Performance Art: Deciding on Acceptable Sensitivity and ...hivstar.lshtm.ac.uk/files/2017/09/P2.4-Elliot-Cowan.pdf · CONSISTENCY AS HIGH AS POSSIBLE? Partners in Diagnostics, LLC

Partners i n Diagnost ics, LLCR eg u latory Consulting to Advance Global H ea lth

Elliot P. Cowan, PhDPrincipal

13817 Congress Drive Rockville, Maryland 20853-2632 USA

Tel: +1 [email protected]

PerformanceArt:DecidingonAcceptableSensitivityand

SpecificityforHIVSelfTests

ElliotP.Cowan,Ph.D.Principal,PartnersinDiagnostics,LLC

STAR“HIVSelfTesting- GoingtoScale”Workshop29March2017





GoalsofthisTalk

2

• TodescribetheevolutionofthinkingthatledtotheapprovalbytheUSFoodandDrugAdministrationofthefirstover-thecounterhome-userapidHIVtest

• Toappreciatetheflexibilitythatcan(should?)beexercisedtomeetacriticalpublichealthneed





AssessingHIVST

3

CONSISTENCY

AS HIGH AS POSSIBLE?





Goal

Recognizingthatnotestis100%and100%specific,demonstratethatitissafeandeffective

foritsintendeduse

4





HOWTHEUSFDAAPPROVEDANHIVST

5





WhyHIVSTfortheUS?

HIV-infectedpeopleintheU.S.whodonotknowtheyareinfected

1in5

NumberofAmericansnewlydiagnosedwithHIVinfectioneachyear

~50,000

NumberofHIV-infectedpeopleintheU.S. 1.2MILLION

Source: US Centers for Disease Control and Prevention





OraQuickÒ In-HomeHIVTestSystem





ExpectedPerformance(FDABloodProductsAdvisoryCommittee)

• Professionalusetest:– Sensitivityandspecificity>98%asthelowerboundofthe95%confidenceinterval

• Selftest:– Sensitivityandspecificity>95%asthelowerboundofthe95%confidenceinterval

• Rationale:– Expecteddecreaseinperformanceinthehandsofnon-professionals





Home-Use TestPerformanceasaMeasureofSafetyandEffectiveness

TEST PERFORMANCE SAFETY ANDEFFECTIVENESS





ProfessionalTestPerformance(OraQuickADVANCE® HIV-1/2AntibodyTestwithOralFluidSpecimens:

PackageInsert)

Performance of the OraQuick ADVANCE® Rapid

HIV-1/2 Antibody Test(2-sided 95% CI)

BPAC Minimum Recommended Performance

Specificity 99. 8%(99.6 – 99.9%)

98% (lower bound of the 95% CI)

Sensitivity 99.3%(98.4 - 99.7%)






Home-UseTestPerformance(OraQuick® In-HomeHIVTestforOralFluidSpecimens:Datashownat

BloodProductsAdvisoryCommittee,May2012)

Performance of the OraQuick® In-Home HIV Test Kit (2-sided 95% CI)

BPAC Minimum Recommended Performance

Specificity 99.98%(99.90 – 100%)


Sensitivity 92.98%(86.64 – 96.92%)






Home-Use TestPerformanceasaMeasureofSafetyandEffectiveness

TEST PERFORMANCE SAFETY ANDEFFECTIVENESS

?

PUBLIC AND INDIVIDUALHEALTH IMPLICATIONS

RISKANALYSIS





VeryHighLevelViewofFDA RiskAnalysis

• Estimatedtestresultsfornumbersofindividualsprojectedtobetestedannuallywhowouldnototherwisebetestedinthe1st year• Truepositive,falsenegative

• Truenegative,falsepositive

• Estimatednettransmissionsavertedinthe1st year

• Impactofswitchingfromprofessionaltestingtoself-testing

• Impactofwhowillusethetest

• Publichealthimplicationsandindividualhealthimplications

RISK MODEL





FDA Projected Outcomes of Testing with the OraQuick® In-Home HIV Test in the 1st Year

(Based on sensitivity and specificity at the 95% confidence interval lower bound)

6 TP : 1 FN

770 TN :1 FP

True PositiveFalse Negative

True NegativeFalse Positive

42,0007,000

2,700,0003,600

(vs. 249:1)

(vs. 62:1)

Professional use test

From FDA presentation at Blood Products Advisory Committee, May 2012





ProjectedNetTransmissionsAverted(CombinedProfessionalandHomeTesting)

44 7344 23

43 4 1

4 17 5

1 0

2 5

5 0

1 0 0

% S

wit

ch

ing

to

Ho

me

-Us

e T

es

tin

g

20 0 0 30 0 0 4 0 00 5 00 0 60 0 0 7 00 0Pred icte d Ne t Ave rted H IV Tra nsm ission s

5 th to 9 5 th Pe rce ntile M e an Tra nsm ission s Ave rte d

Pred icted Net A ve rte d H IV T ra ns m issio nsby P ercen t S w itch ing to Ho m e-us e Te sts

About300fewertransmissionsavertedifallcurrentusersofprofessionaltestsswitchtohomeusetests

FromFDApresentationatBloodProductsAdvisoryCommittee,May2012





SummaryofFDAAssessment

• Basedonariskassessmentmodel,FDAprojectedanetpublichealthbenefittotheOraQuick® In-HomeHIVTest– NetincreaseinnumberofHIVinfectionsnewlyidentifiedinthefirstyear

– Nettransmissionsaverted• Individualriskremainsintheformofincreasednumbersoffalsenegativeresults





MessagestoMitigateRisk• Apositiveresultwiththistestdoesnotmeanthatyou

aredefinitelyinfectedwithHIV,butratherthatadditionaltestingshouldbedoneinamedicalsetting.

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• AnegativeresultwiththistestdoesnotmeanthatyouaredefinitelynotinfectedwithHIV,particularlywhenexposuremayhavebeenwithinthepreviousthreemonths.

• RetestingisrecommendedifyoutestnegativeandcontinuetoengageinbehaviorthatputsyouatriskforHIVinfection.

• AnegativeresultdoesnotmeanitissafetoengageinriskbehaviorforHIVinfection.





GeneralizingtheApproach:PracticalConsiderationsforSTAR

• TheresultsoftheriskmodelingdonefortheUSpopulationdonotnecessarilycarryovertoSTAR

• Requiresitsownsetofinputs

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Challenges

• Wheredoyoudrawthelinebetweenacceptableandnotacceptable?

• Monitoringtodetermineiftherightchoicesweremade





PotentialPitfalls





ConcludingMessages

• Beflexibletomeetthedefinedpublichealthneed.

• Berationalinyourdecision-making.• Consideringbenefitsandrisksmaytakeyouindirectionsyoudon’texpect,butsometimeswhat’snotexpectedisagoodthing.

• Bewillingtoacceptrisks,butalsoacknowledgethemandmitigatethemasmuchaspossible.





THANKYOU!

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Documents

Performance Art: Deciding on Acceptable Sensitivity and ...hivstar.lshtm.ac.uk/files/2017/09/P2.4-Elliot-Cowan.pdf · CONSISTENCY AS HIGH AS POSSIBLE? Partners in Diagnostics, LLC