Good morning, and welcome to Agios Fourth Quarter and Year-End 2022 Conference Call. At this time, all participants are in a listen-only mode. There will be a question-and-answer session at the end. Please be advised that this call is being recorded at Agios request. I would now like to turn the call over to Jessi Rennekamp, Senior Director of Corporate Communications. Please go ahead.

Thank you, Operator. Good morning, everyone, and welcome to Agios fourth quarter and year-end 2022 conference call. You can access slides for today's call by going to the Investors section of our website, agios.com. With me on the call today with prepared remarks are Brian Goff, our Chief Executive Officer; Dr. Sarah Gheuens, our Chief Medical Officer and Head of Research and Development; Tsveta Milanova, our Chief Commercial Officer; and Cecilia Jones, our Chief Financial Officer. Before we get started, I would like to remind everyone that some of the statements we make on this call will include forward-looking statements. Actual events and results could differ materially from those expressed or implied by any forward-looking statements as a result of various risks, uncertainties and other factors, including those set forth in our most recent filings with the SEC and any other future filings that we may make with the SEC. With that, I will turn the call over to Brian.

Good morning, everyone, and thank you for joining us. Agios is the pioneering leader in PK activation and is dedicated to developing and delivering transformative therapies for patients living with rare diseases. Driven by the cross-functional commitment of the Agios team, we made tremendous progress over the past year toward our goal of building a PK activation franchise focused on hematologic diseases that share a common underlying pathophysiology, limited treatment options, and profound unmet need. In particular, I'd like to highlight the excellence in execution displayed across our research and development team to bring forward PYRUKYND our first-in-class PK activator as the first and only approved disease-modifying therapy for adults living with PK deficiency. PYRUKYND was approved in the U.S., EU, and Great Britain in 2022 and represents the cornerstone of our growing PK activation franchise with the potential for two additional indications by 2026. In parallel with these approvals, we made significant advances across our broader clinical-stage pipeline, including our five ongoing pivotal studies, and met the ambitious clinical development targets we outlined at the beginning of last year. Notably, we continue to generate consistent and compelling data with our PK activators across multiple disease areas, highlighting the potential of this differentiated mechanism of action to transform patient function, quality of life, and long-term outcomes in not only PK deficiency, but also thalassemia, sickle cell disease, and lower risk MDS. In 2022, data across our clinical portfolio were presented at major medical meetings, including the annual meetings of the European Hematology Association and the American Society of Hematology, and were published in top-tier medical journals including The Lancet and the New England Journal of Medicine. Following the third full quarter of the launch of PYRUKYND in PK deficiency, we continue to be encouraged by the positive reception from patients, physicians, and payers, and the impact PYRUKYND is having for a community that previously had no treatment options. As we've said in the past, we continue to believe that this launch will be slow and steady and will provide a capability building platform to support potential expansion in meaningfully larger patient populations. That said, our ambition is to improve the launch trajectory and realize the full potential of the opportunity we have in front of us. To that end, in December of last year, we appointed Tsveta Milanova as Chief Commercial Officer. Tsveta is a seasoned commercial leader who brings deep expertise in launching and commercializing medicines in rare diseases and hematology with a particular focus on global market access and operations. Her experience and leadership will be critical as we continue to strengthen our commercial capabilities in order to both maximize the potential of the current launch in PK deficiency and prepare for potential future launches in thalassemia and sickle cell disease over the next few years. We ended 2022 in an enviable cash position with approximately $1.1 billion on the balance sheet. This includes the one-time payment we received in the fourth quarter of 2022, following the sale of our royalty rights on U.S. net sales of TIBSOVO to Sagard. We expect our cash position to support the completion of our ongoing programs, as well as enable us to expand our portfolio beyond PK activation through disciplined business development and the advancement of our earlier-stage pipeline. We anticipate significant progress on each of these objectives in 2023. Specifically, in the middle of this year, we expect to complete enrollment of the Phase 3 ENERGIZE and ENERGIZE-T studies of PYRUKYND in thalassemia and announce the data readout of the Phase 2 RISE UP study of PYRUKYND in sickle cell disease and the go/no-go decision to Phase 3. By the end of the year, we expect to enroll more than half of the patients in the Phase 3 ACTIVATE-kids and ACTIVATE-kidsT studies of PYRUKYND in pediatric PK deficiency. Complete enrollment of the Phase 2a study of our novel PK activator AG-946 in lower risk MDS and file the IND for our PAH stabilizer for the treatment of PKU. Throughout the year, we aim to continue to strengthen our commercial capabilities through our ongoing launch in PK deficiency and continue to evaluate BD opportunities to expand the pipeline. Looking forward to 2024 to 2026, we anticipate a catalyst-rich period with the potential for two additional PYRUKYND indications in this timeframe. Specifically in 2024, we're expecting the readouts of the Phase 3 studies of PYRUKYND in thalassemia, as well as the readout of the Phase 2a study of AG-946 in lower risk MDS. In 2025, we're expecting the potential approval of PYRUKYND in thalassemia as well as the Phase 3 readouts of PYRUKYND in sickle cell disease and pediatric PK deficiency. And in 2026, we're expecting the potential approvals of PYRUKYND in sickle cell disease and in pediatric PK deficiency. With this slate of potential near-term catalysts, I look forward to a productive year as we work toward our 2026 vision of Agios, an established hematology franchise with approval spanning three hemolytic anemias, an expanded portfolio fueled by business development, and advancement of our internal pipeline that is aligned with our core expertise in rare disease and cash flow positivity. With that, I'll now turn the call over to Sarah.

Thanks, Brian. In 2022, our research and development organization made significant progress advancing our PK activator development programs across multiple disease areas united by the shared underlying pathophysiology of red blood cell metabolic stress. Representing the largest datasets generated for any PK activator, the consistent and compelling data we have generated to date with PYRUKYND in PK deficiency, thalassemia, and sickle cell disease highlights the potential for PK activation to correct red blood cell metabolism and transform patient function, quality of life, and long-term outcomes in each of these disease areas. The most recent data updates across our clinical portfolio were presented at ASH in December where Agios and our external collaborators were pleased to present a total of 22 abstracts. These included long-term data from the Phase 2 study of PYRUKYND in thalassemia, demonstrating durable improvements in hemoglobin and hemolysis and stabilized or improved erythropoiesis and iron homeostasis over 72 weeks in patients with alpha or beta non-transfusion dependent thalassemia. In PK deficiency, we presented updated long-term extension data demonstrating that adults treated with PYRUKYND exhibited sustained improvements in hemoglobin; iron overload, transfusion burden, and patient-reported outcomes regardless of transfusion status. And we presented new data from the Phase 1 study of our novel PK activator AG-946 in healthy volunteers, which showed a favorable safety profile at pharmacologically active doses and a PK profile supportive of once-a-day dosing. Taken together, the clinical data we have generated to date suggests that PYRUKYND's differentiated mechanism of action is correcting red blood cell metabolism and leading to consistent improvements in hemoglobin, hemolysis, and erythropoiesis. With that context, let me now provide a brief update on the PYRUKYND development program beginning with thalassemia. As a reminder, the Phase 3 program of PYRUKYND in thalassemia comprises two randomized placebo-controlled trials, each of which are enrolling patients with both alpha and beta thalassemia. ENERGIZE is enrolling patients who are not regularly transfused with a primary endpoint of hemoglobin response and ENERGIZE-T is enrolling patients who are regularly transfused with a primary endpoint of transfusion reduction response. More than half of patients in each of these studies have now been enrolled, and we aim to complete enrollment of both studies in the middle of this year. Based on the data we have generated in this program to date, we believe strongly in the potential for PYRUKYND to become the first therapy to improve hemolytic anemia and ineffective erythropoiesis in all subtypes of thalassemia and become a foundational therapy in the treatment of this devastating disease. We look forward to the readouts from these Phase 3 studies next year. I'll now turn to sickle cell disease where we aim to deliver a novel oral therapy that both improves anemia and reduces vaso-occlusive crises or VOCs. To this end, we are advancing the operationally seamless Phase 2/3 RISE UP study of PYRUKYND in adults with sickle cell disease and I am pleased to announce that the Phase 2 portion of this study is now fully enrolled. The primary endpoints of the Phase 2 portion of the study are hemoglobin response and safety, and we expect to announce the Phase 2 data readout and the go/no-go decision to Phase 3 in the middle of this year. This decision will be informed by the protocol-defined go/no-go criteria in the Phase 2 portion of RISE UP, as well as any additional data from the Phase 2 secondary endpoints and longer-term data from the ongoing extension studies of the investigator-sponsored trials at the NIH and the University of Utrecht. To date, these investigator-sponsored trials have generated compelling data suggesting that in adults with sickle cell disease, PYRUKYND reduces red blood cell sickling and similar to what we have observed in PK deficiency and thalassemia also resulting in consistent improvements in hemoglobin, hemolysis, and erythropoiesis. Finally, we continue to advance the Phase 3 ACTIVATE-kids and ACTIVATE-kidsT studies of PYRUKYND in pediatric PK deficiency as we aim to deliver the first approved therapy for children living with this disease. We aim to enroll at least half of the patients in each of these studies by the end of the year. In parallel with the PYRUKYND development program, we continue to advance the development of AG-946, a novel PK activator, which provides the opportunity to further strengthen our PK activator franchise and pursue multiple therapeutic paths including lower risk MDS. As we presented at ASH, pharmacokinetic data from the healthy volunteer cohorts of the Phase 1 single and multiple ascending dose study were supportive of a once-daily dosing regimen and pharmacodynamic data suggested sustained activation of the glycolytic pathway, including dose-dependent increases in ATP and dose-dependent decreases in 2,3-DPG. Taken together with a favorable safety profile, we look forward to progressing the ongoing Phase 2 study of AG-946 in lower risk MDS and expect to complete enrollment of the Phase 2a portion of this study by the end of this year. As Brian mentioned, we aim to expand our pipeline beyond PK activation through both disciplined business development and the advancement of our earlier-stage pipeline. Within our earlier-stage pipeline, we continue to progress our lead research program aimed at addressing phenylketonuria or PKU. PKU is a rare genetic disease with limited treatment options that impact a total of approximately 35,000 to 40,000 patients in the U.S. and EU5, and it's caused by a deficiency of the phenylalanine hydroxylase or PAH enzyme. Lack of PAH activity leads to the accumulation of phenylalanine and downstream sequelae, and patients with PKU are therefore often advised to consume a highly restricted diet in order to minimize phenylalanine intake, which can further reduce patient quality of life. To directly address the underlying cause of PKU, we are developing an oral PAH stabilizer with the goal of reducing phenylalanine levels and we are targeting an IND filing for this program by the end of this year. Overall, I'm very pleased with the significant progress the team made executing across our portfolio in 2022 and look forward to the continued maturation of our five ongoing pivotal studies over the course of 2023. With that, I will now turn the call over to Tsveta.

Thank you, Sarah. Since joining Agios last month, I've been impressed and energized by the rigor of the commercial team, the compelling data generated across our clinical programs, and the potential of our portfolio to transform the treatment paradigm of multiple rare hematologic diseases. It is truly a privilege to have the opportunity to join a company so clearly poised for near- and long-term growth. For the last 20 years, I've led global rare disease launches at leading biopharmaceutical companies. While each of those launches presented unique challenges, my core focus has remained the same, to reduce the length of the patient journey and improve patient health outcomes as efficiently as possible. To achieve that goal, particularly for an ultra-rare disease, it is critical to implement and deploy a comprehensive commercial strategy that addresses each stage of the patient journey from disease awareness to reimbursement. Specifically, that strategy must be underpinned by a focus on three key areas: increasing awareness of the disease and educating on available treatment options; accelerating access by reducing the time between diagnosis and treatment initiation; and supporting adherence and maintaining reimbursement over the long term. Leveraging this strategy, my top priority is to drive operational excellence in the current launch of PK deficiency and build the capabilities we need to fully realize the commercial potential of PYRUKYND in anticipated future launches in thalassemia and sickle cell disease. In reviewing the launch to date, I've been particularly encouraged by the progress the team has made on market access. Payer policies are aligned to the label or clinical trial inclusion criteria and prior authorization criteria are in line with expectations with the majority of patients initiating therapy four to six weeks after completion of the prescription enrollment form or PEF. Launch to date, discontinuations continue to remain low overall and reauthorizations have not been a barrier. This progress highlights both the positive impact of PYRUKYND and the strength of our market access and patient services capabilities. In the fourth quarter of 2022, which represented the third full quarter of launch, we generated $4.3 million in net PYRUKYND revenue. A total of 105 patients have now completed a PEF, including 21 in the fourth quarter of 2022, a 25% increase versus the third quarter. Given our strong conversion rate, this has translated to a net of 78 patients on therapy, a 39% increase over Q3. Patients on therapy stem from a growing and diverse prescriber base of 96 physicians and represent a broad demographic in disease manifestation range that is consistent with the adult PK deficiency population. Despite its progress, we have identified multiple opportunities for improvement. As is common in ultra-rare disease launches, we have observed a general lack of disease awareness and a corresponding lack of urgency to diagnose, monitor, and treat. This presents a clear opportunity to focus greater attention on the earlier stages of the patient journey and thereby increase disease awareness and diagnostic efficiency. Specifically, as the ICD-10 code for diagnosing PK deficiency was established less than two years ago, we plan to bolster our disease awareness efforts by augmenting our AI and machine learning capabilities to identify high-potential clinicians likely to treat patients with PK deficiency. Additionally, given the breadth and diversity of the prescriber base, we aim to strengthen our capacity to engage and educate treating physicians, including on the availability of the anemia ID program, which provides no-cost genetic testing to identify a range of hemolytic anemia, including PK deficiency. I'm confident that further strengthening these rare disease capabilities will help us maximize the potential of the current launch. But PK deficiency is only the beginning; building our capabilities to support diagnosis, education, access, and adherence will directly translate to future potential launches in meaningfully larger patient populations and will help us unlock the full commercial potential of our PK activated franchise. With that, I will now turn the call over to Cecilia.

Thanks, Tsveta. Our fourth quarter and full-year 2022 financial results can be found in the press release we issued this morning, which I will summarize. More detail will be included in our 10-K, which will be filed later today. Full-year 2022 net PYRUKYND revenue was $11.7 million, including $4.3 million in the fourth quarter, an increase of $0.8 million compared to Q3. As PYRUKYND is the first therapy for this ultra-rare patient population, we continue to gather data and insights on the launch trajectory and will not be providing guidance at this time. Consistent with other rare disease launches, gross to net continues to be in the 10% to 20% range. Cost of sales for the quarter was $0.4 million. Moving to expenses and the balance sheet. R&D expenses were $70.3 million for the fourth quarter and $279.9 million for the full-year 2022, an increase of $22.9 million compared to the full-year 2021. This year-over-year increase was primarily driven by increased cost for our five ongoing PYRUKYND pivotal studies and for the AG-946 studies, and increased workforce spend across R&D. SG&A expenses were $32.8 million for the fourth quarter and $121.7 million for the full-year 2022, an increase of $0.3 million compared to full-year 2021. Full-year TIBSOVO royalty revenue, which is recorded under royalty income from gain on sale of oncology business on our income statement, was $9.9 million. As a reminder, TIBSOVO royalty income ceased after Q3 2022 given the sale of our rights to 5% royalties on U.S. net sales of TIBSOVO to Sagard for a one-time payment of $131.8 million in October of which we recorded $127.9 million under other income in Q4. As part of the divestiture of our oncology business to Servier, we retain rights to a potential $200 million milestone upon approval and 15% royalties on potential U.S. net sales of vorasidenib, a clinical stage dual inhibitor of mutant IDH1/2. We ended the year with cash, cash equivalents, and marketable securities of approximately $1.1 billion. We expect our cash, cash equivalents, and marketable securities, together with anticipated product revenue and interest income, will enable us to execute our operating plan, including funding the currently planned development programs for mitapivat, AG-946, and PAH and commercializing mitapivat outside of the U.S. through one or more partnerships to achieve cash flow positivity without the need to raise additional equity. To maintain our strong cash position, we will remain focused on proactively managing our cost base and deploying a disciplined capital allocation approach to ensure the full development of our ongoing pivotal studies and flexibility to expand our pipelines through business development. I'll now turn the call back over to Brian for his closing remarks.

Thanks, Cecilia. 2022 was a year of tremendous progress at Agios. With the approval of PYRUKYND in adults with PK deficiency, we've taken an important first step toward our 2026 vision, and we remain focused on advancing our industry-leading pipeline of PK activators to address the profound unmet needs of patients suffering from rare hematologic diseases. In 2023, we're anticipating a number of key clinical and regulatory milestones that will lay the foundation for potential Phase 3 data readouts in thalassemia, sickle cell disease, and pediatric PK deficiency over the next few years. As always, we'll strive to be responsible stewards of our balance sheet and will continue to evaluate meaningful opportunities for value creation. Finally, I'd like to thank all of our employees for their hard work and dedication to our mission of transforming the lives of patients living with rare diseases and all of our partners, including physicians, caregivers, patients, and participants in our clinical development programs. With that, we'll now open the call for questions.

Our first question comes from Chris Raymond with Piper Sandler. Your line is now open.

Thank you for taking my question. I have a few queries. First, regarding the Phase 2 sickle cell trial reading out mid-year, I understand that the primary endpoint is hemoglobin response, but is there a possibility to show a VOC signal at least in this part of the trial? Could you clarify that for me? I also have a follow-up.

Sure. So, hi, this is Sarah. For the Phase 2 portion of the trial, indeed we have a primary endpoint of hemoglobin response and safety as the first path. But then in our secondary endpoints, we are indeed capturing the rate of VOCs as well. That being said, it is indeed a 12-week period for the randomized control trial. So the data coming from that is going to be limited by the time that patients have been exposed to the drug. As always, we've always been saying this as well that we will be looking at the totality of the data generated in the trial, specifically in the RISE UP trial, and we will also be looking at our investigator-sponsored trials in which patients have been exposed for a longer duration.

Okay. Great. Thanks. And then just on PYRUKYND in Europe, I know you have marketing authorization in Europe and the UK in hand, and you've talked about not wanting to build really an infrastructure there, Brian, I guess until you get a larger indication. So maybe any update on that strategy for launch there, especially, given that you now have marketing authorization?

Yes. Good morning, Chris. Great question. So as you noted, we have mentioned that we have interest in a partner or partners as we think about commercialization outside the U.S. PKD, as you know, is an ultra-rare indication, and just to have commercialization on its own for PKD would be quite a challenge. So what we're looking towards is as we make progress, as Sarah just mentioned with the sickle cell data and particularly thalassemia where we've stated that we expect to be fully enrolled by mid-year, that puts us on a path to really methodically look for partners that we believe will represent very well the footprint we anticipate globally for those launches to come. PKD, of course, as I mentioned is very rare, thalassemia is meaningfully larger as an opportunity and it does just like sickle cell disease have a unique global footprint. So those are the factors that'll go into our partnership.

Our next question comes from Marc Frahm with Cowen. Your line is now open.

Hi, thank you for taking my questions. I would like to follow up on Chris' question regarding the Phase 2 data as we receive it. For the decision on whether to proceed to Phase 3, do you simply need to see stronger yet similar data to what you have already observed concerning hemoglobin and related factors? Are there new endpoints in this data that need to be disclosed to motivate your progression into Phase 3?

So the endpoints indeed are relatively similar to what we have in our other trials. However, this is the first placebo-controlled datasets in our Phase 2. So we're actually very excited about that. And yes, we are eagerly looking forward to mid-year.

And I think, Marc, I would just add to, I mean, one of the things that we've been talking about that's so appealing of PYRUKYND is the consistency of the data that we've seen across hemolytic anemias, PKD, all the way through launch of course, and then thalassemia, which is already through Phase 2, and we have the Phase 3 underway. And as you know, RISE UP where we're waiting for Phase 2 data. We're not expecting, say, surprises, but it'll be confirmatory if we see compelling data coming out of the Phase 2 RISE UP study. And we have the endpoints, of course, identified, and then we will look at the totality of data as Sarah just noted.

Thank you. Regarding the launch in PKD, Q4 marks the first full quarter where patients are undergoing reauthorizations and similar processes, and you continue to observe this trend this quarter. What are your observations regarding the reauthorization standards being applied? What percentage of patients do you anticipate will continue on therapy for the long term?

Thanks a lot for the question. It's Tsveta here. As we said, we have 78 net patients on therapy at the end of the fourth quarter of 2022. And this really net patient number is inclusive of all the patients who have started on therapy and all the patients who have discontinued. We have not prepared to report any specific numbers on discontinuations. But as we noted, the reauthorization rate for patients that are reaching that six months assessment has not been a barrier so far at all. The discontinuations continue to remain low overall for the products and for me, that truly reinforces the positive reception that we get from patients, physicians, and payers on the profile of PYRUKYND in the U.S.

Please standby for our next question. Our next question comes from Greg Harrison with Bank of America. Your line is now open.

Good morning. This is Mary Kate on for Greg. Thanks for taking our questions. I guess as we hit one year since the approval of PYRUKYND in PKD, you've mentioned that you have about 96 unique physicians prescribing. Maybe how do you expect usage and updates to change as physicians become more aware of and experienced with PYRUKYND?

So we are actually very pleased with the progress that we've made on breadth of prescribing. As you mentioned already, we have 96 unique physicians who have generated 105 prescription enrollment forms. It is an ultra-rare disease. And from that perspective, expanding the breadth of prescribing is going to be our core focus to data and moving forward. We have to keep in mind that it does take time because each of the unique prescribers will need to basically go on their own journey of disease awareness, diagnosis, and prescription as well. And this is one of the main reasons actually we'll put a greater emphasis on this first part of the patient journey from really shortening the time from diagnosis to treatment and invest greater efforts in the data and analytics to help diagnostic efficiency and very importantly help us improve our targeting efforts with clinicians as well.

Yes, I'll add that the dynamics of launching a treatment for an ultra-rare disease will focus on the extent of prescribing. We often describe it as being broad but shallow, since it's uncommon for a physician to manage more than a couple of patients at most with PKD. The educational efforts that Tsveta mentioned are crucial, as well as the machine learning capabilities we are developing through analysis of claims databases, which are essential for launching therapies for rare diseases. Mastering this modern approach will enable us to effectively target high-potential providers who are likely to treat PKD patients, enhancing our outreach efforts. This is a critical area of focus for us.

Great. Thanks. And then, if I could one more for those on treatment or already prescribing PYRUKYND, what kind of feedback have you been receiving from patients and physicians who either use or prescribe the drug? Thank you.

We're very pleased with the feedback that we are getting across the board from patients, physicians, and payers as well. I think the success of our market access efforts definitely speaks to the positive reception of payers both for patients who are initiating therapy but also the great success we see with the reauthorization rate. We get a lot of positive anecdotal feedback from our patient services team, which is fantastic to hear. And I actually had the opportunity to hear some of the direct feedback from our customers when I had actually went out on the field and met with some of them in my first month on the job. And it really reinforces the positive, not only perception of the product, but already experience that early in the launch with how PYRUKYND is performing for those patients. So we are excited. As we said, it's going to take some time, but I believe we're putting some of the right elements in place to continue the right breadth of prescribing.

And that's for PKD, which is really encouraging. And Sarah, do you want to comment on the clinical trial experience?

Sure. So it's very similar in a way the clinical trial continues to gather data in the long term for patients with PKD who have been on PYRUKYND for now a long time and what we see is our data is getting stronger as it matures, even because the hemoglobin effect is maintained, the impact on hemolysis is maintained. Very importantly, we see patient-reported outcomes that are also maintained and really reach this clinically significant threshold for feeling better and functioning better. And then on top of that, what we are very excited about is our iron overload data as well, where we start seeing more and more an impact on iron overload as well. So I think we're very excited about what PYRUKYND has already delivered and is continuing to deliver for patients with PKD.

Please standby for our next question. Our next question comes from Tessa Romero with J.P. Morgan. Your line is now open.

Good morning, Brian and team. Thank you for taking our questions. So just one from me on the sickle cell disease program, if I could. So thinking a little bit about the Phase 2 RISE UP data in your go/no-go decision here. Specifically, is there a quantitative hemoglobin response rate that you view as differentiated here? And I know in the past we've talked a little bit about vaso-occlusive crises as also being important to monitor. So could you help us understand a little bit better what an encouraging trend might look like there for VOCs as well?

Our primary endpoint is the hemoglobin response. We have set the bar at 1 gram per deciliter to be considered a hemoglobin response at specific time points in the clinical trial. Our protocol outlines what we consider statistically significant results for the primary endpoints and how we will proceed with our secondary endpoint testing. This is a typical setup for Phase 2. In Phase 2, we are looking for trends in our VOCs, which we are capturing over time. We will accumulate that data, but we are not expecting anything drastically impactful or meaningful from it, as Phase 3 will ultimately provide those results. Phase 3 is designed to deliver on our target product profile, aiming to treat the entirety of sickle cell disease by addressing both hemolytic anemia and sickle cell pain crises, while also exploring patient-reported outcomes, ultimately developing a drug that has significant value for all aspects of sickle cell disease.

Please standby for our next question. Our next question comes from Greg Renza with RBC. Your line is now open.

Great. Thanks. Good morning, Brian and team. Congrats on the progress, and thanks for taking my question. Brian, just maybe turning to 2026 and just the remarks on cash flow positivity. I just wanted to give you an opportunity to perhaps provide some color on some of those assumptions and how you're thinking about the inputs to get there. Certainly keeping in mind the launch, the many programs in development, and then, of course, your mention on looking at external assets and the pipeline. Thank you very much.

Sure. Thanks. Good morning, Greg. I'm going to have Cecilia start.

Yes. Thanks, Greg, for the question. As we mentioned, our cash, cash equivalents, and marketable securities, along with expected product revenue and interest income, will allow us to implement our current plan. This includes all the key trials for mitapivat, PKD pediatric, thalassemia, and sickle cell, as well as AG-946 and the earlier program in PAH. Additionally, part of the plan involves the commercialization of mitapivat outside the U.S.

Got it. Can you provide any insight on the top-line performance? I understand we're not seeking guidance, but as you consider PYRUKYND as a foundational therapy and its potential across various indications, how do you view the progression of that potential as you move through development and anticipated approvals in the mid-2020s? Thank you.

Yes, Greg. So with PKD, we certainly have an ambition to maximize the PKD launch opportunity. And the bigger picture, of course, for us is to strengthen our commercial capabilities for these meaningfully larger sequential launches potentially to come, namely thalassemia and sickle cell disease. In the case of PKD, it's ultra-rare by name and by nature. So it will take some time to refine the prevalence as well as the peak sales estimates as we learn more. And then I would say peak sales depend on a whole lot of factors, including the time to peak sales, the approval timelines, the distribution and partnerships as we talked about outside the U.S. From where we are today, this discussion reflects only the third full quarter of launch, and so far it's clear to us that the PKD launch will be slow and steady. And I think that's reflected in the numbers that we continue to report out. I will say, and I'm just going to take the opportunity to reiterate that I am super pleased that Tsveta Milanova has joined us as CCO because Tsveta has deep expertise and experience in rare disease launches. And I think that's not a moment too soon for us as we look at continuing the momentum of the PKD launch and, more importantly, getting ready for these bigger launches potentially to come.

Please standby for our next question. Our next question comes from Mark Breidenbach with Oppenheimer. Your line is now open.

Hey, good morning. Most of my questions have been answered, but let me dip down into kind of the early-stage pipeline. Maybe you could just remind us how the PAH stabilizer for PKU is differentiated from sapropterin and related drugs that are already approved or in late development for PKU? Thanks.

Sure. This is Sarah. So our program is really indeed, it has a different mechanism of action than the others that are currently in development or those approved and have been on the market for a while. So it's indeed a PAH stabilizer, which is different. Where we see an opportunity is with this product is because the two that are currently available do have their own limitations in the treatment of PKU in the sense that either there's a lot of drug to take or it's subcutaneous administration. So there is a lot that goes along with that, that where we are looking to develop an oral therapy that would treat the majority of PKU. Of course, the hope is for us to provide something that can be meaningfully different in the sense that it is providing all of the benefits as measured on phenylalanine reductions, but also easier to use, easier to tolerate. And then we will disclose more details on our CDPs as we progress the program.

Mark, I want to emphasize that the addressable market is substantial. We're looking at a significant increase in prevalence from our current situation with PKD, estimating around 35,000 to 40,000 patients in the U.S. and EU5. Additionally, this insight stems from our expertise in cellular metabolism at Agios. Although we're still in the early stages and have mentioned a potential pathway toward an IND by the end of this year, we are enthusiastic about the opportunity to further diversify our pipeline.

Please standby for our next question. Our next question comes from Danielle Brill with Raymond James. Your line is now open.

Good morning everyone. Thank you for the questions. I have a couple. First, regarding AG-946, could you remind us of the plans for the Phase 1 sickle cell cohort that you're enrolling? How is that progressing and what are your plans for the data? Also, for PYRUKYND, I wanted to clarify if the 78 patients currently on the drug includes those who have discontinued, or if that number represents the total patients who have received PYRUKYND? I have a follow-up to that.

Sure. So Sarah can start with the first one.

Yes, we have completed and disclosed all the results of our Phase 1 trial in healthy volunteers for 946 in sickle cell disease. Within that trial, there is a cohort ongoing for sickle cell disease that involves a multiple ascending dose scheme. We are particularly focused on generating data related to hemolytic anemia. This is a short-duration trial, and we have not disclosed when we will release the results. The trial is ongoing and is currently on track, and we are very excited about it. Additionally, I want to mention our enthusiasm for the progress with MDS, which is currently in the Phase 2a stage of that specific trial.

And then Tsveta, I think that's going to be an easy one on the patients, but I'm glad you asked Danielle. It's good to clarify.

To clarify. Yes, so 78 patients on therapy at the end of Q4 is really a net number of patients. So that includes the patients who have started therapy and deducts the patients who have discontinued. Still, all of the 78 patients were actually actively receiving PYRUKYND at the end of the quarter.

And the only thing I'll add is again, the discontinuation rates launched to date have been low, which is super encouraging because it shows us that PYRUKYND is performing very well at the patient and provider level. And as we look beyond PKD, that's a very important data point as we think about bigger launches to come.

Okay. Thanks. That's very helpful. And then I guess my follow-up was for the enrollment form. So I'm just curious what proportion of those actually translate to patients on drug?

Well, when it comes to the PEF actually we are very pleased with the progress we've made on market access as well as patient services because we do see the majority of the PEF to actually progress to treatment initiation. There is a time delay between the completion of a PEF and treatment initiation. At the moment, it's about four to six weeks. We do not expect for that timeframe to shorten significantly. That is really primarily driven by the fact that a lot of the payer policies and prior authorization criteria require genetic testing. And if a patient has not completed a genetic test or they don't have the results, they'll need to go through the process and the pure timing of genetic testing is the driving force of the four to six weeks.

Yes. The challenge really in an ultra-rare disease launch is the generation of the PEF, the demand because it's so rare and there's so much heavy lifting required in terms of educational components. I think the pull-through PEF to patient on therapy will take time, but that's not per se the real challenge of the launch.

Please standby for our next question. Our next question comes from Salveen Richter with Goldman Sachs. Your line is now open.

Good morning. This is on behalf of Salveen. Regarding the mid-2023 sickle cell update, what should we prioritize? Additionally, what do you consider a successful outcome in the Phase 2 portion? Conversely, what factors might lead you to decide against proceeding? Thank you.

In Phase 2, we have established criteria for our primary endpoints, which include hemoglobin response and safety. For our secondary endpoints, we will evaluate hemolytic markers, patient-reported outcomes, and VOCs. Our primary goal is to meet the requirements for our primary endpoints with two doses tested against a placebo. We will assess both doses to determine which is more effective for moving ahead to Phase 3. These criteria are outlined in our protocol. Additionally, in making an overall decision for the program, we will consider other data, including results from investigator-sponsored trials. As with any program, we ensure we are confident in meeting our target product profile before advancing to the next phase of development. We look forward to mid-year when we can share data.

Thank you. I guess just to follow-up on that, what would be the ideal target profile for PYRUKYND and sickle cell?

So our ideal target product profile is truly some like product that can deliver benefit for the pathology of sickle cell disease, meaning that we are programs designed to enter hemolytic anemia and have a reduction on sickle cell pain crisis. But then we are also hoping to be able to demonstrate a benefit on CROs.

If you don't see an improvement in the VOC rates, would that affect your decision to proceed with the trial?

So the data that we have in our Phase 2 on VOCs will be very limited just because of the duration of the trial. It's a 12-week randomized controlled trial portion. So that that's not how the trial is designed to show a huge benefit on VOC. So we continue to collect data on VOCs in our open-label extension in the Phase 2, and then we, of course, have much longer exposure via our investigator-sponsored trials.

I am showing no further questions. I would now like to turn the conference back to Brian for closing remarks.

All right. Well, thanks a lot everybody for participating in today's call and of course, for your continued interest in Agios. As you heard this morning, we're generating significant momentum towards our long-term vision, and we are confident in our potential to deliver significant value for both patients and shareholders. So thanks again and we'll look forward to speaking with all of you real soon.

This concludes today's conference call. Thank you for participating. You may now disconnect.