Study Finds Pill May Represent Promising Treatment for Stubborn Blood Cancers

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Study Finds Pill May Represent Promising Treatment for Stubborn Blood


WASHINGTON, March 10, 2014 /PRNewswire-USNewswire/ -- A pill that

suppresses a key regulator of cancer growth may provide hope to

relapsed leukemia and lymphoma patients running out of treatment

options for their aggressive, treatment-resistant disease, according

to three reports* published online today in Blood, the journal of the

American Society of Hematology.

Patients with blood cancer are typically administered a combination of

chemotherapy and immunotherapy, the latter using the body's own immune

system to help fight disease, as a first line of treatment. While

chemotherapy has traditionally been successful in destroying cancer

cells, it is accompanied by many harmful side effects and patients

typically develop resistance, prompting researchers to investigate new

targeted therapies that may be able to block the production of cancer

cells while leaving normal cells unharmed.

One such targeted therapy, called idelalisib, is a highly selective

compound that, unlike chemotherapy, can target a specific mechanism

that fuels cancer growth. Taken as a pill, idelalisib first targets

and then blocks the expression of the delta isoform of the PI3 kinase

enzyme, which is critical for the activation and survival of cancerous

B cells. Idelalisib's narrow targeting of the PI3 kinase delta make it

an attractive potential therapy for patients with cancers that form in

the B-cell pathway such as chronic lymphocytic leukemia (CLL),

indolent non-Hodgkin lymphoma (iNHL), and mantle cell lymphoma (MCL).

While idelalisib is currently under review by the U.S. Food and Drug

Administration (FDA) for the treatment of treatment-resistant iNHL,

another drug in its class called ibrutinib, which specifically targets

a different cell regulator, has been approved as a second-line therapy

for CLL and MCL.

"Idelalisib is a part of a revolutionary new class of treatments that

can hone in on a specific target without causing the wide range of

side effects seen with chemotherapy," said study author Jennifer R.

Brown, MD, PhD, Director of the Chronic Lymphocytic Leukemia Center at

Dana-Farber Cancer Institute in Boston.

In three manuscripts published today in Blood, investigators present

data from a large Phase I study evaluating the safety and efficacy of

idelalisib in more than 150 patients with CLL, iNHL, and MCL. Before

joining the trial, patients had received several previous treatments -

some as many as 14 - that either failed to destroy the disease or

provided only a temporary reprieve. After an initial study involving

all trial participants, patients were separated into CLL, iNHL, and

MCL disease cohorts and received varied doses of idelalisib. The

therapy appeared to be effective, as patients suffered few side

effects and demonstrated promising response rates, with 72 percent of

CLL patients, 47 percent of iNHL patients, and 40 percent of MCL

patients achieving either a complete or partial response.

"Considering the high number of previous therapies that these patients

had received, higher than we sometimes see in comparable studies, the

efficacy of idelalisib that we observed was remarkable," said study

author Ian Flinn, MD, PhD, Director of the Hematologic Malignancies

Research Program at Sarah Cannon Research Institute in Nashville and a

widely recognized expert in lymphoma. "It was this initial excitement

that has inspired further studies of this therapy in patients with

treatment-resistant blood cancers."

While patients in the CLL and iNHL cohorts experienced significant and

prolonged reduction of disease activity, patients with MCL, a more

aggressive and treatment-resistant type of lymphoma, experienced less

favorable responses. Despite MCL patients' high overall response rate

of 40 percent to idelalisib, the duration of their response to the

drug was not as impressive; only a small fraction (22 enjoyed

prolonged benefits. Despite the modest duration of survival

facilitated by idelalisib in the MCL group, the strong response rate

suggests that investigators have identified a key regulator of cancer

growth; however, more research is needed to further understand the

potential of this therapy in MCL patients.

"While idelalisib is unlikely to receive designation as a single-agent

therapy in mantle cell lymphoma due to the short duration of response,

the path forward will likely include administering it in combination

with other agents or developing second-generation PI3 kinase

inhibitors," said study author Brad S. Kahl, MD, Director of the

Lymphoma Service at the University of Wisconsin Carbone Cancer Center

in Madison. "This study offers a strong foundation for future research

on idelalisib in this disease."

*Studies referenced in this release include:

Idelalisib, an Inhibitor of Phosphatidylinositol 3-Kinase p110?, for

relapsed/refractory chronic lymphocytic leukemia, Brown et al.

Idelalisib, a selective inhibitor of phosphatidylinositol 3-kinase-?,

as therapy for previously treated indolent non-Hodgkin lymphoma, Flinn

et al.

Results of a phase I study of idelalisib, a PI3K? inhibitor, in

patients with relapsed or refractory mantle cell lymphoma (MCL), Kahl

et al.

Blood (, the most cited peer-reviewed publication

in the field of hematology, is available weekly in print and online.

Blood is the official journal of the American Society of Hematology

(ASH) (, the world's largest professional society

concerned with the causes and treatment of blood disorders.

ASH's mission is to further the understanding, diagnosis, treatment,

and prevention of disorders affecting blood, bone marrow, and the

immunologic, hemostatic, and vascular systems by promoting research,

clinical care, education, training, and advocacy in hematology.

blood@ is a registered trademark of the American Society of


SOURCE American Society of Hematology

-0- 03/10/2014

/CONTACT: Amanda Szabo,; 202-552-4914

/Web Site:

CO: American Society of Hematology

ST: District of Columbia




-- DC79927 --

0000 03/10/2014 14:06:00 EDT

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