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Follitropin delta in repeated ovarian stimulation for IVF: Phase 3 safety trial to evaluate the immunogenicity of follitropin delta in repeated ovarian stimulation.1



Design: Controlled, assessor-blind trial in in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) patients undergoing repeated cycles of ovarian stimulation (cycles 2 and 3), following initial stimulation with follitropin delta or follitropin alfa (cycle 1) in a preceding randomised trial. In cycles 2 and 3, 513 and 188 women, respectively, were treated as randomised in cycle 1, with dosing based on ovarian response in the previous cycle.

Primary endpoint: The primary endpoint was the proportion of women with treatment-induced anti–follicle-stimulating hormone (FSH) antibodies after up to two repeated cycles of ovarian stimulation.

Secondary endpoints:

  • Secondary endpoints covered the proportion of women with neutralising antibodies, and treatment induced antibodies by cycle (overall and neutralising).
  • Additional secondary endpoints included pregnancy and live birth rates, ovarian response, embryology, adverse events and ovarian hyperstimulation syndrome (OHSS) (including OHSS of moderate/severe grade) and/or OHSS preventive measures.


The incidence of treatment-induced anti-FSH antibodies with follitropin delta was 0.8% and 1.1% in cycles 2 and 3, respectively, which was similar to the incidence in cycle 1 (1.1%). No antibodies were of neutralising capacity. Women with pre-existing anti-FSH antibodies were treated with follitropin delta without boosting an immune response. Treatment with follitropin delta and follitropin alfa gave similar outcomes for mean number of oocytes retrieved (9.2 versus 8.6 [cycle 2]; 8.3 versus 8.9 [cycle 3]), ongoing pregnancy (27.8% versus 25.7%; 27.4% versus 28.0%) and live birth rates (27.4% versus 25.3%; 26.3% versus 26.9%). The presence of anti-FSH antibodies did not affect the ovarian response.



The trial demonstrated the low immunogenic potential of follitropin delta in repeated ovarian stimulation, and confirmed the appropriateness of the follitropin delta dosing regimen in repeated cycles, with documented efficacy and tolerability.



  1. Bosch E et al. Reproductive BioMedicine Online 2019;38:195–205.

Job Code: UK-REK-2300017 - Date of preparation: July 2023


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