Dose selection of corifollitropin alfa by modeling and simulation in controlled ovarian stimulation.

In controlled ovarian stimulation (COS), a single subcutaneous dose of corifollitropin alfa is used to initiate and sustain multifollicular growth for 7 days. The objective of this study was to determine the optimal dose of corifollitropin alfa. A pharmacokinetic model was developed to describe the time profile of corifollitropin alfa concentrations. Multiple parameters reflecting ovarian response were included in a pharmacokinetic-pharmacodynamic (PK-PD) model framework. An early decline in serum inhibin B was shown to be a sensitive marker for COS failure. Simulations were performed to select the lowest corifollitropin alfa dose that would result in a minimal cancellation rate: 100 microg for a group of women weighing 60 kg. With these doses, the predicted mean number of oocytes per started COS cycle was similar in the two groups, i.e., 12.1 and 13.2, respectively. The selected doses were tested in prospective clinical trials and were proven to be adequate.

A double-blind, non-inferiority RCT comparing corifollitropin alfa and recombinant FSH during the first seven days of ovarian stimulation using a GnRH antagonist protocol.

BACKGROUND: Corifollitropin alfa, a fusion protein lacking LH activity, has a longer elimination half-life and extended time to peak levels than recombinant FSH (rFSH). A single injection of corifollitropin alfa may replace seven daily gonadotrophin injections during the first week of ovarian stimulation. METHODS: In this large, double-blind, randomized, non-inferiority trial the ongoing pregnancy rates were assessed after one injection of 150 microg corifollitropin alfa during the first week of stimulation and compared with daily injections of 200 IU rFSH using a standard GnRH antagonist protocol. RESULTS: The study population comprised 1506 treated patients with mean age of 31.5 years and body weight of 68.6 kg. Ongoing pregnancy rates of 38.9% for the corifollitropin alfa group and 38.1% for rFSH were achieved, with an estimated non-significant difference of 0.9% [95% confidence interval (CI): -3.9; 5.7] in favor of corifollitropin alfa. Stratified analyses of pregnancy rates confirmed robustness of this primary outcome by showing similar results regardless of IVF or ICSI, or number of embryos transferred. A slightly higher follicular response with corifollitropin alfa resulted in a higher number of cumulus-oocyte-complexes compared with rFSH [estimated difference 1.2 (95% CI: 0.5; 1.9)], whereas median duration of stimulation was equal (9 days) and incidence of (moderate/severe) ovarian hyperstimulation syndrome was the same (4.1 and 2.7%, respectively P = 0.15). CONCLUSION: Corifollitropin alfa is a novel and effective treatment option for potential normal responder patients undergoing ovarian stimulation with GnRH antagonist co-treatment for IVF resulting in a high ongoing pregnancy rate, equal to that achieved with daily rFSH. The trial was registered under ClinicalTrials.gov identifier NTC00696800.

Advances in recombinant DNA technology: corifollitropin alfa, a hybrid molecule with sustained follicle-stimulating activity and reduced injection frequency.

BACKGROUND: Recombinant DNA technologies have been used to develop longer-acting therapeutic proteins. One approach is to introduce sequences containing additional glycosylation sites. Using this technique, a new chimeric gene has been developed containing the coding sequences of the FSH beta-subunit and the C-terminal peptide of the hCG beta-subunit, which bears four O-linked oligosaccharide binding sites. Co-expression of the alpha-subunit and the chimeric FSH beta-subunit produces a new recombinant molecule, named corifollitropin alfa, with a prolonged elimination half-life and enhanced in vivo bioactivity compared with wild-type FSH. METHODS: Medline searches by subject and additional searching by hand. RESULTS: Initial studies in pituitary suppressed female volunteers confirmed the extended half-life of the compound. Phase II studies have shown that corifollitropin alfa is able to induce and sustain multi-follicular growth for an entire week in women undergoing ovarian stimulation using GnRH antagonist co-treatment for IVF. Corifollitropin alfa regimens have been developed with dosages of 100 and 150 microg, for patients with body weight 60 kg, respectively. CONCLUSIONS: Corifollitropin alfa is the first long-acting hybrid molecule with sustained follicle-stimulating activity developed for the induction of multi-follicular growth along with GnRH antagonist co-treatment for IVF. This new treatment option may be simpler and more convenient for patients compared with conventional long protocols of daily FSH injections in combination with GnRH agonist co-treatment. The safety and efficacy of such regimens is currently being evaluated in large comparative phase III clinical trials. The development of corifollitropin alfa is the first step towards a new generation of recombinant gonadotrophins.

LH suppression following different low doses of the GnRH antagonist ganirelix in polycystic ovary syndrome.

Elevated LH concentration is a common feature in polycystic ovary syndrome (PCOS). This study was designed to establish whether elevated LH levels in PCOS might be suppressed to normal range values by the administration of different low doses of GnRH antagonist, which subsequently might reverse the anovulatory status of these patients. Twenty-four PCOS patients with elevated endogenous LH concentrations were randomized into 3 different dose groups, receiving either 0.125 mg (Group A), 0.250 mg (Group B) or 0.500 mg (Group C) ganirelix sc daily for 7 subsequent days. During the first day of treatment, LH and FSH levels were assessed at 20 min intervals, during 8 h. Thereafter LH, FSH, androgens, estradiol (E2) and inhibins were assessed daily and frequent ultrasound scans were performed for 7 days to record follicle development. Repeated GnRH antagonist administration induced a significant suppression of LH (and to a lesser extent of FSH) serum levels, which was comparable between the different doses. Six hours after ganirelix administration, endogenous LH was suppressed by 49, 69 and 75%, and endogenous FSH was suppressed by 23, 19 and 25%, respectively. The decrease in serum LH and FSH levels was transient and lasted for 12 h, after which serum levels returned to baseline levels at 24 h after drug administration. Androgen levels were not significantly suppressed using this regimen. E2 levels decreased significantly (p < 0.001) and suppression was most pronounced in Group C. Spontaneous follicle development or ovulations were not recorded during the course of treatment. In conclusion, the present study demonstrates that the GnRH antagonist ganirelix is capable of normalising elevated LH levels in PCOS patients, in doses similar to the ones previously shown to prevent a premature LH rise during ovarian hyperstimulation for in vitro fertilization (IVF). In addition, the transient suppression of elevated endogenous LH levels per se does not re-establish normal follicle development in PCOS. However, follicle development may be insufficiently supported by the accompanied subtle suppression of endogenous FSH. Similarly, a transient decline in E2 levels does not effectively restore normal pituitary ovarian feedback. Moreover, these results support the contention of a limited role of LH in the pathogenesis of PCOS.