Fully human glyco-optimized recombinant FSH (follitropin epsilon) - a randomized, comparator-controlled phase II clinical trial

The study aimed to determine the standard treatment dose of follitropin epsilon for ovarian stimulation in the context of IVF treatment. A total of 247 women aged 18-37 years were treated with either 52.5, 75, 112.5 or 150 IU follitropin epsilon daily, or 150 IU every other day, or 150 IU follitropin alfa daily in a long gonadotrophin-releasing hormone agonist protocol.

The study was performed as a randomized, assessor-blinded, comparator-controlled, six-armed phase II trial in eight fertility clinics in two European countries. The primary results were as follow. First, none of the doses of follitropin epsilon showed superiority for the main outcome measure, i.e. number of follicles ≥12 mm in size.

Follitropin epsilon 75 IU produced results most similar to those of follitropin alfa 150 IU. In terms of secondary results, stronger effects of follitropin epsilon 112.5 IU compared with follitropin alfa 150 IU were seen for secondary outcome measures such as hormone concentrations (oestradiol, inhibin B and progesterone) and oocyte number.

Follitropin epsilon 75 IU daily results in a similar ovarian response to a standard dose of 150 IU follitropin alfa. This dose could be tested in a phase III trial.