Note: Descriptions are shown in the official language in which they were submitted.
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Gonadotropin releasing hormone antagonist
The present invention relates to the use of GnRH antagonists in controlled
s ovarian hyperstimulation (COH) as well as to a method to prevent premature
LH surge. It also relates to a cartridge comprising said antagonist and a kit
comprising said cartridge and FSH.
The glycoprotein hormones Luteinizing Hormone (LH) and Follicle
~o Stimulating Hormone (FSH) are released from the pituitary gland under
control
of Gonadotropin Releasing Hormone (GnRH). They act on the ovary to
stimulate steroid synthesis and secretion and thus play a central role in the
reproductive cycle.
In the normal cycle, there is a mid-cycle surge in LH concentration which is
~5 followed by ovulation. The LH surge is a consequence of the raise in
estrogen
levels brought about by the endogenous secretion of LH and FSH. The
estrogen is part of a positive feedback mechanism resulting in the elevated LH
level.
2o GnRH analogues are useful for a variety of disorders in which immediate
reversible suppression of the pituitary-gonadal axis is desired. This can in
principle be achieved with GnRH agonists as well as with GnRH antagonists.
In comparison to GnRH agonists, GnRH antagonists have the advantage of
not inducing an initial release of gonadotropins (flare-up) and steroids
before
25 suppression.
Currently, GnRH agonists are clinically applied for the prevention of
endogenous LH-surges during controlled ovarian hyperstimulation for Assisted
Reproduction Techniques (ART). Specific disadvantages of GnRH agonists
are the initial flare-up and the rather long period until pituitary
suppression
3o becomes effective. Usually, patients undergoing COH start only treatment
with
(recombinant) FSH after 2 to 3 weeks pretreatment with GnRH agonists.
Women treated for this purpose without GnRH analogues, all show
attenuated LH rises irrespective of the treatment schedule used. Usually these
rises occur prematurely due to a positive feedback of rising estradiol (E2)
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produced by a cohort of relative small follicles. The exposure of non-mature
follicles to high levels of LH leads to premature iuteinisation of granulosa
cells
and hence to increased production of progesterone and decreased synthesis
of E2. These changes lead to disrupted maturation and decreased fertilization
J and implantation rates. Success rates of COH cycles in which premature LH
rises are detected, are reported to be low and often these cycles are canceled
because the number and/or size of follicles is still too small.
GnRH antagonists by GnRH receptor competition provide an immediate
~o inhibition of gonadotropin secretion, especially of LH. Thus, during COH by
FSH, GnRH antagonist treatment is only required during the few days when
there is an increased risk for a premature LH surge. It has been found that
the
GnRH antagonist dosage range is critical: too low a GnRH antagonist dosage
leading to Armature LH rises, while too high a GnRH antagonist dosage
~5 hampered follicular maturation. For the antagonist ganirelix for example a
fixed
amount being at least 0.125 mg but less than 1 mg and preferably about 0.25
mg was suggested (W098/58657).
Surprisingly, however, it has now been found that there is no relationship
between the implantation rate and level of LH (AUC), whereas there does exist
Zo a relationship between the GnRH antagonist levels (AUC) and the
implantation
rate. It has now been found that antagonist is to be administered in an amount
depending on the body weight (BW).
The invention therefore relates to a pharmaceutical preparation comprising
GnRH antagonist, while applying a dosage adjusted for body weight sufficient
z5 to prevent a premature LH surge and ensuring successful treatment outcome.
Such preparation is useful in the treatment of women undergoing COH.
A preferred antagonist according to the present invention is ganirelix which
has the following chemical name:
N-Acetyl-3-(2-naphtyl)-D-alanyl-4-chloro-D-phenylalanyl-3-(3-pyridyl)-D-
3o alanyl-L-seryl-L-N9,N'°-diethyl-D-homoarginyl-L-leucin-N9,N'°-
diethyl-L-
homoarginyl-L-propyl-D-alanylamide acetate. The abbreviated structure is [N-
Ac-D-Na(2)' , D-pCIPhe2,D-Pal(3)3, D-hArg(Et2)6, L-hArg(Et2)8, D-Ala'
°-GnRH.
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The GnRH antagonist ganirelix is disclosed in US patent No. 4,801,577 for
nonapeptide and decapeptide analogs of LHRH useful as LHRH antagonists.
This patent, which is fully incorporated herein by reference, describes the
method for the preparation of these compounds. It is indicated that the
s compounds described therein can be used for the prevention of ovarian
hyperstimulation. For human therapy a daily range is suggested for
administration of the active ingredient between 0.001 and 5 mglkg body
weight, preferably between 0.01 and 1 mglkg.
It has now been found that the optimal relationship between body weight
~o and GnRH antagonist dosage can be defined (in micrograms) by the Formula:
(5.5*BW - 166) ~ 7% (Formula I) wherein BW represents the body weight of
the patient in kg.
The preparation is administered together with FSH during the days of
ovarian stimulation when a premature LH rise may easily occur e.g. from day 5
~s of FSH administration onwards. The preparation in its proposed dosage range
has the advantage of providing an immediate effect that prevents an LH surge
and at the same time maximizes the chances of establishing pregnancy.
Administration is usually stopped when sufficient follicles have matured and
exogenous hCG/LH is given for induction of ovulation. The amount of hCG/LH
2o usually amounts 5000-10000 IU. Alternatively, induction of ovulation can be
performed by administration of a GnRH agonist. The agonist instead of
hCG/LH is usually given on the same day in an amount sufficient to trigger
ovulation. A suitable range is 10-1000 fig. Suitable agonists are e.g.
buserelin,
triptorelin and luprorelin.
2s The exact regimen for administration might depend on the individual
response and is finally to be decided by the clinician who treats the subject.
For this reason the duration of initial ovarian stimulation with FSH alone as
well
as the duration of combined treatment with FSH/GnRH antagonist treatment
may vary. FSH treatment usually starts at menses day 1, 2 or 3. Ovarian
so stimulation with FSH alone may be continued up to 5 days in an amount of
e.g.
150-225 IU. FSH is administered preferably as a recombinant protein.
Treatment with GnRH antagonist may be started at the first day of FSH, but
preferably such treatment starts at FSH treatment day 4 or 5. The GnRH
antagonist is administered in the previously determined amount according to
35 the invention in combination with FSH in amounts between 50 - 600 IU,
preferably between 100 - 300 IU. GnRH antagonist treatment may last 2 - 14
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days i.e. up to the moment whereupon the patient is treated with exogenous
LHIhCG or a GnRH or GnRH agonist for ovulation induction.
According to another aspect of the invention ganirelix in an amount
according to Formula I is used for the manufacture of a medicament to prevent
s a premature LH surge in women undergoing controlled ovarian
hyperstimulation.
The pharmaceutical preparations for use according to the invention can be
prepared in accordance with standard techniques such as for example are
~o described in the standard reference, Gennaro et al. (Ed.), Remmington's
Pharmaceutical Sciences, (18t" ed. Mack Publishing Company, 1990, e.g. Part
8: Pharmaceutical Preparations And Their Manufacture). For the purpose of
making the pharmaceutical preparations according to the invention, the active
substance is mixed with or dissolved in a pharmaceutical acceptable carrier.
~s Any conventional pharmaceutical carrier that does not interfere with
performance of the active ingredient can be used in the preparations according
to the present invention. Formulations may contain as common excipients
sterile water or saline, alkylene glycols such as propylene glycol,
polyalkylene
glycols such as polyethylene glycol, oils of vegetable origin, hydrogenated
2o naphtalenes and the like.
The pharmaceutical preparation of the antagonist may be administered
parenterally. Preferably it is administered subcutaneously, particularly in
the
form of liquid solutions or suspensions. A typical formulation is a solution
containing, in addition to the active substance in an amount as indicated
2s above, glacial acetic acid, mannitol, and water adjusted to pH 5 with
sodium
hydroxide and / or hydrochloric acid. Optionally preservations such as e.g.
methyl- and propylparaben or benzylalcohol can be added. The solutions can
be packaged e.g. in glass vials, cartridges or in syringes.
3o In a further aspect of the invention there is provided a cartridge
containing
a sterile liquid formulation of ganirelix. As used herein a cartridge means a
closed container, such as an ampoule, a vial, a bottle or a bag comprising an
amount of GnRH antagonist so as to administer accurately and preferably
repeatedly to a patient a dosage of GnRH antagonist according to Formula I.
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Thus, a cartridge may contain an amount of the liquid antagonist
formulation corresponding to one or more therapeutic dosages of the
antagonist. Preferably these dosages are to be applied in a single regimen.
Preferably the cartridges contain an amount of GnRH antagonist sufficient for
s 5 administrations. The cartridges are preferably used in combination with a
device making it possible to deliver adjustable dosages needed in the regimen.
In another aspect of the invention there is provided a device for
administration comprising a cartridge containing a sterile liquid formulation
according to the invention. A preferred device for administration is a pen-
type
~o injector, which comprise means for easy adjustment of the amount of a
formulation that is to be injected. Such pen type injectors are known per se,
such as for instance the well known B-D Pen (a trademark of Becton Dickinson
and Company), an insulin-injection system.
Adjustable cartridges according to the invention have the advantage of
~5 accurate self-administration thereby increasing the convenience for the
patients.
In yet another aspect of the invention there is provided a kit for use in
controlled ovarian hyperstimulation in female patients. Such a kit comprises a
zo GnRH antagonist in a dosage form and quantity so as to accurately
administer
to a patient in an amount according to Formula I, in a frequency effective to
prevent a premature LH surge. In addition the kit comprises FSH in a dosage
form and quantity suitable for administering in an amount and frequency
effective to stimulate growth of follicles. Optionally the kit may comprise
also
z5 hCGILH or GnRH agonists in a dosage form and quantity suitable for
administering in an amount and frequency effective to induce ovulation. The
GnRH antagonist preferably is packaged in a cartridge. This cartridge
preferably is to be used in combination with a device for administration such
as
a pen type injector allowing an adjustable and accurate administration of
so GnRH antagonist. Thus, the kit might also comprise a pen type injector
system.
The invention is further explained by reference to the following Examples.
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Legends to the Figures
Figure 1: LH levels were measured at the start (just before the first
injection of ganirelix) and end of ganirelix treatment. The graph shows the
s pregnancies in relation to the various levels. LH levels are indicated in
IU/L.
Figure 2: Area under the curve of ganirelix versus body weight of subjects
in three pharmacokinetic studies. Circles mean protocol A; triangles mean
protocol B and squares mean protocol C.
Figure 3: Chance of pregnancy versus body weight; results from Phase III
efficacy study. Dots in the top of the graph correspond to pregnant subjects
(100%), while for subjects not pregnant (0%) these dots are displayed at the
bottom of the graph. The spline function (chance of pregnancy vs body weight)
is the resulting curve of these observations.
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Examples
Example 1
LH serum levels versus pregnancy
Recombinant FSH (recFSH) treatment was started on day 2 or 3 of the
s menstrual cycle by a once daily SC injection. Just prior to the first
injection of
recFSH an hCG test was performed to exclude pregnancy, a blood sample for
hormone analysis was taken and an ultrasonography (USS) was performed.
During recFSH treatment day 1 through 5, the daily dose of recFSH was fixed
to 150 international units (IU). On day 6 of recFSH treatment ganirelix
~o treatment was started by daily SC administration until and including the
day
before the day of hCG.
During ganirelix treatment, the dose of recFSH was adjusted depending on
the individual ovarian response as assessed by USS. From the first day of
ganirelix i.e. from recFSH treatment day 6 onwards up to and including the day
~s of hCG, a blood sample for hormone analysis was taken prior to drug
administration. And an USS was performed, at least every two days.
LH levels were assessed by a standard LH specific assay at the Central
Laboratory of the Analytisch Biochemisch Laboratorium (Assen, The
Netherlands). From the data on LH levels, a plot was constructed in order to
zo investigate the possible role of LH on pregnancy.
LH levels were measured at the start (just before the first injection of
ganirelix) and end of ganirelix treatment. Figure 1 shows the pregnancies in
relation to the various levels.
Clearly, from this graph, no relationship between LH serum levels and
z5 pregnancy outcome was found.
Example 2
Body Weight versus pregnancy
For the body weight parameter the treated groups of example 1 were divided
3o into categories of a 10 kg range and the pregnancy rates found for these
separate categories were investigated. The results are indicated in Table 1
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Weight (kg) Pregnancy rate
<50 9%
50-60 16%
60-70 22%
70-80 22%
>=80 22%
Table 1: Relationship
between pregnancy
and body weight
From this table a relationship between the parameter body weight and
clinical outcome (i.e. pregnancy) was observed.
Example 3
Body weight vs AUC
Several pharmacokinetic studies were carried out with ganirelix. Protocol
A: an open-label two-way crossover study to assess the absolute bioavailablity
of 0.25 mg ganirelix after single injection. Protocol B: an open-label
randomized, multiple dose parallel-design study to assess the dose-
proportionality and the pharmacokinetic properties of ganirelix (0.125 , 0.25
and 0.5 mg) after repeated subcutaneous administration. Protocol C: an open,
randomized, two-way crossover study to establish the local tolerance and
bioavailability of ganirelix after multiple subcutaneous administration (2
mg).
In all these trials A, B and C, blood samples were taken at regular intervals
and the amount of ganirelix present in the blood was determined. Plots were
prepared showing the amount of ganirelix as a function of time. This allowed
zo the determination of the AUC. Next, the AUC was related to the body weight
of
the subjects. Results are indicated in Figure 2.
A pooled analysis of the three pharmacokinetic studies has demonstrated
that the clearance of ganirelix is positively related to body weight. This is
expressed in a lower area under the curve (AUC) for subjects with a higher
25 body weight (Figure 2). Thus at the same dose level, individuals with a
relatively high body weight will be exposed to lower levels of ganirefix, and
individuals with a low body weight to relatively high levels.
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As body weight is related to ganirelix levels it can be expected that body
weight influences the clinical outcome.
This hypothesis is supported by the results of a large Phase III efficacy
study. At lower body weights a significant decrease in pregnancy rate was
s observed (see example 1 and Figure 3). These subjects have been exposed to
relatively higher levels of ganirelix. The pregnancy rate therefore could be
optimized in these individuals by adjustment of the dose, according to their
body weights.
Example 4
Dose finding
Pharmaco-statistical models have been set up to describe the influence of
body weight on the effectiveness of ganirelix for both the prevention of LH-
rises and pregnancy outcome. Spline functions have been applied to give the
best and assumptionless mathematical description of the available data. Using
these models optimal doses with respect to the prevention of LH-rises and
pregnancy have been determined for different body weights.
Weight (kg) Optimal dose ( Ng)
<50
<128
50-55 128
55-60 158
60-65 185
65-70 211
70-75 238
75-80 264
>=g0 >264
Table 2: Relationship
between body weight
and optimal dose
Results are indicated in Table 2. Linear regression shows that these
dosages can be given by the formula: (5.5*BW -166) ~ 7% wherein BW is the
body weight in kg.
