pharmacoepidemiologyand drugsafety(2014)

PublishedonlineinWiley OnlineLibrary(wileyonlinelibrary.com)DOI:10.1002/pds.3658

ORIGINALREPORT

Reductionsinreporteddeathsfollowingtheintroductionofextended- releaseoxycodone(OxyContin)withanabuse-deterrentformulation†

NelsonE.Sessler1,JerodM.Downing1,HrishikeshKale1,HowardD.Chilcoat1,3,ToddF.Baumgartner4

andPaulM.Coplan1,2*

1DepartmentofRiskManagementandEpidemiology,PurduePharmaL.P.,Stamford,CT,USA

2DepartmentofClinicalBiostatisticsandEpidemiologyUniversityofPennsylvaniaPerelmanSchoolofMedicine(Adjunct)Philadelphia, PA,USA

3DepartmentofMentalHealth,JohnsHopkinsBloombergSchoolofPublicHealth(Adjunct),Baltimore,MD,USA

4DepartmentofRegulatory Affairs,PurduePharmaL.P.,Stamford,CT,USA

ABSTRACT

Purpose Abuseofopioidanalgesicsfortheirpsychoactiveeffectsisassociatedwithalargenumberoffatalities.Theeffectofmakingopi- oid tabletshardertocrush/dissolveonopioid-relatedfatalitieshasnot beenassessed.Theobjectiveofthisstudywastoassesstheimpactof introducingextended-release oxycodone(ERO[OxyContin®])tabletscontainingphysicochemicalbarrierstocrushing/dissolving (reformulatedERO)ondeathsreportedtothemanufacturer.

Methods AllspontaneousadverseeventreportsofdeathintheUSreportedtothemanufacturerbetween 3Q2009and3Q2013 involving EROwereused.Themeannumbersofdeaths/quarterinthe3yearsafterreformulatedEROintroductionwerecomparedwiththeyear before.Changesintheslopeoftrendsindeathswereassessedusingsplineregression.Comparisongroupsconsistedofnon-fatalreports involvingEROandfatality reportsinvolvingERmorphine.

Results Reportsofdeathdecreased82%(95%CI: 89, 73)fromtheyearbeforetothethirdyearafter(131to23deathsperyear) reformulation;overdosedeathreportsdecreased87%(95%CI: 93, 78)andoverdosedeathswithmentionofabuse-relatedbehavior decreased86%(95%CI: 92, 75).Incontrast,non-fatalEROreportsdidnotdecreasepost-reformulation,andreportedERmorphinefa- talitiesremainedunchanged.The ratioof EROfatalitiestoalloxycodonefatalitiesdecreasedfrom21% to8%intheyearpre-reformulation tothesecondyearpost-reformulation.

Conclusions Thesefindings,whenconsideredinthecontextofpreviouslypublishedstudiesusingothersurveillance systems,suggestthat theabuse-deterrentcharacteristicsofreformulatedEROhavedecreasedthefatalitiesassociatedwithitsmisuse/abuse.©2014TheAuthors.PharmacoepidemiologyandDrugSafetypublishedbyJohnWiley &Sons,Ltd.

keywords—OxyContin; extended-releaseoxycodone;abuse-deterrent;overdosedeath; pharmacovigilance;pharmacoepidemiology

Received11September2013;Revised1May2014;Accepted12May2014

INTRODUCTION

Opioidanalgesicsarerecommendedforthetreatment of serious,persistentpain after non-pharmacologic therapies and non-opioid medications have been

*Correspondence to:P.Coplan,ExecutiveDirector, Department ofRisk ManagementandEpidemiology,PurduePharmaL.P,OneStamford Forum, Stamford,CT06901,USA.E-mail:

†PriorPresentation:Aportion of thesedatawaspresentedat PAINWeek2012in LasVegas,NV,USA2012;thesecondInternational ConferenceonOpioids Boston,MA,USA2012;the29thInternational ConferenceonPharma- coepidemiologyand TherapeuticRiskManagementinMontreal,Canada2013.

used.1–5 Extended-release(ER)andimmediate-release (IR)opioidanalgesicsaredispensedtoover4million and56millionpatients intheUSAperyear,respec- tively(IMShealth). However,overthelastdecade, prescription opioidabuse(forpsychoactiveeffects) has increasedgreatly,resultingin increaseddeaths andburdentopublichealth.6–9 Theaddictionpotential andsequelae ofabuseincreaseexponentiallywhen tabletsarecrushed/dissolved fornon-oraladministra- tion(e.g.,snorting,injecting, andsmoking)toobtain rapidabsorptionoftheopioidexperienced asa “high.”10–12 Initial oral abuse often progresses to

©2014TheAuthors.PharmacoepidemiologyandDrugSafetypublishedbyJohnWiley &Sons,Ltd.

ThisisanopenaccessarticleunderthetermsoftheCreativeCommonsAttribution-NonCommercial-NoDerivsLicense,whichpermitsuseand distributioninanymedium,providedtheoriginalworkisproperlycited,theuseisnon-commercialandnomodificationsoradaptationsaremade.

non-oralabusebythetimeofadmissiontoasubstance abusetreatmentfacility.11,13–15

Scientificinnovation ofabuse-deterrentformulations topromotesafeprescriptionopioiduseisafocusofre-

searchanddevelopmentamongpharmaceutical compa- nies.16,17 Pharmacologicalapproachesto incorporate

characteristics designedtodeterabusehaveincluded: (i)addinganopioidantagonist(e.g.,buprenorphine andnaloxone[Suboxone®],ERmorphine andseques- terednaltrexone[Embeda®], aswellaspentazocine andnaloxone[Talwin®NX]);(ii)addingagentsthatin- duceunpleasant symptomswithexcessiveintake(e.g., IRoxycodoneandaversive agent[Oxecta®]);and(iii) incorporatingphysicochemicalbarriersintendedtocon- ferresistancetotablettampering(e.g.,ERoxycodone [OxyContin®], ERoxymorphone[Opana® ER],and ERtapentadol[Nucynta® ER]).

OxyContin(ERO)isER-formulated oxycodoneap- provedintheUSA in 1995forthetreatmentof moder- ate-to-severechronicpain,18 whichhasbeenwidely abused,19–21 especiallybysnorting/injecting,requiring tabletcrushing/dissolving.22–25 InApril2010, theFood andDrugAdministration (FDA)approvedare- formulatedEROcontainingphysicochemical barriers tobreaking,crushing/dissolving todeterabuse,which remainsthe only availableER form of oxycodone availablein the USA. Pre-approvalstudies demon- stratedthatreformulated EROisbioequivalentto,is moredifficult toextractoxycodonefrom,andisless liked by abusersthan the originalformulation.26–28

AllshipmentsoforiginalEROtowholesalersstopped on 5 August, and shipments of reformulatedERO startedon9August2010.Thetransitiontothereformu- lationwasconductedwithoutnotificationofthegeneral public. Post-marketingstudies have demonstrateda

reductioninreportedEROabuseindrugtreatmentcen- terpopulationsandcallstopoisoncenters.29–32InApril

2013,EROreceivedFDA-approved labeling,indicat- ingthatitisexpectedto beabuse-deterrentviaintrana-

sal and intravenous routes of administration.33

However,theeffectsonfatalityhavenotbeenreported.

Thisreportfocusesontheimpactofreformulated

ERO on reports of US fatalities submitted to the

manufacturer’spharmacovigilancedatabase.Mortality databases,suchastheNationalDeathIndexandstate

medicalexaminerdatabaseswerenotusedbecause

theydonotdifferentiate betweenIRandERoxyco- done,andonly5%ofpatientsprescribedoxycodone

intheUSAreceivedERoxycodone(IMSHealth).

However,theratioofdeathsassociatedwithEROre- ported to the manufacturer versus all oxycodone

deathsreportedtotheFDA’sAdverseEventReporting

System(AERS)wasassessed toprovideadditional contexttothefindings.

METHODS

Manufacturersreceive,archive,andsubmitspontane- ousreportsofadverseeventsonmarketed drugsto nationaldrug-regulatoryauthorities,suchastheFDA intheUSA.34,35Searchingthemanufacturer’sadverse eventreporting databaseidentifiedallreportsoffatal eventsoriginatingintheUSAinvolvingEROfrom

3Q2009–3Q2013.Individualcasereportnarrativede- scriptionswerereviewedandcategorizedasmention- ing an opioid overdose-related event and/or drug

abuse-related behavior using criteria developed a

priori (Table1).Thisreviewwasconductedbythe twoprimaryauthorswithanydisagreementsresolved

byconsensus.

Table 1. Criteriatoidentifyoverdose-relatedeventandabuse-relatedbehaviormentions

Overdose-relatedevent •Reporterdescribedeventusingverbatimterm“overdose”oramedicallyrelatedterm(e.g.,drugpoisoning,polydrug toxicity,drugintoxication,andovermedicated);or

•Circumstancessurroundingdeathsuggestanoverdose-relatedevent(e.g.,ingestedmanypills,dosingmistake,tampering/

snorting/injectionofdrug,anddrugobtainedandingestedataparty);or

•Coronerorphysician deemedfatalitywasassociatedwithopioidoverdoseorpolydrugoverdose (with orwithout toxicology evidenceofoxycodoneoropioidingestion).

Abuse-relatedbehavior •Subjectcurrentlyorpreviouslymanipulatedextended-releaseoxycodone withintentionofabuse(e.g.,crushedand

snorted,dissolvedandinjected);or

•Extended-releaseoxycodonewasnot prescribedto thesubjectand/orsubjectwasobtainingdrugviaunlawfultransfer

(e.g.,stolen,ataparty,fromparentssupply,andfromthestreet);or

•Subjectwasobtainingextended-releaseoxycodoneprescriptionsfromapillmill,multiplehealthcareproviders,and/or multiplepharmacies;or

•Reporterstates subjecthashistoryofaddictiondisorderand/ordrugrehabilitationorindicatesthatsubjectiscurrently addicted;or

•Reporterstatessubjecthadbeenusingillicitdrugsoralcoholincombinationwithextended-releaseoxycodone

(e.g.,heroin,cocaine,marijuana,andamphetamines),or

•There wasevidenceofsubjectexposure toabenzodiazepine,anopioidother thanoxycodone,and/ormusclerelaxant/

hypnoticinabsenceofmentionofprescription.Forthispurpose,anexposurewas definedas:theindividualwas observed takingdrug,orreportedtohavetakenthedrug,ordrugwasrevealedintoxicologicalresults.

Theanalysisfocusedonspontaneousfatalityreports thatincludedmonth/year ofdeath,astimetrendsin mortalitycannotbeascertainedwherethisinformation isunknownandthedatewhenthereportwasreceived bythemanufacturerdoesnot necessarilycorrelatewith thedate ofdeath.Reportsassociatedwithpost-market- ingstudies(includingthemanufacturer’sindividualpa- tientassistanceprogram),litigation(becausethesewere not spontaneousreports),and those lacking a core reportingelement(patient,reporter,suspectproduct, oradverseevent)wereexcluded.Allreportscontaining month/year ofdeathfrom3Q2009–2Q2013wereana- lyzedusingSASv9.2(SASInstitute,Inc,Cary,NC).

Fatalitiesweredividedintofourperiodscorresponding to1yearpre-reformulation(3Q2009–2Q2010)andthe first (3Q2010–2Q2011), second (3Q2011–2Q2012),

andthird(3Q2012–2Q2013)yearpost-reformulation.

The mean fatalitiesper quarterandchangesin theslope oftrendsinfatalitieswerecalculatedbysplineregression

usingaPoissonmodelwiththeinflection pointcorre- spondingtothetimeofEROreformulation.36,37

Severalsensitivity analyseswereconductedtoas- sesstherobustnessoftheresults.Toassesstheimpact ofprescription changesonfatalities,countswere adjusted for 100,000 ERO prescriptionsdispensed (IMSNationalPrescriptionAuditdatabasesystem).38

Becausereporting accuracy variesbysource,cases reportedby healthcareprofessionalswereanalyzed separately. Toassesstheimpactofintentionalharm, fatalitiesexcluding suicide/homicidewere analyzed separately.Theimpactofcaseswithoutdateofdeath wasassessedbycombiningallcasesandusingreport receiptdateasaproxyfordateofdeath.Toassess theimpact ofcasescontainingmissingornonspecific formulationinformation, fatalitychangeswerecalcu- latedforcasesinwhichthereporter mentionedbrand name “OxyContin.”A sensitivityanalysisassessed theimpactofdelayedreportingbyremovingcasesthat werereportedmorethan3months(or6months)after eachquarterinthestudyperiod.

TheratioofdeathsassociatedwithERO reportedto themanufacturerversusalloxycodonedeathsreported totheFDA’sAERSsystem(dataavailablethrough

4Q2012)wascalculated.Dateofdeathisnot included

intheFDAAERSdatabecauseofprivacyregulations;

therefore,reportreceiptdatebytheFDAwasusedin theanalysis.

RESULTS

Populationcharacteristics

Atotalof326uniquefatalities involvingERO,origi- natingintheUSA,werespontaneouslyreportedto

themanufacturerwitha month/yearofdeathfrom

3Q2009–2Q2013(Table2).Overdosewasmentioned

in240reports,andabuse-related behaviorwasmen- tionedin206reports.Reportsinvolvingfatalover-

doses were most frequently received from a

healthcareprofessional,morefrequently involvingan adult (age 18–64years) and often involving

polysubstance use.

Overall,therewerenolargedifferences inreport characteristics between the pre-reformulation and

post-reformulation periodsintermsofreportsource,

gender,age,reportsource/type,andsourceoftoxicol- ogyinformation.However,forfataloverdoses,nota-

ble decreases in the proportion of reports from

southernregions(40% to29%) andthosewith mentionsofbenzodiazepines(42%to33%)orother

opioids(37%to24%)wereobserved.

Decreaseinreportsoffatalities

Therewas a reductionin reportsoffatalitiesinvolving EROinthepost-reformulationperiods,particularlyfor thesubsetofcases ofoverdose andoverdosewith mentionofabuse(Figure 1).Thesereductionsbegan thefirstyearpost-reformulation andweremorepro- nouncedinsubsequentyears.Specifically,themean ofall reportsoffatalitiesintheyearpre-reformulation was32.8perquarter,whichdecreased by82%(95% CI: 89%to 73%)to5.8reportsperquarterinthe thirdyearpost-reformulation;themeanoffatalityre- portsinvolvingoverdosein theyearpre-reformulation was26.0perquarter,whichdecreased by87%(95% CI: 93%to 78%)to3.3reportsperquarterinthe thirdyearpost-reformulation;andthemeannumber offatality reports involvingbothoverdoseandabuse- relatedbehavior in the year pre-reformulationwas

23.3perquarter,decreasingby86%(95%CI: 92% to 75%)to3.3reportsperquarterinthethirdyear post-reformulation(Table3).

Increasing trendsinmeanquarterlyfatalityreports wereobservedinthepre-reformulationyear.Incon- trast,inthepost-reformulationyears,theslopeofthe

3-yeartrendforallEROfatalreportsdecreased an average of15.6%(95%CI: 18.7%, 12.3%)per quarter,representingachangeof 20.7%(95%CI:

31.3%to 8.5%) frompre-reformulationtopost-re- formulation, which was statistically significant (p=0.0015).Similarstatisticallysignificantchanges inquarterlyslopeswereobservedforreportsoffatali- tiesinvolvingoverdose( 22.9%;CI: 34.7 %to

8.9%,p=0.0022)andoffatalitiesinvolvingboth overdoseandabuse( 22.2%;CI: 34.9%to 7%, p=0.0058).Changesfornon-overdosefatalities (e.g.,

Table2. Characteristicsofextended-releaseoxycodonefatalityreportsreceivedbymanufacturerwithdateofdeathduring 1-yearperiod beforeand3-year periodafterintroductionofreformulatedextended-releaseoxycodone

Allfatalcases(N=326) Subsetoffatalcases ofoverdose (N=240)

Oxycodonemention

*Oxycodonenototherwisespecified.Reportsinvolvingoxycodonetabletsthatdonotspecifyformulation(e.g.,immediate-release orextended-release formulation)areimpliedtohaveinvolvedextended-release oxycodone(OxyContin)becausethereporterhastakenthetimetospecificallytransmitthe informationtothemanufacturer.Duringtheevaluationperiodofthisstudy,onlyextended-releaseoxycodonewassoldbythemanufacturer,andnogeneric extended-releaseoxycodone productwasapprovedorsold.

†Illicitdrugsincludemarijuana,cocaine,amphetamines,andheroin.

deathnototherwise specified,suicide/homicide,and cancer) were not statistically significant ( 15.8%; CI: 36.8%to12.3%,p=0.2421)buttrendeddown.

Trendsincomparators

Nosubstantialchangeinadverseeventcasehandling orpharmacovigilanceprocedures weremadebythe manufacturer duringthestudyperiod.Non-fatalre- portstothemanufacturerforEROwere384perquar- terintheyear pre-reformulationcomparedwith 3129,

395,and294perquarterinthefirst,second,andthird yearpost-reformulation,respectively.Thesecompara- tor results suggest that the reductions in fatalities

involvingEROpost-reformulationwerenotdueto temporalchangesinreportingpatterns.

Aspikeinadverse eventreportsappearedshortly afterreformulation,mostofwhichoccurredwithin

3monthsofthemarketplacetransition.Asurveyof

1967subjectswhoreportedadverseeventsatthattime indicatedthat93%werefromindividualswhohad

usedEROforsometimeandwerereportingchanges

fromwhattheywereaccustomedto.Thetransitionto thereformulationwasconductedwithoutnotification

ofthegeneralpublic.

ReportsoffatalitiestothemanufacturerforERmor- phine(MSContin®)were toofewtoprovideastatisti- calcomparatortrend(2.7,1.5,2.5,and 2.0perquarter

Figure1. Number ofextended-releaseoxycodone(ERO)fatalityreportsperquarter.Categoriesentitledoverdose andoverdosewith mention ofabuse- related behavioraredefinedinmethods.DistributionofreformulatedEROtowholesalerswasinitiated 9August2010(indicatedbythearrow).

intheyearpre-reformulation, andfirst,second,and third year post-reformulation,respectively),though therewasnosubstantialdecrease.

Fatalityreportsforextended-releaseoxycodone versusalloxycodone

Theratioofthenumbersoffatalities involvingERO reportedtothemanufacturerrelativetofatalitieswith anyoxycodonecategorizedassuspectdrugreported to FDA decreased significantly (p0.0001) from

21%(131/637)intheyearpre-reformulationto22% (122/551),8%(50/616),and10%(12/120)inthefirst, second,andfirst6monthsofthirdyearpost-reformu- lation, respectively.

Sensitivityanalyses

Toassesstherobustnessoftheprimaryresults, sensi- tivityanalyseswereconductedadjustingforthenum- berofdispensedEROprescriptions,missingdateof deathinformation, reportertype,reportersource,for- mulationspecificity,andreportingtimelag(Table 3). Relativetothepre-reformulationyear,thenumber

ofEROprescriptions dispensedinretail,long-term care, and mail-orderpharmaciesdecreasedby 2% from1.72millionto1.69millionperquarterinthe

first,by9%to1.57millionperquarterinthesecond,

andby12%to1.51millionperquarter inthethird post-reformulationyear(Figure2).Decreasing trends infatalitycountsweredetectably, butnotsubstan- tially,altered whenadjustedforEROprescription numbers.Theprescription-adjustedrateofallfatality reportsdecreasedby80%(95%CI: 87%to 69%) comparingtheyearpre-reformulationtothethirdyear post-reformulation. Significantdecreasesinreported fataloverdosecases andfataloverdosecases thatalso mentionedabuse-relatedbehaviorwerealsoobserved.

Limiting theanalysistoreportsreceived from healthcareprofessionals, confiningtheanalysistofa- talitycaseswherebrandname “OxyContin”was men- tioned,removingfatalityreports withtextualmention of suicideor homicide(42 cases),or inclusionof post-marketing studies(82cases)didnotchangethe resultssubstantially. Imposingaconsistentreporting lagperiodof3or6monthsforallquartersacrossthe studyperiodshowedsimilardecreases infatalityre- portspost-reformulation,suggestingthattheobserved decreaseswerenotaffectedbyareportinglag.

Duringthestudyperiod,themanufacturerreceived

376fatalitycasesmissingthedateofdeath.Incompar- isonwithreportsthatincludedthisinformation,these

reports,ingeneral,lackeddetailedinformationregard- ingautopsyfindings,toxicologyresults,patientage,

and concomitant drugs. Analysis combining the

Table3. Changesinthe numberofextended-releaseoxycodonefatalityreportsperquarterreceivedbythe manufacturerfrom1yearbeforeto3yearsafter introductionofreformulatedextended-releaseoxycodone

1-yearpre-reformulation

(3Q2009–2Q2010)

Firstyear post-reformulation

(3Q2010–2Q2011)

Secondyearpost- reformulation(3Q2011–

2Q2012)

Third yearpost- reformulation(3Q2012–

2Q2013)

%change / %change / %change
Mean* / Mean / (95%CI) / Mean / (95%CI) / Mean / (95%CI)

Caseswith dateofdeathreported(n=326) Allfatalreports

All

O

Non-overdose 6.8 9.5 41( 14,130) 2.8 59( 80, 18) 2.5 63( 82, 23) Allfatalreports,per100000prescriptionsofOxyContin†

All 1.903 1.802 5( 26,21) 0.794 58( 70, 42) 0.380 80( 87, 69)

Overdose1.516 1.241 18( 38,10) 0.619 59( 72, 41) 0.213 86( 92, 75) Abuse-relatedbehavior 1.359 1.033 23( 44,5) 0.475 65( 77, 47) 0.213 84( 91, 72)

Non-overdose 0.387 0.561 43( 12,135) 0.176 55( 78, 10) 0.167 58( 80, 13)

Subsetofallfatalreportsfromhealthcareprofessionals

All19.8 15.8 20( 43,11) 6.0 70( 81, 52) 2.8 86( 93, 74) Overdose 15.8 11.3 29( 51,5) 5.0 68( 81, 42) 2.0 87( 94, 74) Abuse-relatedbehavior 14.8 11.0 25( 50,10) 4.0 73( 84, 53) 2.0 86( 94, 72)

Non-overdose 4.0 4.5 12( 43,121) 1.0 75( 92, 25) 0.8 81( 95, 36)

Subsetofallfatalreportsmentioning brandname“OxyContin”

All17.0 15.8 7( 34,31) 6.5 62( 76, 40) 3.0 82( 90, 67) Overdose 12.0 9.0 25( 51,16) 4.3 65( 80, 38) 1.3 90( 96, 74) Abuse-relatedbehavior 10.5 7.8 26( 54,17) 3.3 69( 83, 42) 1.3 88( 95, 70)

Non-overdose 5 6.8 35( 24,141) 2.3 55( 80, 1) 1.8 65( 85, 17)

Subsetofallfatalreportswithdataconfinedtocasesreceivedduring3-monthperiodfollowingdateofdeath

All11.5 18.0 57(8,127) 4.0 65( 80, 39) 4.0 65( 80, 39) Overdose 9.5 10.5 11( 29,71) 3.3 66( 82, 36) 2.0 79( 90, 55) Abuse-relatedbehavior 9.0 8.5 6( 41,51) 2.8 69( 84, 40) 2.0 78( 90, 52)

Non-overdose 2.0 7.5 275(72,718) 0.8 62( 90,41) 2.0 0( 62,166)

Subsetofallfatalreportswithdataconfinedtocasesreceivedduring6-monthperiodfollowingdateofdeath

All17.3 21.5 25( 9,71) 7.3 58( 73, 35) 5.0 71( 82, 52) Overdose 13.8 13.5 2( 33,43) 5.3 62( 77, 37) 2.5 82( 91, 64)

Abuse-relatedbehavior 12.8 11.0 14( 42,29) 4.8 63( 78, 37) 2.5 80( 90,61) Non-overdose 3.5 8.0 129(22,328) 2.0 43( 76,36) 2.5 29( 68, 61)

Caseswith dateofdeathreported(n=326)andnotreported(n=376)

Fatalreportswithdateofdeath+fatalreportswithoutdateofdeath(usingmanufacturerreceiptdateasproxy) All

Overdose

Abuse-relatedbehavior 31.8 29.0 9( 29,17) 16.3 49( 62, 31) 11.3 65( 75, 50)

Non-overdose 22.3 26.5 19 ( 10, 58) 11.0 51 ( 66, 29) 10.5 53 ( 67, 32)

*Meannumberoffatalitycases perquarterwithvaluesroundeduptoonedecimal.

†IMSNationalPrescriptionAuditdatabase(includesretail, mailorderandlong-termcarepharmacyprescriptions).

fatality reports withoutdateofdeath,usingmanufac- turerreport-receipt dateasaproxyfordateofdeath, withthosereportscontainingdateofdeath,showeda

47%(95%CI: 58%to 34%)decreaseinallfatality

reportsinthethirdyearpost-reformulation. Significant decreasesinthenumberofoverdosefatalities,over-

dosefatalitieswithmentionofabuse-relatedbehavior,

andnon-overdose fatalitieswerealsoobserved.

DISCUSSION

Thenumberofspontaneousreportsofdeathinvolving

ERO reported to the manufacturerdecreasedafter

introductionofareformulatedEROthatwasdesigned tobeabuse-deterrent. Asvoluntaryspontaneousad- versereportsdonotcaptureallevents,temporaltrends in thesereportsmaynotbea reliablesourceforcausal interpretation.39–41 However,thelargemagnitudeof thedecreaseinreportedfatalities, whilenon-fatality adverseeventsremainedunchangedorincreased,sug- geststhedecrease wasnotduetochangingprocesses forreporting/collecting ofEROadverseevents.The relativestability ofdeathreportsforanother opioid productduringthesame period,thoughmuchfewer (becauseoffewerprescriptions), suggeststhatthere wasno systematicprocesschangeforreportingor

Figure2. OxyContinprescriptions perquarter.Retail,mailorder,and long-term care pharmacy dispensing of OxyContin prescriptions for

3Q2009–2Q2013extractedfromIMSNationalPrescriptionAuditdata-

base.DistributionofreformulatedOxyContintowholesalerswasinitiated

9August2010(indicatedbythearrow).

collectingreportsofdeathsbythemanufacturerduring thisperiod.Furthermore,analysesconductedtoassess whethermethodologicalartifactsmightberesponsible forthedeclineshowedlittleimpactofpotential arti- facts,suchaschangesinprescription numbers,re- portertypeorsource,formulationspecificity,missing dateofdeath,andreportingtimelag.Therefore,these resultssuggestadecrease inthenumberoffatalities associatedwithEROabuse/misuseasaresultofitsre- formulationwithphysicochemicalpropertiesthatdeter crushing/dissolving.

Other studieshave reportedsimilardecreasesin abuse/misuse of ERO post-reformulation. Cicero etal.29 reportedthatinpatientswithopioiddepen- dence who were enteringtreatment,the choice of EROastheprimarydrugofabuseanduseofERO togethighatleastonceinthelast30days,decreased significantlypost-reformulation(SurveyofKeyInfor- mantsPatients’ ProgramoftheRADARS® System). Butleretal.30 reportedthatforindividualsassessed forsubstanceabusetreatment,oraland non-oralabuse ofreformulated EROwere17%and66%lower,re- spectively, thanhistoricabuseoforiginalERO (NAVIPPROSurveillanceSystem), whereasabuseof ERoxymorphoneandERmorphineincreased or remained relativelyunchanged,respectively. Severtsonetal.31 reportedthatEROabuseexposure callsto poisoncentersand reportsofdiversionof ERO,onaper-catchment areapopulationbasis,de- creased38%and53%,respectively,andthatthestreet priceforreformulated EROwassignificantlylower thanoriginal ERO(PoisonCenterStudyandDrug Diversion Program of RADARS System). Coplan etal.32 reportedthatpoisoncenterEROabuse,suicide, therapeuticerrorsamong patients,accidentalexpo- suresamongchildren,andadversereactionexposures

decreasedsignificantlypost-reformulation butin- creasedorremainedsteadyforothersingle-entityoxy- codoneproducts(National PoisonDataSystem). Havensetal.42 reported thatexperiencedopioid abusersin a ruralKentuckycountyself-reporteda lowfrequencyofabuseofreformulated EROwhile maintainingaconsistentlyhighfrequencyofabuseof IRoxycodone.TheFloridaMedicalExaminersCom- missionReportshowedadecreaseindeathsdueto allformsofoxycodone,bothER andIR formulations, from apeakof1516in2010to735in2012.43 How- ever,duringthisperiod,astatelawwasenactedtoim- posestricterrequirementsfordispensingofcontrolled substancestargetedspecificallyatpillmillsthatwere primarilyprescribingordispensingIRoxycodone.50

Nationally,theratiooffatalitiesinvolvingEROversus anyoxycodone morethanhalved(from21%to8%) afterreformulation,furtherendorsingthespecificity oftheeffectofthereformulation.

Otherresearchers haveusedspontaneousadverse eventreports toassesstheeffects ofopioidformula- tionsintendedtodeterabuse.Post-marketingadverse

eventreportsreceivedforanERmorphinecapsule

combined with naltrexone(anopioidantagonist)indi- catedalownumberofproducttamperingreportsand nocasesofconfirmedtamperingresultinginfatality.44

Therearelimitationstocausalinferencefromvolun- taryspontaneousfatalityreports. However,whenthe results ofthisstudyareconsideredinthecontextof thefiveadditionalpublishedarticlesandtheonestate surveillance reportthatdemonstrateanabuse-deterrent impactofreformulated ERO,theBayesianpriorthat theobservedchangeinreportedfatalitiesiscaused bythereformulationisincreased.45

Alternateexplanations for the declinein fatality reporting wereconsidered.AreductioninEROdis- pensingoccurredduringthestudyperiod.However,

combined prescription reductions of original and

reformulatedERO(2%,9%,and12%in thefirst, second,andthirdyearpost-reformulation,respectively)

were insufficienttoaccountforthemuchlargerreduc-

tioninfatalities.DispensingoforiginalERO gradually decreasedinthe18monthsafterwholesaleshipments

stopped.Ofnote,reportsreceivedbythemanufacturer

post-reformulationincludedexposurestobothoriginal andreformulatedEROandthereforeaportionofthe

fatalreportsinthepost-periodlikelyinvolvedoriginal

ERO,whichmayaccountforthegradualdecrease in fatalitiespost-reformulation.

Severalinitiativestodeteropioidabuse/overdose

commenced orwereongoingduringthestudyperiod. TheFDA’sRiskEvaluationandMitigationStrategy

forERandlong-actingopioidswasapprovedinJuly

2012.46 However,itsprimarycomponentiscontinuing educationofprescribers,whichbeganinMarch2013, subsequentto the reductionin ERO deaths.State prescriptiondrugmonitoringprogramswereoperating orinitiatedduringthe study period.47 Preliminary evaluationoftheseprograms indicateapositive impactonopioidabuse/misuse,48 buttheireffect on fatalities isnotclear.49,50 Community-basedopioid overdosepreventionprogramshavereduceddeaths inthefewlocalregionswhereimplemented but cannotaccountforlargenationalchanges.51,52 Drug disposalprogramshavebeenestablishedbuthave notfocusedspecifically onEROandhavenotbeen showntoimpactdeathsassociated withopioids.53,54

Theseinitiativesmayhavecontributedtodecreases in opioid-relatedfatalities;however, they are un- likelytoaccountforthelevelofdecrease inERO fatalities. The ratio of fatalities involving ERO versusanyoxycodonemore thanhalvedafter reformulation.

Someauthorsattributedanincreaseinheroinabuse tothereformulation ofEROwhenitwasfirstintro- duced,29 andthishasledtowidespreadattribution of thecauseoftherapidlyescalating heroinabuseto EROinmediareports.55 However,currently,1.7%of individualsdispensedopioidanalgesics intheUSA receiveERO,and2.5%ofopioidprescriptions dis- pensedareforERO.Theseproportionshaveremained roughlyconstantoverthepast5years(IMSHealth, unpublisheddata).Furthermore, approximately4.3% ofdiagnosedoverdoseeventsininsuranceclaimsdata- basesin2011wereamongpeopleprescribed ERO (MarketScan,unpublisheddata)andtheprevalence ofreformulatedEROabuseamongprescriptionopioid abusersindrugtreatment centersis12.1%.22 There- fore, itisunlikelythatreducedabuseofERO,which occurredinasingle,abruptinterventionbeginningin August2010,couldaccountforspikesinheroinabuse

3½yearslater.

Inconclusion,thenumberofspontaneousreports of fatalities involving ERO has significantly de-

creasedafteritsreformulation, whereasnon-fatal reports involving ERO remained unchanged or

increased.Thesefindings,whenconsideredin the

contextofpreviouslypublishedstudies usingother surveillancesystems,suggestthatthe abuse-deterrent

characteristicsofreformulatedEROhavedecreased

fatalitiesassociatedwith its misuse/abuse.Abuse- deterrent formulations may be a valuable risk

management tool, such that innovation, policing,

regulation,carefulprescribing,andeducationcanbe combinedtomitigate serious riskandimprovethe benefit-riskbalance ofopioidanalgesics.56

CONFLICTOFINTEREST

NelsonSessler, JerodDowning,HrishikeshKale, Howard Chilcoat, Todd Baumgartner, and Paul Coplanarefull-timeemployeesofPurduePharmaL.P.

KEYPOINTS

•Abuseofprescriptionopioidanalgesicsforthepsy-

choactiveeffectsisassociatedwithalargenumberof

fatalities. However,theeffectofmakingopioidtablets

hardertocrushordissolveinordertodeterabuseon opioid-relatedfatalitieshas notbeenassessed.

•Themanufacturer’spharmacovigilancedatabase

wasusedtoassesschangesinfatalitiesassoci-

ated with extended-releaseoxycodone (ERO, OxyContin)aftertheproductwasreformulated

tobehardertocrushordissolve.

•Alargedecreaseinthenumberoffatalityreports

associatedwithEROoccurredfollowingintro-

ductionofreformulatedOxyContin,especially reportsof fatalitiesinvolvingoverdose-related

eventsandinvolvingabuse.

•Thesefindings,whenconsideredinthecontextof

previouslypublishedstudiesusingothersurveillance

systems,suggestthattheabuse-deterrentcharacteris-

tics of reformulated ERO have decreased the fatalitiesassociatedwithitsmisuseandabuse.

ETHICSSTATEMENT

Theauthors statethatnoethicalapprovalwasneeded. ACKNOWLEDGEMENTS

CasereviewassistancewasprovidedbyBarbaraHar- ding.Manuscriptpreparationassistancewasprovided byMelindaPhilbrook.Writingassistance waspro- videdbyLouisAlexander. Thisstudywassponsored byPurduePharmaL.P.

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