A biological, immunological and physico-chemical comparison of the current clinical batches of the recombinant FSH preparations Gonal-F and Puregon

The immunopotency and in-vitro biopotency of clinical batches of Gonal-F((R)) and Puregon((R)) (recombinant human follicle stimulating hormones) were compared and their carbohydrate chains investigated for charge heterogeneity and internal carbohydrate complexity. Immunopotency (IU/pmol) for both Gonal-F and Puregon was 0.35 +/- 0.01 and biopotency (ED(50), pmol/l) was similar, being 7.3 +/- 0.6 and 5.4 +/- 0.2 respectively. Charge distributions were essentially the same with no difference either in median isoelectric point (pI) (between 4.26 and 4.50), or in the bulk of material fractionated between pI 4 and 5 (66.0 +/- 1.8% Gonal-F and 72.0 +/- 1.8% Puregon). However, there were minor differences in charge at extremes of pI, Gonal-F being slightly more acidic: 18.2% Gonal-F versus 9.8% Puregon at pI 3.5-4.0 (P: = 0.03) and 6.7% Gonal-F versus 10.7% Puregon at pI 5.0-5.5 (P: = 0.03). Carbohydrate complexity was the same: 9.3 versus 10.9 (complex), 76.6 versus 78.6 (intermediate) and 14.1 versus 10.5% (simple). In summary, Gonal-F and Puregon have similar immunopotency, in-vitro biopotency and internal carbohydrate complexity, differing slightly in charge heterogeneity, Gonal-F having more acidic glycoforms. We conclude them to be intrinsically very similar, expecting no difference in clinical efficacy on the basis of respective structure.     

A prospective, randomized, assessor-blind, multicentre study comparing recombinant and urinary follicle stimulating hormone (Puregon versus Metrodin) in in-vitro fertilization

Urinary follicle stimulating hormone (FSH) is being used forthe treatment of human infertility. Recently, FSH manufacturedby means of recombinant DNA technology with a much higher purity(>99%) has become available. A prospective, randomized, assessor-blind,multicentre (n = 18) study was conducted in infertile womenundergoing in-vitro fertilization comparing recombinant FSH(Org 32489, Puregon®) and urinary FSH (Metrodin®). Eligiblesubjects were randomized (recombinant versus urinary FSH = 3:2)and pretreated with buserelin for pituitary suppression. FSHwas given until three or more follicles with a diameter of atleast 17 mm were seen. After oocyte retrieval, fertilizationroutines were applied according to local procedures. No morethan three embryos were replaced. In all, 585 subjects receivedrecombinant FSH and 396 urinary FSH. Significantly more oocyteswere retrieved after recombinant FSH treatment (mean adjustedfor centre 10.84 versus 8.95, P < 0.0001). Ongoing pregnancyrates per attempt and transfer in the recombinant FSH groupwere 22.17 and 25.97% respectively, and in the urinary FSH group,18.22 and 22.02% respectively (not significant). Ongoing pregnancyrates including pregnancies resulting from frozen-thawed embryocycles were 25.7% for recombinant and 20.4% for urinary FSH(P = 0.05). Compared to urinary FSH, the total dose of FSH wassignificantly lower with recombinant FSH (2138 versus 2385 IU,P < 0.0001) in a significantly shorter treatment period (10.7versus 11.3 days, P < 0.0001). No clinically relevant differencesbetween recombinant and urinary FSH were seen with respect tosafety variables. It is concluded that recombinant FSH (Puregon)is more effective than urinary FSH in inducing multifolliculardevelopment and achieving an ongoing pregnancy.     

Recombinant follicle stimulating hormone (rFSH; Puregon) in assisted reproduction: More oocytes, more pregnancies. Results from five comparative studies

The clinical assessment of recombinant follicle stimulatinghormone (rFSH; Puregon) in assisted reproduction technologiessuch as in-vitro fertilization (IVF) has probably been the mostextensive clinical trial programme ever performed for the evaluationof a new fertility drug. It started with a pilot study to evaluatethe potential of rFSH to stimulate the ovaries in the absenceof luteinizing hormone (LH) - using various gonadotrophin-releasinghormone (GnRH) agonists. After it became clear that FSH-inducedsteroidogenesis was not jeopardized even after severe pituitarysupression, comparisons between rFSH and urinary FSH or humanmenopausal gonadotrophins were made using different GnRH agonistsor no agonists at all. In addition, the effects of the routeof administration (s.c. or i.m.) were assessed. The study withthe strongest statistical power to truly assess clinically relevantdifferences between rFSH and urinary FSH included ~1000 patientcycles. It indicated that after rFSH treatment, significantlymore oocytes were retrieved, more embryos obtained and, as aresult, more pregnancies achieved when the results of the cryoprogrammewere included.     

Ovulation induction with low dose alternate day recombinant follicle stimulating hormone (Puregon)

We investigated whether a recombinant follicle stimulating hormone (FSH) (Puregon) can be administered less frequently and at lower doses during ovulation induction than is current practice. Patients (20-35 years, body mass index <30 kg/m(2)) with infertility and chronic anovulation secondary to polycystic ovarian syndrome and resistant to previous clomiphene treatment received (Puregon); 100 IU, n = 17 patients, or 50 IU, n = 10 patients) on alternate days. After 2 weeks and in the absence of follicular recruitment, doses were increased stepwise at weekly intervals (50 IU/alternate days). Twenty-two cycles out of 27 were ovulatory. There were six pregnancies, five from Puregon (100 IU) and one from Puregon (50 IU); four pregnancies proceeded to term. The duration of stimulation (mean, range) with Puregon (100 IU) was 16.4, 7-29 and Puregon (50 IU) 19.1, 8-38 days. The gonadotrophin doses administered (mean; range) were 689, 200-1800 IU (Puregon 50 IU) and 939, 400-2300 IU (Puregon 100 IU). We conclude that low dose alternate day Puregon treatment is suitable for this difficult patient group.     

Recombinat hormones: Structure-function relationship of recombinant follicle stimulating hormone (Puregon(R))

After separation by means of preparative isoelectrofocusing,the isohormones of a Chinese hamster ovary (CHO)-derived recombinantfollicle stimulating hormone (rFSH, Puregon^®) were characterizedwith respect to structural and functional features. A carbohydrateanalysis revealed that rFSH isohormones with a low isoelectricpoint (pI) have a high sialic acid/galactose ratio and are richin tri- and tetra-antennary N-linked carbohydrate chains incomparison with the high pI isohormones. The relative basicisohormones exhibit receptor binding activity and intrinsicbioactivity 2–3-fold higher than the relative acidic isohormones.However, due to their lower clearance rate these acidic isohormonesdisplayed a 20-fold higher in-vivo bioactivity in the rat. Acomparison of the isohormone profile of rFSH and urinary FSH(Metrodin^®) revealed that rFSH contains about 2-fold morebasic isohormones with pl     

Efficacy and safety of recombinant follicle stimulating hormone (Puregon(R)) in infertile women pituitary-suppressed with triptorelin undergoing in-vitro fertilization: a prospective, randomized, assessor-blind, multicentre trial

The objective of this study was to compare the efficacy andsafety of a recombinant follicle stimulating hormone (FSH) preparation(Org 32489, Puregon^®) with a urinary FSH preparation (Metrodin^®)in infertile women undergoing in-vitro fertilization (IVF andembryo transfer and who were pituitary-suppressed with triptorelin.In an assessor-blind, group-comparative, multicentre study,60 women were randomized to Org 32489 and 39 to urinary FSH.An evaluation of the main parameter, the mean total number ofoocytes recovered, indicated a similar efficacy for the twopreparations: 9.7 with Org 32489 versus 8.9 with urinary FSH.In addition, there were no significant between-group differenceswith respect to other efficacy variables such as the total doseused, the duration of the treatment, the number of follicles17 mm in diameter and embryo quality. The ongoing pregnancyrates per attempt (30.2 versus 17.4%) and per transfer (34.0versus 18.8%) were higher with Org 32489, but this differencewas not statistically significant. No clinically relevant differencesbetween Org 32489 and urinary FSH were seen with respect tosafety variables. Serum antibodies were not detected in anyof the subjects. It is concluded that Org 32489 compares favourablywith urinary FSH in the treatment of infertile pituitary-suppressedwomen undergoing IVF and embryo transfer.     

Endocrinology:Follicle stimulating hormone (FSH) dynamics of low dose step-up ovulation induction with FSH in patients with polycystic ovary syndrome

Pharmacodynamics of follicle stimulating hormone (FSH) werestudied during low dose step-up gonadotrophin therapy in patientswith polycystic ovary syndrome (PCOS). To obtain stable levelsof FSH, Metrodin was administered i.v. By making daily determinations,the FSH concentration was slowly increased in steps of 1 IU/I.A total of 16 patients were treated for a maximum of three treatmentcycles. Out of 38 treatment cycles, in 26 (68%) a single dominantfollicle developed. The overall ovulation rate was 78%. FSHconcentrations were evaluated with regard to intra–andinter–individual variability of the FSH threshold andwith regard to the relationship between FSH concentrations,FSH dose and treatment outcome. The high variability of theFSH threshold, ranging from 5.7 to 12 IU/I, appeared to be mainlya function of inter-individual variability. Higher FSH concentrationswere associated with multifollicular growth as opposed to monofolliculargrowth, whereas the increases in concentration from a substimulatingto a stimulating level were not. Multifollicular growth mightthus be associated with a higher elevation of FSH concentrationabove the threshold. Different patterns of FSH concentrationin the course of the growth phase of the dominant follicle inmono– compared to multifollicular cycles suggested a differencein the effect of endogenous FSH on the plasma concentration.Endogenous feedback on FSH release may therefore still playa role during treatment with exogenous FSH     

Biological characterization of recombinant human follicle stimulating hormone isoforms.

It has been established that follicle stimulating hormone (FSH) circulates in the bloodstream as a heterogeneous population of molecules. Individual FSH isoforms, while displaying identical amino acid sequences, differ in their extent of post-translational modification. As a result of these variations, the FSH isoforms exhibit differences in overall charge, degree of sialic acid or sulphate incorporation, receptor binding affinity and plasma half-life. Taking advantage of the fact that these forms can be separated from each other on the basis of their charge, we have evaluated in rats the metabolic clearance rates of the acidic [with an isoelectric point (pI) 4.8) isoforms of recombinant human FSH (rhFSH) obtained after chromatofocusing. The less acidic isoform group was found to have a faster clearance from the circulation in rats as compared with the acidic isoform group. This finding is in agreement with the lower bioactivity in vivo (as determined by the Steelman-Pohley assay) of the less acidic isoform group, compared with the acidic one. The mass spectra of the two groups of isoforms showed a difference in the sialic acid content thus highlighting the importance of these residues on the in-vivo activity of FSH. Conversely, when the two groups of isoforms were tested in vitro by using the Y1 human FSH receptor (Y1 hFSHR) assay and a reporter gene assay, no significant differences in the biological activities between these preparations were detected when test concentrations were based on mass.     

Bioequivalence of subcutaneous injections of recombinant human follicle stimulating hormone (Puregon(R)) by Pen-injector and syringe.

A randomized, single-centre, cross-over study was designed to compare the bioavailability of two pharmaceutical formulations of recombinant human follicle stimulating hormone (recFSH; Puregon(R)): (i) a dissolved cake injected by a normal syringe; and (ii) a ready-for-use solution injected using a device referred to as Puregon(R)Pen. Twenty-two healthy female volunteers underwent one of two administration sequences: Puregon(R)Pen/syringe or syringe/Puregon(R)Pen, by which they received a single subcutaneous dose of recFSH (150 IU). Endogenous gonadotrophin production had been previously suppressed using an oral contraceptive (Lyndiol(R)). Pharmacokinetic parameters characterizing rate [peak concentration (Cmax) and time of peak concentration (tmax)] and extent [area under the curve (AUC) and clearance (CL)] of absorption were obtained from 20 subjects. After injection with both formulations, serum FSH concentrations reached a peak of 3.4 IU/l at 13 h after injection. The elimination half-life was approximately 34 h, irrespective of formulation. A difference of approximately 18% was found between serum FSH concentrations obtained using the two formulations, which was caused by differences between the anticipated and the actual volume injected with the normal syringe. After correction for injection losses by weighing the amount injected with a normal syringe, the two formulations were found to be bioequivalent with respect to Cmax, AUC and CL. For tmax, bioequivalence could not be proven due to high intra-subject variability and broad absorption peaks of FSH. Both methods were well tolerated, local reactions being generally mild and short-lived.     

A prospective, randomized, double-blind clinical trial to study the efficacy and efficiency of a fixed dose of recombinant follicle stimulating hormone (Puregon) in women undergoing ovarian stimulation

A prospective, randomized, double-blind, multicentre (n = 5) study was conducted to compare the influence of either a 100 or 200 IU daily fixed-dose regimen of recombinant follicle stimulating hormone (FSH) on the number of oocytes retrieved and the total dose used in down-regulated women undergoing ovarian stimulation. Fertilization was done by intracytoplasmic sperm injection or conventional in-vitro fertilization. A total of 199 women were treated with FSH, 101 subjects with 100 IU and 98 subjects with 200 IU. In subjects of the 200 IU treatment group, significantly more oocytes were retrieved compared to the 100 IU group (10.6 versus 6.2 oocytes, P < 0.001). The total dose needed to develop at least three follicles with a diameter of > or = 17 mm was significantly lower in the 100 IU treatment group (1114 IU versus 1931 IU, P < 0.001). In the low-dose group, significantly lower serum concentrations of oestradiol, progesterone and FSH were observed at the day of human chorionic gonadotrophin administration. Although more cycle cancellations due to low response were seen in the 100 IU group (n = 24 versus n = 3), the clinical pregnancy rate per started cycle was similar (24.7% in the 100 IU group versus 23.3% in the 200 IU group). In the high-dose group, more side-effects, in particular more cases of ovarian hyperstimulation syndrome, were noted. It is concluded that compared to 200 IU, the use of a 100 IU fixed dose is less efficacious in terms of the number of oocytes retrieved, but more efficient as indicated by a lower total dose.     

Endocrinology: Effects of recombinant human follicle stimulating hormone on cultured human granulosa cells: comparison with urinary gonadotrophins and actions in preovulatory follicles

The effects of recombinant human follicle stimulating hormone(rFSH; Org 32489) have been examined in human granulosa cellsfrom ovaries obtained from women with spontaneous menses. Inthe first series of experiments the actions of rFSH on productionof oestradiol and progesterone were compared with those of urinary-derivedgonadotrophins. Recombinant FSH induced dose-dependent increasesin production of both oestradiol and progesterone which weresimilar to the effects of ’pure‘ FSH (Metrodin®)and the International Standard IS 71/223. In further studies,the actions of rFSH on oestradiol production by individual preovulatoryfollicles were investigated; rFSH increased oestradiol accumulationfrom cells obtained from follicles before the luteinizing hormone(LH) surge. In contrast, rFSH inhibited oestradiol productionby granulosa cells derived from a follicle after the onset ofthe LH surge, whereas the gonadotrophic action of growth hormonewas maintained. Following preliminary reports of the in-vivoeffects of rFSH in women, these findings provide further validationof the efficacy of rFSH in the human ovary. The results of studiesof the preovulatory follicle illustrate the experimental importanceof the availability of recombinant preparations of pure gonadotrophins,produced by recombinant technology, in the understanding ofhuman ovarian function.     

Case Report: First established pregnancy and birth after ovarian stimulation with recombinant human follicle stimulating hormone (Org 32489)

This case report describes the first established pregnancy andbirth after ovarian stimulation with Org 32489, pure recombinanthuman follicle stimulating hormone (recFSH, Organon International).A patient with tubal infertility participated in an open efficacystudy of recFSH evaluating the efficacy of combined gonadotrophin-releasinghormone (GnRH)agonist/recFSH treatment in women undergoing in-vitrofertilization (IVF) and embryo transfer. Ovarian stimulationwas induced by recFSH in association with buserelin (Suprecur^®,4 x 150 µg/day) using a short protocol. After 9 days ofrecFSH treatment (75 IU/day), six pre-ovulatory follicles (15mm) were observed and 10 000 IU human chorionic gonadotrophinwere administered. Nine mature oocytes were retrieved by oocytepuncture and after IVF, three embryos were replaced in the uterus.A viable singleton intra-uterine pregnancy was revealed at agestational age of 7 weeks. The pregnancy progressed normallyand ended with a vaginal delivery at a gestational age of 39.5weeks. A healthy girl was born and paediatric examination didnot demonstrate any abnormality.     

Single dose pharmacokinetics and effects on follicular growth and serum hormones of a long-acting recombinant FSH preparation (FSH-CTP) in healthy pituitary-suppressed females

BACKGROUND: A long-acting FSH preparation has been developed by site-directed mutagenesis and gene transfer techniques. METHODS: In this open-label trial, we investigated the pharmacokinetic and pharmacodynamic properties of FSH-CTP (corifollitropin alpha, Org 36286) in healthy female volunteers. Twenty-four subjects were treated with a high-dose oral contraceptive (OC) to suppress pituitary function. A single dose of 15, 30 or 60 micro g FSH-CTP was injected (s.c., eight subjects per dose group) and seven of these 24 subjects were subsequently treated with a single dose of 120 micro g. RESULTS: Maximum serum FSH-CTP concentrations (0.42, 0.66, 1.49 and 3.27 ng/ml after administration of 15, 30, 60 and 120 micro g Org 36286 respectively) were reached between 36 and 48 h after injection and t(1/2) varied between 60 and 75 h. Dose proportionality was shown across the studied dose range, whereas t(max) and t(1/2) were dose independent. In most subjects follicular growth was observed; the number and maximum diameter of the follicles increased with the dose. Follicles with a diameter vertical line 8.0 mm were observed only in the 60 and 120 micro g dose groups, diameters between 12.0 and 15.9 mm occurred only in the 120 micro g group. Serum LH and 17beta-oestradiol levels remained low due to profound pituitary suppression whereas inhibin-B levels increased with dose. Maximum mean inhibin-B levels were 30.4, 322.7 and 1059.3 pg/ml in the 30, 60 and 120 micro g dose group respectively. The preparation was safe and well tolerated, and no FSH-CTP antibody formation was observed. CONCLUSIONS: The pharmacokinetics of FSH-CTP were shown to be proportional with the dose. The elimination half-life was approximately two times longer than that of rFSH. A single dose of FSH-CTP was shown to be safe and able to induce multiple follicular growth accompanied by a dose-dependent rise in serum inhibin-B concentrations.     

A prospective, randomized clinical trial comparing 150 IU recombinant follicle stimulating hormone (Puregon((R))) and 225 IU highly purified urinary follicle stimulating hormone (Metrodin-HP((R))) in a fixed-dose regimen in women undergoing ovarian stimulation.

A prospective, randomized, open, multicentre (n = 3) study was conducted to compare the efficacy and efficiency of a fixed daily dose of 150 IU (3x50 IU) recombinant follicle stimulating hormone (recFSH, Puregon((R))) and 225 IU (3x75 IU) highly purified urinary FSH (uFSH-HP, Metrodin-HP((R))) in women undergoing ovarian stimulation prior to in-vitro fertilization treatment. A total of 165 women were treated with FSH, 83 subjects with recFSH and 82 subjects with uFSH-HP. In the recFSH group a mean number of 8.8 oocytes were retrieved, compared with 9.8 in the uFSH-HP group (not statistically significant). In the recFSH group, a significantly lower total dose was required compared to the uFSH-HP group, 1479 versus 2139 IU, respectively (P < 0.0001; 95% confidence interval -747 to -572). Treatment with recFSH resulted in a significantly higher embryo development rate (69.6 versus 56.2%; P = 0.003) and more embryos accessible for the embryo freezing programme (3.3 versus 2.0; P = 0.02) compared to uFSH-HP. The vital pregnancy rate per cycle started was 30.2 versus 28.3% in the recombinant and urinary FSH group, respectively. It is concluded that treatment outcome of a fixed daily dose of 150 IU recFSH is comparable to a fixed daily dose of 225 IU uFSH-HP. However, a significantly lower total dose was needed in the recFSH group (nearly 700 IU less).     

Recombinant hormones: In-vitro biopotency and glycoform distribution of recombinant human follicle stimulating hormone (Org 32489), Metrodin and Metrodin--HP

In this study the in-vitro biopotency and glycoform distributionof human recombinant follicle stimulating hormone (FSH, Org32489) has been assessed. The biopotency of recombinant FSHwas studied using animal (rat Sertoli) and human (granulosa—lutein)cell models. Recombinant FSH, as measured in the rat Sertolicell assay, was more potent than the urinary preparations Metrodin,Metrodin—HP and IS 70/45 with half maximal stimulation(ED₅₀; mean ± SEM, n > 3) occurring at 2.2 ±0.5 IU/I (recombinant FSH), 4.7 ± 1.1 IU/I (Metrodin),13.2 ± 0.7 IU/I (Metrodin—HP) and 6.4 ±0.3 IU/I (IS 70/45); the pituitary preparation IRP 83/575 hadan ED₅₀ of 10.4 ± 0.1 IU/I. Using human granulosa—luteincells, cultured for up to 4 days in the absence of exogenoussteroid precursors, recombinant FSH was either without effect(three out of five patients) or inhibited both oestradiol andprogesterone secretion. FSH (83/575) was without effect on oestradiolwith preparations from any of the patients but slightly stimulated(134 ± 8%; mean ± SEM, P < 0.05) progesteroneproduction at the highest dose (80 IU/I). The distribution ofFSH isoforms, assessed by polyclonal radioimmunoassay, followingchromatofocusing over the ranges pH < 3.5 and pH 3.5–7.0respectively was recombinant FSH, 12.4 and 87.6%; Metrodin,19.8 and 80.2%; Metrodin—HP, 50.2 and 49.8%; IS 70/45,15.0 and 85.0%; IS 83/575, 70.9 and 29.1%. All glycoforms werepl <7.0 for the five preparations. In conclusion: (i) thepotency of FSH as measured in the rat Sertoli cell assay increasesin the order Metrodin—HP < pituitary IRP 83/575 <<Metrodin < IS 70/45 < recombinant FSH; (ii) in contrastto 83/575, recombinant FSH inhibits steroidogenesis in humangranulosa—lutein cells isolated from some patients; (iii)the glycoform distribution of recombinant FSH resembles Metrodinmore closely than Metrodin—HP which is far more acidicin nature.     

Recombinant follicle stimulating hormone stimulation in poor responders with normal basal concentrations of follicle stimulating hormone and oestradiol: improved reproductive outcome.

A total of 30 young infertile patients who exhibited a poor response in two previous consecutive cycles, despite having normal basal follicle stimulating hormone (FSH) and oestradiol concentrations, were invited to participate in a prospective randomized study comparing the clinical efficacy of recombinant (rFSH) and urinary (uFSH) follicle stimulating hormone. An evaluation of the total dose used (3800 IU versus 4600 IU, P < 0.05) and duration of treatment (10.2 days versus 13.2 days, P < 0.05) showed a significantly shorter treatment period as well as a significantly lower total dose of FSH required to induce ovulation successfully in the group of patients treated with rFSH. Significantly more oocytes (7.2 versus 5. 6, P < 0.05) as well as mature oocytes (5.9 versus 3.2, P < 0.01) were retrieved after rFSH treatment. In addition, significantly more good quality embryos were obtained (3.4 versus 1.8, P < 0.05) in the group of patients treated with rFSH and, as a result, higher pregnancy (33 versus 7%, P < 0.01) and implantation (16 versus 3%, P < 0.01) rates were achieved in these patients. It is concluded that rFSH is more effective than uFSH in inducing multifollicular development and achieving pregnancy in young low responders.     

Pharmaco-dynamics of human menopausal gonadotrophin (HMG) and follicle-stimulating hormone (FSH). The importance of the FSH concentration in initiating follicular growth in polycystic ovary-like disease

Using a randomized double-blind cross-over design, the pharmaco-dynamicand pharmaco-kinetic properties of ‘pure’ follicle-stimulatinghormone (FSH) (Metrodin) and human menopausal gonadotrophin(HMG) (Pergonal) were studied in 24 women with polycystic ovary-likedisease (PCOD) during induction of ovulation. Fifty-six cycleswere stimulated with FSH and 60 cycles with HMG, according toa standard protocol. Gonadotrophins were administered i.v. ina pulsatile fashion using pulse frequencies of either 30 or120 min. The cycles stimulated with either 30 or 120 min pulseintervals showed no differences among themselves. During thestimulation phase, the FSH and HMG stimulated cycles showedequal and dose dependent FSH concentrations (mean ± SD).The luteinizing hormone (LH) concentrations (mean ± SD)were also equal but unchanged compared to the mean basal concentration.The LH, FSH, total urinary oestrogen excretion, and testosteroneprofiles (mean ± SD) obtained from cycle days –10to 0 as well as the pregnanediol profiles obtained from cycledays 0 to +14 showed no differences either. The occurrence ofan endogenous preovulatory LH surge was significantly more frequentin the cycles stimulated with a pulse interval of 30 min comparedto the cycles stimulated with a pulse interval of 120 min. Theaddition of LH as provided in HMG did not influence the FSHthreshold concentration above which initiation of folliculargrowth occurred, since no differences were found in the FSH‘stable’ concentrations between FSH and HMG stimulatedcycles. However, intra- and inter-individual variation in theFSH ‘stable’ concentration at which follicular growthwas initiated became obvious. It has been hypothesized thateither diminished circulating bioactive FSH or intrafollicularparacrine factors may influence the FSH threshold concentrationabove which the ovary responds with follicular growth.     

Current concepts of the roles of follicle stimulating hormone and luteinizing hormone in folliculogenesis

Around 400 follicles sequentially mature and ovulate duringan average women‘s reproductive lifetime. From birth tothe menopause, the other 99.98% of her follicles begin developmentbut never complete it. Instead they default to atresia due toinadequate stimulation by follicle stimulating hormone (FSH).Follicular growth to the stage of antrum formation (0.25 mmdiameter) is independent of gonadotrophic stimulation. Antrumformation and further growth to the stage at which folliclesbecome potentially able to begin pre-ovulatory development (2–5mm diameter) require tonic stimulation by FSH. Before onsetof puberty, blood concentrations of FSH do not rise sufficientlyto sustain development beyond this stage, therefore all antralfollicles become atretic. After puberty, as each menstrual cyclebegins, FSH concentrations rise beyond a critical ‘threshold’and multiple follicles are recruited to begin pre-ovulatorydevelopment. Due to increases in its responsiveness to FSH andluteinizing hormone (LH), one of these follicles becomes selectedto ovulate while the remainder become atretic. At mid-follicularphase, the dominant follicle reaches 10 mm in diameter and increasinglysynthesizes oestradiol. Tonic stimulation by FSH and LH, underpinnedby local paracrine signalling, maintains oestrogen secretionby the dominant follicle, which grows to 20 mm in diameter beforeit ovulates in response to the mid-cycle LH surge. The development-relatedresponse to LH shown by the pre-ovulatory follicle raises thepossibility that exogenous LH might be used as an adjunct totherapy with exogenous FSH in clinical ovulation induction regimenswhere the aim is to induce monovulation.     

Recombinat hormones: Molecular biology and biochemistry of human recombinant follicle stimulating hormone (Puregon(R))

Follicle stimulating hormone (FSH) is a heterodimeric glycoproteinhormone produced in the anterior pituitary gland. The hormoneis essential in the regulation of reproductive processes, suchas follicular development and ovulation. It is clinically usedfor treatment of anovulation and in assisted reproduction technologiessuch as in-vrtro fertilization (IVF) and intracytoplasmic sperminjection (ICSI). Until recently, the only source for humanFSH has been the urine from post-menopausal women. Such a naturalsource implies limited availability and potential product variability.Thus, we have cloned the genes encoding the     

A bioequivalence study of two urinary follicle stimulating hormone preparations: Follegon and Metrodin

The purpose of this study was to demonstrate bioequival-encebetween two follicle stimulating hormone (FSH)-only gonadotrophinpreparations (Follegon and Metrodin1) after a single i.m.injection of 300IU FSH in-vivo bioactivity. A total of 16 healthynormally cycling females were treated for 7 weeks with a high-doseoral contraceptive containing 50 µg ethinyl oestradiolplus 2.5 mg lynestrenol (Lyndiol) to suppress endogenous gonadotrophinproduction. After 3 and 5 weeks of oral contraceptive treatment,each subject received 300 IU Follegon or Metrodin in a randomorder. Frequent blood sampling was performed to measure immunoreactiveFSH for pharmacokinetic analysis. After normalization for theimmunodose administered, Follegon and Metrodin were bioequivalentwith respect to the extent and the rate of absorption, the eliminationhalf-life and plasma clearance per kg. The time taken to reachpeak plasma FSH concentrations was shorter with Follegon thanwith Metrodin. Because bioequivalence was proved for the majorpharmacokinetic variables, it can be assumed that Follegon andMetrodin are also equally effective in ovula-tion induction,in-vitro fertilization and embryo transfer programmes and thetreatment of male infertility.