CLINICAL PHARMACOLOGY
Gonal-f® (follitropin alfa for injection) stimulates ovarian follicular growth in women who do not have
primary ovarian failure. FSH, the active component of Gonal-f® is the primary hormone responsible for
follicular recruitment and development. In order to effect final maturation of the follicle and ovulation in
the absence of an endogenous LH surge, human chorionic gonadotropin (hCG) must be given following
the administration of Gonal-f® when monitoring of the patient indicates that sufficient follicular
development has occurred. There is interpatient variability in response to FSH administration. The
physico-chemical, immunological, and biological activities of recombinant FSH (r-hFSH) are
comparable to those of pituitary and human menopausal urine-derived FSH. Gonal-f® (follitropin alfa
for injection), when administered with hCG, stimulates spermatogenesis in men with hypogonadotropic
hypogonadism. FSH, the active component of Gonal-f® , is the primary hormone responsible for
spermatogenesis.
Pharmacokinetics
Single dose pharmacokinetics of follitropin alfa were determined following intravenous, subcutaneous
and intramuscular administration of 150 IU Gonal-f® to 12 healthy, down-regulated female volunteers.
Steady-state pharmacokinetics were also determined in 12 healthy down-regulated female volunteers
who were administered a single daily dose of 150 IU for seven days. These pharmacokinetics were
confirmed in pituitary down-regulated women undergoing in vitro fertilization and embryo transfer
(IVF/ET), treated with FSH doses of up to 450 IU per day. Additionally, single dose pharmacokinetics
of follitropin alfa were determined following subcutaneous administration of 225 IU Gonal-f® to 12
healthy adult male volunteers in a cross-over design. Steady state pharmacokinetics were also
determined in 6 healthy adult male volunteers who were administered a single daily dose of 225 IU
Gonal-f® for 7 days. No significant difference in pharmacokinetics is expected in males versus females
when administered Gonal-f® subcutaneously. The pharmacokinetic parameters from these studies are
included in Table 1.
Table 1: Pharmacokinetic parameters (mean ± SD) of FSH following administration of Gonal-f®
Population |
Female |
|
Male |
Healthy Female Volunteers |
IVF/ET
Patients |
Healthy Male Volunteers |
Dose (IU) |
Single Dose
IM
(150 IU) |
Single Dose
SC
(150 IU) |
Multiple
Dose
SC
(7 × 150 IU) |
Multiple
Dose
SC
(5 × 225IU)* |
Single Dose
SC
(225IU) |
Multiple
Dose
SC
(7 × 225 IU) |
AUC (IU-hr/L) |
206 ± 66 |
176 ± 87 |
187 ± 61† |
- |
220 ± 109 |
186 ± 23† |
Cmax(IU/L) |
3 ± 1 |
3 ± 1 |
9 ± 3 |
- |
2.5 ± 0.8 |
8.3 ± 0.9 |
tmax(hr) |
25 ± 10 |
16 ± 10 |
8 ± 6 |
- |
20 ± 14 |
10.7 ± 6.7 |
t1/2terminal (hr) |
50 ± 27 |
24 ± 11 |
24 ± 8 |
- |
41 ± 14 |
32 ± 4 |
CL/F (L/hr) |
- |
- |
- |
32‡ |
0.86 ± 0.48 |
0.90 ± 0.12 |
V/F (L) |
- |
- |
- |
0.7 ± 0.2 |
- |
- |
F (%) |
76 ± 30 |
66 ± 39 |
- |
10 ± 3 |
- |
- |
Abbreviations are: IVF/ET: in vitro fertilization/embryo transfer;
Cmax: peak concentration (above baseline);
tmax: time of Cmax;
CL/F: apparent clearance;
V/F: apparent volume of distribution; calculated using a one-compartment model.
t1/2: absorption half-life;
F: bioavailability compared to IV
*First five days of fixed regimen followed by adjustment of the dose depending on response
†Steady-state AUC (After the 144-168 7th daily SC dose)
‡increases with body mass index
|
Absorption
The absorption rate of Gonal-f® following subcutaneous or intramuscular administration was found to
be slower than the elimination rate. Hence the pharmacokinetics of Gonal-f® are absorption rate-limited.
Distribution
Human tissue or organ distribution of FSH has not been determined for Gonal-f® .
After intravenous administration to pituitary down-regulated, healthy female volunteers, the serum
profile of FSH appears to be described by a two compartment open model with a distribution half-life
of about 2-2.5 hours. Steady-state serum levels were reached after 4 to 5 days of daily administration.
Metabolism/Excretion
FSH metabolism following administration of Gonal-f® has not been studied in humans. Total clearance
after IV administration in healthy females was 0.6 L/hr; mean residence time was 17-20 hours. FSH
renal clearance was 0.07 L/hr after intravenous administration representing approximately 1/8 of total
clearance.
Pharmacodynamics
Following daily subcutaneous administration of 150 IU of Gonal-f® for 7 days in healthy female
volunteers, serum inhibin and estradiol, and total follicular volume responded as a function of time, with
pronounced inter-individual variability. Pharmacodynamic effect lagged behind FSH serum
concentration. Of the three pharmacodynamic parameters, serum inhibin levels responded with the least
delay and declined rapidly after discontinuation of Gonal-f® . Follicular growth was most delayed and
continued even after discontinuation of Gonal-f® administration, and after serum FSH levels had
declined. Maximum follicular volume was better correlated with either inhibin or estradiol peak levels
than with FSH concentration. Inhibin rise was an early index of follicular development. In healthy male
volunteers, despite high interindividual variation and the absence of down-regulation, daily
administration of 225 IU Gonal-f® was shown to increase the levels of inhibin to reach a plateau during
the whole administration period and then return to baseline.
Population Pharmacokinetics And Pharmacodynamics
To establish the pharmacokinetics and pharmacodynamics of FSH in a target population, measurements
performed during a clinical study of in vitro fertilization/embryo transfer were used in conjunction with
pharmacokinetic data from studies in healthy female volunteers. The apparent clearance was comparable
to that in healthy volunteers. The absorption rate was found to be influenced by the body mass index
(BMI), suggesting that the higher the BMI, the lower the rate of absorption. However, FSH serum
levels following fixed (during the first five days) and then adjusted doses of Gonal-f® were found to be
poor predictors of follicular growth rate. High pre-treatment serum FSH levels may predict lower
follicular growth rates.
Special Populations
Safety, efficacy, and pharmacokinetics of Gonal-f® in patients with renal or hepatic insufficiency have
not been established.
Drug-Drug Interactions
No drug-drug interaction studies have been conducted (see PRECAUTIONS).
Clinical Studies
Women
The safety and efficacy of Gonal-f® have been examined in four clinical studies, two studies for
ovulation induction and two studies for assisted reproductive technologies (ART). In these comparative
studies, there were no clinically significant differences between treatment groups in study outcomes.
Ovulation Induction
The safety and efficacy of Gonal-f® administered subcutaneously vs. urofollitropin administered
intramuscularly were assessed in a phase III, open-label, randomized, comparative, multinational,
multicenter study in oligo-anovulatory infertile women who failed to ovulate or conceive following
adequate clomiphene citrate therapy (Study 5642).
The primary efficacy parameter was the ovulation rate. Two hundred and twenty-two patients entered
into the first cycle of treatment, of whom 110 received Gonal-f® and 112 received urofollitropin.
Ovulation rates were similar between Gonal-f® and urofollitropin treatment groups. The study results
for the 222 patients who received treatment in at least one cycle are summarized in Table 2.
Table 2: Cumulative Patient Ovulation and Clinical Pregnancy Rates by
Treatment Group in Ovulation Induction
Study 5642 |
Gonal-f® (n=110) |
Urofollitropin
(n=112) |
Cumulative Ovulation Rate |
Cycle 1 |
64% |
59% |
Cycle 2 |
78% |
82% |
Cycle 3 |
84% |
91% |
Cumulative Clinical Pregnancy* Rate |
Cycle 1 |
21% |
21% |
Cycle 2 |
28% |
38% |
Cycle 3 |
35% |
46% |
*A clinical pregnancy was defined as a pregnancy during which a fetal sac (with or
without heart activity) was visualized by ultrasound on day 34 -36 after hCG
administration. |
For the 90 patients who had a clinical pregnancy (39 in Gonal-f® group; 51 in urofollitropin group), the
outcome of the pregnancy was:
Table 3: Pregnancy Outcome by Treatment Group in Ovulation
Induction
Study 5642 |
Gonal-f® (n=39) |
Urofollitropin
(n=51) |
Pregnancies not reaching term |
20.5% |
13.7% |
Single births |
74.4% |
74.5% |
Multiple births |
5.1% |
11.8% |
A second randomized, comparative, open-label, multicenter study was conducted in 23 U.S. centers
(Study 5727). The primary efficacy parameter was ovulation rate. Ovulation rates were similar between
Gonal-f® and urofollitropin treatment groups. Two hundred and thirty-two patients with oligoanovulatory
infertility received treatment with up to three cycles of Gonal-f® administered
subcutaneously (118 patients) or urofollitropin administered intramuscularly (114 patients).
The cumulative patient ovulation rate and clinical pregnancy rates by cycle are presented for the 232
patients who received treatment in at least one cycle.
Table 4: Cumulative Patient Ovulation and Clinical Pregnancy Rates by
Treatment Group in Ovulation Induction
Study 5727 |
Gonal-f® (n=118) |
Urofollitropin
(n=114) |
Cumulative Ovulation Rate |
Cycle 1 |
58% |
68% |
Cycle 2 |
72% |
86% |
Cycle 3 |
81% |
93% |
Cumulative Clinical Pregnancy* Rate |
Cycle 1 |
13% |
14% |
Cycle 2 |
25% |
25% |
Cycle 3 |
37% |
36% |
*A clinical pregnancy was defined as a pregnancy during which a fetal sac (with or
without heart activity) was visualized by ultrasound on day 34 -36 after hCG
administration. |
For the 85 patients who had a clinical pregnancy (44 in Gonal-f® group; 41 in urofollitropin group), the
outcome of the pregnancy is shown in Table 5.
Table 5: Pregnancy Outcome by Treatment Group in Ovulation
Induction
Study 5727 |
Gonal-f®
(n=44) |
Urofollitropin (n=41) |
Pregnancies not reaching term |
22.7% |
22.0% |
Single births |
63.6% |
65.9% |
Multiple births |
13.7% |
12.2% |
Assisted Reproductive Technologies (ART)
The safety and efficacy of Gonal-f® administered subcutaneously vs. urofollitropin administered
intramuscularly were assessed in a phase III, open-label, randomized, comparative, multinational,
multicenter study in ovulatory, infertile women undergoing stimulation of multiple follicles for In Vitro
Fertilization and Embryo Transfer (IVF/ET) after pituitary down-regulation with a GnRH agonist (Study
5503). The purpose of the study was to demonstrate that Gonal-f® , administered subcutaneously, was
clinically not different in terms of safety and efficacy from urofollitropin, administered intramuscularly.
The initial and maximal doses of Gonal-f® were 225 and 450 IU, respectively. The primary efficacy
parameter was the number of mature pre-ovulatory follicles on the day of hCG administration. One
hundred and twenty-three patients were randomized and received either Gonal-f® (60 patients) or
urofollitropin (63 patients).
The results summarized in Table 6 are mean data with Gonal-f® and urofollitropin administered to
ovulatory infertile women undergoing multiple follicular development for IVF/ET.
Table 6: Treatment Outcomes by Treatment Group in ART
Study 5503 |
Gonal-f®
(n=60) |
Urofollitropin
(n=63) |
Mean number of follicles ≥ 14mm
diameter on day of hCG |
7.8 |
9.2 |
Mean number of oocytes recovered per
patient |
9.3 |
10.7 |
Mean Serum E2 (pg/mL) on day of hCG |
1576 |
2193 |
Mean treatment duration in days (range) |
9.9 (5-20) |
9.4 (5-14) |
Clinical pregnancy* rate per attempt |
20% |
16% |
Clinical pregnancy* rate per embryo
transfer |
24% |
19% |
*A clinical pregnancy was defined as a pregnancy during which a fetal sac (with or
without heart activity) was visualized by ultrasound on day 34 -36 after hCG
administration. |
For the 22 patients who had a clinical pregnancy (12 in Gonal-f® group; 10 in urofollitropin group), the
outcome of the pregnancy is shown in Table 7.
Table 7: Pregnancy Outcome by Treatment Group in ART
Study 5503 |
Gonal-f®
(n=12) |
Urofollitropin (n=10) |
Pregnancies not reaching term |
25.0% |
20.0% |
Single births |
41.7% |
50.0% |
Multiple births |
33.3% |
30.0% |
A second randomized, comparative, open-label, multicenter study was conducted in 7 U.S. centers
(Study 5533). One hundred and fourteen patients with ovulatory infertility undergoing IVF/ET were
randomized and received either Gonal-f® by subcutaneous administration (56 patients) or urofollitropin
by intramuscular administration (58 patients) following pituitary down-regulation with a GnRH agonist.
The primary efficacy parameter was the number of mature pre-ovulatory follicles on the day of hCG
administration. Results are summarized in Table 8.
Table 8: Treatment Outcomes by Treatment Group in ART
Study 5533 |
Gonal-f®
(n=56) |
urofollitropin
(n=58) |
Mean number of follicles ≥ 14mm
diameter on day of hCG |
7.2 |
8.3 |
Mean number of oocytes recovered per
patient |
9.3 |
12.3 |
Mean Serum E2 (pg/mL) on day of hCG |
1236 |
1513 |
Mean treatment duration in days (range) |
10.1(5-15) |
9.0 (5-12) |
Clinical pregnancy* rate per attempt |
21% |
22% |
Clinical pregnancy* rate per embryo
transfer |
26% |
25% |
*A clinical pregnancy was defined as a pregnancy during which a fetal sac (with or
without heart activity) was visualized by ultrasound on day 34 -36 after hCG
administration. |
For the 25 patients who had a clinical pregnancy (12 in Gonal-f® group; 13 in urofollitropin group), the
outcome of the pregnancy is shown in Table 9.
Table 9: Pregnancy Outcome by Treatment Group in ART
Study 5533 |
Gonal-f®
(n=12) |
Urofollitropin (n=13) |
Pregnancies not reaching term |
33.3% |
30.8% |
Single births |
41.7% |
38.5% |
Multiple births |
25.0% |
30.8% |
Men
The safety and efficacy of Gonal-f® administered concomitantly with hCG have been examined in three
open-label clinical studies for induction of spermatogenesis in men with primary and secondary
hypogonadotropic hypogonadism.
The three multicenter studies involved three to six months of pretreatment with chorionic gonadotropin
for injection to normalize serum testosterone levels, followed by 18 months of treatment with Gonal-f®
and hCG. The objective of each study was induction of spermatogenesis (a sperm density of ≥ 1.5 ×
106/mL).
Study 5844 enrolled 32 patients in six centers in the United Kingdom, France and Germany. The second
trial, Study 6410, was conducted in Australia and enrolled 10 patients in two centers. Study 6793,
conducted in 7 centers in the United States, was planned to enroll 32 patients. The interim data for the US
study includes 30 of the planned 32 patients. For all 3 studies, a total of 72 patients were enrolled and
received hCG and 56 of those patients entered the Gonal-f® treatment phase of the trials.
The populations enrolled in the three studies were similar: Study 5844 studied a naïve population who
had had no prior treatment with gonadotropins; mean age was 25.9 (range 16 to 48) years, mean (± SD)
testis volume was 2.0 ± 1.2 mL, and 12 of the 32 patients (37.5%) were anosmic. Thirty-one of the
patients were Caucasian and one was Asian. In Study 6410, mean age was 36 (range 26 to 48) years, 6
and 1 of the 10 patients had previously been treated with gonadotropins and GnRH, respectively; mean
testis volume was 4.5 ± 2.9 mL; and 2 of the 10 patients (20%) were anosmic. Seven patients were
Caucasian and three were Asian. In the 30 patients reported in the interim analysis of Study 6793, the
mean age was 30.1 (range 22 to 44) years; 4 and 3 of the 30 patients had been treated with gonadotropins
and GnRH, respectively, in the past; mean testis volume was 4.4 ± 1.3 mL; and 10 of the 30 patients
(33.3%) were anosmic. Twenty five of the patients were Caucasian, three were Asian, and one each of
Moroccan and Indian ancestry.
The primary efficacy endpoint of all three studies was the achievement of a sperm density ≥ 1.5 ×
106/mL. The study results for the patients treated with Gonal-f® and hCG are summarized in Table 10.
Table 10: Number of Men Receiving Gonal-f® Who Achieved a Sperm
Density ≥ 1.5 × 106/mL
|
Study 5844
(n=26) |
Study 6410
(n=8) |
Study 6793
(n=22)* |
Sperm Concentration ≥ 1.5 ×
106/mL |
|
|
|
Yes |
12 (46.2%) |
5 (62.5%) |
14 (63.6%) |
No |
14 (53.8%) |
3 (37.5%) |
8 (36.4%) |
95% Confidence Interval |
(26.6% -
66.6%) |
(24.5% -
91.5%) |
(40.7% -
82.8%) |
*Interim data |
The time to achievement of the primary efficacy endpoint is summarized in Table 11.
Table 11: Time to Achievement of Sperm Density ≥ 1.5 × 10 / mL in Men
Receiving Gonal-f®
|
Study 5844
(n=26) |
Study 6410
(n=8) |
Study 6793
(n=22)* |
Number of Men
Achieving Sperm
Concentration |
|
|
|
n |
12 |
5 |
14 |
Time (Months) to
Sperm Concentration ≥
1.5 × 106/mL |
5 (71%) |
2 (20%) |
1 (5%) |
Median |
12.4 |
9.1 |
6.8 |
Range |
(2.7 – 18.1) |
(8.8 – 11.7) |
(2.8 – 15.7) |
*Interim data |
Table 12: Pregnancy Outcome in Partners of Men Desiring Fertility
|
Study 5844
(n=7) |
Study 6410
(n=10) |
Study 6793
(n=20)* |
Pregnancy |
6 (86%) |
3 (30%) |
3 (15%) |
Pregnancy not reaching
term |
1 (14%) |
1 (10%) |
2 (10%) |
Single births |
5 (71%) |
2 (20%) |
1 (5%) |
*Interim data |
Of the 56 patients who received Gonal-f® in Studies 5844, 6410, and 6793, 12 pregnancies were
achieved in 10 partners of the 37 patients who were seeking pregnancy and who currently had a partner
during the studies. Thus, pregnancy (clinical and chemical) was documented to have been achieved by
27% of the patients' partners seeking pregnancy during the exposure period to Gonal-f® in the 3 trials.
Eight pregnancies continued to term, and 8 healthy babies were born to 7 couples as a result of those
studies.