6 December 2016
After a great deal of evidence gathering, consultation and discussion, the Department of Health has announced its approval of the introduction of non-invasive prenatal testing (NIPT) as part of the NHS antenatal screening pathway.
NIPT enables highly accurate detection of certain genomic abnormalities - such as those that cause Down's, Patau's or Edward’s syndromes – directly from a maternal blood sample and so, unlike invasive prenatal testing using amniocentesis or chorionic villus sampling, poses no risk of harm to the foetus.
The National Screening Committee recommended that NIPT is introduced as a second line test within the antenatal screening pathway and so will only be offered to women who – having undertaken a biochemical screening test – are found to be carrying a foetus at ‘high risk’ (greater than a 1:150 chance) of having one of these conditions. Currently such women have two options: to continue with their pregnancy without further testing, or to have an invasive test to obtain a definitive diagnosis. These invasive procedures carry a small but significant risk of miscarriage (around 1%), and so women must choose between the desire to know for certain whether or not their foetus is affected, and the risk that they might lose the foetus in the act of finding out.
The great breakthrough of NIPT is that it offers women the option to obtain highly accurate information about whether their foetus is affected by one of these conditions without undergoing an invasive procedure.
For the majority of ‘high risk’ women the test will confirm with almost 100% certainty that their foetus is not affected. And for the 10% of ‘high risk’ women whose foetus is affected, they can get a more confident (albeit still less than 100% accurate) prediction of this fact, and can then choose either to continue their pregnancy without further testing or to achieve definitive diagnosis through invasive testing. The RAPID trial, which evaluated the use of NIPT in the NHS, found that its use in high risk women could avoid nearly 5000 invasive tests per year resulting in 25 fewer miscarriages.
NIPT is not a new technique. More than seven years ago its use in antenatal testing was discussed in a PHG Foundation report; FDA-approved commercially developed NIPT tests are in widespread use in the USA; and NIPT is available in the UK in private clinics. The National Screening Committee reviewed the evidence for NIPT use in 2015, yet the test is not going to be available as part of NHS care until 2018, constituting a further delay, during which time many women will continue, unnecessarily, to face the dilemmas associated with the choice to undergo or decline invasive testing during pregnancy.
Could the evidence of effectiveness, cost-benefit and feasibility have been gathered more quickly? Should the health service be more responsive to the emergence of innovations (one of the recommendations of the Accelerated Access Review)? Or, given the stellar work of the RAPID study - evaluating this test in ‘real world’ NHS settings and providing guidance on efficient and responsible implementation - is it apposite in this case to look at decision making processes in our health system today and ask how is it possible that the addition of a single test into a nationally standardised, rigorously performance managed care pathway can take so long?
Some of the delay will be due to the entirely justifiable care taken to ensure that healthcare practitioners are properly trained to deliver the test safely, effectively, consistently and appropriately nationwide. However, the time taken to reach key decisions, and the wider context of the current financial strain on the health system, are likely to have contributed as well. One can only hope that the Department of Health, NHS England and Public Health England will take a long hard look at their processes, particularly in light of the Accelerated Access Review, and challenge themselves to do better.
Furthermore, if NHS England and others do not learn from the example of NIPT as they move towards implementation of other population wide programmes arising from the 100,000 Genomes Project we run the risk of perpetuating or indeed enhancing inequity in access to this important new healthcare tool. Currently, any woman in the UK with £300-£600 to spare can undergo NIPT privately, often in the same hospital by the same staff using the same equipment as are providing their ‘free’ NHS antenatal care. Is it acceptable that access to the advances in safety and effectiveness offered by genomic medicine is accelerated only for those with deep enough pockets to afford it?
NIPT has stimulated considerable debate in the UK about the appropriateness of the way in which antenatal screening for Down's syndrome is offered and whether it should even be offered at all. Ethical, legal and social questions were first addressed by experts in 2009; a Nuffield Council on Bioethics working group is currently considering the same issues about the use of NIPT in the NHS and commercial sector.
NIPT is of course not just a test for Down's syndrome; the same method is already being used to offer a safer route to prenatal genetic diagnosis for a number of rare diseases where suspected in the foetus. Looking forward, as the analytical performance of NIPT improves, it will become possible to test foetuses in utero for an increasing range of genetic and chromosomal conditions. Evaluating the extent to which whole exome and whole genome analysis (for diagnostic purposes) of the foetus would be possible, and whether or not it is ethically and socially acceptable, are goals of the PAGE study.
There will always be a range of views on the acceptability of prenatal screening and testing for genetic diseases, and the acceptability of the uses to which parents put the resulting information. Personal choice in these matters is extremely important for women, and it is right to consider carefully the impact of new technologies. However (in my opinion), given that antenatal screening for Down's syndrome and some related conditions already constitutes part of the healthcare ‘offer’ to parents in the UK, and that we strive to make all healthcare as safe and effective as possible, the swift implementation of NIPT is desirable. This is a test that we know will save many women unnecessary distress and, in some cases, the tragedy of miscarriage.