintain the

dominance of the less-aggressive CLLcell clones in the proliferation

centers. In effect, such a strategy might return the symptomatic

previously untreated patient back to an indolent stage, with

less-aggressive CLLcells continuing to dictate only slow progression

of the disease.

So far, clinical results for both PCI-32765 and CAL-101 do not appear

to completely eliminate disease, which may make them ideal

monotherapies for untreated low-risk patients. These patients may

not require continuous use of these agents in order to maintain a

long-term, indolent PFS status. Non-continuous use of the agents

would make it less likely patients would develop CLLcell clones

resistant to these agents and/or serious side-effects from long-term

exposure to the agents.

However, these agents also seem to provide clinical benefit to some

high-risk, refractory patients, as long as these patients continue

receiving the agents. That latter benefit could simply be a result

of continuous use of these agents that allows continuous flushing of

CLL cells from enough proliferation centers, making it irrelevant

whether resistant or non-resistant clones are dominating those

proliferation centers.

I am hopeful that Dr. Byrd's optimistic expectations become reality

for patients in both risk categories.

REFERENCE:

" B-chronic lymphocytic leukemia chemoresistance involves innate and

acquired leukemic side population cells. " , E. Gross et al.; Leukemia

24, 1885-1892 (November 2010)

http://www.nature.com/leu/journal/v24/n11/full/leu2010176a.html

Al Janski

[Guest guest]

Re: More from Dr. Byrd on PCI-32765

At 10:44 AM 6/6/2011, S wrote:

>http://www.eurekalert.org/pub_releases/2011-06/osum-nea060311.php

>SNIP (quote from above press release):

> " The ongoing phase II clinical trial involves 78 patients with

>previously untreated or relapsed and refractory CLL or small

>lymphocytic leukemia. "

Dr. Byrd expressed agreement in an off-list reply (see below) to my

initial post (also below), which discussed the importance of a

difference in therapy responses of low-risk (IgVH mutated) vs.

high-risk (e.g. 11q del positive) untreated patients, and which used

Dr. Byrd's FR study as an example of that importance.

However, Dr. Byrd believes that both low-risk and high-risk CLL

patients will respond similarly ( " the same " ) to PCI-32765 or to CAL-101.

Athough I can think of biochemical reasons why patients with

different risk status might respond differently to either of these

two agents, I can also think of biochemical reasons why those

differences would not prevent the agents from being effective for

both risk groups. Read on........

>>>>>> quote <<<<<<<<

From: " Byrd, "

" Al Janski "

Date: Sat, 4 Jun 2011 00:37

Subject: RE: PCI-32765 pushes the cells out of the lymph nodes

Al, I agree with you and believe these drugs may also have the same

properties for high risk disease. Come to our ASCO presentation on

Monday if you are at this meeting

JB

C. Byrd M.D.

=====

From: Al Janski

Date: Sat, 04 Jun 2011 00:27

Subject: Re: PCI-32765 pushes the cells out of the lymph nodes

SNIP.......

Achieving minimal residual disease (MRD) may not be a necessary

objective, or even the best objective, for all CLL patients.

For example, Dr. Byrd & coworkers reported (Woyach et al., Feb/2011),

............

http://jco.ascopubs.org/content/early/2011/02/14/JCO.2010.31.1811

SNIP.........

..........monotherapy with low-toxicity agents (like PCI-32765 or

CAL-101) that push CLL cells out of nodes may be sufficient therapy

for long-term PFS & OS in low-risk patients.

SNIP......

..........the definition of " low-risk " previously untreated CLL

patients may include any patient, regardless of mutation status, who

only slowly progresses (e.g. arbitrarily >5yrs after diagnosis) to

becoming symptomatic enough to require treatment.

SNIP......

A theory I've suggested for slow progression of CLL disease is that

proliferation centers (like lymph nodes) are more dominated by

less-aggressive CLLcell clones than more-aggressive CLLcell clones.

>>>>>>> end of quote <<<<<<<<

I do not know whether Dr. Byrd was indicating he agreed with all of

the above SNIPs, but he did not take issue with any of them.

I have been proposing that both less-aggressive and more-aggressive

CLLcell clones exist in most (all?) CLL patients and the rate of

progression of the disease is at least partially related to which

type of clone is competing most effectively for space in

proliferation centers (nodes, spleen, marrow).

One possible importance of this clonal competition situation (if it

exists) is that disruption of the relative ability of less-aggressive

clones to out-compete more -aggressive clones could cause a

slowly-progressive disease to evolve into a rapidly progressive disease.

For example, a patient may be positive for 17p del, yet, because the

CLL clones dominating proliferation centers in that patient are

negative for 17p del, these patients may progress slowly. However,

if the patient were treated with a fludarbine therapy (e.g. FCR),

which could greatly reduce the population of the CLL cell clones

negative for 17p del, to a level at which the fludarabine-resistant

clones (17p del positive) become the dominant clones in those

proliferation centers, it could permit an acceleration of the

proliferation of those resistant CLL cells and, thus, an acceleration

of the progression of the disease.

This clonal competition theory in general, as well as the above

specific example of fludarabine altering the mix of different

populations of CLL cells, are supported by research reported in

Nov/2010 (reference below). In that report, E. Gross et al. observed

that treatment with fludarabine, bendamustin or rituximab resulted in

emergence of chemoresistant " side-populations " of CLL cells as the

dominant cells.

Consequently, Gross concluded that the treatment goal should be to

eliminate both the resistant side-populations and the non-resistant

populations of CLL cells, which indeed may be the best strategy for

many high-risk (rapidly-progressing patients).

However, the best strategy to achieve the longest-term PFS & OS for

low-risk (slowly-progressing) patients may be to only partially

reduce the population of total CLL cells in proliferation centers,

sufficiently to eliminate CLL-related symptoms, yet maintain the

dominance of the less-aggressive CLLcell clones in the proliferation

centers. In effect, such a strategy might return the symptomatic

previously untreated patient back to an indolent stage, with

less-aggressive CLLcells continuing to dictate only slow progression

of the disease.

So far, clinical results for both PCI-32765 and CAL-101 do not appear

to completely eliminate disease, which may make them ideal

monotherapies for untreated low-risk patients. These patients may

not require continuous use of these agents in order to maintain a

long-term, indolent PFS status. Non-continuous use of the agents

would make it less likely patients would develop CLLcell clones

resistant to these agents and/or serious side-effects from long-term

exposure to the agents.

However, these agents also seem to provide clinical benefit to some

high-risk, refractory patients, as long as these patients continue

receiving the agents. That latter benefit could simply be a result

of continuous use of these agents that allows continuous flushing of

CLL cells from enough proliferation centers, making it irrelevant

whether resistant or non-resistant clones are dominating those

proliferation centers.

I am hopeful that Dr. Byrd's optimistic expectations become reality

for patients in both risk categories.

REFERENCE:

" B-chronic lymphocytic leukemia chemoresistance involves innate and

acquired leukemic side population cells. " , E. Gross et al.; Leukemia

24, 1885-1892 (November 2010)

http://www.nature.com/leu/journal/v24/n11/full/leu2010176a.html

Al Janski

[Guest guest]

Thought provoking and nicely presented, Al. Reminding of how

the gut is regulated by friendly bacteria.

Is enough known about the aggressive clones to begin to

target them selectively? And how will responses specific to

the aggressive or indolent population of CLL cells be measured?

All the best,

Karl

Al wrote:

Consequently, Gross concluded that the treatment goal should

be to eliminate both the resistant side-populations and the

non-resistant populations of CLL cells, which indeed may be

the best strategy for many high-risk (rapidly-progressing

patients).

However, the best strategy to achieve the longest-term PFS &

OS for low-risk (slowly-progressing) patients may be to only

partially reduce the population of total CLL cells in

proliferation centers, sufficiently to eliminate CLL-related

symptoms, yet maintain the dominance of the less-aggressive

CLLcell clones in the proliferation centers. In effect,

such a strategy might return the symptomatic previously

untreated patient back to an indolent stage, with less-

aggressive CLLcells continuing to dictate only slow

progression of the disease.

[Guest guest]

At 07:32 AM 6/7/2011, karlamonyc wrote:

>Is enough known about the aggressive clones to begin to target them

>selectively? And how will responses specific to the aggressive or

>indolent population of CLL cells be measured?

Actually, in three postings on 9/20/2010 ( thread =

" competition between CLL clones " ), when I first suggested this

theory, I answered similar questions (posed by Andy Gach) about

discovering what mechanism makes the " SP " CLL cells (terminology used

in Gross et al.) resistant, and then targeting that mechanism.

My thinking now about that is pretty much the same as it was then, so

see my response to Andy then, which is below.

In reading that response, recall that Gross et al. not only observed

that the 'innate' resistant SP cells existed pre-treatment in low

levels and that SP cells became dominant after exposure to

fludarabine, bendamustin or rituximab, but they also observed that

the exposure induced the development of new " acquired " SP cells " from

drug-driven evolution " of " non-SP cells " (i.e. non-resistant CLL cells).

Gross et al. http://www.nature.com/leu/journal/v24/n11/full/leu2010176a.html

This would imply that any therapeutic action to specifically target

the more-aggressive CLLcell clones may need to be highly targeted

and, possibly, short-term in duration to minimize the induction of

the evolution of non-resistant cells to resistant CLL

cells. However, the first step is the challenge of identifying

enough unique biochemical characteristics to target in the (possibly)

'many' types of minority more-aggressive clones, characteristics that

do not exist in the dominant less aggressive clones.

>>>>>> quote <<<<<<

Cc: .Byrd@...

From: Al Janski <aljanski@...>

Date: Mon, 20 Sep 2010 20:08

Subject: Re: competition between CLL clones

SNIP.........

" .....it seems likely that the SP-CLL population of cells is very

heterogeneous, such that in a single patient there may be many,

possibly dozens, of mechanisms (and thus dozens of unique CLL clones)

by which this SP-CLL population is conferred its resistance. As

such, it may take many drugs to attack enough of these resistance

mechanisms so as to eliminate enough of the resistant clones. The

more drugs it takes to accomplish this, the greater the probability

that new resistant clones may be induced as a result of the treatment.

By contrast, the simplistic, crude mechanism of just allowing an

existing dominant non-resistant CLL clone(s) to continue to

out-compete (in proliferation centers) the underlying resistant

clones (by only partial elimination of the non-resistant clones) is a

mechanism that does not require knowing the mechanisms of resistance

of the resistant CLL clones.

It seems more likely that a single therapeutic agent (or maybe just a

couple of agents) might be able to lower the burden of the dominant

non-resistant CLL population sufficiently so as to make the

pathologies tolerable again, but to retain a sufficient population to

continue to prevent, or at least slow, the resistant clones from

becoming dominant, with the caveat that the agent(s) would need to

induce little or no clonal evolution to new resistant CLL clones. "

>>>>>> end of quote <<<<<<

Since this earlier discussion, a couple of important things have

happened that add more definition to what I was thinking about.

First, the perspective that low-risk (slowly-progressing) symptomatic

untreated patients might be the best patient population for a

strategy that maintains dominance of a less-aggressive CLLcell clone,

by only partial elimination of disease, was mostly developed after

reading the later report by Dr. Byrd & coworkers (Woyach et al.,

Feb/2011) of long-term PFS & OS for low-risk (but not high-risk)

previously untreated patients who received FR as their first therapy,

even though these patients demonstrated only partial elimination of disease.

http://jco.ascopubs.org/content/early/2011/02/14/JCO.2010.31.1811

And, of-course, the recent clinical successes of PCI-32765 and

CAL-101 in both their effectiveness and low toxicity, from only

partial elimination of disease, seemed to have identified two good

candidate monotherapies for a strategy that maintains dominance of

less-aggressive CLLcell clones while achieving the goal of

eliminating CLL-related pathologies for longer-term PFS, and possibly

for longer-term OS, of low-risk untreated patients.

For some of these patients, maybe occasional monotherapy (when the

patients become symptomatic again) with one of these low-toxicity

agents may be the only therapy these patients would ever need.

Al Janski

[Guest guest]

We do see this phenomenon with other lymphomas, most notably

mantle cell lymphoma. T cells and normal B cells are also

pushed out of the nodes as well, so almost everyone will

have an increase in their lymphocytes.

Regarding PCR, the utility of it has been established for

determining prognosis after fludarabine based chemotherapy.

Two issues:

1. using an agent to mobilize additional cells from another

compartment would require the methodology to be retested to

prove its validity.

2. There are no data that PCR detected minimal residual

disease predicts outcome in patients treated with PCI-32765.

Rick Furman

>

> Dr. Furman,

>

> Is this specific to CLL or has it been observed in other

> lymphomas as well?

>

> Might this effect also be exploited to measure for minimal

> residual disease status? - one rap being that PCR can only

> detect disease in the compartment tested?

>

> Best,

>

> Karl

>

[Guest guest]

Al, I read with interest your post about dominant cells.

Perhaps this is the explanation as to why Rituxan

monotherapy worked so well for my husband for 8 years in

spite of his fairly aggressive 11Q disease. Very

interesting theory. He is now on CAL101.

[Guest guest]

At 05:49 PM 6/8/2011, chsngrnbos@... wrote:

>....... dominant cells. Perhaps this is the explanation as to why

>Rituxan monotherapy worked so well for my husband for 8 years in

>spite of his fairly aggressive 11Q disease.

What you describe sounds like a possible example of a situation in

which a high-risk patient has less aggressive disease than

expected. It may also be an example of the corollary I proposed,

i.e. that the rate of progression prior to initial treatment of

untreated patients may be an indicator (maybe even a better indicator

than markers like 11q del) of whether that initial treatment

objective should be partial or complete elimination of disease.

I assume the hypothesis you suggest is that maybe successful

competition by dominant less-aggressive CLLcell clones against 11q

del positive CLLcell clones might have lessened, in some way, the

aggressiveness of your husband's disease, such that Rituxan

monotherapy was enabled to be effective for so long.

Below is some biochemical speculation that might fit with a clonal

competition role in how a CLL patient could achieve long-term (8yrs)

benefit from Rituxan, despite being positive for 11q del.

I think it is generally accepted that Rituxan's activity against CLL

is primarily related to its ability to clear CLL cells from the

blood, but maybe for some patients Rituxan may also lower the CLLcell

load in the proliferation centers (e.g. nodes, spleen, marrow).

For example, if Rituxan is clearing CLL cells from the blood, that

could have an indirect effect of reducing CLL cells in other

locations that are vascularized by the blood.

One possibility for that scenario may be related to the fact that

much of what happens inside a cell and inside the body is regulated

by different concentration gradients (concentrations of molecules in

different spaces inside cells, concentrations of cells in different

places inside the body). If a given type of cell population inside a

vascularized tissue compartment (e.g. nodes, spleen, marrow) senses a

drop in the concentration of that cell type in the blood that 'baths'

that tissue, molecular signals (e.g. chemokines) may be altered so as

to stimulate cells in that tissue to leave that tissue and migrate

into the blood.

Specifically, maybe, in some CLL patients, Rituxan-dependent

reduction in blood CLL cells can indirectly reduce (but not

eliminate) the total CLL burden in some tissue proliferation centers

for CLLcells by this mechanism of sensing a drop in the CLLcell

concentration in the blood, and after those CLLcells are released

into the blood, Rituxan is able to clear (kill) them.

Such a partial reduction in CLL burden in the tissue may be

sufficient to reverse symptomatic conditions, at least until the

remaining CLLcells in that tissue proliferate to an extent that they

again cause symptomatic conditions.

The above mechanism may even be common for many CLL patients treated

with Rituxan, but what might differentiate CLL patients is what

happens in the tissue after some of the CLLcells are induced to

migrate out of the tissue into the blood.

The duration of time between Rituxan treatment and becoming

symptomatic again may depend on which CLLcell clone dominates the

tissue after treatment.

If less-aggressive (slowly-proliferating) CLLcell clones originally

dominated the space in the tissue proliferation center, then partial

elimination of CLLcells in that tissue (in response to such indirect

effects of Rituxan) may allow those less aggressive CLLcells to

continue to compete for that space against more-aggressive CLLcell

clones (e.g. 11q del positive).

The thinking has been that Rituxan treatment becomes less effective

over time because fewer and fewer of the remaining CLL cells contain

the target molecule (i.e. CD20) of Rituxan on their cell surface,

which is a requirement for Rituxan to bind to before being able to

clear those CLL cells from the blood.

However, in a scenario in which only a partial reduction of CLL cells

with CD20 on their surfaces is achieved in a tissue, the remaining

CLLcell clones could proliferate, creating new cells of the same

clone with CD20 on their surfaces. And if a slowly-proliferating

CLLcell clone is the dominant CLLcell clone in the proliferation

centers of that and other tissues, before and after treatment, then

that patient could again be responsive to Rituxan when the

proliferation again results in symptomatic conditions.

Rituxan-induced mutations that lower levels of cell surface CD20 have

been suspected after exposure to Rituxan. However, such mutations

seem less likely if Rituxan is primarily interacting with CLLcells in

the blood, where little proliferation (for creation of new mutant

clones) is expected. Combination of Rituxan with agents that

directly clear proliferation centers may increase Rituxan contact

with CLLcells in those compartments, potentially increasing the

possibility of induction of mutations that decrease cell surface CD20.

If a patient is positive for CLLcells with aggressive characteristics

(e.g. 11q del), then that patient has a greater probability (relative

to patients who are not positive for such aggressive characteristics)

for the aggressive clones to eventually become dominant in

proliferation centers. However, as long as such a patient is only

slowly-progressing, then it may be only necessary to partially

eliminate the disease, e.g. with low-toxicity agents like PCI-32765 or CAL-101.

In this context, it may be insightful to re-analyze data from past

clinical studies in which Rituxan monotherapy was evaluated in

symptomatic untreated CLL patients, by comparing patients who

slowly-progressed to becoming symptomatic with patients who

rapidly-progressed to becoming symptomatic.

More specifics about your husband's case might either make the above

speculation more or less relevant. Presumably, he began treatment

with CAL-101 because he became refractory to Rituxan after 8 yrs.

For example:

1. What are the specifics about the nature of your husband's

aggressive disease? Did he have symptoms (e.g. low levels of

neutrophils, platelets and/or red blood cells) that inferred CLL

infiltration of the marrow?

2. How were those disease characteristics successfully treated for

8yrs with Rituxan monotherapy? For example, was Rituxan therapy

given in response to symptomatic conditions? Or was Rituxan given

(at different intervals) as a maintenance preventative of those

symptomatic conditions?

Al Janski

[Guest guest]

Al, I have often wondered why no one was interested in

looking into this question. People have (for 8 years)

preferred instead to tell me that R does not work in CLL,

while looking at an individual in which it did work very

well, and there are many others with similar paths. In the

case of my husband, he had a BMB in early 2003 that

indicated 90% infiltration of the marrow, platelets were

dropping below normal, nodes and spleen enlarging, RBC

beginning to go down. We were told it was time to treat.

We decided on Rituxan, worked out his treatment schedule

with our research into others who were using Rituxan in the

same way, and by trial and error. So in his case we decided

years ago that the best protocol for him would be to treat

when numbers/ nodes indicated. Therefore he never had any

symptoms except for unrelenting growth of nodes and spleen,

and dropping platelets. So for example his nodes would

slowly become large over the time period of 7 - 9 months,

and the platelets would begin to drop, RBC etc would start

to drift. That is when we scheduled another round of R.

The R worked very well to drop the large nodes and spleen

back to near normal, bring the platelets back to normal,

keep the other counts in good territory. That was our

protocol. We could have abandoned this procedure at any

time we felt it was not working, and in fact that is what

we did in 2011. But for him (and many others) this did work

very well and kept him symptom free as long as we did not

wait too long between rounds. On a couple of notable

occasions we did put off treatment and things progressed

quickly, doctors described his disease as " having legs " .

His immune system is good, he has never had symptoms, and

he never lost a day of work in 8 years, and no, his disease

was not indolent, those 11q clones were ever relentless. So

your theory sounded very interesting to me as a possible

explanation, just as a matter of interest. We all know every

patient is different. Still it seemed like something of

interest..... I remember reading in 2001 when he was first

diagnosed that treating CLL was more an art than it was

medical. I always remembered that, and we set to work to

artistically create something that would work for him, in

his case. There again, when starting the CAL101+R trial, I

wondered if the R had anything left to give. Wondered if

he was too refractory to it. But I did not need to worry,

the CAL cleared then huge nodes and spleen (R alone no

longer working) and the R took the lymphs from 150 to 10 in

4 months. Still had a punch. Just think it is worth

mentioning, and wondered why no one wanted to even take a

look all these years!

Al wrote:

/message/15320

[Guest guest]

At 04:42 PM 6/10/2011, chsngrnbos@... wrote:

>....when starting the CAL101+R trial, I wondered if the R had

>anything left to give. Wondered if he was too refractory to it. But

>I did not need to worry, the CAL cleared then huge nodes and spleen

>(R alone no longer working) and the R took the lymphs from 150 to 10

>in 4 months. Still had a punch.

It may make sense that Rituxan can lose its ability to control

disease as a monotherapy, yet provide adjunct benefit in clearing

CLLcells in blood after CAL-101-induced release of those cells from nodes.

Was the percentage of lymphocytes that were positive for 11q del

measured at different times during the 8 yrs of treatment of Rituxan

monotherapy?, particularly during the latter period when Rituxan

monotherapy became less effective in controlling the disease.

One might expect that the 11q del percentage (from blood samples)

would have increased if the CLLcell clones that are positive for 11q

del became more prominent in the proliferation centers.

Because of the defects in apoptosis associated with deletion of 11q,

a higher ratio of these cells is expected to shorten the time to

developing indications (e.g. low platelet levels) for treatment.

The refractory patients in clinical trials who are responding to

treatment with CAL-101 (or PCI-32765) have had clinical benefit as

long as these patients continue receiving CAL-101 (or PCI-32765).

That latter benefit could simply be a result of continuous use of

these agents that allows continuous flushing of CLL cells from enough

proliferation centers, making it irrelevant whether resistant or

non-resistant clones are dominating those proliferation centers.

I do not know whether any refractory patients who were responding to

either of these agents have yet to be withdrawn from either

agent. When that happens it will be interesting to know whether the

" disease flare " (described by Dr. Furman) in patients who did not

respond also occurs in the patients who did respond.

Because neither agent has been observed to completely eliminate

disease (MRD negativity), my guess is that whether or not disease

flare occurs will be partially dependent on the nature of the disease

before the treatment in a given patient.

For example, what was happening with the 11q del clone before CAL-101

treatment may be relevant in some ways to what happens when CAL-101

is withdrawn.

When withdrawing these agents, if the theory of clonal competition

I've been suggesting has any relevance in reality, then one might ask

whether possibilities exist for making it more likely for

less-aggressive (vs. more-aggressive) CLLcell clones to re-populate

the proliferation centers cleared by these agents.

Al Janski