CLINICAL PHARMACOLOGY
Mechanism Of Action
Sargramostim (GM-CSF) belongs to a group of growth
factors termed colony stimulating factors which support survival, clonal
expansion, and differentiation of hematopoietic progenitor cells. GM-CSF
induces partially committed progenitor cells to divide and differentiate in the
granulocyte-macrophage pathways which include neutrophils,
monocytes/macrophages and myeloid-derived dendritic cells.
GM-CSF is also capable of activating mature granulocytes
and macrophages. GM-CSF is a multilineage factor and, in addition to
dose-dependent effects on the myelomonocytic lineage, can promote the
proliferation of megakaryocytic and erythroid progenitors. However, other factors
are required to induce complete maturation in these two lineages. The various
cellular responses (i.e., division, maturation, activation) are induced through
GM-CSF binding to specific receptors expressed on the cell surface of target
cells.
The biological activity of GM-CSF is species-specific.
Consequently, in vitro studies have been performed on human cells to
characterize the pharmacological activity of GM-CSF. In vitro exposure of human
bone marrow cells to GM-CSF at concentrations ranging from 1-100 ng/mL results
in the proliferation of hematopoietic progenitors and in the formation of pure
granulocyte, pure macrophage and mixed granulocyte macrophage colonies.
Chemotactic, anti-fungal, and anti-parasitic activities of granulocytes and
monocytes are increased by exposure to GM-CSF in vitro. GM-CSF increases the
cytotoxicity of monocytes toward certain neoplastic cell lines and activates
polymorphonuclear neutrophils to inhibit the growth of tumor cells.
Pharmacodynamics
LEUKINE stimulates hematopoietic precursor cells and
increases neutrophil, eosinophil, megakaryocyte, macrophage, and dendritic cell
production. In AML adult patients undergoing induction chemotherapy [see
Clinical Studies], LEUKINE at daily doses of 250 mcg/m² significantly
shortened the median duration of ANC <500/mm³ by 4 days and <1000/mm³ by 7
days following induction; 75% of patients receiving sargramostim achieved ANC
greater than 500/mm³ by day 16 compared to day 25 for patients receiving
placebo. Animal data and clinical data in humans suggest a correlation between
sargramostim exposure and the duration of severe neutropenia as a predictor of
efficacy. At doses of 250 mcg/m² (approximately 7 mcg/kg in a 70 kg human with
a body surface area of 1.96), daily LEUKINE treatment reduced the duration of severe
neutropenia.
Pharmacokinetics
Intravenous Administration (IV)
Peak concentrations of sargramostim were observed in
blood samples obtained during or immediately after completion of LEUKINE
infusion. For LEUKINE injection, the mean maximum concentration (Cmax) was 16.7
ng/mL and the mean area under the time-concentration curve (AUC)0–inf was 32.9
ng•h /mL. There is no accumulation of GM-CSF after repeat dosing and steady
state conditions are met after a single dose.
Subcutaneous Administration (SC)
LEUKINE injection and LEUKINE for injection, at a dose of
6.5 mcg/kg (approximately 250 mcg/m²) given by the SC route, have been
determined to be bioequivalent. Based on a population pharmacokinetics analysis
of lyophilized LEUKINE data, the mean Cmax after a 7 mcg/kg SC dose (equivalent
to a 250 mcg/m² dose in a 70 kg human with a body surface area of 1.96) was 3.03
ng/mL and mean AUC0-24 was 21.3 ng•h/mL (Table 4). There is no accumulation of
GMCSF after repeat SC dosing and steady state conditions are met after a single
SC dose.
Table 4: Sargramostim serum Cmax and AUC Exposure
(CV%) in Humans after Subcutaneous Administration
Data type |
Sargramostim dose |
Formulation |
Number of healthy subjects |
AUC (CV%) (ng-h/mL ) |
Cmax (CV%) (ng/mL) |
Observed |
250 mcg/m² a |
LEUKINE injection |
29 29 |
21.9 (28.1%) 20.3 (32.4%) |
3.75 (45.5%) 3.24 (50.5%) |
Observed |
6.5 mcg/kg |
Lyophilized LEUKINE |
39 |
20.4 (28.7%) |
3.15 (35.2%) |
Population PK model simulation |
7 mcg/kg |
Lyophilized LEUKINE |
500 |
21.3 (32.6) |
3.03 (31.0) |
a 250 mcg/m² is approximately 7 mcg/kg in 70 kg patient with a body surface area of 1.96 M2 |
Absorption
After SC administration GM-CSF was detected in the serum
early (15 min) and reached maximum serum concentrations between 2.5 and 4 h.
The absolute bioavailability with the SC route, when compared to the IV route,
was 75%.
Distribution
The observed volume of distribution after IV (Vz)
administration was 96.8.
Elimination
When a 500 mcg dose of LEUKINE (injection) was
administered IV over two hours to healthy volunteers, the mean terminal
elimination half-life was approximately 3.84 h and the mean clearance rate was
approximately 17.2 L/h. When LEUKINE (lyophilized product) was administered SC
to healthy adult volunteers, GM-CSF and had a terminal elimination half-life of
1.4 h. The observed total body clearance/subcutaneous bioavailability (CL/F)
was 23 L/h. Specific metabolism studies were not conducted, because LEUKINE is
a protein and is expected to degrade to small peptides and individual amino
acids.
Special Populations
Adult patients acutely exposed to myelosuppressive doses
of radiation (H-ARS)
The pharmacokinetics of sargramostim are not available in
adult patients acutely exposed to myelosuppressive doses of radiation. Pharmacokinetic
data in irradiated and non-irradiated nonhuman primates and in healthy human
adults were used to derive human doses for patients acutely exposed to
myelosuppressive doses of radiation. Modeling and simulation of the healthy human
adult pharmacokinetic data indicate that sargramostim Cmax and AUC exposures at
a LEUKINE dose of 7 mcg/kg in patients acutely exposed to myelosuppressive
doses of radiation are expected to exceed sargramostim Cmax (97.6% of patients)
and AUC (100% of patients) exposures at a LEUKINE dose of 7 mcg/kg in non-human
primates.
Pediatric patients acutely exposed to myelosuppressive
doses of radiation (H-ARS)
The pharmacokinetics of sargramostim was not available in
pediatric patients acutely exposed to myelosuppressive doses of radiation. The
pharmacokinetics of sargramostim in pediatric patients after being exposed to
myelosuppressive doses of radiation were estimated by scaling the adult population
pharmacokinetic model to the pediatric population. The model-predicted mean AUC0-
24 values at 7, 10, and 12 mcg/kg doses of LEUKINE in pediatric patients
weighing greater than 40 kg (~adolescents), 15 to 40 kg (~young children), and
0 to less than 15 kg (~newborns to toddlers), respectively, were similar to AUC
values in adults after a 7 mcg/kg dose.
Clinical Studies
Following Induction Chemotherapy For Acute Myelogenous
Leukemia
The efficacy of LEUKINE in the treatment of AML was
evaluated in a multicenter, randomized, double-blind placebo-controlled trial
(study 305) of 99 newly-diagnosed adult patients, 55-70 years of age, receiving
induction with or without consolidation. A combination of standard doses of
daunorubicin (days 1-3) and ara-C (days 1-7) was administered during induction
and high dose ara-C was administered days 1-6 as a single course of
consolidation, if given. Bone marrow evaluation was performed on day 10
following induction chemotherapy. If hypoplasia with <5% blasts was not
achieved, patients immediately received a second cycle of induction chemotherapy.
If the bone marrow was hypoplastic with <5% blasts on day 10 or four days following
the second cycle of induction chemotherapy, LEUKINE (250 mcg/m²/day) or placebo
was given intravenously over four hours each day, starting four days after the
completion of chemotherapy. Study drug was continued until an ANC ≥1500 cells/mm³
for three consecutive days was attained or a maximum of 42 days. LEUKINE or
placebo was also administered after the single course of consolidation
chemotherapy if delivered (ara-C 3-6 weeks after induction following neutrophil
recovery). Study drug was discontinued immediately if leukemic regrowth occurred.
LEUKINE significantly shortened the median duration of
ANC <500 cells/mm³ by 4 days and <1000 cells/mm³ by 7 days following
induction (see Table 5). Of patients receiving LEUKINE, 75% achieved ANC
>500 cells/mm³ by day 16, compared to day 25 for patients receiving placebo.
The proportion of patients receiving one cycle (70%) or two cycles (30%) of
induction was similar in both treatment groups. LEUKINE significantly shortened
the median times to neutrophil recovery whether one cycle (12 vs. 15 days) or
two cycles (14 vs. 23 days) of induction chemotherapy was administered. Median
times to platelet (>20,000 cells/mm³) and RBC transfusion independence were
not significantly different between treatment groups.
Table 5: Hematological Recovery (in Days) in Patients with
AML: Induction
Dataset |
LEUKINE
n=52a
Median (25%, 75%) |
Placebo
n=47
Median (25%, 75%) |
p-valueb |
ANC >500/mm³ c |
13 (11, 16) |
17 (13, 25) |
0.009 |
ANC >1000/mm³ d |
14 (12, 18) |
21(13, 34) |
0.003 |
PLT >20,000/mm³ e |
11 (7, 14) |
12 (9, >42) |
0.10 |
RBCf |
12 (9, 24) |
14 (9, 42) |
0.53 |
a Patients with missing data censored
b p = Generalized Wilcoxon
c 2 patients on LEUKINE and 4 patients on placebo had missing values
d 2 patients on LEUKINE and 3 patients on placebo had missing values
e 4 patients on placebo had missing values
f 3 patients on LEUKINE and 4 patients on placebo had missing values |
During the consolidation phase of treatment, LEUKINE did
not shorten the median time to recovery of ANC to 500 cells/mm³ (13 days) or
1000 cells/mm³ (14.5 days) compared to placebo. There were no significant
differences in time to platelet and RBC transfusion independence.
The incidence of severe infections and deaths associated
with infections was significantly reduced in patients who received LEUKINE.
During induction or consolidation, 27 of 52 patients receiving LEUKINE and 35
of 47 patients receiving placebo had at least one grade 3, 4 or 5 infection
(p=0.02). Twenty-five patients receiving LEUKINE and 30 patients receiving placebo
experienced severe and fatal infections during induction only. There were
significantly fewer deaths from infectious causes in the LEUKINE arm (3 vs. 11,
p=0.02). The majority of deaths in the placebo group were associated with
fungal infections with pneumonia as the primary infection.
Autologous Peripheral Blood Progenitor Cell Mobilization And
Collection
A retrospective review was conducted of data from adult
patients with cancer undergoing collection of peripheral blood progenitor cells
(PBPC) at a single transplant center. Mobilization of PBPC and myeloid
reconstitution post transplant were compared between four groups of patients
(n=196) receiving LEUKINE for mobilization and a historical control group who
did not receive any mobilization treatment [progenitor cells collected by
leukapheresis without mobilization (n=100)]. Sequential cohorts received
LEUKINE. The cohorts differed by dose (125 or 250 mcg/m²/day), route (IV over
24 hours or SC) and use of LEUKINE post transplant. Leukaphereses were
initiated for all mobilization groups after the WBC reached 10,000 cells/mm³.
Leukaphereses continued until both a minimum number of mononucleated cells (MNC)
were collected (6.5 or 8.0 Ã 108/kg body weight) and a minimum number of
aphereses (5-8) were performed. Both minimum requirements varied by treatment
cohort and planned conditioning regimen. If subjects failed to reach a WBC of
10,000 cells/mm³ by day 5, another cytokine was substituted for LEUKINE.
Marked mobilization effects were seen in patients
administered the higher dose of LEUKINE (250 mcg/m²) either IV (n=63) or SC
(n=41). PBPCs from patients treated at the 250 mcg/m²/day dose had a
significantly higher number of granulocyte-macrophage colony-forming units
(CFU-GM) than those collected without mobilization. The mean value after
thawing was 11.41 Ã 104 CFU-GM/kg for all LEUKINE-mobilized patients, compared
to 0.96 Ã 104/kg for the non-mobilized group. A similar difference was observed
in the mean number of erythrocyte burst-forming units (BFU-E) collected (23.96
à 104/kg for patients mobilized with 250 mcg/m² doses of LEUKINE administered
SC vs. 1.63 Ã 104/kg for non-mobilized patients).
A second retrospective review of data from patients
undergoing PBPC at another single transplant center was also conducted. LEUKINE
was given SC at 250 mcg/m²/day once a day (n=10) or twice a day (n=21) until
completion of apheresis. Apheresis was begun on day 5 of LEUKINE administration
and continued until the targeted MNC count of 9 Ã 108/kg or CD34+ cell count of
1 Ã 106/kg was reached. There was no difference in CD34+ cell count in patients
receiving LEUKINE once or twice a day.
Autologous Peripheral Blood Progenitor Cell And Bone
Marrow Transplantation
The efficacy of LEUKINE to accelerate myeloid
reconstitution following autologous PBPC was established in the retrospective
review above. After transplantation, mobilized subjects had shorter times to
neutrophil recovery and fewer days between transplantation and the last
platelet transfusion compared to non-mobilized subjects. Neutrophil recovery
(ANC >500 cells/mm³) was more rapid in patients administered LEUKINE
following PBPC transplantation with LEUKINE-mobilized cells (see Table 6).
Mobilized patients also had fewer days to the last platelet transfusion and
last RBC transfusion, and a shorter duration of hospitalization than did non-mobilized
subjects.
Table 6: ANC and Platelet Recovery after PBPC
Transplantation
|
LEUKINE Route for Mobilization |
Post transplant LEUKINE |
Median Day ANC >500 cells/mm³ |
Median Day of Last platelet transfusion |
No Mobilization |
- |
No |
29 |
28 |
LEUKINE 250 mcg/m² |
IV |
No |
21 |
24 |
IV |
Yes |
12 |
19 |
SC |
Yes |
12 |
17 |
The efficacy of LEUKINE on time to myeloid reconstitution
following autologous BMT was established by three single-center, randomized,
placebo-controlled and double-blinded studies (studies 301, 302, and 303) in
adult and pediatric patients undergoing autologous BMT for lymphoid
malignancies. A total of 128 patients (65 LEUKINE, 63 placebo) were enrolled in
these three studies. The median age was 38 years (range 3-62 years), and 12
patients were younger than 18 years of age. The majority of the patients had
lymphoid malignancy (87 NHL, 17 ALL), 23 patients had Hodgkin lymphoma, and one
patient had AML. In 72 patients with NHL or ALL, the bone marrow harvest was
purged with one of several monoclonal antibodies prior to storage. No chemical
agent was used for in vitro treatment of the bone marrow. Preparative regimens
in the three studies included cyclophosphamide (total dose 120-150 mg/kg) and
total body irradiation (total dose 1,200-1,575 rads). Other regimens used in
patients with Hodgkin's disease and NHL without radiotherapy consisted of three
or more of the following in combination (expressed as total dose): cytosine
arabinoside (400 mg/m²) and carmustine (300 mg/m²), cyclophosphamide (140-150
mg/kg), hydroxyurea (4.5 grams/m²), and etoposide (375- 450 mg/m²).
Compared to placebo, administration of LEUKINE in two
studies (study 301: 44 patients, 23 patients treated with LEUKINE, and study
303: 47 patients, 24 treated with LEUKINE) significantly improved the following
hematologic and clinical endpoints: time to neutrophil recovery, duration of
hospitalization and infection experience or antibacterial usage. In the third study
(study 302: 37 patients who underwent autologous BMT, 18 treated with LEUKINE)
there was a positive trend toward earlier myeloid engraftment in favor of
LEUKINE. This latter study differed from the other two in having enrolled a
large number of patients with Hodgkin lymphoma who had also received extensive
radiation and chemotherapy prior to harvest of autologous bone marrow. In the
following combined analysis of the three studies, these two subgroups (NHL and
ALL vs. Hodgkin lymphoma) are presented separately.
Patients With Lymphoid Malignancy (Non-Hodgkin's Lymphoma
And Acute Lymphoblastic Leukemia)
Neutrophil recovery (ANC ≥500 cells/mm³) in 54
patients with NHL or ALL receiving LEUKINE on Studies 301, 302 and 303 was
observed on day 18, and on day 24 in 50 patients treated with placebo (see
Table 7). The median duration of hospitalization was six days shorter for the
LEUKINE group than for the placebo group. Median duration of infectious
episodes (defined as fever and neutropenia; or two positive cultures of the
same organism; or fever >38°C and one positive blood culture; or clinical
evidence of infection) was three days less in the group treated with LEUKINE.
The median duration of antibacterial administration in the post transplantation
period was four days shorter for the patients treated with LEUKINE than for placebo-treated
patients.
Table 7: Autologous BMT: Combined Analysis from
Placebo-Controlled Clinical Trials of Responses in Patients with NHL and
ALLMedian Values (days)
|
ANC ≥500 cells /mm³ |
ANC ≥1000 cells/mm³ |
Duration of Hospitalization |
Duration of Infection |
Duration of Antibacterial Therapy |
LEUKINE n=54 |
18a,b |
2b |
25 a |
1 a |
21 a |
Placebo n=50 |
24 |
32 |
31 |
4 |
25 |
a p <0.05 Wilcoxon or Cochran-Mantel-Haenszel
RIDIT chi-squared
b p <0.05 Log rank |
Allogeneic Bone Marrow Transplantation
A multicenter, randomized, placebo-controlled, and
double-blinded study (study 9002) was conducted to evaluate the safety and
efficacy of LEUKINE for promoting hematopoietic reconstitution following
allogeneic BMT. A total of 109 adult and pediatric patients (53 LEUKINE, 56
placebo) were enrolled in the study. The median age was 34.7 years (range 2.2- 65.1
years). Twenty-three patients (11 LEUKINE, 12 placebo) were 18 years old or
younger. Sixty-seven patients had myeloid malignancies (33 AML, 34 CML), 17 had
lymphoid malignancies (12 ALL, 5 NHL), three patients had Hodgkin's disease,
six had multiple myeloma, nine had myelodysplastic disease, and seven patients
had aplastic anemia. In 22 patients at one of the seven study sites, bone
marrow harvests were depleted of T cells. Preparative regimens included
cyclophosphamide, busulfan, cytosine arabinoside, etoposide, methotrexate, corticosteroids,
and asparaginase. Some patients also received total body, splenic, or
testicular irradiation. Primary GVHD prophylaxis was cyclosporine and a
corticosteroid.
Accelerated myeloid engraftment was associated with
significant laboratory and clinical benefits. Compared to placebo, administration
of LEUKINE significantly improved the following: time to neutrophil
engraftment, duration of hospitalization, number of patients with bacteremia,
and overall incidence of infection (see Table 8).
Table 8: Allogeneic BMT: Analysis of Data from
Placebo-Controlled Clinical Trial Median Values (days or number of patients)
|
ANC ≥ 500/mm³ |
ANC ≥ 1000/mm³ |
Number of Patients with Infections |
Number of Patients with Bacteremia |
Days of Hospitalization |
LEUKINE n=53 |
13a |
14 a |
30 a |
9b |
25 a |
Placebo n=56 |
17 |
19 |
42 |
19 |
26 |
a p <0.05 generalized Wilcoxon test
b p <0.05 simple chi-square test |
Median time to myeloid recovery (ANC ≥500
cells/mm³) in 53 patients receiving LEUKINE was 4 four days less than in 56
patients treated with placebo (see Table 8). The numbers of patients with
bacteremia and infection were significantly lower in the LEUKINE group compared
to the placebo group (9/53 versus 19/56 and 30/53 versus 42/56, respectively).
There were a number of secondary laboratory and clinical endpoints. Of these,
only the incidence of severe (grade 3/4) mucositis was significantly improved
in the LEUKINE group (4/53) compared to the placebo group (16/56) at p<0.05.
LEUKINE-treated patients also had a shorter median duration of post transplant
IV antibiotic infusions, and a shorter median number of days to last platelet
and RBC transfusions compared to placebo patients, but none of these
differences reached statistical significance.
Treatment Of Delayed Neutrophil Recovery Or Graft Failure
After Allogeneic Or Autologous Bone Marrow Transplantation
A historically-controlled study (study 501) was conducted
in patients experiencing graft failure following allogeneic or autologous BMT
to determine whether LEUKINE improved survival after BMT failure.
- Three categories of patients were eligible for this
study:
- patients displaying a delay in neutrophil recovery (ANC ≤100
cells/mm³ by day 28 post transplantation);
- patients displaying a delay in neutrophil recovery (ANC
≤100 cells/mm³ by day 21 post transplantation) and who had evidence of an
active infection; and
patients who lost their marrow graft after a transient neutrophil
recovery (manifested by an average of ANC ≥500 cells/mm³ for at least one
week followed by loss of engraftment with ANC <500 cells/mm³ for at least
one week beyond day 21 post transplantation).
A total of 140 eligible adult and pediatric patients from
35 institutions were treated with LEUKINE and evaluated in comparison to 103
historical control patients from a single institution. One hundred sixty-three
patients had lymphoid or myeloid leukemia, 24 patients had NHL, 19 patients had
Hodgkin's disease and 37 patients had other diseases, such as aplastic anemia,
myelodysplasia or non-hematologic malignancy. The majority of patients (223 out
of 243) had received prior chemotherapy with or without radiotherapy and/or
immunotherapy prior to preparation for transplantation. The median age of
enrolled patients was 27 years (range 1-66 years). Thirty-seven patients were
younger than 18 years of age.
One hundred-day survival was improved in favor of the
patients treated with LEUKINE for graft failure following either autologous or
allogeneic BMT. In addition, the median survival was improved by greater than
two-fold. The median survival of patients treated with LEUKINE after autologous
failure was 474 days versus 161 days for the historical patients. Similarly,
after allogeneic failure, the median survival was 97 days with LEUKINE
treatment and 35 days for the historical controls. Improvement in survival was
better in patients with fewer impaired organs. The Multiple Organ Failure (MOF)
score is a clinical and laboratory assessment of seven major organ systems:
cardiovascular, respiratory, gastrointestinal, hematologic, renal, hepatic and
neurologic.Median survival by MOF category is presented in Table 9.
Table 9: Median Survival by Multiple Organ Failure
(MOF) Category Median Survival (days)
|
MOF ≤2 Organs |
MOF >2 Organs |
MOF (Composite of both groups) |
Autologous BMT |
LEUKINE |
474 (n=58) |
78.5 (n=10) |
474 (n=68) |
Historical |
165 (n=14) |
39 (n=3) |
161 (n=17) |
Allogeneic BMT |
LEUKINE |
174 (n=50) |
27 (n=22) |
97 (n=72) |
Historical |
52.5 (n=60) |
15.5 (n=26) |
35 (n=86) |
Acute Exposure To Myelosuppressive Doses of Radiation
(H-ARS)
Efficacy studies of LEUKINE could not be conducted in
humans with acute radiation syndrome for ethical and feasibility reasons. The
use of LEUKINE in the H-ARS indication was based on efficacy studies conducted
in animals and data supporting LEUKINE's effect on severe neutropenia in
patients undergoing autologous or allogeneic BMT following myelosuppressive chemotherapy
with or without total body irradiation, and in patients with acute myelogenous leukemia
following myelosuppressive chemotherapy [see DOSAGE AND ADMINISTRATION].
The recommended dose of LEUKINE for adults exposed to
myelosuppressive doses of radiation is 7 mcg/kg as a single daily SC injection [see
DOSAGE AND ADMINISTRATION]. The 7 mcg/kg dosing regimen is based on
population modeling and simulation analyses. The sargramostim exposure
associated with the 7 mcg/kg adult dose is expected to be higher than
sargramostim exposure in the nonclinical efficacy study and therefore are
expected to provide sufficient pharmacodynamic activity to treat humans exposed
to myelosuppressive doses of radiation [see CLINICAL PHARMACOLOGY]. The
safety of LEUKINE at a dose of 250 mcg/m²/day (approximately 7 mcg/kg) has been
assessed on the basis of clinical experience in myeloid reconstitution in
patients after autologous or allogeneic BMT, and in patients with AML [see ADVERSE
REACTIONS].
The efficacy of LEUKINE was studied in a randomized,
blinded, placebo-controlled study in a nonhuman primate model of radiation
injury. Rhesus macaques (50% male) were randomized to a control (n = 36) or
treated (n = 36) group. Animals were exposed to total body irradiation at a dose
that would be lethal in 50% to 60% of animals (655 cGy) by day 60 post
irradiation (lethal dose [LD]50-60/60). Starting 48 ± 1 hour after irradiation,
animals received daily SC injections of placebo (sterile water for injection,
USP) or LEUKINE (7 mcg/kg/day). Blinded treatment was stopped when one of the
following criteria was met: ANC ≥1,000 cells/mm³ for 3 consecutive days
or if the ANC ≥10,000 cells/mm³. Animals received minimal supportive care
that included a prophylactic antibiotic, antiemetic, analgesics and parenteral
fluids. No whole blood, blood products or individualized antibiotics were
provided.
LEUKINE significantly (p=0.0018) increased survival at
day 60 in irradiated nonhuman primates: 78% survival (28/36) in the LEUKINE
group compared to 42% survival (15/36) in the control group.
In the same study, an exploratory cohort of 36 rhesus
macaques randomized to control (n=18) or treated (n=18) was exposed to total
body irradiation at a dose that would be lethal in 70-80% of animals (713 cGY)
by day 60 post irradiation. LEUKINE increased survival at day 60 in irradiated
nonhuman primates: 61% survival (11/18) in the LEUKINE group compared to 17% survival
(3/18) in the control group.