Corporate OverviewNovember 2022At the Forefront of Therapies for Rare Diseases

2 Forward-Looking Statements Thispresentationcontains"forward-lookingstatements"withinthemeaningofthePrivateSecuritiesLitigationReformActof1995relatingtopreclinicalandclinicaldevelopmentofourproductcandidates,thetimingandreportingofresultsfrompreclinicalstudiesandclinicaltrials,theprospectsandtimingofthepotentialregulatoryapprovalofourproductcandidates,commercializationplans,manufacturingandsupplyplans,financingplans,andtheprojectedrevenues,expenses,cashposition,andfutureprofitabilityfortheCompany.Theinclusionofforward-lookingstatementsshouldnotberegardedasarepresentationbyusthatanyofourplanswillbeachieved.Anyoralloftheforward-lookingstatementsinthispressreleasemayturnouttobewrongandcanbeaffectedbyinaccurateassumptionswemightmakeorbyknownorunknownrisksanduncertainties.Forexample,withrespecttostatementsregardingthegoals,progress,timing,andoutcomesofdiscussionswithregulatoryauthorities,andinparticularthepotentialgoals,progress,timing,andresultsofpreclinicalstudiesandclinicaltrials,includingastheyareimpactedbyCOVID-19relateddisruption,arebasedoncurrentinformation.ThepotentialimpactonoperationsfromtheCOVID-19pandemicisinherentlyunknownandcannotbepredictedwithconfidenceandmaycauseactualresultsandperformancetodiffermateriallyfromthestatementsinthisrelease,includingwithoutlimitation,becauseoftheimpactongeneralpoliticalandeconomicconditions,includingasaresultofeffortsbygovernmentalauthoritiestomitigateCOVID-19,suchastravelbans,shelterinplaceordersandthird-partybusinessclosuresandresourceallocations,manufacturingandsupplychaindisruptionsandlimitationsonpatientaccesstocommercialorclinicalproduct.InadditiontotheimpactoftheCOVID-19pandemic,actualresultsmaydiffermateriallyfromthosesetforthinthisreleaseduetotherisksanduncertaintiesinherentinourbusiness,including,withoutlimitation:thepotentialthatresultsofclinicalorpreclinicalstudiesindicatethattheproductcandidatesareunsafeorineffective;thepotentialthatitmaybedifficulttoenrollpatientsinourclinicaltrials;thepotentialthatregulatoryauthorities,includingtheFDA,EMA,andPMDA,maynotgrantormaydelayapprovalforourproductcandidates;thepotentialthatwemaynotbesuccessfulincommercializingGalafoldinEurope,Japan,theUSandothergeographies orourotherproductcandidatesifandwhenapproved;thepotentialthatpreclinicalandclinicalstudiescouldbedelayedbecauseweidentifyserioussideeffectsorothersafetyissues;thepotentialthatwemaynotbeabletomanufactureorsupplysufficientclinicalorcommercialproducts;andthepotentialthatwewillneedadditionalfundingtocompleteallofourstudies,manufacturingandlaunchpreparations.Further,theresultsofearlierpreclinicalstudiesand/orclinicaltrialsmaynotbepredictiveoffutureresults.WithrespecttostatementsregardingprojectionsoftheCompany'srevenue,expenses,cashposition,andfutureprofitability,actualresultsmaydifferbasedonmarketfactorsandtheCompany'sabilitytoexecuteitsoperationalandbudgetplans.Inaddition,allforward-lookingstatementsaresubjecttootherrisksdetailedinourAnnualReportonForm10-KfortheyearendedDecember31,2021andForm10-QforthequarterendedSeptember30,2022.Youarecautionednottoplaceunduerelianceontheseforward-lookingstatements,whichspeakonlyasofthedatehereof.Allforward-lookingstatementsarequalifiedintheirentiretybythiscautionarystatement,andweundertakenoobligationtoreviseorupdatethisnewsreleasetoreflecteventsorcircumstancesafterthedatehereof. Non-GAAPFinancialMeasuresInadditiontofinancialinformationpreparedinaccordancewithU.S.GAAP,thispresentationalsocontainsadjustedfinancialmeasuresthatwebelieveprovideinvestorsandmanagementwithsupplementalinformationrelatingtooperatingperformanceandtrendsthatfacilitatecomparisonsbetweenperiodsandwithrespecttoprojectedinformation.Theseadjustedfinancialmeasuresarenon-GAAPmeasuresandshouldbeconsideredinadditionto,butnotasasubstitutefor,theinformationpreparedinaccordancewithU.S.GAAP.WetypicallyexcludecertainGAAPitemsthatmanagementdoesnotbelieveaffectourbasicoperationsandthatdonotmeettheGAAPdefinitionofunusualornon-recurringitems.Othercompaniesmaydefinethesemeasuresindifferentways.Whenweprovideourexpectationfornon-GAAPoperatingexpensesonaforward-lookingbasis,areconciliationofthedifferencesbetweenthenon-GAAPexpectationandthecorrespondingGAAPmeasuregenerallyisnotavailablewithoutunreasonableeffortduetopotentiallyhighvariability,complexityandlowvisibilityastotheitemsthatwouldbeexcludedfromtheGAAPmeasureintherelevantfutureperiod,suchasunusualgainsorlosses.Thevariabilityoftheexcludeditemsmayhaveasignificant,andpotentiallyunpredictable,impactonourfutureGAAPresults.

3 A Rare Company Patient-dedicated, Rare Disease Biotechnology Company with Sustained Double-digit Revenue Growth, a Global Commercial Infrastructure, and Late-stage Development Capabilities AT-GAAa Two-component TherapyUnder GlobalRegulatory Reviews forPompe Disease GLOBAL COMMERCIAL ORGANIZATIONWorld-class CLINICAL DEVELOPMENT Capabilities EMPLOYEESin 20 Countries GALAFOLD&AT-GAA Gene Therapy PLATFORMLeveraging Experience in Protein Engineering & Glycobiology $354.7MCashas of 9/30/22 15% -20%FY22 Galafold Revenue Growth at CER Non-GAAP PROFITABILITY expected in 2H2023 Cumulative $2B Peak Potential

2022 Strategic Priorities to Drive Value 12345Double-digit Galafold growth (15-20%) with revenue of $350M to $365M at CER1Secure FDA approval and positive CHMP opinion for AT-GAA Initiate successful, rapid launch in U.S. for AT-GAAAdvance best-in-class, next-generation genetic medicines and capabilitiesMaintain strong financial position on path to profitability 4 1CER: Constant Exchange Rates; 2022 Galafold revenue guidance is based on the average exchange rates for 2021

5 INDICATIONDISCOVERYPRECLINICALPHASE 1/2PHASE 3REGULATORYCOMMERCIALFABRY FRANCHISEGalafold®(migalastat) Fabry Gene TherapyNext-Generation ChaperonePOMPE FRANCHISEAT-GAA (cipaglucosidase alfa + miglustat)Pompe Gene TherapyOTHERCLN3 Batten Disease Gene Therapy Next-Generation Research ProgramsAmicus Pipeline Streamlined Rare Disease Pipeline with Focus on Fabry Disease and Pompe Disease ODD ODD BTDODD-Orphan Drug Designation BTD -Breakthrough Therapy Designation

6 Positioned for Significant Value Growth Focused on Execution and Driving Sustainable Double-digit Revenue Growth on Path to ProfitabilityContinue to bring Galafold®to as many patients as possible, sustain double-digit revenue growthSuccessful launch of AT-GAA for people living with Pompe diseaseAdvance next-generation gene therapies in Fabry and Pompe diseasesFully leverage global capabilities and infrastructure as a leader in rare diseases Achieve non-GAAP profitabilityin 2H20231 1 Basedon projections of Amicus non-GAAP Net Incomeundercurrentoperating plans, whichincludessuccessfulAT-GAA regulatoryapprovalsand continuedGalafold growth. Non-GAAP Net Incomedefinedas GAAP Net Incomeexcludingthe impact of share-basedcompensation expense, changes in fairvalue of contingent consideration, losson impairmentof assets, depreciationand amortization, acquisition relatedincome(expense), losson extinguishmentof debt, losson impairmentof assets, restructuringcharges and incometaxes.

7 Galafold® (migalastat)Continued Growth… building a leadership position in the treatment of Fabry disease

8 Global Fabry Market Fabry Disease is believed to be significantly underdiagnosed–Newborn screening studies suggest Fabry could be one of the more prevalent human genetic diseases (~1:1,000 to ~1:4,000 incidence) In 2021, Galafold was the fastest growing medicine for Fabry disease and the greatest contributor to Fabry market growth–Introduction of Galafold has led to market expansion with 800+ naive patients diagnosed and treated for the first time Global Fabry Disease Market Growth Continues to be Driven by Diagnosing New Patientsin Addition to the Introduction of Galafold(millions)1Global market measured by reported sales of approved therapies for Fabry disease –2025 sales projected using 8% CAGR $0$500$1,000$1,500 $2,000$2,500$3,00020172018201920202021E2022E2023E2024E2025E Global Fabry market to exceed $1.9B in 2021 and tracking toward ~$2.6B by 20251

9 GalafoldSuccess (as of September 30, 2022) Building on Galafold’s Success and LeveragingLeadership Position to Drive Continued Growth Galafold is indicated for adults with a confirmed diagnosis of Fabry Disease and an amenable variant. The most common adversereactions reported with Galafold (≥10%) were headache, nasopharyngitis, urinary tract infection, nausea and pyrexia. For additional information about Galafold, including the full U.S. Prescribing Information, please visithttps://www.amicusrx.com/pi/Galafold.pdf .. For further important safety information for Galafold, including posology and method of administration, special warnings, drug interactions and adverse drug reactions, please see the European SmPC for Galafold available from the EMA website atwww.ema.europa.eu ..Galafold is the first and only approved oral treatment option with a unique mechanism of action for Fabry patients with amenable variants 350Amenable Variants in U.S. Label44Countries with Regulatory Approvals Continued Geographic Expansion in 2022$81.6M3Q22 Galafold Revenue15%-20%2022 Galafold Operational Growth1,384Amenable Mutations in EU Label

10 GalafoldPerformance YTD Reported Revenue Growth of +7.9% to $241.0M –Strong Operational Growth of +16.2% at CER Global demand remains strong: 3-month net new patients trend best in 2 years Call volume increasing from same period last year Global mix of switch (~55%) and previously untreated patients (~45%) Compliance and adherence over 90%+ Expect non-linear quarterly growth to continue due to uneven ordering patterns and FX fluctuations $223.4M$241.0M-8.3%+16.2%9M21OperationalGrowthFX Impact9M22Year-over-Year Sales Growth

11 Penetration of the diagnosed untreated populationIncrease in newborn screening and diagnostic initiativesStrong IP rights, includingCOM protection through 2038Continued penetration into existing marketsExpansion into new geographiesBroadening of labels Galafold Growth Opportunity$1B Annual Sales Opportunity at Peak Sustaineddouble-digit revenue growth: Near-term growth to $500M driven by: Long-term growth towardspeak sales potential driven by:3Q operational revenue growth of +13.4%COM: Composition of Matter

12 Galafold Initiatives Building the Body of the Evidence around Galafold Broadening Labels: Adolescents and Additional Variants Publications and Medical Presentations Ongoing and Planned Phase IV Studies Over 500 Patients Enrolled in a Global Registry Strengthening our IP Portfolio

13 AT-GAA (cipaglucosidase alfa + miglustat)… potential to establish a new standard of care for people living with Pompe disease

14 Deficiency of GAA leading to lysosomal glycogen accumulation and cellular dysfunction Age of onset ranges from infancy to adulthood Symptoms include muscle weakness, respiratory failure, and cardiomyopathy Respiratory and cardiac failure are leading causes of morbidity and mortality Estimated incidence of ~1:28,000; newborn screening suggests significant underdiagnosis ~$1.2B+ global Pompe ERT sales1 Majority of patients on current standard of care decline after ~2 yearsPompe Disease Overview 1. Based on 12 months ended December 31, 2021. Source: Sanofi Press ReleasePompe is a Severe and Fatal Neuromuscular Disease Caused by the Deficiency of Lysosomal Enzyme GAA

15 AT-GAA: An Innovative Approach to Pompe Disease Our Scientists Created a Uniquely Glycosylated and Highly Phosphorylated ERT (ATB200) that Significantly Enhances Targeting to Key Affected Muscles AT-GAA is a two-component therapy combining ATB200, an ERT, with AT2221, an orally administered enzyme stabilizer Consists of a naturally occurring cell line that can be properly processed within the lysosome to its mature form which is required to optimally break down glycogen1 ATB200AT2221 1Selvan et al. 2021, J Biol Chem 2021 Jan-Jun;296:100769ERT: Enzyme Replacement Therapy

16 Phase 3 PROPEL Study ResultsPrimary, Key Secondary and Biomarker Endpoint Heat Map Endpoints Across Motor Function, Pulmonary Function, Muscle Strength, PROs, and Biomarkers Favored AT-GAA over alglucosidase alfa

17 Phase 3 PROPEL Study ResultsOverall Population (n=122*) Primary and First Key Secondary Endpoint Showed Greater Improvement with AT-GAA vs. alglucosidase alfa in the Overall Population of ERT-Naïve and ERT-Experienced Patients6MWD=6-minute walk distance;; FVC=forced vital capacity; SE=standard error. P values are nominal 2-sided; FVC data normally distributed and P value is from ANCOVA. 6MWD data not normally distributed and P value is for nonparametric ANCOVA; *Results exclude one outlier subject 6MWD (m): Change from baseline (n=85, n=37) FVC (% predicted): Change from baseline(n=85, n=37)

18 Phase 3 PROPEL Topline Results:ERT Experienced Population (n=95) ERT Experienced Patients Treated with AT- GAA Demonstrated Improvements over Time in 6MWD and Stabilization over Time in FVC Versus alglucosidase alfa NOTE: Baseline is Mean (STDEV); CFBL is Mean (SE); P-values are nominal 2-sided; FVC data normally distributed and p–values are from ANCOVA6MWD data not normally distributed and 6MWD p-value is for non-parametric ANCOVA; 6MWD parametric MMRM p-value was p=0.078 6MWD (m): Change from baseline (n=65, n=30) FVC (% predicted): Change from baseline(n=65, n=30)

19 Phase 3 PROPEL Study Publication Clinically Meaningful Outcomes from Phase 3 PROPEL Study Provide the Basis for Global Regulatory Submissions of AT-GAA Peer-reviewed results from PROPEL suggest that treatment with AT-GAA provided clinically meaningful improvements over standard of care, including ERT-experienced patients with high unmet need The authors deemed AT-GAA to provide a differentiated mechanism of action and potential alternative treatment option for people living with late-onset Pompe Disease Schoseret al. 2021, The Lancet Neurology, Volume 20, Issue12, P1027-1037

20 Long-Term Data from Phase 1/2 Clinical Study (ATB200-02) Persistent and Durable Improvements in Motor and Respiratory Function and Reductions in Biomarkers of Muscle Damage and Disease Substrate Observed in Patients out to 48 Months NOTE: * One patient in the ERT-naïve cohort experienced a large drop in % predicted FVC at month 21, which returned to previous levels at the following visit (month 24). CFBL in 6MWD in (A) ERT-Experienced and (B) ERT-Naïve Patients CFBL in FVC in (A) ERT-Experienced and (B) ERT-Naïve Patients

21 AT-GAA: Ongoing Evidence Generation Indirect Treatment Comparison across Pompe ERT Studies Recently Presented at World Muscle Society 2022 Congress Highlights Potential Clinical Differentiation of AT-GAA 6MWD: Relative effect estimates with 95% credible intervals in base-case scenario -100-50-050100 Cipa+mig vs AlgluCipa+mig vs AvalRelative effect (95% Crl)16.3 (9.6, 24.3)29.5 (7.4, 52.6) <0.0010.011P-valueFavours latterFavours former -10-010 Cipa+mig vs AlgluCipa+mig vs AvalRelative effect (95% Crl)3.1 (2.4, 3.8)2.8 (0.9, 4.6) <0.0010.003P-valueFavours latterFavours former FVC: Relative effect estimates with 95% credible intervals in base-case scenario Relative Effect (6MWD Change from Baseline at Week 52)Any comparisons are based on published data. No clinical, safety, or efficacy conclusions may be drawn from this data. Relative Effect (FVC Change from Baseline at Week 52)

22 Global Pompe Market Global Pompe Disease Market Growth Continues to be Driven by the Diagnosis of New Patients -Only One Approved Therapy on the Market up until 2021 Pompe Disease believed to be significantly underdiagnosed–Newborn screening studies suggests Pompe to be more prevalent than medical literature suggest (~1:10,000 to ~1:30,000)–Newborn screening already occurring in 27 U.S. states with 9 additional U.S. states pursuing NBS implementation for Pompe diseaseGlobal Pompe Market to exceed $1.1B in 2021and tracking toward $1.5B+ by 20251(millions) $0$200$400$600 $800$1,000 $1,200 $1,400$1,600$1,800201720182019202020212022202320242025 1Global market measured by reported sales of approved therapies for Pompe disease –2025 sales projected using 8% CAGR

23 AT-GAA: Key Takeaways U.S. Regulatory status update: –PDUFA action date deferred due to Agency‘s inability to conduct manufacturing inspection in China1–At the Agency’s direction, the Company has scheduled a Type A meeting to develop plans and logistics for a pre-approval inspection European Regulatory status update: –Expect de-coupled CHMP opinions for cipaglucosidase alfa and miglustat respectively•Cipaglucosidase alfa: CHMP opinion expected as early as December 2022 •Miglustat: CHMP opinion expected 2Q 2023 based on 4-month clock stop in order to complete requested confirmatory analytical testing Multiple expanded access mechanisms in place, including in the U.S., U.K., Germany, France, Japan, and others ~190 people living with Pompe disease are now on AT-GAAacross our clinical extension studies and expanded access programs Ongoing supportive studies in children and adolescents2with LOPD as well as in Infantile-Onset Pompe Disease (IOPD) Focused on Advancing AT-GAA to as Many Patients as Possible through Global Regulatory Pathways and Expanded Access Mechanisms 1 FDA has not provided anticipated action dates as they continue to monitor the public health situation and travel restrictionsinChina; The Company expects the FDA to approve the NDA and BLA applications together2 Children and adolescents aged 0 to <18 years old

24 AT-GAA Launch Preparations Experienced and Passionate Rare Disease Medical and Commercial Organization Poised for SecondSuccessful Launch Key Strengths Commitment to patient accessClear focus on launchIdentification of key Pompe disease treatment centersDevelopment of educational materials Planning Access Education Team Great experience and passionEagerness to introduce a new therapy upon approvalsHighly leverageable team in place, few new hires neededPublished Phase 3 PROPEL data in The Lancet NeurologyActive medical conference and publication scheduleMultiple Expanded Access Programs in placeContinued education on biology of disease and diagnosisDemonstrating value to payors including parity pricing strategy

25 Financial & Operational Strategy… maintaining a strong financial outlook

26 Q3 2022 Revenue Performance Q3 2022 Reported Revenue Growth of +2.7% to $81.7M resulting from Strong Operational Growth of +13.6% at CER Offset by Negative FX impact of -10.9% Significant currency exposure as 63% of Galafold revenue generated outside the U.S. Applying average October 2022 exchange rates, the negative FX impact on full-year 2022 reported sales would be approximately -9%, or ~$28.5 million. $79.5M$81.7M-10.9%+13.6%3Q21OperationalGrowthFX Impact3Q22Year-over-Year Sales Growth

Financial Outlook and Path to Profitability Clear Strategy to Build Our Business, Advance Our Portfolio, and Achieve Profitability 27 Sustain Galafold Revenue GrowthDeliver on Financial GoalsSecure Approvals of AT-GAA$241M YTD revenue, +16.2% YoY Operational Growth 2022 Galafold revenue growth guidance of +15-20% YoY at CERGalafold and AT-GAA expected to drive strong double-digit growth long termFocused on prudent expense managementAchieve profitability1in 2H2023 1Based on projections of Amicus non-GAAP Net Income under current operating plans, which includes successful AT-GAA regulatory approvals and continued Galafold growth. We define non-GAAP Net Income as GAAP Net Income excluding the impact of share-based compensation expense, changes in fair value of contingent consideration, depreciationand amortization, acquisition related income (expense), loss on extinguishment of debt, loss on impairment of assets, restructuring charges, and income taxes.2022 non-GAAP operating expense guidance of$430M-$440M

28 True Measure of Success: Impacting the Lives of Patients Living with Rare Diseases YE17 2023+Thousands of Patients*>1,900+ Patients* YE21 >350 Patients* *Clinical & commercial, all figures approximate

Thank You

Appendix

31 Environmental, Social, & Governance (ESG) Snapshot Board of Directors Eco-friendly decision-making has unearthed economic efficiencies while continuing to bolster our standing as a good corporate citizen.Committed to ongoing Board refreshment and diversity of background, gender, skills, and experience:Contributions allocated:$1,677,000 US$832,976 Intl.770Volunteer hours (US):20+Amicus supported community programs: 80%Board Independence60%Overall Board DiversityAddress a rare genetic disease First-in-class or best-in-classImpart meaningful benefit for patients 496Global Employees58%% female employees Who We ServeEnvironmental Management Green building design Energy & water conservation Hazardous waste management Pledge for a CureDesignate a portion of product revenue back into R&D for that specific disease until there is a cure.Pricing PROMISE Programs we invest in have 3 key characteristics:Committed to never raising the annual price of our products more than consumer inflation.Diversity, Equity & Inclusion (DEI) 2023 and Beyond:•Maintain strength in global gender diversity•Increase US diversity through intentional and ongoing action•Continuously evaluate compensation practices to ensure pay parity Pledge to support a more inclusive culture to impact our employees, our communities, and society. 3 Female2 Veteran Status1 African AmericanDirector Diversity % Hiring Slate Diversity 82% Leverage employee capabilities and expertise to provide a culture that drives performance and ultimately attracts, energizes, and retains critical talentEmployee Recruitment, Engagement, and Retention Pulse surveys reveal employees feel high personal satisfaction in their job, are proud of their work and what they contribute to the communityCharitable Giving71 patients /21countriesExpanded Access through Nov 2022: Career DevelopmentReimagined performance management process to measure the what and the how, rewarding those who role-model our Mission-Focused Behaviors.

32 Appendix