Subcutaneous administration of a depot gonadotropin-releasing hormone agonist induces profound reproductive axis suppression in women

Implantable device actuated by manual button clicks for noninvasive self-drug administration

Self-injectable therapy has several advantages in the treatment of metabolic disorders. However, frequent injections with needles impair patient compliance and medication adherence. Therefore, we develop a fully implantable device capable of on-demand administration of self-injection drugs via noninvasive manual button clicks on the outer skin. The device is designed to infuse the drug only at the moment of click actuation, which allows for an accurate and reproducible drug infusion, and also prevents unwanted drug leakage. Using a mechanical means of drug infusion, this implantable device does not contain any electronic compartments or batteries, making it compact, and semi-permanent. When tested in animals, the device can achieve subcutaneous injection-like pharmacokinetic and pharmacodynamic effects for self-injection drugs such as exenatide, insulin, and glucagon.

First pre-filled pen device with highly purified human menopausal gonadotropin (HP-hMG, Menopur) in liquid is shown to be bioequivalent to powder for reconstitution

OBJECTIVE

To determine whether serum human follicle-stimulating hormone (FSH) levels after single subcutaneous dosing of highly purified human menopausal gonadotropins (HP-hMG) in a liquid formulation and a powder formulation are bioequivalent.

MATERIALS AND METHODS

This was a randomized, two-way, crossover, single-dose, bioequivalence trial comparing Menopur liquid injected by pre-filled pen, with Menopur powder injected by conventional syringe and needle. The primary endpoints were AUC_t and C_max of baseline-adjusted FSH. Pituitary-suppressed, healthy women were administered single subcutaneous injections of 450 IU Menopur liquid (600 IU/0.96 mL) and 450 IU Menopur powder (by 2 subcutaneous injections of 225 IU in 1 mL) in a randomized order. The pharmacokinetic parameters of FSH and human chorionic gonadotropin (hCG) were assessed by non-compartmental methods with adjustment for endogenous pre-dose levels.

RESULTS

In total, 76 women were randomized, and 56 completed the trial. The mean FSH and hCG serum concentration-time profiles were comparable between the two HP-hMG formulations. The geometric mean ratios and 90% confidence intervals of FSH for HP-hMG liquid versus HP-hMG powder were 1.12 (1.0562 - 1.1889) for AUC_t and 1.17 (1.0946 - 1.2490) for C_max, showing that the two formulations were bioequivalent. The incidence and severity of adverse events were similar between the two preparations, and both preparations were well tolerated.

CONCLUSION

The 90% CIs for the geometric mean ratios of serum FSH AUC_t and C_max were both within 0.8000 - 1.2500, thus the two formulations are bioequivalent.

Ovarian suppression failure during GnRH agonist treatment: A report of three breast cancer patients

In premenopausal women treated for breast cancer, endocrine therapy combining an aromatase inhibitor (AI) and a gonadotropin-releasing hormone (GnRH) agonist (GA) for ovarian suppression may be indicated in high-risk or in metastatic cancer. AIs are effective in premenopausal women only when ovarian estrogen production is suppressed, a state achievable through the use of GAs. However, a complete suppression sometimes proves elusive. We report here three cases of ovarian suppression failure in premenopausal breast cancer patients who received adjuvant AI+GA. Frequency of GA administration, BMI, and young age could affect gonadotropin suppression and may be implied in these failures. Clinical monitoring of these patients is advisable, and hormone assays and pelvic ultrasound should be performed in case of symptoms of estrogen activity.

Effect of GnRHa 3.75 mg subcutaneously every 6 weeks on adult height in girls with idiopathic central precocious puberty

OBJECTIVE

To evaluate the long-term efficacy of triptorelin 3.75 mg subcutaneously every 6 weeks on the final height in girls with idiopathic central precocious puberty (ICPP).

METHODS

Forty females with ICPP received triptorelin 3.75 mg every 6 weeks subcutaneously in our hospital from 2002 to December 2010 and reached their final heights were enrolled. These patients were treated with triptorelin alone (group A, n=17) or triptorelin+recombinant human growth hormone (rhGH) (group B, n=23). Height, weight, annual growth velocity (GV), sexual development, predicted adult height (PAH), and adverse effects were observed. Bone age (BA) and height standard deviation score (SDS) were monitored yearly.

RESULTS

Final adult heights (FAHs) were 159.81±1.20 cm and 161.01±1.02 cm in group A vs. group B, which exceeded target height (THt) by 1.51±1.04 cm, 4.86±0.94 cm, respectively. The values of (FAH-THt), (FAH-PAH posttreatment) showed significant difference between the two groups (p<0.05). FAH was positively correlated with Ht SDS-BA at the end of treatment, THt, course of rhGH treatment, and age of menarche (r2=0.66). Body mass index (BMI) increased after treatment in group B. However, there was no significant tendency of increase compared with healthy children at the same age. Ages of menarche and time to menarche from discontinuation were 11.74±0.16 vs. 12.18±0.15 years and 17.41±1.69 vs. 14.71±1.04 months in two groups.

CONCLUSION

The FAH was improved effectively by triptorelin 3.75 mg subcutaneously every 6 weeks, and more height gain could be achieved when rhGH was used concomitantly. BMI maintained steadily and ovarian function restored quickly after treatment discontinuation with the age of menarche similar to that of normal children. Neither significant side effect nor polycystic ovary syndrome was observed.

Efficacy of subcutaneous administration of gonadotropin-releasing hormone agonist on idiopathic central precocious puberty

In order to assess the feasibility of subcutaneous administration of Triptorelin with 6-week intervals for the suppression of pituitary-gonadal axis and changes of clinical signs in girls with idiopathic central precocious puberty (ICPP), 46 girls with ICPP were treated with GnRHa. Triptorelin (Decapeptyl, 3.75 mg) was administered subcutaneously (SC) at 6-weeks intervals or intramuscularly (IM) at 4-weeks intervals randomly for more than 12 months consecutively. During GnRHa therapy, clinical parameters and laboratory data, including height, weight, pubertal stage, bone age, uterine volume and ovarian size, serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and estradiol (E2), were monitored and analyzed. It was found that both treatment regimes led to regression of precocious puberty and reversal of secondary sexual characteristics. Breast developments regressed. Uterine volume was decreased after treatment, but there was no statistically significant difference. Mean ovarian volume did not change significantly during treatment. The height velocity was decreased significantly from 6.3+/-1.4 cm/year to 5.8+/-1.2 cm/year in group SC and 6.7+/-1.3 cm/year to 5.4+/-1.0 cm/year in group IM, respectively. The rate of bone maturation was reduced significantly during treatment. The ratio of deltaBA/deltaCA was 1.2+/-0.2 or 1.3+/-0.3 at the onset of therapy and decreased significantly after the treatment to 0.7+/-0.2 or 0.9+/-0.1, respectively. The predicted adult height was increased significantly and progressively during therapy. The levels of serum LH, FSH and E2 returned to the prepubertal condition. No significant side effects of therapy were noted. The most common side effect during SC treatment was that a non-irritating, 1 cm in diameter mass was palpated at the site of subcutaneous injection in the abdominal wall of patients, which disappeared after 6-12 weeks. Two girls had minimal withdrawal vaginal bleeding episodes after the first injection. It was concluded that both IM and SC triptorelin administrations were clinically effective. They induce profound suppression of hypothalamic-pituitary-gonadal axis while stabilizing height velocity, slowing bone maturation and increasing predicted adult height. These results suggest that subcutaneous injection of triptorelin in 6-weeks intervals at a dosage of 3.75 mg be a safe and acceptable regimen for ICPP

Population pharmacokinetic/pharmacodynamic (PK/PD) modelling of the hypothalamic-pituitary-gonadal axis following treatment with GnRH analogues

AIMS

To develop a population pharmacokinetic/pharmacodynamic (PK/PD) model of the hypothalamic-pituitary-gonadal (HPG) axis describing the changes in luteinizing hormone (LH) and testosterone concentrations following treatment with the gonadotropin-releasing hormone (GnRH) agonist triptorelin and the GnRH receptor blocker degarelix.

METHODS

Fifty-eight healthy subjects received single subcutaneous or intramuscular injections of 3.75 mg of triptorelin and 170 prostate cancer patients received multiple subcutaneous doses of degarelix of between 120 and 320 mg. All subjects were pooled for the population PK/PD data analysis. A systematic population PK/PD model-building framework using stochastic differential equations was applied to the data to identify nonlinear dynamic dependencies and to deconvolve the functional feedback interactions of the HPG axis.

RESULTS

In our final PK/PD model of the HPG axis, the half-life of LH was estimated to be 1.3 h and that of testosterone 7.69 h, which corresponds well with literature values. The estimated potency of LH with respect to testosterone secretion was 5.18 IU l(-1), with a maximal stimulation of 77.5 times basal testosterone production. The estimated maximal triptorelin stimulation of the basal LH pool release was 1330 times above basal concentrations, with a potency of 0.047 ng ml(-1). The LH pool release was decreased by a maximum of 94.2% by degarelix with an estimated potency of 1.49 ng ml(-1).

CONCLUSIONS

Our model of the HPG axis was able to account for the different dynamic responses observed after administration of both GnRH agonists and GnRH receptor blockers, suggesting that the model adequately characterizes the underlying physiology of the endocrine system.

An open and randomized study comparing the efficacy of standard danazol and modified triptorelin regimens for postoperative disease management of moderate to severe endometriosis

OBJECTIVE

To compare the efficacy of danazol and triptorelin (Decapeptyl CR, Ferring, Kiel, Germany) in the management of moderate and severe endometriosis in terms of symptom control and revised American Fertility Society (AFS) score reduction, and to evaluate the hormonal profile of patients treated with triptorelin every 6 weeks.

DESIGN

Open and randomized trial.

SETTING

Kwong Wah Hospital, a large public hospital in an urban location (Hong Kong).

PATIENT(S)

Forty patients after their first conservative operation for endometriosis, with surgical confirmation of revised AFS stage III or IV endometriosis.

INTERVENTION(S)

Postoperative 6 months' therapy of danazol or triptorelin every 6 weeks, postmedical therapy second-look laparoscopy.

MAIN OUTCOME MEASURE(S)

Symptom control and patients' tolerance during medical therapy, posttherapy revised AFS score, hormonal profile during triptorelin therapy.

RESULT(S)

Pain control was similar between danazol and triptorelin therapy. There was less breakthrough bleeding with triptorelin. More patients failed to complete the whole course of danazol because of its side effects. The revised AFS score at second-look laparoscopy did not show a significant difference between the two medications. Adequate pituitary suppression was observed with injection of triptorelin every 6 weeks.

CONCLUSION(S)

Lengthening of triptorelin administration intervals from 4 weeks to 6 weeks is effective in maintaining a hypoestrogenic state. Patients were more compliant with triptorelin than danazol. Thus, triptorelin injection every 6 weeks is more cost-effective than conventional regimens.

A crossover study of triptorelin and leuprorelin acetate

OBJECTIVE

To compare the potency, side effects, and duration of action of triptorelin and leuprorelin acetate after i.m. injections.

DESIGN

Prospective, double-blind crossover clinical study.

SETTING

A teaching hospital.

PATIENT(S)

Fifty-four patients with pelvic endometriosis.

INTERVENTION(S)

Twenty-seven patients had three doses of i.m. triptorelin (3.75 mg) followed by three doses of i.m. leuprorelin acetate at 4-week intervals. Twenty-one patients had three doses of i.m. leuprorelin acetate (3.75 mg) followed by three doses of i.m. triptorelin, also at 4-week intervals.

MAIN OUTCOME MEASURE(S)

Menopausal symptoms, time taken for menstruation to return, serum E(2), FSH, LH levels, lipid profiles, and liver function tests.

RESULT(S)

The potencies of triptorelin and leuprorelin acetate in lowering the serum E(2), FSH, and LH levels were comparable. The severity of menopausal symptoms, changes in the lipid profile and liver function parameters were similar after triptorelin and leuprorelin acetate. The resurgence of ovarian activities and the spontaneous return of menstruation occurred significantly earlier after leuprorelin acetate than triptorelin.

CONCLUSION(S)

Both drugs are equally potent in down-regulating the pituitary-ovarian function, and their side effects are similar. Triptorelin has a longer duration of drug action and can be administered over a longer interval period.