Transcript No Slide Title

Clinical experience of PB biopsy
and CGH micro-array
in poor prognosis IVF patients
Stuart Lavery
Consultant Gynaecologist
Director IVF Hammersmith
Hammersmith and Queen Charlotte’s Hospitals
Imperial College
London
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Clinical experience of PB biopsy
and CGH micro-array
in poor prognosis IVF patients
A new chapter in PGS?
Stuart Lavery
Consultant Gynaecologist
Director IVF Hammersmith
Hammersmith and Queen Charlotte’s Hospitals
Imperial College
London
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Background
What is the evidence?
Clinical experience
Ethical challenges
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Preimplantation genetic diagnosis (PGD) is a form of very
early prenatal diagnosis. The technique combines assisted
reproductive technology with molecular and cyto-genetics to
allow the identification of abnormalities in embryos prior to
implantation. Couples at risk of having children with serious
genetic diseases can have unaffected embryos transferred to
the uterus, eliminating the need for prenatal diagnosis and
termination of pregnancy.
Screening of preimplantation embryos for aneuploidy (PGS)
may ameliorate the effect of female age on reproduction:
improving pregnancy rates and decreasing the chance of
multiple birth and miscarriage.
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Background
• 20% of all UK births are to women >35
• 2009: 706 248 live births in England and Wales, 114 288 women
aged 35-39, and 26 976 births to women over 40, 71 over 50
• Background of media sensationalism
• Under-explored in serious discussion
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Background
• Pregnancy and live birth rates
decline rapidly with advancing
age
• Main factor is oocyte quality:
– Age <35: 32% embryos abnormal
– Age 35-37: 42%, >37:53%
– IVF failure x3: 54% embryos
abnormal
– IVF failure x5: 63%
Age
Livebirth/cycle started
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40-42
43-44
>44
10.6%
(262/2466)
4.9%
(25/513)
0.8%
(1/129)
Hypothesis: screening oocytes and preimplantation
embryos should increase pregnancy rates, decrease
miscarriage and multiple pregnancy rates and help
prevent the birth of affected children
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Hypothesis: screening oocytes and preimplantation
embryos should increase pregnancy rates, decrease
miscarriage and multiple pregnancy rates and help
prevent the birth of affected children
Lavery S, El-Shawarby SA, Moissidou M, Taylor D, Turner C, Lavender B, Trew G, Margara R,
Winston R. Live birth following preimplantation genetic screening for trisomy 21. Should
aneuploidy screening be offered to all older patients undergoing IVF? Hum Fertil
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What is the evidence?
• Sound, self-evident, easily understood hypothesis
• Which patients: advanced maternal age, recurrent
implantation failure, recurrent miscarriage,
previous aneuploidy, MESA/TESE ?
• Different biopsy technique:1 or 2 cells?
• Which chromosomes and how many?
• Multiple case series, retrospective case controlled,
prospective randomised controlled trials, metaanalysis
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What is the evidence?
To date there is insufficient data to determine whether PGS
is an effective intervention in IVF/ICSI for improving live
birth rates. Available data on PGS for advanced maternal
age showed no difference in live birth rate and ongoing
pregnancy rate. However, only two randomised trials were
found, of which one included only 39 patients. For both
studies comments on their methodological quality can be
made. Therefore more properly conducted randomised
controlled trials are needed. Until such trials have been
performed PGS should not be used in routine patient care.
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Is PGS dead?
Yes, for FISH on cleavage stage embryos
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Is PGS dead?
Yes, for FISH on cleavage stage embryos
What about for alternative genetic techniques
looking at different stages of biopsy?
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Is PGS dead?
Yes, for FISH on cleavage stage embryos
What about for alternative genetic techniques
looking at different stages of biopsy?
We just don’t know…
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New Scientific Developments
• Whole Genome
Amplification (WGA)
• Comparative Genomic
Hybridisation (CGH)
– Metaphase spread
– Micro-array
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Euploid
-4, +5, +7, -9, +17, -22, +X
-8p, -15
+3, +15
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CGH Aneuploidy Screening
Preliminary Evidence
• Blastomere biopsy, CGH metaphase and cryopreservation Wilton 2003
• PB biopsy CGH microarray
Obradors 2008
• 45 couples, mean age 38, 2.4 previous failed cycles
–
–
–
–
–
Blastocyst biopsy: CGH 24 chromosomes
94% embryos diagnosed
51% aneuploid
Implantation rate 69%
Pregnancy rate 82%
Schoolcraft Nov 2009
• ESHRE call for proof of concept trial of PB biopsy and CGH
microarray
Geraedts Dec
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2009
ESHRE trial of PB biopsy and
CGH microarray
‘Proof of principle’
• 2 centres: 226 eggs, 41 couples in 42 cycles, average
maternal age 40
• 177 eggs analysed: 34 euploid, 122 aneuploid (69%)
• 19 cycles, all eggs aneuploid (45%)
• 37 embryos transferred in 23 cycles, 8 clinical
pregnancies, 27% implantation rate/ET
• PB1 72% aneuploidy in eggs
• PB1+2 89 % aneuploidy in eggs
• Reliable and accurate
Geraraedts 2010
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Recent Work:
why not just culture to blastocyst?
• Aneuploid embryos cannot be distinguished
from euploid embryos by culturing to
blastocyst
Cater 2011
• 554 blastocysts: 57% were aneuploid, 41%
were mosaic, 72% of most advanced were
male
Alfarawati 2011
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CGH Aneuploidy Screening
IVF Hammersmith experience
• 93 cycles started
– 20 patients age 36 and under
– 61 patients 37 and above
– 55 patients had >3 failed implantations
• all 93 got to egg collection
• 89 had polar body 1 biopsied (96%)
• 12 patients had non-fertilisation (13%)
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CGH Aneuploidy Screening
IVF Hammersmith experience
• 629 eggs injected
• 421 fertilised (67%)
• 437 PB analysed
– No result
– Euploid
– Aneuploid
56 (13%)
84 (19%)
297 (68%)
• All PB aneuploid in 14 cycles (15%)
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CGH Aneuploidy Screening
IVF Hammersmith experience
• 85 embryos transferred in 53 cycles
57%
• Clinical pregnancy rate/cycle started 16/93 17%
• Clinical pregnancy rate/ET 16/53
30%
<37 years CPR/ET
>37 years CPR/ET
5/14
11/39
36%
28%
• 1 ectopic, 2 miscarriages, 5 livebirths, 8 ongoing
pregnancies
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Comparison with matched controls
Age
Previous cycles
CPR/cycle started
CPR/ET
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CGH
40
2.8
17%
30%
Controls
40
40
2.5
25%
16%
31%
20%
Impressions
• High attrition rate, low success rate
• Strong patient demand despite high cost and
unproven efficacy
• What to do when no diagnosis?
• What is significance of all eggs aneuploid?
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Impressions
• Move towards PB1 and 2
• Are there two groups of patients?
Handyside 2011
– Older patients offer PB 1 and 2 biopsy
– Young patients with recurrent implantation failure offer
blastocyst biopsy and CGH
• Blastocyst biopsy?
– 2 cases of blastocyst biopsy, vitrification, thaw and
transfer in drug-assisted cycle, no pregnancy
– 2 cases analysis performed with ET on morning of day
6, 1 pregnancy
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Ethical challenges
• Is it ethical to offer this treatment
in absence of robust evidence
from prospective RCT?
• Is it ethical to deny this treatment
to a fully informed patient who
has a poor prognosis?
• Could we do any harm?
– High non fertilisation rate
– ? Discarding normal
undiagnosed eggs
– Possibility of self-correction
– CGH does not diagnose triploidy
– Comparisons against SNP arrays
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In Conclusion
• Efficacy of PGS remains hotly disputed
• PB biopsy and CGH micro-array can
predict chromosomal abnormality in 89% of
cases
• Initial clinical data looks promising, adds to
our understanding
• Await ESHRE’s prospective multicentre
RCT for confirmation
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Thanks to Tony Gordon at Bluegnome and Dagan Wells, Elpeda Fragouli
at Reprogenetics
IVF Hammersmith Team
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