Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT03520933 |
| Other study ID # |
IGX1-NIP-CS-18-02-SUB1 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
April 27, 2018 |
| Est. completion date |
February 10, 2023 |
Study information
| Verified date |
May 2023 |
| Source |
Igenomix |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
Abnormal chromosome number, or aneuploidy, is common in human embryos. It is responsible for
more than half of all miscarriages, and it is the leading cause of congenital birth defects.
Besides, it has been described that aneuploidy may also affect embryo implantation.
Therefore, selecting embryos that have the best chance of implanting and growing into a
healthy baby is one of the most important steps in the field of assisted reproduction.
Recent advances in genetic technologies, such as Next-Generation Sequencing (NGS), have
allowed aneuploidy to be detected with greater sensitivity. The application of this technique
to trophectoderm biopsies, taken from embryos before transfer to the uterus, has provided
insight into the clinical impact of chromosomal status. This process of screening embryos to
make sure they have the right number of chromosomes and to look for any structural
abnormalities in the chromosomes is called Preimplantation Genetic Testing for Aneuploidy
(PGT-A). It requires specific equipment and trained personnel that will add costs and risks,
so non-invasive techniques are sought as an alternative. These non-invasive procedures have
been explored by some groups analyzing the spent culture medium where the embryo is cultured
up to the time of transfer or freezing. In daily routine, this media is discarded after
finishing the embryo culture, but it has been reported that contains traces of embryonic
cell-free DNA (cfDNA) that can represent the genetic load of the embryo. However, at the
moment there is a high variability in results across studies, with a percentage of concordant
results between the media and the trophectoderm biopsy ranging from 3.5 to 85.7%.
Thus, the main objective of this project is to validate a new non-invasive method for PGT-A
(niPGT-A), based on improved collection and analysis of the culture media to achieve higher
rates of sensitivity and specificity and to decrease the effect of some intrinsic
difficulties such as low embryonic cfDNA input, mosaicism and maternal contamination.
Description:
Human embryos have higher aneuploidy rates (20-80%) than other species. A considerable
proportion of these aneuploid embryos have the ability to reach the blastocyst stage.
However, depending on the aneuploidy type, some will fail to implant in the uterus, while
others will implant but will be unable to carry out early embryonic development
(miscarriage), or very rarely, result in liveborn children with specific abnormalities. It is
therefore important to identify aneuploid embryos. The identification of aneuploidies is
especially important in embryos from patients with higher aneuploidy risk such as those with
advanced maternal age (AMA), recurrent implantation failure (RIF), or recurrent miscarriage
(RM).
PGT-A technique analyse the full chromosome content of the embryo with high sensitivity and
specificity but requires an invasive biopsy to obtain embryonic material for the genetic
analysis. Thus, non-invasive methods to replace the existing invasive testing method would be
useful in the improvement of maternal and fetal safety.
Recently, there have been many research advances in the field of genetic testing. Cell-free
DNA (cfDNA) has been observed in spent embryo culture media. The origin of the cfDNA at the
blastocyst stage remains unknown and this has encouraged different research groups to carry
out analysis of the spent culture media.
Various studies were initially carried out to detect specific genes associated with monogenic
disorders (MTHFR9, HBA1/HBA210, SRY11). Recently, non-invasive PGT-A has been developed, with
highly variable results on the concordance rate (3.5%,59.1%, and 85.7%, 30.6%). The
chromosomal status of the embryo from the DNA present in the spent culture medium was
compared to the one obtained following the standard protocol using trophectoderm biopsy. The
difference in the reported results can be related to the different methodologies applied
because different amplification and detection methods -aCGH or NGS- were used. Moreover, the
concordance rates were defined differently on each study, i.e. aneuploid results in spent
culture media and trophectoderm biopsy could be considered concordant despite of showing not
the same aneuploid chromosomes.
The impact of culture conditions in the efficiency of the non-invasive approach has been
thoroughly investigated. There could be influence of these relevant factors: external
contamination from laboratory personnel or equipment, contamination with maternal DNA from
granulosa cells (MCC) and mosaicism threshold for diagnosis..
To improve the results of IVF (In vitro Fertilization) programs, there is a need to identify
the embryo with highest implantation potential. Embryo chromosomal analysis allows the
selection of euploid embryos, which have a higher implantation success rate.
The development of a non-invasive PGT-A protocol will improve the current methodologies used
to identify those euploid embryos avoiding the detrimental effect of the biopsy on the embryo
and decreasing the economic cost.
The main objective of the current study is to validate a new non-invasive method for PGT-A
(niPGT-A), based on improved collection and analysis of the culture media to achieve higher
rates of sensitivity and specificity and to decrease the effect of some intrinsic
difficulties such as low embryonic cfDNA input and maternal contamination. The initial
estimated sample size calculated was 3245embryos (each embryo is considered as a subject in
the study), considering a dropout rate of 30%.
Data exported from the medical records and source documents will be duly codified to protect
the clinical and personal information of patients in accordance with the current legislation.
This information will be exported to an electronic Case Report Form (eCRF). Data will be
grouped and analyzed at Igenomix at three time points of the study: once 25 embryos of each
center have been processed (to assess the implementation of the methodology), after the 30%
of the samples have been processed (as an interim to check the results) and at the end of the
study for the final analysis including the follow up of the clinical outcomes (defined
following The International Glossary on Infertility and Fertility Care, 2017).
After the interim analysis, the total sample size has been recalculated as 2620 samples,
considering a drop-out rate of 5% according to the drop-out rate observed. Results of the
interim analysis were published in Rubio et al., AJOG 2020.
