Background: Poor ovarian response remains one of the biggest challenges for reproductive endocrinologists. The introduction of corifollitropin alpha (CFA) offered an alternative option to other gonadotropins for its longer half-life, its more rapid achievement of the threshold and higher FSH levels. We compared two different protocols with CFA, a long agonist and a short antagonist, and a no-CFA protocol.
Methods: Patients enrolled fulfilled at least two of the followings: AFC < 5, AMH < 1,1 ng/ml, less than three oocytes in a previous cycle, age > 40 years. Ovarian stimulation with an antagonist protocol was performed either with 300 UI rFSH and 150 UI rLH or 300UI HMG. In the long agonist group, after pituitary suppression with triptorelin, CFA was given the 1-2th day of cycle and 300 UI rFSH and 150 UI rLH the 5th day. In the short antagonist group CFA was given the 1-2th day of cycle and 300 UI rFSH and 150 UI rLH the 5th day. The primary objective was the effect on the number of oocytes and MII oocytes. Secondary objective were pregnancy rates, ongoing pregnancies and ongoing pregnancies per intention to treat.
Results: The use of CFA resulted in a shorter lenght of stimulation and a lower number of suspended treatments. Both the CFA protocols were significantly different from the no-CFA group in the number of retrieved oocytes (p < 0,05), with a non-significant difference in favour of the long agonist protocol. Both CFA groups yielded higher pregnancy rates, especially the long protocol, due to the higher number of oocytes retrieved (p < 0,05), as implantation rates did not differ. The cumulative pregnancy rate was also different, due to the higher number of cryopreserved blastocysts (p < 0,02).
Conclusions: The long agonist protocol with the addition of rFSH and rLH showed the best results in all the parameters. A short antagonist protocol with CFA was less effective, but not significantly, although provided better results compared to the no-CFA group. We suggest that a long agonist protocol with CFA and recombinant gonadotropins might be a valuable option for poor responders.
Trial registration: The study was approved by the local Ethics Committee (EudraCT2015-002817-31).
Keywords: Agonist; Antagonist; Corifollitropin alfa; Poor responders.