Impact of letrozole co-treatment during ovarian stimulation on oocyte yield, embryo development, and live birth rate in women with normal ovarian reserve: secondary outcomes from the RIOT trial.
Does letrozole (LZ) co-treatment during ovarian stimulation with gonadotropins for in IVF impact follicle recruitment, oocyte number and quality, embryo quality, or live birth rate (LBR)?
No impact of LZ was found in follicle recruitment, number of oocytes, quality of embryos, or LBR.
Multi-follicle stimulation for IVF produces supra-physiological oestradiol levels. LZ is an aromatase inhibitor that lowers serum oestradiol thus reducing negative feedback and increasing the endogenous gonadotropins in both the follicular and the luteal phases, effectively normalizing the endocrine milieu during IVF treatment.
Secondary outcomes from a randomized, double-blind placebo-controlled trial (RCT) investigating once-daily 5 mg LZ or placebo during stimulation for IVF with FSH. The RCT was conducted at four fertility clinics at University Hospitals in Denmark from August 2016 to November 2018 and pregnancy outcomes of frozen-thawed embryo transfers (FET) registered until May 2023.
One hundred fifty-nine women with expected normal ovarian reserve (anti-Müllerian hormone 8-32 nmol/l) were randomized to either co-treatment with LZ (n = 80) or placebo (n = 79). In total 1268 oocytes were aspirated developing into 386 embryos, and morphology and morphokinetics were assessed. One hundred twenty-nine embryos were transferred in the fresh cycle and 158 embryos in a subsequent FET cycle. The effect of LZ on cumulative clinical pregnancy rate (CPR), LBR, endometrial thickness in the fresh cycle, and total FSH consumption was reported.
The proportion of usable embryos of retrieved oocytes was similar in the LZ group and the placebo group with 0.31 vs 0.36 (mean difference (MD) -0.05, 95% CI (-0.12; 0.03), P = 0.65). The size and number of aspirated follicles at oocyte retrieval were similar with 11.8 vs 10.3 follicles per patient (MD 1.5, 95% CI (-0.5; 3.1), P = 0.50), as well as the number of retrieved oocytes with 8.0 vs 7.9 oocytes (MD 0.1, 95% CI (-1.4; 1.6), P = 0.39) in the LZ and placebo groups, respectively. The chance of retrieving an oocyte from the 13 to 16 mm follicles at trigger day was 66% higher (95% CI (24%; 108%), P = 0.002) in the placebo group than in the LZ group, whilst the chance of retrieving an oocyte from the ≥17 mm follicles at trigger day was 50% higher (95% CI (2%; 98%), P = 0.04) in the LZ group than in the placebo group. The proportion of fertilized oocytes with two-pronuclei per retrieved oocytes or per metaphase II oocytes (MII) (the 2PN rates) were similar regardless of fertilization with IVF or ICSI with 0.48 vs 0.57 (MD -0.09, 95% CI (-0.24; 0.04), P = 0.51), and 0.62 vs 0.64 (MD -0.02, 95% CI (-0.13; 0.07), P = 0.78) in the LZ and placebo groups, respectively. However, the MII rate in the ICSI group was significantly lower with 0.75 vs 0.88 in the LZ vs the placebo group (MD -0.14, 95% CI (-0.22; -0.06), P = 0.03). Blastocysts on Day 5 per patient were similar with 1.5 vs 2.0, P = 0.52, as well as vitrified blastocysts per patient Day 5 with 0.8 vs 1.2 in (MD -0.4, 95% CI (-1.0; 0.2), P = 0.52) and vitrified blastocysts per patient Day 6 with 0.6 vs 0.6 (MD 0, 95% CI (-0.3; 0.3), P = 1.00) in the LZ vs placebo group, respectively. Morphologic evaluation of all usable embryos showed a similar distribution in 'Good', 'Fair', and 'Poor', in the LZ vs placebo group, with an odds ratio (OR) of 0.8 95% CI (0.5; 1.3), P = 0.68 of developing a better class embryo. Two hundred and ninety-five of the 386 embryos were cultured in an embryoscope. Morphokinetic annotations showed that the odds of having a high KIDscore™ D3 Day 3 were 1.2 times higher (CI (0.8; 1.9), P = 0.68) in the LZ group vs the placebo group. The CPR per transfer was comparable with 31% vs 39% (risk-difference of 8%, 95% CI (-25%; 11%), P = 0.65) in the LZ and placebo group, respectively, as well as CPR per transfer adjusted for day of transfer, oestradiol and progesterone levels at trigger, progesterone levels mid-luteal, and number of oocytes retrieved (adjusted OR) of 0.8 (95% CI (0.4; 1.6), P = 0.72). Comparable LBR were found per transfer 28% vs 37% (MD -9%, 95% CI (-26%; 9%), P = 0.60) and per randomized women 24% vs 30% (MD of -6%, CI (-22%; 8%), P = 0.60) in the LZ group and placebo group, respectively. Furthermore, 4.8 years since the last oocyte aspiration, a total of 287 of 386 embryos have been transferred in the fresh or a subsequently FET cycle, disclosing the cumulative CPR, which is similar with 38% vs 34% (MD 95% CI (8%; 16%), P = 0.70) in the LZ vs placebo group.
Both cleavage stage and blastocyst transfer and vitrification were permitted in the protocol, making it necessary to categorize their quality and pool the results. The study was powered to detect hormonal variation but not embryo or pregnancy outcomes.
The similar utilization rate and quality of the embryos support the use of LZ co-treatment for IVF with specific indication as fertility preservation, patients with previous cancer, or poor responders. The effect of LZ on mature oocytes from different follicle sizes and LBRs should be evaluated in a meta-analysis or a larger RCT.
Funding was received from EU Interreg for ReproUnion, Sjaelland University Hospital, Denmark, Ferring Pharmaceuticals, and Gedeon Ricther. Roche Diagnostics contributed with assays. A.P. has received grants from Ferring, Merck Serono, and Gedeon Richter, consulting fees from Preglem, Novo Nordisk, Ferring, Gedeon Richter, Cryos, & Merck A/S, speakers fees from Gedeon Richter, Ferring, Merck A/S, Theramex, & Organon, and travel support from Gedeon Richter. The remaining authors declare that they have no competing interests in the research or publication.
NCT02939898 and NCT02946684.
Bülow NS
，Warzecha AK
，Nielsen MV
，Andersen CY
，Holt MD
，Petersen MR
，Sopa N
，Zedeler A
，Englund AL
，Pinborg A
，Grøndahl ML
，Skouby SO
，Macklon NS
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Ovulation triggering with hCG alone, GnRH agonist alone or in combination? A randomized controlled trial in advanced-age women undergoing IVF/ICSI cycles.
Is a dual ovulation trigger with a combination of GnRH agonist (GnRHa) and hCG superior to single hCG and/or single GnRHa trigger in improving treatment outcomes in advanced-age women (aged ≥ 35 years) undergoing IVF/ICSI treatment?
Co-administration of GnRHa and hCG as a dual trigger increases the number of good-quality embryos but it is not associated with a higher number of oocytes retrieved, compared with single hCG or GnRHa trigger.
Many studies have demonstrated that a dual trigger has positive impact on oocyte maturation, retrieval rate and pregnancy rate without increasing the risk of ovarian hyperstimulation syndrome (OHSS) in some groups of IVF patients, when compared with single hCG trigger. Few studies have however been conducted to compare a dual trigger with a single GnRHa trigger, and insufficient evidence exists to support which trigger can achieve the best outcomes in IVF patients aged ≥35 years.
This was an open-label randomized controlled trial of 510 participants conducted at single reproductive medical center from January 2019 to December 2021. After a sample size calculation performed by retrospectively analyzing our previous clinical data, we planned to recruit 170 patients in each group and 510 patients in total for the study.
Women aged ≥35 years undergoing IVF/ICSI treatment, receiving a non-pituitary down-regulation protocol, and with low risk of OHSS, were enrolled in this trial. On the trigger day, patients were randomized into three groups: hCG alone (who received 6000 IU of hCG), GnRHa alone (who received 0.2 mg of triptorelin) and dual trigger (who received 0.2 mg of triptorelin plus 2000 IU of hCG) groups. The primary outcome parameter was the number of retrieved oocytes. The secondary outcome parameters included, among others, the number and rates of mature oocytes, two pronuclei (2PN) embryos and good-quality embryos, as the rates of OHSS, clinical pregnancy, miscarriage and live birth.
There were no significant differences in the baseline demographic characteristics among the three groups. The dual trigger was associated with a higher retrieval rate (87.9% vs 84.1% in the hCG group, P = 0.031; 87.9% vs 83.6% in the GnRHa group, P = 0.014). However, the number of retrieved oocytes in the dual trigger group was comparable with those in the hCG group (4.08 ± 2.79 vs 3.60 ± 2.71, P = 0.080) and the GnRHa group (4.08 ± 2.79 vs 3.81 ± 3.38, P = 0.101); comparable data between the groups were also found when analyzing the number of 2PN embryos and the 2PN rate. In the dual trigger group, the numbers of good-quality embryos and viable embryos were both significantly higher than in the hCG group (1.74 ± 1.90 vs 1.19 ± 1.45, P = 0.016 and 2.19 ± 2.11 vs 1.56 ± 1.66, P = 0.008, respectively) and the GnRHa group (1.74 ± 1.90 vs 1.20 ± 1.67, P = 0.003 and 2.19 ± 2.11 vs 1.45 ± 1.75, P = 0.001, respectively). Pregnancy outcomes after fresh embryo transfer (ET) were comparable between the groups. The live birth rate and ongoing pregnancy rate after frozen ET in the dual trigger group were significantly higher than those in the GnRHa group (32.6% vs 14.1%, P = 0.007 and 34.8% vs 17.6%, P = 0.013, respectively), but not superior to those in the hCG group (32.6% vs 27.9%, P = 0.537 and 34.8% vs 27.9%, P = 0.358, respectively).
Women of advanced age are quite a heterogeneous population and overlap with poor ovarian responders or patients with diminished ovarian reserve. We therefore could not entirely exclude selection biases or confounding factors. This study was also not a double-blinded trial; the patients in the GnRHa and dual trigger groups could have been affected by the placebo effect.
The results of this study suggest that in advanced-age women with low risk of OHSS, a dual trigger or even a single hCG trigger may be a better choice than a single GnRHa trigger.
This study was supported by the Shanghai Municipal Health Commission of Science and Research Fund (20184Y0289). The authors declare no conflict of interest.
This trial was registered in the Chinese Clinical Trial Registry (ChiCTR-1800016285).
24 May 2018.
2 January 2019.
Zhou C
，Yang X
，Wang Y
，Xi J
，Pan H
，Wang M
，Zhou Y
，Xiao Y
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ResearchGate
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