Patients and treatment exposure
A total of 2972 women were included in the FAS. Women had a mean (± standard deviation [SD]) age of 29.7 ± 3.33 years; a mean BMI of 22.3 ± 2.96 kg/m2; and a mean duration of infertility of 43.0 ± 28.26 months. The types of infertility were female infertility alone (n=1223; 41.2%), male and female infertility (n=983; 33.1%), male infertility alone (n=650; 21.9%), and unexplained (n=116; 3.9%).
The most common reasons for female infertility included tubal factor infertility (n=1719; 57.8%), ovulatory dysfunction (n=896; 30.1%) and other reasons (n=358; 12.0%) such as intrauterine insemination failure (n=103; 3.5%), abdominal surgery (n=69; 2.3%), and pelvic disorders (n=28; 0.9%). The mean ± SD baseline FSH, luteinizing hormone, and estradiol levels within 3 months prior to initiating treatment were 6.2 ± 1.6 IU/L, 5.0 ± 4.0 IU/L, and 43.0 ± 22.0 pg/mL, respectively (Table 1). The mean duration of treatment with cetrorelix was 4.8 ± 1.56 days. The mean daily cetrorelix dose was 0.250 ± 0.0 mg, and the mean total dose of cetrorelix was 1.214 ± 0.4293 mg.
Table 1. Demographic and clinical baseline characteristics (Full analysis set)
Characteristic
|
Total
N = 2972
|
Age, years
|
29.7 ± 3.33
|
Body mass index, kg/m2
|
22.3 ± 2.96
|
Duration of infertility, months
|
43.0 ± 28.26
|
Type of infertility
|
|
Female and male
|
983 (33.1)
|
Female only
|
1223 (41.2)
|
Male only
|
650 (21.9)
|
Unexplained
|
116 (3.9)
|
Causes of female infertility
|
|
Tubal factor
|
1719 (57.8)
|
Endometriosis
|
30 (1.0)
|
Ovulatory dysfunction
|
896 (30.1)
|
Other
|
358 (12.0)
|
Follicle stimulating hormone level, IU/L
|
6.2 ± 1.6
|
Luteinizing hormone level, IU/L
|
5.0 ± 4.0
|
Estradiol level, pg/mL
|
43.0 ± 22.0
|
Data in the table are presented as (mean ± standard deviation) or n (%).
Study outcomes
Primary analysis: Factors associated with clinical outcomes
A multivariate logistic regression analysis was performed using data from 671 patients with available data for the independent variables considered in the model building process, with clinical pregnancy outcome (yes/no) set as the dependent variable (Table 2). As only patients with a complete set of variables could be included in the statistical modeling by logistic regression, the total number of patients was substantially reduced in the development and validation of this model.
Table 2. Multivariate logistic regression analysis with clinical pregnancy outcome as the dependent variable
|
Total (N = 1981)
|
Independent variables
|
n
|
Regression coefficient
|
Standard error
|
P-value
|
Odds ratio (95% CI)
|
Progesterone level on the day of hCG triggering, ng/mL
|
671
|
−0.5948
|
0.2036
|
0.0035
|
0.55 (0.37–0.82)
|
Endometrial thickness on the day of hCG triggering, mm
|
671
|
0.1744
|
0.0477
|
0.0003
|
1.19 (1.08–1.31)
|
Total number of embryos on Day 3/blastocysts on Day 5
|
671
|
0.0635
|
0.0138
|
<0.0001
|
1.07 (1.04–1.09)
|
Number of oocytes obtained
|
671
|
0.3518
|
0.1555
|
0.0236
|
1.42 (1.05–1.93)
|
Confounding factors adjusteda
|
Progesterone level on the day of hCG triggering (ng/mL)
|
675
|
−0.4278
|
0.1916
|
0.0256
|
0.65 (0.45–0.95)
|
Endometrial thickness on the day of hCG triggering (mm)
|
675
|
0.1854
|
0.0474
|
0.0001
|
1.20 (1.10–1.32)
|
aThe following factors were considered: serum luteinizing hormone and estradiol levels on the day of starting cetrorelix, number of ≥14 mm follicles, endometrial thickness on the day of hCG triggering, number of oocytes obtained, number of good quality embryos/ blastocysts transferred, age, duration of infertility, type of infertility, cause of infertility, body mass index and smoking status. Of these, only the factors that showed >10% changed in the odds ratio of at least one independent variable were considered as the confounding factor.
Abbreviations: CI, confidence interval; hCG, human chorionic gonadotropin
The analysis revealed that an increased endometrial thickness on the day of human chorionic gonadotropin (hCG) triggering (p=0.0003; odds ratio: 1.19; 95% CI: 1.08–1.31), a higher total number of embryos on Day 3/blastocysts on Day 5 (p <0.0001; OR: 1.07; 95% CI: 1.04–1.09), a higher number of good quality embryos/blastocysts transferred (p=0.0236; OR: 1.42; 95% CI: 1.05–1.93), and a lower progesterone level on the day of hCG triggering (p=0.0035, OR: 0.55, 95% CI: 0.37–0.82) were associated with a higher probability of pregnancy outcome after fresh ET per initiated cycle.
After adjusting for confounding factors, an increased endometrial thickness on the day of hCG triggering was associated with a higher probability of pregnancy outcome (p=0.0001, OR: 1.20; 95% CI: 1.10–1.32). A higher progesterone level on the day of hCG triggering was associated with a lower probability of pregnancy outcome after fresh ET per initiated cycle (p=0.0256; OR: 0.65; 95% CI: 0.45–0.95).
Data from 326 patients were used for model validation. The sensitivity and specificity analyses results are shown in Table 3. A predictive model was established with a sensitivity and specificity of 53.3% and 64.6%, respectively. The overall accuracy of the model was 58.9%.
Table 3. Sensitivity and specificity analyses
|
Clinical pregnancy outcome (observed)
(N = 326)
|
Yes
|
No
|
Total
|
Clinical pregnancy outcome (predicted)
|
Yes
|
88
|
57
|
145
|
No
|
77
|
104
|
181
|
Total
|
165
|
161
|
326
|
The value 0.56 was considered as the cut-off point of the Youden Index for the prediction of clinical pregnancy outcome (Yes [>0.56]/ No [≤0.56]).
Secondary analysis: Clinical outcomes
Clinical outcomes are shown in Table 4. In the FAS, 2972 patients initiated a cycle. Of these, the beta-hCG test was positive in 1215 patients (40.9% per initiated cycle). A total of 1138 patients had confirmed clinical pregnancies (38.3% per initiated cycle) and 970 patients had ongoing pregnancies (32.6% per initiated cycle). The mean number of viable fetuses per initiated cycle was 1.3 ± 0.48 fetuses. The ongoing pregnancy and clinical pregnancy rates per ET cycle were 45.2% and 53.0%, respectively, and the implantation rate was 37.3% per ET.
Table 4. Clinical outcomes (full analysis set)
Clinical outcomes
|
Total
N = 2972
|
No. of initiated cycles, n
|
2972
|
No. of embryo transfer cycles, n
|
2147
|
No. of clinical pregnancies, n
|
1138
|
No. of ongoing pregnancies, n
|
970
|
No. of early miscarriages, n
|
152
|
No. of live births reported, n
|
970
|
Proportion of patients reaching clinical outcomes
|
Clinical pregnancy rate,a (%)
Per embryo transfer cycles
|
53.0
|
Ongoing pregnancy rate,b (%)
Per embryo transfer cycles
|
45.2
|
Live birth rate,c (%)
Per embryo transfer cycles
|
45.2
|
Implantation rate,d (%)
|
37.3
|
Cycle canceled rate, (%)
|
5.7
|
Early miscarriage rate,e (%)
|
13.4
|
aClinical pregnancy rate = (Number of clinical pregnancies/Total number of cycles performed) × 100
bOngoing pregnancy rate per embryo transfer cycle = (Number of ongoing pregnancy/No. of embryo transfer cycles) × 100
cLive birth rate = (Number of live births/Total number of cycles performed) × 100
dImplantation rate = (Number of gestational sacs observed/No. of embryos transferred) × 100
eEarly miscarriage rate = (Number of early miscarriages/No. of clinical pregnancies) × 100
A total of 152 early miscarriages were reported out of 1138 clinical pregnancies resulting in an early miscarriage rate of 13.4%. The rate of cancelled cycles was 5.7%. A total of 970 live births were reported with a live birth rate of 32.6% per initiated cycle and a live birth rate of 45.2% per ET cycle.
Subgroup analysis: Clinical outcomes by age and number of oocytes retrieved
In patients aged ≤30 years, implantation rates, clinical pregnancy rates, ongoing pregnancy rates and live birth rates per ET cycles, were slightly higher compared to those aged >30 years. However, clinical pregnancy rates, ongoing pregnancy rates and live birth rates per initiated cycle and aspiration cycle were slightly lower in patients aged ≤30 years than in those aged >30 years. Patients aged ≤30 years had a similar cycle cancellation rate, but a lower early miscarriage rate compared with patients aged >30 years.
Clinical outcomes in terms of implantation rates, clinical pregnancy rates, ongoing pregnancy rates and live birth rates per ET cycle, aspiration cycle, and initiated cycle, were higher in patients for which 4–9 or 10–15 oocytes were retrieved compared with the other subgroups. Overall, clinical outcomes were lower in patients with 1–3 oocytes retrieved, except for ongoing pregnancy rates per initiated cycle, which was lowest in patients with >15 oocytes retrieved (23.7% vs 22.1%).
Safety
Of 2972 patients (100%), 51 patients (1.7%) reported an OHSS event. These events were mild in 24 (0.8%), moderate in 10 (0.3%), and severe in 17 (0.6%) patients. Signs, symptoms, or risk of OHSS led to a freeze-all cycle in 443 (14.9%) patients.