Comparative incidence of ovarian hyperstimulation syndrome following ovarian stimulation with corifollitropin alfa or recombinant FSH

Corifollitropin alfa is a novel recombinant gonadotrophin with sustained follicle-stimulating activity. A single injection can replace seven daily injections of recombinant follicle-stimulating hormone (rFSH) during the first week of ovarian stimulation. All cases of ovarian hyperstimulation syndrome (OHSS) with corifollitropin alfa intervention in a gonadotrophin-releasing hormone antagonist protocol have been assessed in three large trials: Engage, Ensure and Trust. Overall, 1705 patients received corifollitropin alfa and 5.6% experienced mild, moderate or severe OHSS. In the randomized controlled trials, Engage and Ensure, the pooled incidence of OHSS with corifollitropin alfa was 6.9% (71/1023 patients) compared with 6.0% (53/880 patients) in the rFSH group. Adjusted for trial, the odds ratio for OHSS was 1.18 (95% CI 0.81–1.71) indicating that the risk of OHSS for corifollitropin alfa was similar to that for rFSH. The incidence of mild, moderate and severe OHSS was 3.0%, 2.2% and 1.8%, respectively, with corifollitropin alfa, with 1.9% requiring hospitalization, and 3.5%, 1.3% and 1.3%, respectively, in the rFSH arms, with 0.9% requiring hospitalization. Despite a higher ovarian response with corifollitropin alfa compared with rFSH for the first 7 days of ovarian stimulation, the incidence of OHSS was similar.Corifollitropin alfa is a new agent used in ovarian stimulation treatment for IVF fertilization. One injection of corifollitropin alfa can replace seven injections of recombinant FSH (rFSH). In three studies of corifollitropin alfa treatment, we assessed all cases of ovarian hyperstimulation syndrome (OHSS), a potentially serious complication of ovarian stimulation treatment. Overall, 5.6% of the patients (95/1701) experienced OHSS. Two of the trials compared corifollitropin alfa versus rFSH. Because OHSS is relatively rare, we pooled the results of these trials to give a more reliable estimate of the incidence of OHSS. In the pooled analysis, 6.9% (71/1023) of patients receiving corifollitropin alfa had signs or symptoms of OHSS, compared with 6.0% in the rFSH group (53/880). The risk of OHSS with corifollitropin alfa treatment was similar to the risk of OHSS in patients who received rFSH: the incidence of mild, moderate and severe OHSS was 3.0%, 2.2% and 1.8%, respectively, in patients in the corifollitropin alfa treatment groups, with 1.9% requiring hospitalisation, and 3.5%, 1.3% and 1.3%, respectively, in patients in the rFSH treatment groups, with 0.9% requiring hospitalization. Although the ovaries respond more to corifollitropin alfa than to rFSH for the first 7 days of ovarian stimulation, neither treatment regimen was significantly more likely to cause OHSS.