About the project

Moving towards implementing next generation prenatal screening: a new solution could become an integral part of our healthcare system

 

PEGASUS : PErsonalized Genomics for prenatal Aneuploidy Screening USing maternal blood (2013-2017)

Each year, 450,000 Canadian women become pregnant and, as a result of their participation in prenatal screening for Down syndrome, approximately 10,000 of them will have an amniocentesis (i.e. sampling of liquid surrounding the fetus) because of a high risk of carrying a fetus with Down syndrome and of those, 315 will be found to carry a baby with Down syndrome and up to 70 normal pregnancies will be lost from complications of the procedure. It has been discovered recently that, during pregnancy, there is fetal DNA in maternal blood in sufficient quantities to be analysed and methods have been proposed to detect the presence or not of a fetus with Down syndrome using maternal blood. These new methods could reduce significantly the number of amniocentesis performed and thereby prevent the associated loss of normal fetuses. In the the first part of this project we have carried out an independent study that validated the performance and utility of these new genomic technologies for screening in pregnant women using maternal blood in public clinical laboratories. Our team of researchers have identified an evidence-based cost-effective approach for implementation of this new technology in the Canadian health care system. One direct consequence of our study was that on April 22nd 2018, the Québec Minister of Health announced the introduction in the Québec public health care system of the genomic technologies that we developed in this project. Therefore one major goal of the Genome Canada requirements for funding this project, namely the introduction of new health-related genomic-driven practices increasing clinical utility and with important socio-economic benefits, has been achieved.

In addition to developing the laboratory technologies for screening for Down syndrome we have performed economic studies to evaluate the financial impact of introducing these new tests in the public health care system. Such an evaluation is essential for decision-makers given the current context of financial restraints the health care system in general is experiencing. Our analyses suggested that uptake of this new technology as a second tier screening test would be cost-neutral; the increase cost brought about by this new test will be offset by the reduction of amniocentesis procedures performed. These results have also been instrumental in the Ministry of Health’s decision to introduce this technology in the public health care system.

We have developed decision-making tools to assist couples in making informed decisions, as well as educational tools for health care professionals, which are all integral components of the implementation of genomics-based non-invasive prenatal diagnosis. We have explored social and legal issues related to the use of these new technologies to identify gaps that need to be addressed. For example, an analysis of news media reporting on these technologies indicated that the media generally emphasized the benefits and readiness of these technologies, while overlooking the uncertainties and ethical concerns associated with them. We have also performed surveys of pregnant women to identify the factors that influence them with regards to the use of decision-making tools. This knowledge will help us to increase the use of decision-making tools by pregnant women in order for them to make better-informed decisions.

Overall, the deliverables of this first part of the project has enabled decision makers, pregnant women and their partner to make informed choices pertaining to prenatal genetic screening and diagnosis, such as screening for Down syndrome, and reduce the risk to pregnancies associated with amniocentesis.

 

PEGASUS-2 - PErsonalized Genomics for prenatal Abnormalities Screening USing maternal blood : Towards First Tier Screening and Beyond (2018-2022)

The discovery that DNA of fetal origin is present in maternal blood during pregnancy has led to a new genomics-based maternal blood test called non-invasive prenatal screening (NIPS), which is very reliable at screening for Down syndrome. Currently, public healthcare systems pay for this expensive NIPS test only as a second-tier screening for women who have first screened positive on less costly and less accurate biochemical and ultrasound tests. Hence, only after an initial screen has delivered a positive result is NIPS currently used to help women participating in prenatal screening programs avoid a diagnostic amniocentesis. If NIPS were used as the entry-level test for Down syndrome screening, it would benefit women by providing a higher chance of detecting an affected pregnancy and a lower chance of providing a false positive result. It would also enable women to have their final diagnostic result sooner than the current standard of care permits. As well, because NIPS can also detect other fetal chromosome anomalies, its use could enable screening for more conditions.

This project aims to provide high quality evidence to inform decisions by health care organisations about using first-tier NIPS to replace traditional screening tests for Down syndrome, and potentially to screen for other fetal chromosome anomalies. We will compare the current screening approach of second-tier NIPS with the use of first-tier NIPS in a large cohort of pregnant women. We will also study the cost-effectiveness of expanding screening to other conditions, and the ethical, social and legal implications of doing so. As well, we will provide strategies for scaling up shared decision making processes between couples and their health care practitioners. Finally, we will further develop the NIPS technology to lower its costs, expand the detection of other anomalies, and ensure the quality control of clinical-grade NIPS testing in Canada and worldwide. While taking into account the values informing couples’ decisions about participation in prenatal screening, this project will enable publicly funded access to a promising genomics technology for all pregnant women in Canada. Further, it will ensure that couples have access to web-based tools to help their decision making, and that all health care professionals are trained in shared decision making for prenatal screening.

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