Efficacy and safety of frozen thawed embryo transfer in women aged 35 to 42 years from the PURSUE randomized clinical trial

Robert Boostanfar, M.D., Davis Gates, Ph.D., Yanfen Guan, M.S., Keith Gordon, Ph.D., Christine McCrary Sisk, B.S., Barbara J. Stegmann, M.D.


To examine the efficacy and safety of frozen-thawed embryo transfer (FTET) cycles with supernumerary embryos cryopreserved during a randomized clinical trial (PURSUE).

Follow-up clinical study.

In vitro fertilization (IVF) centers.

Infertile women aged 35- to 42-years old.

In PURSUE, women were randomized to a single injection of 150 μg of corifollitropin alfa (n = 694) or daily 300 IU of recombinant follicle-stimulating hormone (recombinant FSH; n = 696) for the first 7 days of controlled ovarian stimulation (COS) in a gonadotropin-releasing hormone (GnRH) antagonist protocol.

Main Outcome Measure(s):
Cumulative vital pregnancy rate per-patient by treatment group, cumulative live-birth rate per-patient by treatment group, and occurrence of adverse events in (pregnant) women and their fetuses/infants and the incidence of congenital malformations in the infants.

Of the 1,390 treated women in PURSUE, 307 were enrolled in the FTET study. In PURSUE or a subsequent FTET cycle, the cumulative vital pregnancy rate (per patient) was 31.1% (95% confidence interval [CI], 27.7%; 34.7%) with corifollitropin alfa versus 33.0% (95% CI: 29.6%; 36.7%) with recombinant FSH; treatment difference, −1.8% (95% CI, −6.5%; 3.0%), and the cumulative live-birth rate (per patient) was 28.2% (95% CI, 24.9%; 31.8%) with corifollitropin alfa versus 29.5% (95% CI, 26.1%; 33.0%) with recombinant FSH; treatment difference, −1.2% (95% CI, −5.7%; 3.4%). There were no clinically relevant differences in safety outcomes collected from pregnant women or their infants after transfer of cryopreserved embryos obtained by treatment with corifollitropin alfa or recombinant FSH.

The cumulative vital pregnancy and live-birth rates (from fresh cycles and FTET) were similar in women treated with corifollitropin alfa and recombinant FSH. No new safety signals were detected in this follow-up FTET study.

Clinical Trial Registration Number:

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