Randomized sibling-oocyte study using recombinant human hyaluronidase versus bovine-derived Sigma hyaluronidase in ICSI patients

BACKGROUND The enzyme hyaluronidase from bovine origin is commonly used for oocyte–cumulus cell removal in ICSI. A recombinant human hyaluronidase (rHuPH20) has been introduced as a quality-controlled and safe alternative. METHODS In order to validate its effectiveness, a non-inferiority trial was started on sibling cumulus–oocyte complexes (135 ICSI patients). Oocyte denudation involved enzyme incubation under Pasteur pipetting, followed by further mechanical stripping. Primary end-points were oocyte intactness after ICSI and fertilization rate. Secondary end-points were embryo development and positive hCG. RESULTS Oocyte intactness after ICSI was 89.6% and 92.9% with rHuPH20 and bovine hyaluronidase, respectively [absolute difference −3.3% (−7.4 to 10.7)]. The fertilization rate was 73.9% after rHuPH20 and 77.1% after bovine hyaluronidase treatment [absolute difference −3.2% (−8.3 to 1.8)]. Embryo development was similar in both treatment groups up till Day 5. Positive hCGs were equally distributed over mixed transfers 21/45 (46.7%) and transfers of only embryos from rHuPH20 treatment 17/35 (48.6%) or transfers of only embryos from bovine hyaluronidase treatment 22/48 (45.8%). CONCLUSIONS Our results indicate that rHuPH20 is not inferior to bovine hyaluronidase for oocyte denudation, with regard to oocyte survival and fertilization. rHuPH20 treatment of human oocytes is compatible with good embryo development, with positive hCG results and with live birth.