Certolizumab in Recurrent Implantation Failure (RIF)

Overview

Recurrent implantation failure (RIF), defined as the absence of clinical pregnancy after the transfer of three good-quality embryos, concerns up to 40% of IVF couples and is associated with a low success rate. The causes remain unexplained in over 50% of cases. Various dysimmune changes (related to immune T cells profiles, pro-inflammatory cytokines levels) have been described in unexplained RIF as compared to fertile controls, and it has been estimated that such dysimmunity may occur in 50% of unexplained RIFs. Previous data on a benefit of general immune modulation by steroids or immunoglobulins are heterogenous and failed to demonstrate clinically significant benefit. The proinflammatory cytokine Tumor Necrosis Factor (TNF) α participates in the regulation of the immune balance of the endometrium, its peripheral blood and endometrial concentrations are increased in RIF patients as compared to fertile controls. In 2009, a pilot placebo controlled study showed that TNF-α antagonist treatment allowed a 56% live birth rate (versus 13% in controls) in 13 women with unexplained RIF. Due to the lack of maternal and fetal tolerance data, TNF-α antagonists were not further evaluated. Today, safety data issued from 1200 pregnancies are reassuring allowing the use of TNF-α antagonists during pregnancy (www.lecrat.org). In addition the TNF-α antagonist certolizumab does not cross the placental barrier. We hypothesize that certolizumab may improve clinical pregnancy rates in women with unexplained RIF with a good safety profile.

The European Society of Human Reproduction and Embryology (ESHRE) consortium has proposed to define recurrent implantation failure (RIF) as the failure to obtain a clinical pregnancy after the transfer of three good-quality embryos according to the Istanbul consensus 2011. Although its prevalence is difficult to estimate, RIF could concern up to 40% of couples undergoing assisted reproductive technology (ART) treatments. More than 50% of RIF cases remain unexplained after extensive exploration and clinical pregnancy rate in this population is particularly low, estimated at about 15%. Endometrial environment plays a crucial role in embryo implantation and early placental development. In normal pregnancy, the survival of the semi-allogeneic fetus is dependent on the induction of maternal immune tolerance, with regulatory T cells and Th-2 anti-inflammatory profile. Several studies show a misbalance of immune cells and cytokines expression in women with implantation failure. Most studies analyze immune cells and cytokines profile in peripheral blood, with few data on cells and cytokines profiles in endometrial tissues during the periimplantation period. However, the immune endometrial balance could be disturbed in up to 80% of RIF cases. Tumor Necrosis Factor (TNF) α, together with other pro-inflammatory cytokines, participates in the regulation of the immune balance of the endometrium. TNF-α and TNF-α / interleukin (IL)-10 ratio are increased in the endometrium of RIF patients, which suggests they could be involved in physiopathology of RIF. To date there is no effective treatment to improve the low clinical pregnancy rate in unexplained RIF. The repeated failure of embryo transfers and the lack of efficient treatment are associated with psychological distress in infertile couples and raises economic problems because of the important cost of in vitro fertilisation (IVF). Some treatments with immunomodulatory effect, such as steroids, were previously evaluated. However, studies were small and included heterogeneous populations, resulting in inconclusive results. Our hypothesis is that TNF-α antagonists may be particularly useful by blocking TNF-α induced excessive immune-response. In a pilot placebo controlled study, TNF-α antagonists were associated with 56% live births versus 13% in controls, in 13 women with unexplained implantation failure. However, this treatment was not further evaluated in this indication because of the lack of tolerance data and the fear of congenital abnormalities. Concerning the safety of TNF-α antagonists, we now have sufficient data as they are widely used since more than 15 years in several autoimmune and inflammatory diseases. More than 1200 women treated with TNF-α antagonists for an inflammatory disease have provided evidence of their safety in early pregnancy and the French national center of drug-related effects (www.lecrat.org) allows the use of TNF-α antagonists during pregnancy, except during the third trimester. Among TNF-α antagonists, certolizumab have the particularity not to cross the placental barrier and thus can be used during pregnancy, This is why we focus on this particular drug for this trial.