Algorithm vs. clinical experience: controlled ovarian stimulations with follitropin-delta and individualised doses of follitropin-alpha/beta.

In the registrational trials, follitropin delta was compared with a fixed dose of 150 UI of follitropin alpha/beta, finding higher chances to reach a target response of 8-14 oocytes compared to controls. For this reason, follitropin delta is marketed as particularly useful in expected hyper-responder patients. The main outcome of this study is to report if comparable results are reached in a real-life scenario with follitropin alpha/beta personalized doses, based on patients' characteristics. This is a retrospective study performed in two public fertility centres. All first cycles from January 2020 to June 2022 with either follitropin delta (cases) or alpha/beta (controls) in patients with antiMüllerian hormone >2.5 ng/ml were compared by an inverse probability weighting approach based on propensity score. The follitropin total dose was higher in controls (1179.06 ± 344.93 vs. 1668.67 ± 555.22 IU, p<0.001). The target response of 8-14 oocytes was reached by 40.2% of cases and 40.7% of controls (odds ratio (OR) 0.99, 95% confidence interval (CI) 0.65-1.53, p=0.98). Fewer than 8 oocytes were collected in 24.1% of cases and 22% of controls (OR 1.10, 95% CI 0.71-1.69, p=0.67); more than 14 oocytes in 35.7% of cases and 37.3% of controls (OR 0.83, 95% CI 0.54-1.28, p=0.40). Our experience did not find worse results in term of proportion of patients who reached the target response with an algorithm-chosen dose of follitropin delta compared to a personalised starting dose of follitropin alpha/beta, with follitropin delta having the advantage of objectivity. Larger numbers are needed to confirm these results.