Selecting IVF Embryos for Normal Numbers of Chromosomes can Significantly Increase Pregnancy Rates
News May 11, 2012
BlueGnome Ltd has announced the results of the first randomized prospective IVF study of pre-implantation chromosome analysis using their 24sure array platform.
The study, published in The Journal of Molecular Cytogenetics by Yang et al (Pacific Reproductive Center, Torrance, USA) has demonstrated that selectively implanting euploid embryos, with a normal number of chromosomes, significantly increases pregnancy rates.
The study blindly randomized 103 IVF cycles. In the treatment group of 55 cycles, 24sure analysis of day 5 biopsies was used to selectively implant a single euploid embryo (as recommended by IVF regulatory bodies such as the HEFA), while in the control group of 48 cycles single embryos were selected using existing morphological scorecard approaches.
The ongoing pregnancy rate, after 20 weeks, per cycle started was 69.1% in the 24sure treatment group vs 41.7% in the control group. This extremely promising result provides direct evidence that 24sure analysis can deliver a 65% increase in pregnancy rates, even in younger patients with more favourable IVF outcomes. Further randomized studies are needed and are underway.
“This study provides crucial evidence that 24 chromosome aneuploidy screening, using 24sure, can offer a dramatic benefit to IVF success rates. While further studies are still needed, this result is incredibly exciting because it indicates for the first time that 24 chromosome screening and single embryo transfer has the potential to become the default standard of care for all IVF cycles worldwide.” Nick Haan, CEO, BlueGnome Ltd, Cambridge, UK.
Quotes from Key Opinion Leaders
24sure comprehensive chromosomal screening has been clinically proven to be the effective means to select the chromosomally normal embryo(s) for transfer to ensure a healthy pregnancy for infertile patients.
As a clinical scientist, I am happy to be a part of the new technology. Dr Zhihong Yang, Executive Director, ART and PGD Laboratories, Pacific Reproductive Center Torrance, CA, USA.
This is a clinical study, showing for the first time how this technology, which CARE helped pioneer, can greatly improve IVF success rates for younger patients.
Here at Care Fertility we have already shown that pre-implantation genetic screening has benefits for older patients, and those with complex histories, so it is great to see the scope of this technology could benefit many more patients. Prof. Simon Fishel, Managing Director, CARE Fertility Group, UK.
I’m not at all surprised by these fantastic results from the Californian group. They mirror our success at Melbourne IVF using BlueGnome’s 24sure technology. We’ve provided this service to our patients for just over a year and already about 20 babies have been born and another 50 are on the way. It’s a significant breakthrough for patients who are struggling to become pregnant. Dr. Leeanda Wilton, Scientific Director, Preimplantation Genetics, Melbourne IVF, Australia.
The preliminary results of this paper highlight the importance of offering PGS also to good prognosis IVF patients. For years the PGD community has focused only on couples with a specific indication for testing (e.g. advanced maternal age), not considering that aneuploidies may arise in every IVF patient.
This is clearly demonstrated from the 45% aneuploidy rate detected also in embryos from young patients, and may explain why many young women fail to achieve a pregnancy even after transfer of good quality embryos.
Embryo assessment by PGS has become a crucial component to the clinical success of IVF techniques. The new array-CGH-based comprehensive chromosome screening technology holds great promise for improving IVF clinical outcomes for every infertile patient, by selecting the most competent embryo(s) for transfer. Dr Francesco Fiorentino, Director, Genoma, Rome, Italy.
This well designed study supports what many of us have expected for a long time; aneuploidy is responsible for most IVF failure. Assessment of an embryo’s ability to create a pregnancy is best done not by morphologic examination, rather it is best done by assessing all 24 chromosomes.
This approach will result in better patient outcomes. Choosing a single high potential embryo will result in fewer multiple pregnancies, fewer miscarriages and will also help us define the population of patients who make few or no euploid embryos. Jamie A Grifo MD PhD, Program Director NYU Fertility Center, USA.
Many fertilized eggs are genetically affected, even in young infertile couples. This study shows conclusively that those embryos cannot be recognized from microscopic assessment alone. This multi-center study performed in two different countries underscores the importance of removing seriously abnormal embryos before transfer into the uterus using so-called comprehensive screening; a contemporary form of preimplantation genetic screening or PGS.
Although the study was relatively modest in size, the results were blinded to observers and embryos were randomized to avoid bias. It opens up the exciting possibility to perform PGS not just in complicated patients such as those with poor ovarian reserve, but also egg donors and young women as abnormal embryos are common at any age. Jacques Cohen, PhD. Director, Tyho-Galileo Research Laboratories, Livingston, NJ, USA.
The work of Dr. Yang is remarkable. We know that chromosome abnormality rates in embryos of young patients are as high as 40%, and increase up to 70% in blastocyst of women >40. Their study means that if young women benefit from blastocyst biopsy, aCGH and day 6 transfer, women of advanced maternal age who have a bigger problem conceiving, would too, provided they produce enough embryos or do banking of embryos.
Indeed work by Gary Harton while at Reprogenetics showed that if euploid blastocysts are available for transfer, they implant at the same rate regardless of maternal age. The approach used, day 5 biopsy and day 6 transfer is also more acceptable for patients, since they are less costly than vitrification and patients do not have to wait another cycle for replacement. Santiago Munne, PhD, Director, Reprogenetics, Livingston, NJ, USA.
While this is a small pilot study, it underscores clearly that even younger infertile couples undergoing IVF will benefit significantly by this powerful technology advance. Since nearly half of a patient’s embryos are chromosomally abnormal, the ability to reliably detect the normal ones for uterine transfer will impressively improve the chances that these rather desperate couples can finally have a healthy family - and one baby at a time, which is the ultimate goal for all involved. Professor Mark Hughes, Genesis Genetics Institute, Detroit, MI, USA.
This well done study adds to the growing evidence that 24 chromosome testing by array CGH will allow PGD to finally reach its potential to identify the best embryos with highest implantation and lowest loss rates.
The study by Yang et al. confirms that chromosome analysis by array CGH is the best approach to identify developmentally competent embryos for eSET. Harvey J. Stern MD, PhD. Director, Reproductive Genetics, Genetics & IVF Institute, USA.