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4/13/2015
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Clinical Value and Cost Effectiveness of Pre‐Natal Testing of Average Risk Patient Populations
.
Peter Benn, PhD, DSc
Department of Genetics and Genome Sciences
University of Connecticut Health Center
Conflicts of interest: Consultant to Natera , Inc.
Conventional Screening Approaches: maternal serum and ultrasound
Approximately 70% women receive conventional screening
• 5% false positive rate
ACOG Practice Bulletin #77, Screening for Fetal Chromosomal Abnormalities
Therefore the majority of patients with a positive result are NOT affected(false‐positive) and
undergo unwanted test with inherent risk for
unnecessary miscarriage
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Non invasive prenatal testing (NIPT) for fetal aneuploidy using sequencing
• First testing in China, early 2011
• Introduced into US in October 2011
• Available in many countries, worldwide
• Now a US industry with a >$1b market value
• Estimated > 650,000 tests performed per year in the US for 4th
quarter 2014
• Aspects of the technology are proprietary; subject of patents
• “Disruptive innovation”: Radically transforming prenatal counseling, screening and diagnostic landscape
Free “fetal” DNA in maternal plasma
• First discovered by Dennis Lo et al (1997)
• Detectable at 7+ weeks gestational age
• Generally ~10‐12% of the cell‐free DNA present in a sample
• Amount approximately constant in the late first trimester through the second trimester
• Origin: placenta (trophoblasts)
• Small size: 99% is <313 bp length, average ~162 bp
• No carry‐over from one pregnancy to the next
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Massively parallel genome-wide shotgun sequencing
Chiu R. W. K. et.al. PNAS 2008;105:20458-20463
10million 25bp sequence tags
Father FatherMother Mother
Counting method identifies the relative excess of DNA for the trisomic chromosome
Fetus, disomy Fetus, trisomy
excess of trisomy chromosome fragments in the plasma
Trisomy in the mother versus fetus cannot be distinguished
reference casecase or normal chromosome
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SNP‐based Approach
Father FatherMother Mother
SNP based method identifies trisomy, the parental origin and recombination
Fetus, disomy Fetus, trisomy
extra copy in plasma
extra copy in plasma
Fetal chromosomes are not identical to parent chromosome due to recombination
SNPs provide a unique characterization (color) for each chromosome
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Slide: Courtesy Natera, Inc (modified)
Maternal blood
Buffy coat = Maternal DNA
Plasma = Maternal + Fetal DNA
SNPSequencing
SNPSequencing
Maternal Genotype
Maternal + Fetal Genotype
Fetal Ploidy stateRisk score for each condition
Concepts behind use of SNPs for non‐invasive prenatal testing
Multiple hypothesesfor each chromosomeHapMap
crossover data
Bayesian analysis
Different Methods ‐ NIPT
Counting SNPs
Baby
Mom
Limited information; not able to distinguish
babyor mom
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Clinical trial DR and FPR for trisomies 21, 18, and 13 combined
Based on 11 reports for shotgun, 6 reports for targeted, 2 reports for SNP‐based NIPTBenn, P. J. Clin. Med. 2014, 3(2), 537‐565
Detection rates, false‐positive rates, and expected PPVs for Down syndrome screening
TEST DR FPR PPV High‐riskpopulation (1/100)
PPVLow‐riskpopulation(1/500)
Combined (NT, PAPPA, hCG)
80% 3% 21% 5%
Quad (AFP, uE3, hCG, INH‐A)
60% 3% 17% 4%
Sequential(Combined & Quad)
93% 3% 24% 6%
NIPT (composite of all methods)
99.3% 0.1% 91% 67%
DR, FPR, for conventional screening: Benn et al. Prenat Diagn. 2013; 31:519‐22NIPT Based on meta‐analysis of 19 validation studies (all methods)
Positive predictive value= True positives / (True + False positives)
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Some expected reasons for discordancy between IPT and NIPT and the method of testing
Cause Genome wide seq Targeted seq SNP‐based
True fetal mosaicism + + +
Confined placental mosaicism + + +
Aneuploid dizygotic twin demise (vanishing twin)
+ + ‐
Non‐mosaic maternal aneuploidy + + ‐
Maternal somatic cell mosaicism + + ‐
Non‐mosaic maternal CNV + + ? ‐
Maternal malignancy + + ‐
Laboratory error + + ? + ?
Low fetal fraction/low counts + + + ?
SNP‐based method distinguishes between fetal maternal imbalances, more than one fetus
Positive predictive values based on clinical practice,confirmed cases, SNP‐based NIPT
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Combined(4 aneuploidies) T21 T18 T13 45X
Aneuploid calls with confirmatory studies
222 154 29 21 18
True positives 184 140 27 8 9
False Positives 38 14 2a 13b 9
Positive Predictive Values (PPV) 83% 91% 93% 38% 50%
Based on a clinical follow-up cohort (n=17,885), mean maternal age 33.3 years and GA 14 weeksa Includes one confined placental mosaic (CPM) case. b Includes two CPM cases.
Dar et al. AJOG 2014; 527.e1-527.e17
Positive predictive value= True positives /(True + False positives)
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Dar ‐ AJOG
Avg Risk Studies
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BCBS Tech Assessment –T21
2012 2013 2014 2015
Norton ‐ NEJMZhang ‐ UOG
Nicolaides ‐AJOG
Song – Pre Diag
Gil ‐ UOGBianchi ‐NEJM
Pergament –Ob Gy
BCBS Tech Assessment – T18, T13
92,117 Average Risk patients have been evaluated in 8 studies since 2012
Low Risk<35 yo
Low Risk, screening
All women
Total Women 11,994 14,957 15,841
Prevalence of T21
19/11,994(0.16%)
8/14,957(0.05%)
38/15,841 (0.24%)
Detection Rate19/19(100%)
8/8(100%)
38/38 (100%)
False Positive Rate
6/11,975(0.05%)
8/14,949(0.05%)
9/15,803(0.06%)
PPV 76.0% 50.0% 80.9%
NEXT study, trisomy 21 in an all risk population
Lower PPV in the low risk group is consistent with the lower prevalence, testing is still highly effectivePPV for conventional screening 3.4%
Norton et al 2015. NEJM Eprint.
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Guidance for offering NIPT
Organization Policy Reference
ACMG All risk (indications unspecified) Gregg et al Genet Med; 2013;15:345‐8
ACOG High risk (AMA, conventional screen positive, etc.)Likely to be revised soon
ACOG Committee on Genetics Opinion. Obstet Gynecol. 2012;120:1532‐4.
ISPD All risk (most effective) Benn et al. Prenat Diagn. 2015. In Press
ESHG/ASHG Different scenarios are possible, including NIPT as an alternative first tier option
Dondorp et al. Europ J Hum Genet. 2015. Eprint.
Blue Cross Blue ShieldAssociation Tec assessment
…in either high‐risk or average‐risk pregnant women...meets the Blue Cross and Blue Shield Association Technology Evaluation Center (TEC) criteria.”
2013, 2014
A barrier to greater utilization is a perceived increase in overall costs
• Evaluated NIPT only for T21
• Mostly based on a comparison of NIPT vs the first trimester Combined test (NT plus serum markers)
• Justified use of NIPT for high risk groups (Contingent screening)
• Based on a “European” public healthcare perspective– US healthcare system is based on ad hoc additional procedures (ultrasound, serum tests, counseling, office visits) which add substantial additional expenditures in prenatal screening
Past Economic Studies
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• Primary goal: Establish the per‐case cost of NIPT that would be cost neutral to the US healthcare system
• Decision analysis model• Based on the US pregnancy population for 2012• Takes into consideration maternal ages• T21, T18, T13, & Monosomy X• Primary model considers patients entering screening in the
first trimester (Combined test plus…)• Includes costs of screening, all related follow‐up testing,
care for an affected child• Use published rates for decisions related to testing• Does not include non‐medical costs such as loss of earnings
New Economic Paper
Benn et al, submitted manuscript, 2015
Total Population
No Screening
Counseling Combined Test
Sonogram
TN, Live birth
FP, Live birth
Quad Test
Counseling ±sonogram amnio
TP, TOP
TP, Live Birth
FP, Live Birth
Sonogram No Action
Counseling CVS
TP, TOP
TP, Live Birth
FP, Live Birth
First Trimester
Second Trimester
Decision tree for Conventional screening
‐+ or ‐
+
+
+
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Total Population
No Screening
± Counseling NIPT
TN, Live birth
FP, Live birth
Counseling CVS or Amnio
TP, TOP
TP, Live Birth
FP, Live BirthNo Action
First or Second Trimester
Decision tree for NIPT
‐
‐
+
+
Model structure: conventional screening rates
• Performance based on modeling using established parameters (SURUSS, etc.)
• 1:270 cut‐off for DS and 1:100 for t18• MX first trimester DR 75% (Spencer et al 2000); DR 54% second
trimester (Benn & Ying 2004)• 53% of first trimester also receive second trimester tests (CAP,
Palomaki et al., 2013) • Invasive testing: 73% DS true positive (Benn et al 2005); 90% T18,
t13, MX true positive, 43.1% false positives (Shah et al 2014)• Separate office visits for NT (73%) (Ad. Board Survey)• Genetic sonogram (43%) for second trimester AMA and high risk
(Shamshirsaz et al. 2013)• For first trimester positives with no other screening CVS: Amnio
24%:76% (Blumenfeld et al 2005)
Benn et al, submitted manuscript, 2015
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Model structure: NIPT screening rates
• NIPT performance based on meta‐analysis of all methods (19 validation studies)
• T21 (DR=99.3% FPR=0.1%)
• T18 (DR= 96.8% FPR=0.1%)
• T13 (DR=87.2% FPR=0.2%)
• MX (89.5%; 0.2%)
• 65% of tests in the first trimester (Dar et al 2014)
• 90% invasive testing for NIPT positive
Benn et al, submitted manuscript, 2015
Not included
• Conditions other than aneuploidy detected through NT• Conditions other than aneuploidy detected through biochemical tests, notably MS‐AFP
• Other cytogenetic abnormalities identified by NIPT (e.g. triploidy, other SCA), serum screening or invasive testing
• Test failures• By‐passing components of screening• Microdeletion/microduplications• Differences between the various NIPT laboratories• Value of early reassurance for unaffected pregnancies
Benn et al, submitted manuscript, 2015
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Model structure : costs
• Medicaid & Medicare (CMS) fee schedule
• Adjusted for inflation to 2014
• +20% for private and carrier payers
• Lifetime costs associated with DS (Walzman et al., 1994) adjusted for inflation
• Hospital cost associated with t18, t13 (Healthcare Cost and Utilization Project)
• Medical costs for MX including human growth hormone, cardiac defects
Benn et al, submitted manuscript, 2015
Model Component Cost (2014 USD)
Clinical Test/Clinical CareAmniocentesis $835Chorionic villus sampling (CVS) $892Second trimester screening $136Sequential screening $136Genetic Counseling $56Prenatal care $6,552Ultrasound $168Office Visit $96NT Charge $147Papp A $25HCG $25Genetic sonogram $223HCG $25AFP $27Unconjugated estriol (uE3) $40Inhibin A $26
Cost of elective terminationEarly, following CVS $562Late, following amniocentesis $2,997
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Lifetime costs of an affected child Cost (2014 USD)
Trisomy 21 (a) $677,000
Trisomy 18 (b) $29,307Trisomy 13 (b) $33,577Monosomy X (c) $271,010
(a) Based on Waitzman et al. 1994, adjusted for medical inflation. A recent study used $1,497,000 (12% medical, 16.4% educational, 71.6% indirect) based on the data form Waitzman adjusted for survival and inflation (Walker et al., 2015).
(b) Based on hospital costs only (Healthcare Cost and Utilization Project ‐Kids’ Inpatient Database (HCUP‐KID)
(c) The cost of HGH therapy $12,000 per year for 12 years ($144,000). Additionally, cost for 30% of patients with congenital heart defects.
Benn et al, submitted manuscript, 2015
Price point NIPT is cost neutral
General Population High Risk
Increase in affected pregnancies prenatally detected
1,403/11,314 (12.4%)
364/6,149 (5.9%)
Reduction in affected births1,213/3,629(33.4%)
604/2,017 (29.9%)
Reduction in invasive tests36,834/61,430
(60%)19,037/26,355
(71.7%)
Reduction in procedure related losses194/264 (73.5%)
100/110 (90.9%)
Cost offset for NIPT <= $744 <= $1,474
Healthcare benefits of NIPT are not confined to high‐risk women and many providers feel they are obligated to offer NIPT to all women
Benn et al, submitted manuscript, 2015
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Cost offset analysis for conventional screening and NIPT for the general pregnancy population; average per/case costs for women
entering testing in the first trimester
Component USD
Cost of conventional screening* 369
Cost of follow‐up diagnostic testing 86
Post test genetic counseling 3
Lifetime costs of affected births 286
TOTAL $744
If NIPT can be provided for <$744 for a total US pregnancy population, there is no net increase in healthcare costs
*Includes $70 for separate office visit for NT; $10 for genetic counseling; $76 for ultrasound; $17 second trimester genetic sonogram; $147 NT measurement; $49 serum analytes
Benn et al, submitted manuscript, 2015
Sensitivity analysis of the cost offset
Baseline Model Range
Model Input Variable VariableNIPTValue
VariablesNIPTValue
Practice Patterns% entering first trimester for conventional screening
100% 0%-100% $486-744
% entering first trimester for NIPT 66% 0%-100% $743-745
Invasive testing uptake for conventional screen FPs
45% 25%-100% $738-747
Termination Rates 65-90% 0%-100% $459-788
Key Cost Variables
Cost of first trimester screening $369 $222-443 $597-818
Cost of sequential screening $136 $744 $82-164 $714-759
Cost of invasive testing (amnio/CVS) $835 / $892 $501-1,070 $740-747
Lifetime costs of an affected child
Trisomy 21 $677,000 $541,600-812,400
$687-802Trisomy 18 $29,307 $23,446-35,168
Trisomy 13 $33,577 $26,862-40,292
Monosomy X $271,010 $216,808-325,212
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• NIPT is a substantially better approach to prenatal screening and is likely to become the first tier test for all women, regardless of their prior risk
• Model predicts NIPT is associated with large reductions in affected births, invasive tests and procedure related losses
• Benefits are not limited to advanced maternal age women • NIPT can be cost neutral if the cost is ≤ $744 for the general
pregnancy population• Key variables are cost of conventional screening, lifetime
costs of DS, and pregnancy termination rates• Analysis does not include the intangible value of early
diagnosis or reassurance
Summary