Good morning, ladies and gentlemen. Welcome to the Amicus Therapeutics’ Third Quarter 2021 Fiscal Results Conference Call and Webcast. [Operator Instructions] As a reminder, this conference call is being recorded. I would now like to turn the conference over to your host, Mr. Andrew Faughnan, Head of Investor Relations. You may begin.

Thank you, operator. And good morning, everyone. Thank you for joining our conference call to discuss Amicus Therapeutics' third quarter 2021 financial results and corporate highlights. Speaking on today's call, we have John Crowley, Chairman and Chief Executive Officer; Bradley Campbell, President and Chief Operating Officer; Daphne Quimi, Chief Financial Officer; and Dr. Jeff Castelli, Chief Development Officer. Joining for Q&A, we'll have Dr. Mitchell Goldman, Chief Medical Officer; and Sébastien Martel, Chief Business Officer joining. As referenced on Slide 2, we may make forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 relating to our business as well as our plans and prospects. Our forward-looking statements should not be regarded as representations by us that any of our plans will be achieved. Any or all the forward-looking statements made on this call may turn out to be wrong and can be affected by inaccurate assumptions we might make or by known or unknown risks and uncertainties. You are cautioned not to place undue reliance on any forward-looking statements, which should be regarded according to the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement. And we undertake no obligation to revise or update this presentation and conference call to reflect events or circumstances after the date hereof. For a full discussion of such forward-looking statements and risks and uncertainties that may impact them, we refer you to the forward-looking statements and Risk Factors section on our annual report on Form 10-K for the year ended December 31, 2020, and the quarterly report on Form 10-Q for the quarter ended September 30, 2021, to be filed later today with the Securities and Exchange Commission. At this time, it is my pleasure to turn the call over to John Crowley, Chairman and Chief Executive Officer. John?

Great. Thank you, everyone. Good morning. And welcome to our third quarter 2021 results conference call. I am pleased to report that the third quarter reflected broad execution across our business as we remain on track to achieve our key strategic priorities for the year. As mentioned in this morning's release, I'd like to highlight several key updates. First, Galafold continues its strong performance and remains the cornerstone of our success with $79.5 million in third quarter revenue. We are very pleased with the continued momentum of Galafold globally as we added new patients from both switch and naïve populations throughout the quarter. Second, we continue to make tremendous progress on our global regulatory filings for AT-GAA, our novel next-generation therapy for Pompe disease. In September, the U.S. Food and Drug Administration accepted for review the biologics license application for cipaglucosidase alfa and the new drug application for miglustat, the two components of AT-GAA. The U.S. review is underway. The FDA has set a PDUFA action date of May 29, 2022, for the NDA related to the enzyme stabilizer, and July 29, 2022, for the BLA of the biologic. The two regulatory filings significantly cross-reference each other, and we expect that they will be reviewed together. In the European Union, following our previously announced positive rapport and co-rapport meeting, I am pleased to share for the first time this morning that the marketing authorization applications or MAA for AT-GAA have been submitted to the European Medicines Agency. We are now closer to having another potential treatment option for people living with Pompe disease, both in the United States and in Europe with further regulatory applications planned in the months ahead. We are confident in the potential benefits of AT-GAA and what it can bring to people living with Pompe disease around the world. We look forward to working with regulators to get this important medicine to as many patients as quickly as possible. On the gene therapy front, we continue to make excellent progress in advancing and developing the industry's leading portfolio of next-generation gene therapies for people living with rare genetic diseases. Our teams are preparing and making great progress toward the business combination in which the Amicus gene therapy business will be acquired by ARYA IV, a special purpose acquisition company. Through this business combination, the Amicus gene therapy program technologies, intellectual property, key personnel and relationships will form a new company, Caritas Therapeutics. We strongly believe that separating our business into two highly focused, standalone companies is the best way to unlock value for Amicus shareholders and to properly fund and focus our gene therapy efforts. In a single stroke, we will have created what will be, we believe, one of the world's preeminent, next-generation genetic medicine and gene therapy companies in Caritas, while significantly strengthening Amicus for its future. Caritas, which is the Latin word for compassion, will launch with approximately $400 million in capital. Amicus will become the largest shareholder in Caritas with a 36% ownership stake and retain co-development and commercialization rights to the Fabry and Pompe gene therapy programs, as well as negotiation rights on select future muscular dystrophy programs. As we disclosed at the time of the announcement, I will lead Caritas as its Chairman and CEO, while remaining the Chairman Emeritus and Chief Strategic Advisor for Amicus. In this Amicus role, I will work closely with Bradley and the Board of Directors at Amicus to ensure that we get AT-GAA approved and launched in all the major regions around the world, as well as to support major strategic initiatives. Bradley Campbell will succeed me at Amicus as Chief Executive Officer. The Caritas Form S-4 is now filed with the Securities and Exchange Commission. The launch of Caritas Therapeutics is expected in late 2021 or early 2022, dependent on customary closing conditions. Finally, I would like to provide an update on our CLN6 Batten gene therapy program. We have very recently learned of the loss of two children with CLN6 in this study during the long-term follow-up extension period of this study. As deemed by the investigator, the two participants passed away from disease-related complications unrelated to this study drug. We will continue to assess the data in this extension study. Just as a further reminder of the cruel nature of this disease and the urgency for therapies that may extend and enhance the lives of these children. With the current plan, which includes the intended Caritas transaction, the Amicus cash position is sufficient to achieve self-sustainability and profitability in 2023. During the quarter, the balance sheet of Amicus was strengthened through a $200 million private investment from a syndicate of leading biotechnology investors. Our continued revenue growth, prudent expense management, and growth potential have allowed us to reach this important milestone as we continue to realize our vision of delivering groundbreaking and new medicines for people living with rare diseases. With that introduction, let me hand the call over to Bradley Campbell, our President and Chief Operating Officer, to further highlight the Galafold performance in the quarter. Bradley?

Great. Thanks, John. Good morning, everyone. As mentioned, I will walk you through in more detail our Galafold performance for the quarter. On Slide 7, we give our typical global snapshot on the Galafold commercial progress. For the quarter, total product revenue grew by 18% versus the same quarter last year to $79.5 million globally, driven by strong patient demand, new patient starts, and business continuity. The geographic breakdown revenue during the quarter was $53.9 million or 68% of revenue generated outside the United States, with the remaining $25.6 million or 32% coming within the United States. As we've mentioned before, this is in line with the roughly 70-30 split that we expect as we continue to grow both parts of the business. Turning now to Slide 8, the third quarter was another strong quarter for our global commercial efforts. The business continues to be incredibly resilient with patients added in all of our major markets, and third quarter revenue reflected increased patient demand; it also benefited from continued foreign exchange tailwinds. We do continue to see some sporadic COVID-related slowdowns in new patient starts due to delays at the point of care between patient identification and initiation of treatment. Importantly, our customers have confidence they can access Galafold. Our field team has been able to achieve a substantial majority of their pre-COVID touchpoints. This has been done through a combination of in-person digital, telephonic, and other means of interacting with physicians. So, while COVID is not yet fully abated as we had hoped, it continues to be a very successful year for Galafold with the first three quarters of 2021 in line with our internal expectations. As mentioned on past calls, due to a variety of factors, the rate of growth within the year is typically non-linear. Usually, in a given year, we see stronger quarter-to-quarter growth in the second and fourth quarters versus first and third quarters. That pattern has continued. Based on this momentum and assuming the dynamics I've just highlighted continue, we're confident we will come within our full year 2021 guidance of $300 million to $315 million in global sales. Ahead on Slide 9, I do want to recognize the importance of continuing to build the body of evidence for Galafold. We are pleased to share that long-term data were recently published in the September 2021 issue of Molecular Genetics and Metabolism Reports, as well as presented at the recent ASN Kidney Week Conference. These long-term data highlight stable renal function during treatment up to 8.5 years of Galafold, irrespective of treatment status, gender, or phenotype and inclusive of classic males. An important part of the growing evidence supporting the use of Galafold in patients with amenable mutations. On Slide 10, we've called out several of the drivers and metrics, which will lay the foundation for growth this year and beyond. As we've mentioned, we ended 2020 with more than 1400 patients on Galafold, which was a little under half of the global market share of treated amenable patients. So, while we're achieving higher market shares in countries where we've been approved the longest, there's clearly still plenty of opportunity to continue to switch patients over to Galafold. We also note that there are significant numbers of diagnosed, untreated patients who have amenable variants. While the global mix remains about 60% switch patients and 40% naïve patients, in many geographies, we're starting to see stronger uptake in naïve populations. As we've said previously, over the next few years, we expect to see the balance of switch and naïve patients to be about fifty-fifty. In the long-term, we expect to see that percentage reverse in favor of naïve patients. All of that is underpinned by the impressive compliance and adherence rates that continue to exceed 90%, reiterating our belief that those patients who go on Galafold stay on Galafold. Importantly, the value of Galafold continues to be recognized by payers as well with the vast majority of insurance reauthorizations granted in 2021 by U.S. payers and a very strong track record of successfully negotiating and renegotiating reimbursement outside the United States. Our relentless focus remains on ensuring access to Galafold for anyone who needs it. As we touched upon last quarter, we keep exploring ways to expand the label highlighted with the European Commission approval of the label for Galafold to the adolescent population. We continue to work closely with government authorities to secure access to Galafold for eligible patients as quickly as possible. Finally, another important driver of growth for Galafold is the ongoing geographic expansion. In 2021, we've continued to add to the growing list of countries with reimbursement and expect to add more as we look to expand access to those Fabry patients with amenable variants around the globe. As a reminder, Galafold has received regulatory approval in over 40 countries and commercial sales in over 30 of those today. So, despite the recent COVID-related headwinds in certain geographies, demand for Galafold worldwide continues to grow with some queues of potential new Galafold patients building in multiple regions. Again, we're confident we'll end 2021 within our guidance range of $300 million to $350 million in full year global sales. As a reminder, as part of that guidance, we project net new patient starts this year will be even greater than in 2020, and we're on track for this growth of the number of patients and corresponding revenue to be weighted to the second half of the year as the COVID impact continues to ease. On Slide 11, with several years of performance and a successful track record, we can confidently say we're on a path to achieve the important milestone of $500 million in global revenue in a given year from Galafold within the next few years. The exact timing of this milestone will depend on how quickly things return to normal post-COVID, and we'll have a better sense of that depending on how this year ends. We continue to expect to generate $1 billion in cumulative revenue over the next three years, which will contribute a significant amount towards funding our R&D and operating expenses over that period. We remain confident in the $1 billion peak revenue opportunity for Galafold as we continue to see significant growth in the Fabry market globally driven by diagnosis from high-risk screening, newborn screening, and other diagnostic initiatives, which we continue to support and invest in as well. Finally, we have worked exclusivity in the U.S. and Europe, in addition to our 27 Orange Book listed patents that give us IP coverage into the late 2030s, 13 of which provide protection through 2038. So quite a bit of opportunity to provide access to Galafold globally for a long period to come. And with that, let me now turn the call over to Dr. Jeff Castelli, our Chief Development Officer, who will start on AT-GAA, our next-generation therapy for Pompe disease. Jeff?

Thank you, Brad, and good morning, everyone. Moving on to our R&D updates on Slide 13, we'll start with AT-GAA, our novel next-generation therapy for Pompe disease. First, it's always important to recognize that Pompe continues to pose a range of health challenges for people affected by the disease, and having therapeutic choices and options is crucial. Pompe is a severe and fatal neuromuscular disease and one of the most prevalent lysosomal disorders. In addition to the individual human tragedies we've seen, multiple publications and natural history studies of Pompe patients highlight the initial benefit of treatment followed by continued long-term decline on key measures of disease for many individuals. As a reminder, the sustaining high unmet needs for the ERT experienced population have only ever been studied in a controlled setting in our Phase 3 PROPEL clinical trial. All other controlled late-onset Pompe disease studies to date have been in participants naïve to treatment. Moving on to Slide 14, we present a summary of the primary key, secondary, and biomarker endpoints from our Phase 3 PROPEL study. As a reminder, the study was double-blind, randomized, and set to assess the efficacy and safety of AT-GAA in adult treatment-naïve and ERT-experienced patients against the approved therapy alglucosidase alfa. Here in the slide, grouping these endpoints into domains of motor function, muscle strength, pulmonary function, patient-reported outcomes, and biomarkers, you can see the majority of endpoints across all of these domains favor AT-GAA over alglucosidase alfa in both the overall and ERT-experienced populations. We believe this consistency of effects across the key disease manifestation illustrates the potential impact of AT-GAA for Pompe patients. As our reminder on the primary endpoint of six-minute walk distance, patients on AT-GAA outperformed those on alglucosidase alfa in the overall population with the difference between groups of 14 meters, which did not quite reach statistical significance for superiority. However, on the first key secondary endpoint of percent predicted for vital capacity or FVC, in the overall population, AT-GAA showed a nominally statistically significant and clinically meaningful difference for superiority versus alglucosidase alfa, with the treatment difference of 3% and a P value of 0.023. This is a really important finding as progressive loss of pulmonary function is the leading cause of mortality in Pompe. This was also the main endpoint upon which alglucosidase alfa was initially approved. We remind everyone that the PROPEL study tested for superiority versus an approved therapy, not versus placebo, and that the approval of the second product generally requires demonstration only of non-inferiority to improve therapy. We are also pleased to announce that we expect the Phase 3 PROPEL results to be published shortly in a prestigious peer-reviewed medical journal. Moving on to Slide 15, we have highlighted key updates across the AT-GAA program. First, on the regulatory progress, the U.S. FDA has accepted for review the BLA for cipaglucosidase alpha and the NDA for migalastat, as we previously announced. These two components have PDUFA action date set for May 29, 2022, for the NDA and July 29, 2022, for the BLA. As John mentioned, we expect these filings to be reviewed together. We are also pleased to share, as John announced, that the MAA has now been submitted to the European Medicines Agency. In June, we also announced that AT-GAA was granted a positive scientific opinion through the early access to medicine scheme for by the UK's MHRA. This positive opinion recognizes the high unmet medical need faced by the Pompe community and permits eligible adults living with late-onset Pompe who have received alglucosidase alfa for at least two years to switch and have access to AT-GAA prior to marketing authorization in the UK. We're really excited to see the significant enthusiasm for AT-GAA under this mechanism, with multiple patients and physicians having requested access across the leading Pompe centers. Since that positive scientific opinion in June, the interest and momentum for AT-GAA has grown, and we are pleased to be able to provide access to those who are eligible in the UK. For the younger Pompe community, we continue to enroll the ongoing open-label study in children up to 18 years of age living with late-onset Pompe disease, and we look to expand into patients with infantile onset complete disease as soon as possible. At this point, we're pleased to report that more than 150 patients worldwide are being treated with AT-GAA. Finally, in response to the many requests for expanded access that we've received, our expanded access programs for both those living with infantile onset and late-onset Pompe disease continue to expand to multiple individuals. Moving on now to Slide 17, we briefly highlight our industry-leading portfolio of gene therapies for rare diseases and the planned launch for Caritas. To remind everyone, as John noted, the mission of Caritas is to transform the lives of children and adults living with rare genetic diseases through advanced protein engineering and innovative vector technologies. We see significant opportunities for Caritas to overcome current gene therapy challenges around safety, durability, manufacturability, and immunogenicity. We have and are developing the tools and technologies to address these challenges and realize the promise of gene therapy. The Caritas portfolio includes both clinical and preclinical programs. In addition to the two Batten programs in the clinic for CLN6 and CLN3, we expect to see three new INDs over the next 24 months in other rare genetic diseases, including Fabry and Pompe. This also includes the global rights to approximately 50 rare diseases, which include the majority of lysosomal diseases, as well as nearly a dozen larger rare diseases, and our collaboration with the University of Pennsylvania. We've disclosed previously that these include Angelman, RET, myotonic dystrophy in addition to multiple muscular dystrophies, including DMD. As part of this transaction, we will continue to jointly work with the University of Pennsylvania as well as with Amicus through an attractive risk and cost-sharing partnership. For manufacturing, we have a fully designed, ready-to-build, state-of-the-art clinical manufacturing facility with commercial expansion capabilities planned, and together with our continued strong relationship with Thermo Fisher on the CDMO front. All of this is being led by an experienced leadership team with a fully staffed discovery research and development organization of passionate entrepreneurs and problem solvers. Slide 18 highlights the Fabry and Pompe gene therapy programs, which Amicus and Caritas will share co-development and profit-sharing rights to. These programs utilize a differentiated gene therapy approach for greater potency and optimized cross-correction through protein engineering of stability and targeting. The partnership between Amicus and Caritas will ensure the continued relationship with the leading internal experts in Fabry and Pompe disease working on these programs. The partnership also derisks the funding of those programs and provides a fifty-fifty global profit split. We expect the Fabry IND to be filed first in the second half of next year. Last, to build on John's earlier comments on our CLN6 Batten gene therapy program, I would like to reiterate the sentiment around the loss of the two children during the long-term follow-up period of the study. As John mentioned, the investigator deemed that both participants passed away from disease-related complications unrelated to the study drug. We continue to assess all available information. As a reminder, our Phase 1/2 clinical study enrolled 13 participants who all received a single intrathecal injection of ATGCX501 at a dose of 1.5 to the 13 vector genomes. The first children in the study received their gene transport over five years ago. Medical literature indicates that most individuals with CLN6 Batten disease are diagnosed during infancy and early childhood and do not survive beyond childhood or early adolescence. While extremely sad, we recognize the devastating nature of this disorder and continue to see the potential benefits of gene therapy broadly. With that, I would like to now turn the call over to Daphne Quimi, our Chief Financial Officer, to review our financial results, guidance, and outlook. Daphne?

Thank you, Jeff. And good morning, everyone. Our financial overview begins on Slide 20 with our income statement for the third quarter ending September 30, 2021. For the quarter, we achieved Galafold revenue of $79.5 million, which is an 18% increase over the same period last year. This includes a year-over-year operational revenue growth measured at constant currency exchange rates of 17%, further benefited by a positive currency impact of 1%. Total operating expenses of $110.2 million in the third quarter were down as compared to $111.8 million in the third quarter of 2020. On a non-GAAP basis, total operating expenses were $93.6 million in the third quarter compared to $92.4 million in the third quarter of 2020. We define non-GAAP operating expenses as research and development and SG&A expenses, excluding share-based compensation expense, changes in fair value of contingent consideration, and depreciation. Net loss for the third quarter of 2021 was $50.3 million or $0.19 per share as compared to a net loss of $64 million or $0.25 per share for the prior year period. As of September 30, 2021, we had approximately 279 million shares outstanding. Turning now to Slide 21, the $200 million private investment in the quarter added to our strong cash position. We are on a path to self-sustainability and profitability in 2023. We have achieved this milestone through our continued revenue growth with Galafold, as well as driving efficiencies, cost savings, and careful expense management. For the third straight year, we expect total non-GAAP operating expenses in 2021 to remain relatively flat, as we leverage the commercial infrastructure that is already in place for the AT-GAA launch and other products in our pipeline, transition the costs associated with the development of AT-GAA to multiple gene therapy programs in the pipeline, and maintain financial discipline while meeting our objectives. A few comments about our cash position and 2021 financial guidance. Cash, cash equivalents, and marketable securities were $557 million at September 30, 2021, as compared to $483.3 million at December 31, 2020. We are reiterating our full-year Galafold revenue guidance, expecting to be within the $300 million to $315 million range, and maintaining our non-GAAP operating expense guidance of $410 million to $420 million, as we expect the timing of manufacturing batches to impact fourth-quarter operating expenses. With that, let me turn the call back to John for closing comments.

Great. Thank you, Daphne, and Jeff and Bradley as well. As you can see, we've been relentlessly focused on execution and performance across the business, driven by a global team of passionate entrepreneurs who have led and will continue to lead us on our patient-focused mission. We are immensely excited about what the future of science and biotechnology holds as we continue to advance toward our commitment to people living with rare diseases through not only Amicus, but beginning with the next earnings cycle with Caritas Therapeutics as well. So, with that, operator, we're happy to take any questions.

[Operator Instructions] Thank you. Your first question comes from the line of Ritu Baral with Cowen. Your line is now open.

Good morning team. This is Anvita on for Ritu today. On the two deaths in the CLN6 study, could you provide a little more color on how old these patients were when they were diagnosed? And what was the rate of decline on the Hamburg scores in the extension period? More broadly, could we expect a clinical data update at World from the CLN6 and CLN3 programs?

Sure. Again, I'll remind everybody the Batten program came to us through the acquisition of Celenex, which was a spinout out of Nationwide Children's Hospital more than three years ago. The 13 children dosed in that study. The first children were dosed about 5.5 years ago. The last patient was dosed more than three years ago. So again, to reiterate, the investigator has deemed this not to be related to study drug. I want to be very clear about that. These children were among the oldest; in fact, one of the two was the oldest in the study upon enrollment and had already advanced in their disease prior to the gene therapy. With that said, we'll continue to evaluate all of the children who remain in the study, gather data on the children who did pass away. So, I'll turn it to Jeff or Mitch for any additional color or comments.

John, this is Jeff. I don't have anything to add to what you noted other than we continue to follow the patients across both studies. We're not noting whether we'll have data at World or not, but we do expect to provide data updates next year as we continue to collect data from those extension studies and continue to work on manufacturing at Thermo Fisher to provide GMP material and to have clinical and regulatory discussions with the agencies to move these forward.

Great, thank you.

Your next question comes from the line of Anupam Rama with JPMorgan.

Hey guys. Thanks so much for taking the question. I know you probably can't get into a lot of detail here, but how has the engagement been with the FDA on the AT-GAA filing and on the regulatory side? And has there been any indication of a potential ADCOM for the filing? Thanks so much.

Yes. Thank you, Anupam. I'll say the FDA has been highly engaged and interactive. The review is continuing. Inspections are underway. Everything we would expect. We continue to receive information requests. So, it's been a highly engaged review to date, which we're very pleased with. I will note that we have received in writing from the FDA that there will not be an advisory committee. So, while of course, the FDA will always reserve the right to revisit that, as of now, the FDA has confirmed that there will not be an ADCOM.

Thank you. Your next question comes from the line of Joseph Schwartz with SVB Leerink. Your line is now open.

Hi, thanks very much. I was wondering if you could give us an update on your plans to study infantile onset Pompe disease and get AT-GAA approved in this population? And how should we think about the size of this opportunity? How would it compare with the size of the population with late-onset Pompe disease?

Great. No, thank you for the question, Joe. Studying the infantile-onset Pompe disease population is incredibly important to us. We expect that study to begin, the formal study to begin very shortly as we finalize the protocols with the FDA and the EMA. It is a relatively small portion of the population; we would estimate it to be perhaps 10% or less. In terms of an opportunity for this product, again, based on weight-based dosing and an even smaller proportion there, but obviously incredibly important to be able to treat these children. I will remind everybody that we have treated under our global expanded access or compassionate use program a number of infants, and we're very, very pleased with the results that we've seen in those infants.

Your next question comes from the line of Dae Gon Ha with Stifel.

Great. Good morning. Thanks for taking our questions. And John, if this is my last time speaking with you, good luck on your next adventure and look forward to keeping in touch.

Thank you, Dae.

My one and only question is with regards to Pompe, as we're gearing up for your progress with AT-GAA. Just wondering if you guys have done any latest market research with regards to Lumizyme and NexViazyme uptake? And how that is faring in the current landscape as you're gearing up your commercial sales force? Thanks.

Yes. Let me – Bradley, why don't you go ahead and take that, please. Thanks, Dae.

Sure. Obviously, being careful not to speak on other products in this space, but we can share what's available publicly. We know that the Pompe market continues to grow. We think this reflects the high demand for treatments for Pompe disease. I would encourage you to look at the latest reports on the uptake around the more recently released product in the United States, GAA, and I think Sanofi released those numbers recently. That would be a good indicator of at least their initial uptake there. I will say that focusing on AT-GAA, we continue to expect high demand for that product. Of course, we have to go through the regulatory process. But I think the color that Jeff provided in particular around the EAMS process in the UK shows that where AT-GAA is now available through a formal mechanism, albeit a pre-reimbursement, pre-approval mechanism, we're seeing significant demand and interest for use of that product, and we hope that reflects physicians' confidence that there's an opportunity for AT-GAA to make a major difference here. Clearly for the unmet medical need in the Pompe space.

Your next question comes from the line of Yun Zhong with BTIG. Your line is now open.

Hi. Good morning. Thanks very much for taking the question. So, a question on your Fabry gene therapy program. Given that you have Galafold in the market and also several other gene therapy programs that are already in clinical studies and have reported quite interesting data, how do you think your program will be able to compete with existing programs? What part of the program do you think is most differentiated?

Yes, great. Thank you, Yun. So again, we've had great experience working in the Fabry community since the day we started Amicus, and we think that will be incredibly important to understand the unmet needs in that community, the nature of clinical studies, regulatory pathways, and eventually providing 100% access to everyone living with Fabry disease in the world. I think for gene therapy, we continue to believe that the greatest unmet need will be in those patients who don't have access to Galafold today, so those patients with non-amenable mutations. We've got a commitment; it's part of the Amicus promise to patients that we would continue to designate a substantial portion of our revenue from Galafold into Fabry disease to not only develop treatments but ultimately until there is a cure. We believe this does have the potential to be that cure. We've developed something we think is highly differentiated. We believe importantly in the Fabry market, while several firms may be the first to the clinic, we would hope to be the first out of the clinic. I think that's very important, and that gets to the nature of what we've created. Again, the whole notion for what we've developed in gene therapy at Amicus is to look at each disease, understand its unique biology, the unique aspects of the disease, the clinical manifestations, and develop a therapeutic gene therapy that can best address that. Let me turn it to Jeff. Jeff, if you want to just remind everybody the drug candidate that we've developed in conjunction with Dr. Wilson and his team at Penn, and why we think that's differentiated.

Sure. Thanks, John. Yes, there are really two main components that we can differentiate our approach. One is this is a ubiquitous promoter with the AAV. So, we get expression not only directly in the cells that are transduced but also cross-correction. That ubiquitous expression can help not only create more of the enzyme out in the circulation but also could be more durable. Secondly, and really what's most differentiated is that we've created a transgene that expresses a GLA that has a stabilized dimer through two engineered disulfide bonds. That stabilized enzyme is not only more stable in the blood as it's secreted and then travels to treat other cells and tissues, but even after uptake into tissues and cells, it looks like it is more active. We've done studies comparing that stabilized transgene versus the wild-type GLA transgene and just see that we get much more substrate clearance at a given dose with that more enzyme that's being expressed. We're really excited, as John mentioned, about the opportunity here to have what we believe has the potential for a best-in-class AAV gene therapy in Fabry. In terms of unmet need for that non-amenable Fabry portion of the market, which is over half of the patients out there, their only option is every other week ERT infusions currently. We view there's a real need there for a one-time treatment, which would be a big market expansion from an Amicus perspective.

[Operator Instructions] Our next question comes from the line of Nishant Gandhi with Needham & Co. Your line is now open.

Hi. This is Nishant. I'm on for Gil. Thank you for taking our questions. I know PDUFA date is six, seven months away, but are you planning in any way, like thinking of commercial launch? Are you planning for sales force ramp-up? Or are you waiting on the decision before proceeding?

Yes. Thank you, Bradley, do you want to feel that, please?

Sure. Of course, yes, thanks for the question. We are very much geared towards a commercial launch and anticipating approvals in the summer of next year, as John articulated. We're really excited to do that. Of course, this would be the second product that Amicus has brought from discovery all the way through to launch and will be an exciting milestone for the company. Importantly, to your point about building commercial infrastructure, good news is the infrastructure we've built for Galafold is highly leverageable here. Many of the same physicians and centers are responsible for treating Pompe disease as are treating Fabry disease. What we said previously is that in order to support the launch of AT-GAA, we only anticipate a handful of additional FTEs, maybe in the sort of a dozen or so FTEs, to support that launch primarily in our Amicus Assist team, as well as medical affairs and direct marketing. So, that's one of the great things about the team that we've built to support Galafold is that they'll also be able to support the launch of AT-GAA. Rest assured, we're eagerly anticipating that opportunity and doing all the necessary preparations to be ready for an exciting launch.

Our next question comes from the line of Eliana Merle with UBS. Your line is now open.

Hey, this is Jonny on for Ellie. In terms of the early access in the UK, can you update us on any trends you're seeing there in terms of updating switches from ERT?

Great. Yes, thank you again. To remind everybody, we received the early access approval at the end of May. Since that time, we've been working through all the health authorities, the regional authorities in the United Kingdom to enable the next level of approvals. We've made significant progress there. Again, we are really seeing significant enthusiasm. We've received requests from multiple key opinion leaders and multiple centers throughout the United Kingdom to switch patients from the approved standard of care enzyme therapy to AT-GAA. We've been working through all the approvals necessary for those switches. We're starting to see patients switched now, which we're very encouraged by, and think that momentum will continue to grow in the months ahead. Bradley, anything I missed? Feel free to add color.

No. I think you've captured it, John.

Great. Thank you. Yes. It's a very significant commitment for us, and again, something we're very excited about to provide AT-GAA in the United Kingdom to adults eligible to switch.

We have a follow-up question from Ritu Baral from Cowen. Your line is now open.

Hi, this is Anvita on again for Ritu. Thanks for taking our follow-up question and apologies if I missed this earlier. Of the 150-plus patients on AT-GAA globally, could you provide us a breakdown of open-label extension patients versus early access from the U.S. versus any other compassionate use?

Yes, we don't provide specific numbers for all of that. The vast majority of those patients are on a long-term extension study following the PROPEL data. We also have all of the Phase 1/2 patients who continue on AT-GAA. We now have patients in the adolescent study. Again, we expect to begin the infantile study very quickly. We do have an expanded access program that includes a range of patients, including infants as well. So, it really is a mix in terms of disease onset and characterization within the spectrum of Pompe disease. Importantly, it's also a mix across clinical sites with dozens and dozens of investigators now caring for these patients receiving AT-GAA on five continents. So geographically quite dispersed.

At this time, I would now like to turn the conference back to Mr. John Crowley, Chairman and CEO, for closing remarks.

Great, operator. To all the analysts, thank you for all the great questions today. We've had a strong quarter for Amicus in Q3, and we look forward to a very robust finish to the year. Thanks, everybody. Have a great day. Take care.

This concludes today's conference call. Thank you, and have a great day.