CLINICAL PHARMACOLOGY
Mechanism Of Action
Somatropin (as well as endogenous growth hormone) binds
to dimeric growth hormone receptors located within the cell membranes of target
tissue cells resulting in intracellular signal transduction and a host of
pharmacodynamic effects. Some of these pharmacodynamic effects are primarily mediated
by insulin-like growth factor (IGF-1) produced in the liver and also locally
(e.g., skeletal growth, protein synthesis), while others are primarily a
consequence of the direct effects of somatropin (e.g., lipolysis) [see Pharmacodynamics].
Pharmacodynamics
In vitro and in vivo preclinical and clinical testing
have demonstrated that Nutropin AQ is therapeutically equivalent to
pituitary-derived hGH. Pediatric patients who lack adequate endogenous growth
hormone (GH) secretion, patients with chronic kidney disease (CKD), and
patients with Turner syndrome (TS) that were treated with Nutropin AQ or
Nutropin resulted in an increase in growth rate and an increase in IGF-1 levels
similar to that seen with pituitary-derived hGH.
Tissue Growth
- Skeletal Growth: Nutropin AQ stimulates
skeletal growth in pediatric patients with growth failure due to a lack of
adequate secretion of endogenous GH or secondary to CKD and in patients with
TS. Skeletal growth is accomplished at the epiphyseal plates at the ends of a
growing bone. Growth and metabolism of epiphyseal plate cells are directly
stimulated by GH and one of its mediators, IGF-I. Serum levels of IGF-I are low
in children and adolescents who are GHD, but increase during treatment with
somatropin. In pediatric patients, new bone is formed at the epiphyses in
response to GH and IGF-I. This results in linear growth until these growth
plates fuse at the end of puberty.
- Cell Growth: Treatment with somatropin results
in an increase in both the number and the size of skeletal muscle cells.
- Organ Growth: GH influences the size of
internal organs, including kidneys, and increases red cell mass. Treatment of
hypophysectomized or genetic dwarf rats with somatropin results in organ growth
that is proportional to the overall body growth. In normal rats subjected to
nephrectomy-induced uremia, somatropin promoted skeletal and body growth.
Protein Metabolism
Linear growth is facilitated in part by GH-stimulated
protein synthesis. This is reflected by nitrogen retention as demonstrated by a
decline in urinary nitrogen excretion and blood urea nitrogen (BUN) during
somatropin therapy.
Carbohydrate Metabolism
GH is a modulator of carbohydrate metabolism. For
example, patients with inadequate secretion of GH sometimes experience fasting
hypoglycemia that is improved by treatment with Nutropin AQ. Somatropin therapy
may decrease insulin sensitivity. Untreated patients with CKD and TS have an increased
incidence of glucose intolerance. Administration of somatropin to adults or
children resulted in increases in serum fasting and postprandial insulin
levels, more commonly in overweight or obese individuals. In addition, mean
fasting and postprandial glucose and hemoglobin A1C levels remained in the
normal range.
Lipid Metabolism
In GHD patients, administration of somatropin resulted in
lipid mobilization, reduction in body fat stores, increased plasma fatty acids,
and decreased plasma cholesterol levels.
Mineral Metabolism
The retention of total body potassium in response to
somatropin administration apparently results from cellular growth. Serum levels
of inorganic phosphorus may increase slightly in patients with inadequate
secretion of endogenous GH, CKD, or TS during Nutropin AQ therapy due to
metabolic activity associated with bone growth as well as increased tubular
reabsorption of phosphate by the kidney. Serum calcium is not significantly
altered in these patients. Sodium retention also occurs. Adults with
childhood-onset GHD show low bone mineral density (BMD). Nutropin AQ therapy results
in increases in serum alkaline phosphatase [see WARNINGS AND PRECAUTIONS].
Connective Tissue Metabolism
GH stimulates the synthesis of chondroitin sulfate and
collagen as well as the urinary excretion of hydroxyproline.
Pharmacokinetics
Absorption
The absolute bioavailability of somatropin after
subcutaneous administration in healthy adult males has been determined to be 81
±20%. The mean terminal t½ after subcutaneous administration is significantly
longer than that seen after intravenous administration (2.1 ± 0.43 hours vs.
19.5 ± 3.1 minutes) indicating that the subcutaneous absorption of the compound
is slow and rate-limiting.
Distribution
Animal studies with somatropin showed that GH localizes
to highly perfused organs, particularly the liver and kidney. The volume of
distribution at steady state for somatropin in healthy adult males is about 50
mL/kg body weight, approximating the serum volume.
Metabolism
Both the liver and kidney have been shown to be important
metabolizing organs for GH. Animal studies suggest that the kidney is the
dominant organ of clearance. GH is filtered at the glomerulus and reabsorbed in
the proximal tubules. It is then cleaved within renal cells into its
constituent amino acids, which return to the systemic circulation.
Elimination
The mean terminal t½ after intravenous
administration of somatropin in healthy adult males is estimated to be 19.5 ±
3.1 minutes. Clearance of rhGH after intravenous administration in healthy adults
and children is reported to be in the range of 116-174 mL/hr/kg.
Bioequivalence of Formulations
Nutropin AQ has been determined to be bioequivalent to
Nutropin based on the statistical evaluation of area under the curve (AUC) and
maximum concentration (Cmax ).
Special Populations
Pediatric: Available literature data
suggests that somatropin clearances are similar in adults and children.
Geriatrics: Limited published data suggest
that the plasma clearance and average steady-state plasma concentration of
somatropin may not be different between young and elderly patients.
Race: Reported values for half-lives for
endogenous GH in normal adult black males are not different from observed
values for normal adult white males. No data for other races are available.
Growth Hormone Deficiency: Reported values
for clearance of somatropin in adults and children with GHD range 138-245
mL/hr/kg and are similar to those observed in healthy adults and children. Mean
terminal t½ values following intravenous and subcutaneous
administration in adult and pediatric GHD patients are also similar to those
observed in healthy adult males.
Chronic Kidney Disease: Children and adults
with CKD and end-stage renal disease (ESRD) tend to have decreased clearance
compared to normals. In a study with six pediatric patients 7 to 11 years of
age, the clearance of Nutropin was reduced by 21.5% and 22.6% after the
intravenous infusion and subcutaneous injection, respectively, of 0.05 mg/kg of
Nutropin compared to normal healthy adults. Endogenous GH production may also
increase in some individuals with ESRD. However, no somatropin accumulation has
been reported in children with CKD or ESRD dosed with current regimens.
Turner Syndrome: No pharmacokinetic data
are available for exogenously administered somatropin. However, reported
half-lives, absorption, and elimination rates for endogenous GH in this
population are similar to the ranges observed for normal subjects and GHD
populations.
Hepatic Insufficiency: A reduction in
somatropin clearance has been noted in patients with severe liver dysfunction.
The clinical significance of this decrease is unknown.
Gender: No gender-specific pharmacokinetic studies
have been done with Nutropin AQ. The available literature indicates that the
pharmacokinetics of somatropin are similar in men and women.
Table 2 : Summary of Nutropin AQ
Pharmacokinetic Parameters in Healthy Adult Males 0.1 mg (approximately 0.3 IUa)/kg
SC
|
Cmax (μg/L) |
Tmax (hr) |
t½ (hr) |
AUC 0-∞ (μg•hr/L) |
CL/F sc (mL/[hr• kg]) |
MEANb |
71.1 |
3.9 |
2.3 |
677 |
150 |
CV% |
17 |
56 |
18 |
13 |
13 |
aBased on current International Standard of 3 IU = 1 mg.
bn = 36.
Abbreviations: AUC 0-∞ = area under the curve, C max =maximum
concentration, CL/F sc = systemic clearance, CV% = coefficient of variation in
%; SC = subcutaneous, F sc = subcutaneous bioavailability (not determined), t ½= half-life. |
Figure 1 : Single Dose Mean Growth Hormone Concentrations in Healthy
Adult Males
Clinical Studies
Pubertal Patients With Growth
Hormone Deficiency (GHD)
One open label, multicenter,
randomized clinical trial of two dosages of Nutropin was performed in pubertal
patients with GHD. Ninety-seven patients (mean age 13.9 years, 83 male, 14
female) currently being treated with approximately 0.3 mg/kg/wk of GH were
randomized to 0.3 mg/kg/wk or 0.7 mg/kg/wk Nutropin doses. All patients were
already in puberty (Tanner stage ≥ 2) and had bone ages ≤ 14 years
in males or ≤ 12 years in females. Mean baseline height standard deviation
score (SDS) was -1.3.
The mean last measured height
in all 97 patients after a mean duration of 2.7 ± 1.2 years, by analysis of
covariance (ANCOVA) adjusting for baseline height, is shown below.
Table 3 :Last Measured Height* by Sex and Nutropin Dose for Pubertal
Patients with GHD
|
Age (yr) |
Last Measured Height* (cm) |
Height Difference Between Groups (cm) |
0.3 mg/kg/wk |
0.7 mg/kg/wk |
Mean ± SD (range) |
Mean ± SD |
Mean ± SD |
Mean ± SE |
Male |
17.2 ± 1.3 |
170.9 ± 7.9 |
174.5 ± 7.9 |
3.6 ± 1.7 |
(13.6 to 19.4) |
(n=42) |
(n= 41) |
|
Female |
15.8 ± 1.8 |
154.7 ± 6.3 |
157.6 ± 6.3 |
2.9 ± 3.4 |
(11.9 to 19.3) |
(n=7) |
(n = 7) |
|
*Adjusted for baseline height |
The mean height SDS at last
measured height (n = 97) was -0.7 ± 1.0 in the 0.3 mg/kg/wk group and
- 0.1 ± 1.2 in the 0.7 mg/kg/wk group. For patients completing 3.5 or
more years (mean 4.1 years) of Nutropin treatment (15/49 patients in the 0.3
mg/kg/wk group and 16/48 patients in the 0.7 mg/kg/wk group), the mean last
measured height was 166.1 ± 8.0 cm in the 0.3 mg/kg/wk group and 171.8 ± 7.1 cm
in the 0.7 mg/kg/wk group, adjusting for baseline height and sex.
The mean change in bone age was
approximately one year for each year in the study in both dose groups. Patients
with baseline height SDS above -1.0 were able to attain normal adult
heights with the 0.3 mg/kg/wk dose of Nutropin (mean height SDS at near-adult
height = -0.1, n = 15).
Thirty-one patients had bone
mineral density (BMD) determined by dual energy x-ray absorptiometry (DEXA)
scans at study conclusion. The two dose groups did not differ significantly in
mean SDS for total body BMD (-0.9 ± 1.9 in the 0.3 mg/kg/wk group vs.
-0.8 ± 1.2 in the 0.7 mg/kg/wk group, n = 20) or lumbar spine BMD
(-1.0 ± 1.0 in the 0.3 mg/kg/wk group vs. -0.2 ± 1.7 in the 0.7
mg/kg/wk group, n = 21).
Over a mean duration of 2.7
years, patients in the 0.7 mg/kg/wk group were more likely to have IGF-I values
above the normal range than patients in the 0.3 mg/kg/wk group (27.7% vs. 9.0%
of IGF-I measurements for individual patients). The clinical significance of
elevated IGF-I values is unknown.
Pediatric Patients With Growth
Failure Secondary To Chronic Kidney Disease (CKD)
Two multicenter, randomized, controlled clinical trials
were conducted to determine whether treatment with Nutropin prior to renal
transplantation in patients with CKD could improve their growth rates and
height deficits. One study was a double-blind, placebo-controlled trial and the
other was an open-label, randomized trial. The dose of Nutropin in both
controlled studies was 0.05 mg/kg/day (0.35
mg/kg/week) administered daily by subcutaneous injection. Combining the data
from those patients completing two years in the two controlled studies results
in 62 patients treated with Nutropin and 28 patients in the control groups
(either placebo-treated or untreated). The mean first year growth rate was 10.8
cm/yr for Nutropin-treated patients, compared with a mean growth rate of 6.5
cm/yr for placebo/untreated controls (p < 0.00005). The mean second year
growth rate was 7.8 cm/yr for the Nutropin-treated group, compared with 5.5
cm/yr for controls (p < 0.00005). There was a significant increase in mean
height SDS in the Nutropin group (-2.9 at baseline to -1.5 at Month
24, n = 62) but no significant change in the controls (-2.8 at baseline to
-2.9 at Month 24, n = 28). The mean third year growth rate of 7.6 cm/yr
in the Nutropin-treated patients (n = 27) suggests that Nutropin stimulates
growth beyond two years. However, there are no control data for the third year
because control patients crossed over to Nutropin treatment after two years of
participation. The gains in height were accompanied by appropriate advancement
of skeletal age. These data demonstrate that Nutropin therapy improves growth
rate and corrects the acquired height deficit associated with CKD.
The North American Pediatric
Renal Transplant Cooperative Study (NAPRTCS) has reported data for growth
post-transplant in children who did not receive GH prior to transplantation as
well as children who did receive Nutropin during the clinical trials prior to
transplantation. The average change in height SDS during the initial two years
post-transplant was 0.15 for the 2,391 patients who did not receive GH
pre-transplant and 0.28 for the 57 patients who did1. For patients
who were followed for 5 years post-transplant, the corresponding changes in
height SDS were also similar between groups.
Pediatric Patients With Turner
Syndrome (TS)
Three US studies, two
long-term, open-label, multicenter, historically controlled studies (Studies 1 and
2), and one long-term, randomized, dose-response study (Study 3) and one
Canadian, long-term, randomized, open-label, multicenter, concurrently
controlled study, were conducted to evaluate the efficacy of somatropin
treatment of short stature due to TS.
In the US Studies 1 and 2, the
effect of long-term GH treatment (0.375 mg/kg/week given either 3 times per
week or daily) on adult height was determined by comparing adult heights in the
treated patients with those of age-matched historical controls with TS who
received no growth-promoting therapy. In Study 1, estrogen treatment was
delayed until patients were at least age 14. GH therapy resulted in a mean
adult height gain of 7.4 cm (mean duration of GH therapy of 7.6 years) vs. matched
historical controls by ANCOVA.
In Study 2, patients treated
with early Nutropin therapy (before 11 years of age) were randomized to receive
estrogen-replacement therapy (conjugated estrogens, 0.3 mg escalating to 0.625
mg daily) at either age 12 or 15 years. Compared with matched historical
controls, early Nutropin therapy (mean duration of 5.6 years) combined with
estrogen replacement at age 12 years resulted in an adult height gain of 5.9 cm
(n = 26), whereas girls who initiated estrogen at age 15 years (mean duration
of Nutropin therapy 6.1 years) had a mean adult height gain of 8.3 cm (n = 29).
Patients who initiated Nutropin after age 11 (mean age 12.7 years; mean
duration of Nutropin therapy 3.8 years) had a mean adult height gain of 5.0 cm
(n = 51).
Thus, in Studies 1 and 2, the
greatest improvement in adult height was observed in patients who received
early GH treatment and estrogen after age 14 years.
In Study 3, a randomized,
blinded dose-response study, patients were treated from a mean age of 11.1
years for a mean duration of 5.3 years with a weekly GH dose of either 0.27
mg/kg or 0.36 mg/kg administered in divided doses 3 or 6 times weekly. The mean
near-final height of GH-treated patients was 148.7 ± 6.5 cm (n = 31). When
compared to historical control data, the mean gain in adult height was
approximately 5 cm.
The Canadian randomized study
compared near-adult height outcomes for GH-treated patients to those of a
concurrent control group who received no injections. The somatropin-treated
patients received a dosage of 0.3 mg/kg/week given in divided doses 6 times per
week from a mean age of 11.7 years for a mean duration of 4.7 years. Puberty
was induced with a standardized estrogen regimen initiated at 13 years of age
for both treatment groups. The somatropin-treated group (n =27) attained a mean
(±SD) near final height of 146.0 ± 6.2 cm; the untreated control group (n =19)
attained a near final height of 142.1 ± 4.8 cm. By ANCOVA (with adjustments for
baseline height and mid-parental height), the effect of GH-treatment was a mean
height increase of 5.4 cm (p = 0.001).
In summary, patients with TS
(total n = 181 from the 4 studies above) treated to adult height achieved
statistically significant average height gains ranging from 5.0-8.3 cm.
Table 4 : Summary of Efficacy Results in Turner Syndromea
Study |
Group |
Study Designb |
N at Adult Height |
GH Age (yr) |
Estrogen Age (yr) |
GH Duration (yr) |
Adult Height Gain (cm)c |
US 1 |
|
MHT |
17 |
9.1 |
15.2 |
7.6 |
7.4 |
US 2 |
A* |
MHT |
29 |
9.4 |
15.0 |
6.1 |
8.3 |
|
B* |
|
26 |
9.6 |
12.3 |
5.6 |
5.9 |
|
C* |
|
51 |
12.7 |
13.7 |
3.8 |
5.0 |
US 3 |
|
RDT |
31 |
11.1 |
8-13.5 |
5.3 |
~5d |
Canadian |
|
RCT |
27 |
11.7 |
13 |
4.7 |
5.4 |
aData shown are mean values.
bRCT: randomized controlled trial; MHT: matched historical
controlled trial; RDT: randomized dose-response trial.
cAnalysis
of covariance vs. controls.
dCompared with historical data.
* A = GH age < 11 yr, estrogen age 15 yr. B =GH age < 11 yr, estrogen age
12 yr. C = GH age > 11 yr, estrogen at Month 12. |
Pediatric Patient With Idiopathic
Short Stature (ISS)
A long-term, open-label,
multicenter study was conducted to examine the safety and efficacy of Nutropin
in pediatric patients with ISS, also called non-growth hormone deficient short
stature. For the first year, 122 pre-pubertal subjects over the age of 5 years
with stimulated serum GH ≥ 10 ng/mL were randomized into two treatment
groups of approximately equal size; one group was treated with Nutropin 0.3
mg/kg weekly divided into three doses per week and the other group served as
untreated controls. For the second and subsequent years of the study, all
subjects were re-randomized to receive the same total weekly dose of Nutropin
(0.3 mg/kg weekly) administered either daily or three times weekly. Treatment
with Nutropin was continued until a subject's bone age was > 15.0 years
(boys) or > 14.0 years (girls) and the growth rate was < 2 cm/yr, after
which subjects were followed until adult height was achieved. The mean baseline
values were: height SDS–2.8, IGF-I SDS -0.9, age 9.4 years, bone age 7.8 years,
growth rate 4.4 cm/yr, mid-parental target height SDS –0.7, and Bayley-Pinneau
predicted adult height SDS –2.3. Nearly all subjects had predicted adult height
that was less than mid-parental target height.
During the one-year controlled
phase of the study, the mean height velocity increased by 0.5 ± 1.8 cm (mean
±SD) in the no-treatment control group and by 3.1 ± 1.7 cm in the Nutropin
group (p < 0.0001). For the same period of treatment the mean height SDS
increased by 0.4 ± 0.2 and remained unchanged (0.0 ± 0.2) in the control group
(p < 0.001).
Of the 118 subjects who were
treated with Nutropin (70%) reached near-adult height (hereafter called adult
height) after 2-10 years of Nutropin therapy. Their last measured height,
including post-treatment follow-up, was obtained at a mean age of 18.3 years in
males and 17.3 years in females. The mean duration of therapy was 6.2 and 5.5
years, respectively. Adult height was greater than pretreatment predicted adult
height in 49 of 60 males (82%) and 19 of 23 females (83%). The mean difference
between adult height and pretreatment predicted adult height was 5.2 cm (2.0
inches) in males and 6.0 cm (2.4 inches) in females (p < 0.0001 for both).
The table (below) summarizes the efficacy data.
Table 5 : Long-Term Efficacy in ISS (Mean ± SD)
Characteristic |
Males
(n = 60) |
Females
(n=23) |
Adult height (cm) |
166.3 ± 5.8 |
153.1 ± 4.8 |
Pretreatment predicted adult height (cm) |
161.1 ± 5.5 |
147.1 ± 5.1 |
Adult height minus pretreatment predicted adult height (cm) |
+ 5.2 ± 5.0a |
+6.0 ± 5.0a |
Adult height SDS |
-1.5 ± 0.8 |
-1.6 ± 0.7 |
Pretreatment predicted adult height SDS |
-2.2 ± 0.8 |
-2.5 ± 0.8 |
Adult height minus pretreatment predicted adult height SDS |
+ 0.7 ± 0.7a |
+0.9 ± 0.8a |
ap < 0.0001 versus zero. |
Nutropin therapy resulted in an
increase in mean IGF-I SDS from –0.9 ± 1.0 to –0.2 ± 0.9 in Treatment Year 1.
During continued treatment, mean IGF-I levels remained close to the normal mean.
IGF-I SDS above + 2 occurred sporadically in 14 subjects.
Adult Growth Hormone Deficiency
Two multicenter, double-blind,
placebo-controlled clinical trials were conducted in growth  hormone-deficient
adults. Study 1 was conducted in subjects with adult-onset GHD (n = 166), mean  age
48.3 years, at doses of 0.0125 or 0.00625 mg/kg/day; doses of 0.025 mg/kg/day
were not  tolerated in these subjects. Study 2 was conducted in
previously treated subjects with  childhood-onset GHD
(n = 64), mean age 23.8 years, at randomly assigned doses of 0.025 or  0.0125
mg/kg/day. The studies were designed to assess the effects of replacement
therapy with  Nutropin on body composition.
Significant changes from baseline to Month 12 of
treatment in body composition (i.e., total body  %
fat mass, trunk % fat mass, and total body % lean mass by DEXA scan) were seen
in all Nutropin  groups in both studies (p < 0.0001 for change from
baseline and vs. placebo), whereas no statistically significant
changes were seen in either of the placebo groups. In the adult-onset study,
the Nutropin group improved mean total body fat from 35.0% to 31.5%,
mean trunk fat from 33.9% to 29.5%, and mean lean body mass from 62.2% to
65.7%, whereas the placebo group had mean changes of 0.2% or less (p = not significant). Due to the possible effect
of GH-induced fluid retention on DEXA measurements of lean body mass, DEXA
scans were repeated approximately 3 weeks after completion of therapy;
mean % lean body mass in the Nutropin group was 65.0%, a change of 2.8% from
baseline, compared with a change of 0.4% in the placebo group (p < 0.0001
between groups).
In the childhood-onset study, the high-dose Nutropin
group improved mean total body fat from 38.4% to 32.1%, mean trunk fat from
36.7% to 29.0%, and mean lean body mass from 59.1% to 65.5%; the low-dose
Nutropin group improved mean total body fat from 37.1% to 31.3%, mean trunk fat
from 37.9% to 30.6%, and mean lean body mass from 60.0% to 66.0%; the placebo
group had mean changes of 0.6% or less (p = not significant).
Table 6 : Mean Changes from Baseline to Month
12 in Proportion of Fat and Lean by DEXA for Adult-and Childhood-Onset GHD
Studies
Proportion |
Adult Onset (Study 1) |
Childhood Onset (Study 2) |
Placebo
(n=62) |
Nutropin
(n=63) |
Between- Groups t-test p-value |
Placebo
(n = 13) |
Nutropin 0.0125 mg/ kg/day
(n = 15) |
Nutropin 0.025 mg/ kg/day
(n = 15) |
Placebo vs. Pooled Nutropin t-test p-value |
Total body percent fat |
Baseline |
36.8 |
35.0 |
0.38 |
35.0 |
37.1 |
38.4 |
0.45 |
Month 12 |
36.8 |
31.5 |
— |
35.2 |
31.3 |
32.1 |
— |
Baseline to Month 12 change |
-0.1 |
-3.6 |
< 0.0001 |
+ 0.2 |
-5.8 |
-6.3 |
< 0.0001 |
Post-washout |
36.4 |
32.2 |
— |
NA |
NA |
NA |
— |
Baseline to postwashout change |
-0.4 |
-2.8 |
< 0.0001 |
NA |
NA |
NA |
— |
Trunk percent fat |
Baseline |
35.3 |
33.9 |
0.50 |
32.5 |
37.9 |
36.7 |
0.23 |
Month 12 |
35.4 |
29.5 |
— |
33.1 |
30.6 |
29.0 |
— |
Baseline to Month 12 change |
0.0 |
-4.3 |
< 0.0001 |
+ 0.6 |
-7.3 |
-7.6 |
< 0.0001 |
Post-washout |
34.9 |
30.5 |
— |
NA |
NA |
NA |
— |
Baseline to postwashout change |
-0.3 |
-3.4 |
— |
NA |
NA |
NA |
— |
Total body percent lean |
Baseline |
60.4 |
62.2 |
0.37 |
62.0 |
60.0 |
59.1 |
0.48 |
Month 12 |
60.5 |
65.7 |
— |
61.8 |
66.0 |
65.5 |
— |
Baseline to Month 12 change |
+0.2 |
+ 3.6 |
< 0.0001 |
-0.2 |
+ 6.0 |
+ 6.4 |
< 0.0001 |
Post-washout |
60.9 |
65.0 |
— |
NA |
NA |
NA |
— |
Baseline to postwashout change |
+ 0.4 |
+ 2.8 |
< 0.0001 |
NA |
NA |
NA |
— |
NA=not available |
In the adult-onset study, significant decreases from
baseline to Month 12 in low-density lipoprotein (LDL)
cholesterol and LDL:high-density lipoprotein (HDL) ratio were seen in the Nutropin
group compared to the placebo group, p < 0.02; there were no statistically
significant between-group differences in change from baseline to Month 12 in
total cholesterol, HDL cholesterol, or triglycerides. In the
childhood-onset study significant decreases from baseline toMonth 12 in total cholesterol, LDL cholesterol, and LDL:HDL
ratio were seen in the high-dose Nutropin group only, compared to the placebo
group, p < 0.05. There were no statistically significant between-group
differences in HDL cholesterol or triglycerides from baseline to Month 12.
In the childhood-onset study,
55% of the patients had decreased spine BMD (z-score < -1) at baseline.
The administration of Nutropin (n = 16) (0.025 mg/kg/day) for two years
resulted in increased spine BMD from baseline when compared to placebo (n = 13)
(4.6% vs. 1.0%, respectively, p < 0.03); a transient decrease in spine BMD
was seen at six months in the Nutropin-treated patients. Thirty-five percent of
subjects treated with this dose had supraphysiological levels of IGF-I at some
point during the study, which may carry unknown risks. No significant
improvement in total body BMD was found when compared to placebo. A lower GH
dose (0.0125 mg/kg/day) did not show significant increments in either of these
bone parameters when compared to placebo. No statistically significant effects
on BMD were seen in the adult-onset study where patients received GH (0.0125
mg/kg/day) for one year.
Muscle strength, physical
endurance, and quality of life measurements were not markedly abnormal at
baseline, and no statistically significant effects of Nutropin therapy were
observed in the two studies.
A subsequent 32-week,
multicenter, open-label, controlled clinical trial was conducted using Nutropin
AQ, Nutropin Depot, or no treatment in adults with both adult-onset and
childhood-onset GHD. Subjects were randomized into the three groups to evaluate
effects on body composition, including change in visceral adipose tissue (VAT)
as determined by computed tomography (CT) scan.
For subjects evaluable for
change in VAT in the Nutropin AQ (n = 44) and untreated (n =19) groups, the
mean age was 46.2 years and 78% had adult-onset GHD. Subjects in the Nutropin
AQ group were treated at doses up to 0.012 mg/kg per day in women (all of whom
received estrogen replacement therapy) and men under age 35 years, and up to
0.006 mg/kg per day in men over age 35 years.
The mean absolute change in VAT
from baseline to Week 32 was -10.7 cm² in the Nutropin AQ
group and + 8.4 cm² in the untreated group (p = 0.013 between
groups). There was a 6.7% VAT loss in the Nutropin AQ group (mean percent
change from baseline to Week 32) compared with a 7.5% increase in the untreated
group (p = 0.012 between groups). The effect of reducing VAT in adult GHD
patients with Nutropin AQ on long-term cardiovascular morbidity and mortality
has not been determined.
Table 7 : Visceral Adipose Tissue by Computed Tomography Scan:
Percent Change and Absolute Change from Baseline to Week 32 in Study 3
|
Nutropin AQ
(n = 44) |
Untreated
(n = 19) |
Treatment Difference (adjusted mean) |
p-value |
Baseline VAT (cm²) (mean) |
126.2 |
123.3 |
|
|
Change in VAT (cm²) (adjusted mean) |
- 10.7 |
+ 8.4 |
- 19.1 |
0.013a |
Percent change in VAT (adjusted mean) |
- 6.7 |
+7.5 |
- 14.2 |
0.012a |
aANCOVA using baseline VAT as a covariate
VAT = visceral adipose tissue. |