Blueprint Medicines Corporation (BPMC) CEO Kate Haviland On Q1 2022 Results - Earnings Call Transcript

Blueprint Medicines Corporation (NASDAQ:BPMC) Q1 2022 Earnings Conference Call May 3, 2022 8:30 AM ET

Company Participants

Jenna Cohen - Senior Director and Head of Investor Relations

Kate Haviland - Chief Executive Officer

Christy Rossi - Chief Operating Officer

Philina Lee - Chief Commercial Officer

Becker Hewes - MD, Chief Medical Officer

Mike Landsittel - Chief Financial Officer

Conference Call Participants

Marc Frahm - Cowen

Dane Leone - Raymond James

Elizabeth - Goldman Sachs

Reni Benjamin - JMP Securities

Brad Canino - Stifel

Yige Guo - Guggenheim Securities

Andrew Berens - SVB Securities

Mike Ulz - Morgan Stanley

David Lebowitz - Citi

Eun Yang - Jefferies

Disclaimer*: This transcript is designed to be used alongside the freely available audio recording on this page. Timestamps within the transcript are designed to help you navigate the audio should the corresponding text be unclear. The machine-assisted output provided is partly edited and is designed as a guide.

Operator

00:03 Good morning. My name is Juan, and I will be your conference operator today. At this time, I would like to welcome everyone to the Blueprint Medicine's First Quarter 2022 Financial Results Conference Call. [Operator Instructions] After the speakers’ remarks there will be a question-and-answer session. [Operator Instructions] Thank you.

00:37 I would now like to turn the call over to your host, Jenna Cohen from Blueprint Medicines. Jenna, you may begin your conference.

Jenna Cohen

00:46 Thank you, Juan. Good morning, everyone, and welcome to Blueprint Medicines First Quarter 2022 Financial and Operating Results Conference Call. This morning we issued a press release, which outlines the topics we plan to discuss today. You can access the press release as well as the slides that we'll be reviewing today by going to the Investors Section of our website at www.blueprintmedicines.com.

01:11 Today on our call Kate Haviland, our Chief Executive Officer, will discuss Blueprint Medicines pillars for growth through 2023. Christy Rossi, our Chief Operating Officer, will provide an advanced SM launch update. Philina Lee, our Chief Commercial Officer, will provide a non-advanced SM market opportunity update. Becker Hewes, Chief Medical Officer, will review our recent clinical progress and highlight upcoming milestones across our growing portfolio; and Mike Landsittel, our Chief Financial Officer, will review our first quarter 2022 financial results. Percy Carter, our Chief Scientific Officer, is also joining our call and will be available for Q&A.

01:54 Before we get started, I would like to remind everyone that statements we make on this conference call will include forward-looking statements. Actual events or 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 the Risk Factors section of SEC filings. In addition, any forward-looking statement made on this call represents our views only as of today and should not be relied upon as representing our views as of any subsequent date. We specifically disclaim any obligation to update or revise any forward-looking statement.

2:33 Now here's our CEO, Kate Haviland.

Kate Haviland

02:38 Thank you, Jenna, and good morning, everyone. We appreciate you joining the call today. At Blueprint, we are clear in our goal to be the leading precision medicine company. Building on this quarter's success, the next 12 to 18 months will be unprecedented for us, as we execute on multiple milestones, driving value creation across all aspects of our business. Blueprint has an incredibly unique profile with the diversity of significant growth drivers and a strong balance sheet that will enable us to outperform the sector over time. As we expand global commercial execution; progress our clinical stage portfolio; and drive innovation through our leading precision medicine discovery platform.

03:21 The first quarter of this year was marked by a number of important milestones across our business. We continue to solidify AYVAKIT as the standard-of-care in advanced systemic mastocytosis, or SM, in the US. And we closed the quarter with the European Commission approval for AYVAKIT in advanced SM. Our European launch is now underway. The global logic AYVAKIT in advanced SM is building a strong real world value proposition and an important foundation of relationships as we prepare for the topline data from our registration enabling PIONEER trial and non-advanced SM late in the summer.

04:00 AYVAKIT has the potential to be the first and only treatment approved for non-advanced SM. With positive results from the PIONEER study, we will have developed a comprehensive body of clinical evidence demonstrating the remarkable efficacy and profound benefits to SM patients across the spectrum of disease, while also driving significant near-term growth for Blueprint.

04:24 Another highlight from the first quarter with the data we presented at the AACR Annual Meeting across our EGFR and CDK2 franchises. It is early days for these programs, but there are many reasons for us to be encouraged about the differentiation of our investigational therapies and their prospects to address major medical needs and difficult-to-treat and prevalent cancers. As our strength this past quarter demonstrates, we are well on our way of delivering on the goals we have set for ourselves this year, while also building a foundation to drive value well beyond 2022.

04:57 If you fast forward for instance at the end of 2023, we expect to be launching AYVAKIT in non-advanced SM, engaging regulatory authorities on registration plans for our EGFR and CDK2 development programs, and expanding our pipeline with new programs in areas of significant medical needs.

05:16 With that let me turn the call over to Christy to discuss the progress we have made on the AYVAKIT launch in advanced SM. Christy?

Christy Rossi

05:24 Thanks, Kate. Good morning, everyone. In the first quarter, we continued to build momentum in our ongoing launch of AYVAKIT in advanced SM, generating net products revenue of $23.8 million. The advanced SM indication contributed the majority of this revenue and we anticipate that it will be the primary driver of AYVAKIT revenue growth over the course of the year.

05:50 We are reaffirming our guidance of $115 million to $130 million in AYVAKIT revenue in 2022, based on the strength of the ongoing US launch, which I will speak about in a minute and our recent approval in Europe, where we received the marketing authorization in advanced SM on March 25th.

06:12 AYVAKIT is now the first approved disease modifying precision therapy in the European Union, designed to selectively target KIT D816V, the primary driver of SM. Within one week of approval, the first patient was treated in Germany, where AYVAKIT is now reimbursed for its expanded indication. And we are looking forward to bringing AYVAKIT to patients in additional EU countries as we work through country-specific reimbursement processes.

06:42 Now let's turn to the US, which contributed $21.3 million in revenue this quarter. We expect revenue growth to continue through the year, driven by two key factors: increasing new patient starts as we reach more prescribers and support more patients and extended durations of therapy as we impact patients earlier in their disease. Our continued launch execution is driving positive momentum across both of these important dimensions.

07:14 The launch of AYVAKIT has fundamentally changed the treatment paradigm in advanced SM, driving significant market growth and setting a new standard-of-care. AYVAKIT is now the treatment of choice for approximately 70% of all advanced SM patients starting on or switching to a new therapy. Since the launch of AYVAKIT, the percent of advanced SM patients, who are being treated for their disease has grown by approximately 40%, as healthcare providers are now choosing to intervene where historically they may have chosen to watch and wait. We know there is still significant room for growth as many patients remain untreated.

07:59 At an upcoming medical meeting, we will be sharing new real world evidence, supporting AYVAKIT's impact on overall survival in advanced SM, which we believe will further catalyze urgency to treat. The momentum we are seeing in new patient starts is driven by our growing prescriber base. In Q1, we activated approximately 65 new accounts, particularly impacted given the impact of Omicron early in the quarter. This strong base of AYVAKIT experience we are establishing is characterized by breadth in the community setting and depth in the academic setting.

08:38 We have had strong penetration in the academic centers of excellence and as our prescriber base continues to broaden the majority of new accounts are coming from the community were half or more of advanced SM patients are cared for. This suggests that we are effectively reaching these patients where they are presenting for care and also that provider who may historically have been less comfortable treating SM are now motivated to treat patients with AYVAKIT.

09:10 We are also seeing patients benefiting from extended treatment durations as we continue to progress the launch. Our estimated duration of therapy for AYVAKIT in advanced SM is trending towards 18-months. In our clinical studies patients' data on therapy for an average of two or more years, some for far longer than that. And we expect duration of therapy to continue to extend as we are able to reach and impact patients earlier in the course of their disease when they can derive the most benefit from AYVAKIT.

09:43 This extended treatment duration we are seeing across academic and community settings in the real world also confirms that a broad range of prescribers are comfortable managing their patients with AYVAKIT. The insights that we are gaining throughout this launch to my belief in the growing strength of our integrated organization and the power of the leadership position we have built in SM.

10:08 With that, I'll turn the call over to Dr. Philina Lee, who was recently appointed as our Chief Commercial Officer, and now oversees our Global Commercial Strategy and US commercial organization, to discuss the medical need and market opportunity we see for non-advanced SM.

Philina Lee

10:27 Thanks, Christy, and hello, everyone. I've been a part of AYVAKIT's development from discovery through commercialization. As I step into the role of CCO, I am honored to lead our team and deliver on the promise of this important therapy for patients living with SM.

10:46 Our strong advanced SM launch trajectory, which Christy spoke to, and our growing understanding of the non-advanced SM markets, reinforced our belief that SM is a potential blockbuster opportunity for AYVAKIT. Symptoms of non-advanced SM are debilitating and to rise unpredictably, disrupting patients' ability to go to work and spend time with their families. Patients can experience a range of symptoms such as uncontrolled anaphylaxis, extreme fatigue, diarrhea, skin lesions, and brain fog.

11:25 Patients share that the symptom burden of non-advanced SM leads them feeling depressed, isolated and fearful that the disease will worsen. There are no approved therapies for non-advanced SM today. Current treatment options are inadequate and failed to address the underlying driver of disease. The polypharmacy burden for non-advanced SM patients is significant. 75% of patients have reported taking at least four or more classes of therapies to manage their disease and these interventions are woefully inadequate.

12:04 Greater than 80% of patients still report limitations in their work or daily activities and 64% share that they avoid leaving their home, due to their SM. Another study showed 83% of patients express frustration that current treatments do not address the root cause of disease.

12:27 Together with the SM community our efforts to raise disease awareness and accelerate time to diagnosis are yielding a tangible impact, a 54% growth in the number of SM patients observed in US claims, since the launch of AYVAKIT in January 2020. We now see more than 15,000 unique diagnosed SM patients in claims data and most of these patients have non-advanced SM. We expect this population to continue to grow with our focus on disease education for healthcare providers, patients and caregivers, and our emphasis on high sensitivity blood based testing for KIT D816V.

13:11 In March, we launched a new disease awareness campaign for patients with SM called It's Something. Within the first week of launch, the website had more than 6,000 unique visitors, including many undiagnosed patients seeking information and a path to diagnosis. An educated patient is a catalyst for diagnosis and treatment. As we await the PIONEER data later this summer, we're confident there are many highly engaged SM patients both diagnosed and not yet diagnosed, who are searching for better options to manage their disease.

13:49 With that, I'll turn the call over to Becker to review our R&D progress.

Becker Hewes

13:54 Thank you, Philina, and good morning, everyone. Today I'll provide updates in two areas, expectations for PIONEER, our registrational study in non-advanced SM; and our anticipated clinical data milestones over the next year.

14:10 Let's start with PIONEER, which has two parts. Part 1 was designed to select the optimal dose and demonstrate proof-of-concept to ensure profound reduction of symptoms and so tolerability for long-term dosing. We saw that AYVAKIT demonstrated deep reductions of clinical symptoms at all doses, a rapid reduction in mast cell burden KIT D816V allele burden, serum tryptase and positively impacted patient quality of life. These data from Part 1 were the basis for AYVAKIT's breakthrough therapy designation in non-advanced SM.

14:47 Part 2 was designed to enable registration by demonstrating response rate superiority of AYVAKIT versus placebo as assessed by Total Symptom Score for TSS. TSS is measured using the ISM Symptom Assessment Form or ISM-SAF. This is a patient reported symptom assessment tool that we developed in collaboration with the SM community and regulatory authorities over the last six years. We believe that a roughly 30% difference in the proportion of responders with AYVAKIT versus placebo would be a clinically meaningful result that would be supportive of both regulatory filings and drive real world utilization in non-advanced SM.

15:32 We've also heard consistently from healthcare providers and patients that any reduction in symptom burden, including the most burdensome symptom, will be viewed as clinically meaningful and potentially transformative for patients. We'll also be looking at a range of additional outcome measures, including mast cell burden and other measures of quality of life. Across this constellation of outcomes, we expect to see consistent impact with AYVAKIT treatment. We remain on track to report topline data in late summer of 2022, and pending results we plan to submit an sNDA to the FDA by the end of 2022.

16:11 Now let's shift gears to talk about the additional clinical data milestones that will drive significant growth for Blueprint. Over the next year, Blueprint will be defining and executing registration enabling strategies across our pipeline of investigational medicines. In addition to the PIONEER topline data in late summer of this year, we plan to report multiple clinical proof-of-concept data sets across our EGFR and CDK2 programs into early next year, including combination data that will enable us to expand into earlier lines of treatment and increasing numbers of patients.

16:48 By the end of this year, we expect to have early clinical data for BLU-945 in combination with osimertinib, an initial data for BLU-701 in EGFR-mutant lung cancer. In addition, we expect to have initial clinical data for BLU-451 in the first half of 2023 in EGFR Exon 20 mutant lung cancer. We will continue to initiate combination cohorts and progressively earlier lines of treatment and look forward to seeing early data from some of those cohorts in 2023.

17:20 I'm equally pleased about the speed with which we're advancing towards clinical proof-of-concept for BLU-222 in CDK2-vulnerable cancers with our first clinical data expected in the first half of 2023. Importantly, we plan to explore both monotherapy and combination dose escalation in Part 1 of VELA and accelerate development across multiple populations. This includes previously treated estrogen-receptor-positive breast cancer patients, as well as front line patients in combination with other agents, including CDK4/6 inhibitors and hormonal therapy. Also in patients with CCNE1-amplified tumors, including subsets of ovarian and endometrial cancer, where we plan to explore biomarker-driven strategies with our CDK2 inhibitor alone and in combination with standard-of-care.

18:12 As a leading precision medicine biotechnology company, we continue to build on our successful and strong R&D engine by bringing additional transformative opportunities to patients with severe diseases, including our targeted protein degradation work currently underway. We look forward to sharing more on our vision at our planned R&D Day in the second half of the year.

18:34 With that, I'll turn the call over to Mike to review our financial updates.

Mike Landsittel

18:39 Thanks, Becker. Earlier this morning we've reported detailed financial results in our press release. For today's call, I'll touch on a few highlights from the quarter. Total revenues were $62.7 million for the quarter, including $23.8 million in net product sales of AYVAKIT, and $38.9 million in collaboration revenue. This represents approximately 164% growth in AYVAKIT product sales from the same period last year.

19:09 As Christy noted, we saw solid growth in advanced SM, which is and will continue to be our major driver of AYVAKIT product revenue, given our strong momentum with the US launch and recent approval in Europe. In addition, in the first quarter, we recognized a $30 million development milestone payment from Clementia related to BLU-782, our out-licensed ALK2 inhibitor in development for the rare bone disease fibrodysplasia ossificans progressiva.

19:38 Turning to expenses, our total costs and operating expenses for the first quarter were $168.5 million, including $23.4 million of non-cash stock-based compensation expense. This reflects moderate planned growth in R&D expenses related to the initiation of four new clinical trials across our EGFR and CDK2 programs. These new clinical programs will drive the next wave of value inflection points for Blueprint and highlight our ability to sustain meaningful innovation through our best-in-class discovery platform.

20:14 As Christy noted, we are reiterating our previous revenue guidance for '22 -- for 2022. This includes $180 million to $200 million in total revenues, and $115 million to $130 million in AYVAKIT net product revenues. In addition to our diverse revenue drivers, we are in an exceptionally strong position with nearly $900 million in cash on our balance sheet, and we are now entering a period where we expect our revenue growth rate to exceed our expense growth, moderating our cash burn and setting the stage for us to become a self-sustaining company.

20:49 Earlier in the call Kate and Becker outlined a significant potential we are unlocking as we invest in a breadth of exciting pipeline of discovery plans over the next 12 to 18-months, which we anticipate will lead to continued modest growth in R&D expenses. Our strong cash position and disciplined approach to capital allocation will ensure that we are well positioned to execute on these opportunities, while driving towards sustainable profile.

21:16 With that, I'll now turn the call back over to the operator for any questions. Operator?

Question-and-Answer Session

Operator

21:23 Thank you. [Operator Instructions] And the first question comes from the line of Marc Frahm from Cowen. Please Marc, your line is now open.

Marc Frahm

21:39 Frahm Marc. Thank you for taking my question and congratulations on a strong quarter. Becker, I think you discussed Part 1 results that show the 60% response rate on the 25 milligram arm. And I was wondering if you could remind us what the rate was in the higher doses at the 50 and 100 milligram doses? And also looking forward to the Part 2 results beyond response rate, are there any components of the TSS that you're seeing very important commercially and will drive patient use? Thank you.

Becker Hewes

22:16 Hi, Marc. So with respect to the Part 1 data we saw consistent response rates across all three arms. You'll remember with 10 patients per arm and we saw both consistent rates and depth of response across all three doses. With respect to Part 2, remember the TSS score is not a clinical tool, this is a clinical trial's tool, so it's not something that pay -- providers will be using in the field. However, what it does is it breaks down the patients experience into a number of different measures of potential improvement. So patients tend to have a number of different organ systems where the disease manifests. So really, really Marriott at symptoms with often one that's most bothering some, but it's really just one symptom particularly at this moderate to severe level.

23:07 And so I think that people will pay attention both to the overall score, but they will be particularly interested depending on the types of patients that they're treating on specific domains. You can imagine a patient who's got 22 to 30 episodes of diarrhea, they're being particularly interested in those patients that have diarrhea and the improvement there. And then patients who have a more global manifestation where they're just not able to get out of bed, to go to work or they're really worried about recurrent anaphylaxis.

23:35 Looking at the skin score and the peak and the ability to alter a number of different symptoms and decreased frequency of a number of different types of manifestations, which speak to those providers and patients as well.

Marc Frahm

23:51 Thank you. That's very helpful. And if I can, one more question for Christy. Christy you mentioned 20% -- 70% of market share for the new prescriptions. I was wondering what would -- what market share has AYVAKIT capture for the overall advanced SM market or potential market?

Christy Rossi

24:14 Sure. So, as I said, we're really pleased to see AYVAKIT very quickly through this launch becoming the standard-of-care for treatment and there is really two aspects to kind of overall treatment rates that we look at. So one is market growth rate, so this is the market, where historically a lot of patients unfortunately have not received SM directed therapy. So the launch of AYVAKIT is growing the market for by about 40%. And then we're looking at, of course, how many patients are actually being treated with AYVAKIT with other therapies and that's where we're seeing now 70% of all new initiations going on AYVAKIT. Our overall share is trailing that given where we are in the launch and actually that's a good thing when your new start share is above your total shares, it’s a signal that you're growing and still we're continuing to see it very rapidly. I think we're kind of close to 50% of our patients now being on AYVAKIT and we expect that, that number to continue to grow as we progress the launch.

Marc Frahm

25:17 Okay. Thank you. Appreciate it and congratulations again.

Operator

25:21 Thank you. Our next question comes from the line of Dane Leone from Raymond James. Please Dane, your line is now open.

Dane Leone

25:29 Thank you for taking the questions and congratulations on all the progress over the course of the quarter. Two from me if I may, firstly, could you maybe provide a little bit more commentary about some questions then around -- what you said around 18-months expected treatment duration? Could you maybe contextualize that given that the drug hasn't been commercially launched for 18-months now just kind of how you're doing that math and what you're seeing play out in the clinic?

26:00 And then could you maybe comment on what you're seeing in the second quarter? I think everyone expected the launch in ASM. To experience the normal issues that most drug companies have in the first quarter of the year, but any commentary on maybe how things are now progressing April to May on some of the key metrics that you talked about, would be super helpful?

26:22 And then finally, could you just maybe level set expectations for the clinical updates in the back half of the year for 945, 701, 451. I think investors are always trying to figure out for these early data sets is this really an ORR dataset, where we're going to establish something like an RP2D? Or are we going to be looking more for the safety signals and emerging signs of clinical doses reported? Thank you.

Kate Haviland

26:48 Okay. Thanks, Dane. So, Christy, do you want to take the 18-months and talk a little bit about the -- quarter-on-quarter growth and Becker will you take that clinical updates and what to expect?

Christy Rossi

27:00 Sure. So, thanks for the question, Dane. So duration is obviously one of the few key, sort of, drivers that we're watching very closely. I mentioned the trajectory of the overall launch. And the context here is that we know that AYVAKIT patients can have quite long treatment durations in advanced SM. In our clinical studies, we saw treatment durations of two plus years and so our expectation is that over time, as we continue to find patients closer to a point of diagnosis, we'll continue to extend those treatment durations in a real world setting. You're absolutely right, we have not been on the market for 18-months. And so at this point, we are essentially looking at curves and comparing sort of the curves that we see around duration of therapy in the real world to what we saw in our clinical studies. And so we're estimating how we're trending in terms of the median duration of therapy will continue to take a look at that over time.

28:01 One positive note there is that we're even seeing that patient to have started more recently in the launch seem to be trending even more favorably. And I think again that reinforces this expectation that we have around being able to impact patients, who are not as sick as we move through the launch and see those durations extend.

28:23 Regarding the quarter-over-quarter dynamics, we certainly -- this is our first SM for Q1 that we've gone through and had an expectation that we would see many of the dynamics that certainly other oncology products and more broadly we see in pharma around Q1 in the US, where revenue can be impacted by factors around gross to net compliance, as well as some other factors.

28:51 We were pleased to see really not a lot of impact through the quarter there and certainly we have some minimal impacts on gross to net, because of co-pays et cetera, but some of the other factors that often impact the first quarter did not impact the AYVAKIT as much as we thought they may. Then I attribute some of our excellent patient support services and distribution programs to meeting that impact. So as we go into Q2 where we continue to be really happy with the trends around new patient start and treatment duration. And we expect really more steady growth as we go through the year in line with the overall revenue guidance that we gave.

Kate Haviland

29:32 Hey, Becker, can you?

Christy Rossi

29:33 And Becker do you want to take the question, yes.

Becker Hewes

29:36 Yes. So Dane, with respect to our EGFR-mutant lung cancer program, just a reminder that what we're trying to do is make sure that we bring everyone along with us on this journey to understand our compounds better and the disease better. EGFR-mutant lung cancer has become a disease of combinations as is often the case as we get better and better at treating these tumors. These tumors find more mechanisms of resistance in finding the right combination partners is really important.

30:06 945 is our inhibitor that has a very high winded wild-type. So we see it as a backbone for future treatment. It has activity, not only in preclinical models where there's T790M, but also in the LR mutant population of cells. So we have presented at AACR, initial data showing that this compound behaves exactly as we expected it would, with very little toxicity, really not even much of a hint of EGFR wild-type toxicity and a rapid reduction in the circulating tumor DNA alleles that it's designed to inhibit.

30:46 As we move into the next phase of the study and we start combining with osimertinib, this is a strategy to cover a more heterogeneous tumor population and drive people remissions. We will be in the dose finding phase of this osimertinib combination over the next portion of the study. And similar to what we did at AACR, we expect to continue to update the community on both the combination and the single agent activity.

31:13 With respect to 701, which is our brain-penetrant inhibitor, this one has really high potency on the driver mutation and then activity in central nervous system, it really is class defining with respect to penetration of the central nervous system. We are in escalation right now and we -- similar to the way that we presented data for 945, plan to bring people along and help you understand circulating tumor DNA in the early evidence of activity. And then our strategy and early data as we combined in 2023, both with 945 and with osimertinib in that program.

31:54 And then BLU-451 is a more straightforward biology where the tumors are driven by single driver mutation in Exon 20 mutation. We are in escalation now and we expect to be in escalation for most of the rest of the year. And -- but in that case, we might expect a more straightforward evidence of responses we've seen with some of the other EGFR 20 inhibitors in the clinic and so as we have a good body of data, that's what we'll be updating in that program.

Operator

32:26 Thank you. Our next question comes from the line of Salveen Richter from Goldman Sachs. Please Salveen, your line is now open.

Elizabeth

32:34 Hey, good morning and thanks for taking our question. This is Elizabeth on for Salveen. Just maybe if you could provide some color on the sustainability of the growth drivers underpinning AYVAKIT sales this year and then looking forward? Thank you.

Kate Haviland

32:53 Christy, do you want to take that -- this is --

Christy Rossi

32:57 Yes. Thanks for the question. So, as we shared we're really looking at a very simple level kind of two see drivers around the AYVAKIT launch. New patient starts and duration of therapy. And I think that both of those are trending in a way that really touch this us up nicely for a steady growth as we go through the year. On the new patient start front, as we mentioned, we continue to have a lot of headroom, many advanced SM patients are not receiving a therapy for their disease and AYVAKYT has very quickly grown to become the standard-of-care as new patients are initiating therapy.

33:37 And so we're continuing to focus on broadening our base of prescribers, going out and identifying patients closer to diagnosis and continue to see a lot of room to grow. And then as I mentioned, we're pleased to see the trends and duration that we're seeing already. I think we have some room to continue to prove that as we go through the year, but in general, very happy to see that patients look to be staying on extended periods of time. And as we move through the year that will help us also drive ongoing revenue growth. So reiterating the overall guidance and are looking to see, you know, or steady quarter-on-quarter growth, as we go through the year.

Kate Haviland

34:18 And just to add to it one thought about is that, this as Christy mentioned in the prepared remarks, I mean, SM has been a condition where physicians have been really in a wait and watch for quite a bit of time, right? They just haven't had directed therapies that have been very impactful to patients. And so I think the enthusiasm we're also getting from our -- the physicians that we're talking to about the clinical aspects, their early experiences with AYVAKIT has been really, really promising.

34:45 And as Christy mentioned as well, we at a near kind of upcoming medical conference, we plan to also present data based on some real world evidence on showing improved survival in patients who are receiving AYVAKIT relative to standard-of-care and other therapies, which I think is going to be incredibly compelling. And so you had kind of the early experience plus this kind of additional data as we see the benefits of AYVAKIT to really a life extending type of therapy. I think we'll very much continue to catalyze positions out of this wait and watch kind of attitude they've been in previous life.

Operator

35:24 Thank you. The next question comes from the line of Reni Benjamin from JMP Securities. Please Reni, your line is now open.

Reni Benjamin

35:34 Thanks for taking the questions and congrats on the quarter. Can you provide little bit more color on the European launch? I guess, in particular, how that's going to build out over time? And should we be thinking about a year from now, the revenues, the uptake kind of mirroring what's happening here in the US? And then just kind of related to that the -- I'm pretty intrigued by the US claims data that you guys are showing. How much granularity do you have with that data and can you know -- do you know, which sites per se might be having a lot of amount of advanced SM patients, so that once the launch takes place, you can actively target those sites. Thank you.

Kate Haviland

36:21 Yes, thanks Reni for the questions. Christy, do you -- if you could take the question on the EU launch dynamics. And then Philina can answer the question about the claims data.

Christy Rossi

36:32 Great. So we were really pleased to see the European approval come through several weeks ago. And as I mentioned on the call have already launched in Germany and see a lot of interest coming from German healthcare providers and patients already out of the gate, which is really encouraging. The overall dynamics in Europe, I think will be very similar to the US. Certainly the epidemiology is similar. And in fact, I would argue that down the European markets and Germany is one of them may be a bit more organized in their treatment of SM patients through the efforts of the European cooperative network around treatment of SM or EC&M.

37:16 So we're excited to see this rollout. We expect in terms of the cadence of the launch. Germany is obviously often the first market out of the gate in Europe given the reimbursement dynamic that because we already have a reimbursed price there. We expect Europe -- or Germany to really be kind of that the primary driver in the immediate term. We will have additional European markets coming online as we move through the year and then certainly into next year to work through those reimbursement processes. But generally speaking, would expect kind of the overall cadence of the launch to not look very different. And we now expect AYVAKIT become the standard-of-care for treatment of advanced SM in the Europe over time as well.

Philina Lee

38:00 And speaking to the US claims – absolutely, Christy. So Reni regarding the US claims data, we have visibility into a number of factors in our patients and provider claims. We can see that the majority in fact of these patients have non-advanced SM. And in fact, these patients we think are on the more moderate to severe spectrum of disease in terms of how they're engaging with the healthcare system. We have visibility into the fact that it's mostly medical oncologists and allergist immunologists, who are the most involved in the diagnosis and overall management of these patients with other specialties such as dermatology and GI more focused on the symptom management of these patients. And to your question, we do have some visibility into who is treating and managing these patients and are very focused on efforts to raise disease awareness among these providers.

Reni Benjamin

39:03 Terrific. Thanks for taking the question.

Operator

39:07 Thank you. Our next question comes from the line of Brad Canino from Stifel. Please, Brad, your line is now open.

Brad Canino

39:15 Good morning and congrats on the quarter. Now that we're closer to the ISM readout, can you outline the degree of data disclosure you expected in the top line press release versus what data points you might save for a medical conference? And then I want to ask on the 945 plus OC combination specifically where you're focused on the LR subgroup. What doses are you going to start at? And based on your 945 PK/PD analysis, were those doses already provide predicted therapeutic coverage of all the potential compound in single EGFR mutation combination clones for those LR patients in the trial? Thank you.

Kate Haviland

39:56 Thanks Brad. This is Kate, I'll take the first one and hand over to Becker for the second part of your question. In terms of expectations on topline data, this is going to be very similar to what we've done in the past where GAVRETO able to AYVAKIT and the advance setting and PDGFR alpha-driven GIST. So we will plan to put out, particularly the results on the primary endpoint, a safety overview as the primary kind of anchors to that communication. We will see the majority of that data for your presentation at a medical meeting.

40:28 So we will certainly talk about the overall results of the study and what is -- what are the critical pieces for pursuing FNDA. So that's what you can expect there. And then Becker, do you want to talk about --

Becker Hewes

40:39 Yes. So, Brad, with respect to the combination of osimertinib and BLU-945, we'll be starting BLU-945 at 200 milligrams. This is a dose that begins to approach the LR coverage in the blood. But it's important to remember that we're really trying to get deeply into tumors in patients with very bulky disease in some cases. We have a number of different and we'll start with full dose of osimertinib. We have a number of different combination doses to test during this escalation period to get the right balance between the two. We don't expect there to be additional toxicity by adding BLU-945, because it doesn't hit the wildtype EGFR until very high doses. But nonetheless, we're still need to look at a number of different combinations to get the optimal one for these patients.

Operator

Thank you. Our next question comes from the line of Michael Schmidt from Guggenheim Securities. Please, Michael, your line is now open.

Yige Guo

41:42 Hi, good morning. This is Yige on for Michael. Thanks for taking our questions. One on the long-term strategy for your CDK2 program, you've spoken about potential combinations with CDK4/6 inhibitors. How should we think about that combination from a safety perspective? And in terms of sequencing therapy, and how would be positioned relative to Pfizer's CDK2 4/6 inhibitor in any read through from their initial data in San Antonio? Thank you very much.

Becker Hewes

42:12 Yes. So with respect to CDK2 inhibitors or particularly our CDK2 inhibitors, we don't expect overlapping toxicity. Certainly, we need to look at the single agent data before we know that for sure, but based on our preclinical data, we expect these to be complementary to CDK4/6 inhibitors. We've looked at a number of different combinations with chemotherapy preclinically and 4/6 inhibitors. And so we look at Pfizer's data and we're pleased by the fact that they're seeing activity.

42:44 However, I think that it's been mentioned, both by us and them multiple times to being able to control CDK2 versus 4/6 is going to be important to both manage potential toxicity and make sure that we are in different lines of therapy addressing the either the initial driver or the resistance mechanism or both at the same time.

43:06 With respect to the Pfizer compounds, those are selective CDK2 inhibitor and the 2/4/6 inhibitors. We see this compound is highly competitive. It's a very selective CDK2 inhibitor and we see it is having potential to combine with a number of different CDK4/6 inhibitors in multiple lines of therapy in hormone-resistant breast cancer.

Yige Guo

43:34 That's helpful. Thank you.

Operator

43:37 Thank you. Our next question comes from the line of Andrew Berens from SVB Securities. Please, Andrew, your line is now open.

Andrew Berens

43:47 Hi, thanks. Can you give some additional details on the development plan for the combo of 945 plus Tagrisso. It sounds like initially you are going to go after that L858R sub group to develop the 797S point mutation Tagrisso. Do you expect that to be an accelerated pathway? And then what are the plans to penetrate the first line? Or are you going to test the two drug small molecule cocktail for the MEK inhibitor either a small molecule or large molecule?

Becker Hewes

44:18 So let me address those individually. So with respect to the combination, again as I mentioned, the reason for the combination is two-fold, one is to hit the driver mutation as hard as possible. So the combination of either osimertinib or BLU-701 plus BLU-945 would be expected to do that, but also to in the resistance setting to address heterogeneous tumors and in the frontline setting to prevent the emergence of resistance. Our goal in the frontline setting is to really shut down the EGFR signaling pathway. And it's been shown most of the times in hematologic tumors that when you can do this, you get longer durations of response and eventually longer overall survival.

45:01 With respect to pathways to approval in the relapsed-refractory setting even in the second line following first line osimertinib, there is really not much besides chemotherapy that showing activity at this point. And so we do think that there are potential rapid pathways to approval either for the single agents or a combination with standard-of-care that within the followed up with randomized trials to confirm that clinical benefit of that combination, so we will look early in our study of 945 plus osimertinib for activity -- evidence of activity in the relapse-refractory setting, but then shortly thereafter looking in the front line to show that we can achieve rapid deep responses with that combination.

45:49 With respect to MEK inhibitors, MEK is an important, but certainly not really dominant mechanism of resistance. I think that it is important to remember that some of these other non-EGFR mediated mechanisms of resistance, so really the drivers of early resistance where patients that have been on osimertinib for a longer period of time will have higher rates of on target or EGFR mutations driving resistance. So we will using 945, start to explore combinations with a number of different compounds. And that will likely include a MEK inhibitor and the utility of that in different lines of therapy or maybe an early relapse patients will be something that will be determining over the next year or to 15 months.

Andrew Berens

46:40 Okay. Thank you very much.

Operator

46:41 Thank you. Our next question comes from Mike Ulz from Morgan Stanley. Please, Mike, your line is now open.

Mike Ulz

46:51 Good morning and thanks for taking the question. Maybe just a follow-up on an earlier question related to the claims data and the diagnosis rate. It looks like you're still getting some nice traction there. Just curious, at peak you ultimately expect the majority of SM patients to be diagnosed or for some reason could that number be lower and maybe it's because you're not capturing mild patients, for example. And then secondly, just can you remind us, with the current diagnosis rate is in Europe? Thanks.

Kate Haviland

47:24 Christy, can you take that?

Christy Rossi

47:28 Sure. So we are really excited to see kind of the ongoing growth in diagnose patients. I know many of you remember a couple of years ago when we started talking about non-advanced SM as sort of more detail at that point in time, maybe 10,000 patients were diagnosed in the US, and now are close to half. So our expectation is that the majority of SM patients will be diagnosed as we approach the launch and then move through the launch, through our ongoing efforts and our focus. And we're kind of close to that point now. We also think that moderate to severe patients, because of their symptomatology on the margin more likely to find their way to a diagnosis versus patients who may be milder. So we will continue to really be putting effort against that.

48:13 In Europe either we are building that picture market-by-market. I can say that we were able to get a look at sort of and now I guess claims like data in Germany, and it's been a very similar picture to what we see in the US, which was really encouraging, because I think that validate the idea that these patients are definitely out there. They're being diagnosed and we're continuing to see that growth both through our efforts, as well as I think just the efforts of the overall SM community and these patients who are just so motivated to really seek peak diagnosis and treatment.

Kate Haviland

48:52 And just to add one element to add too for Christy is that, I think one of the things we've seen in other kind of similar launches, whether that be a Jakafi or others is that, we expect a very compelling risk benefit profile coming out the PIONEER study in the non-advance setting. And as physicians start treating and get comfort, we certainly see that less interact patient start to be more included in those treatment paradigms. So I think upon the PIONEER study launching in the non-advance setting, we would expect that patients with less symptomology would start to be included as again as physicians gain that experience and comfort.

Operator

49:35 Thank you. Our next question comes from the line of David Lebowitz from Citi. Please, David, your line is now open.

David Lebowitz

49:43 Thank you very much for taking my questions. First on non-advanced SM, you had indicated that 70% of new patient starts were going to AYVAKIT. I guess, how can we look at the growth trajectory going forward as it seems that it's continued shipped in less for more from I guess new patients to duration over the long haul. How does that express like the run rate?

Kate Haviland

50:09 So, Christy, I think, David, I think you're saying that and it'd be advance setting. So 70% of new patient starts. But, Christy, do you want to answer that run rate?

Christy Rossi

50:18 Yes. Yes, right. So I think the sense really two kind of factors to think about where when we could give our kind of new patient starting in advanced SM. So one is just the overall rates of treatment in this indication and despite the fact that it is such a severe disease with, you know, a very limited life expectancy. We know that many patients have not been treated, providers have taken more of a watch and wait approach, I think largely, because the available therapies simply haven't been very effective actually with the disease.

50:56 And so, the fact that we've seen 40% growth in the number of patients being treated such as sort of the overall market since AYVAKIT has launched, I think those speaks to that. But the majority of patients are still not being treated. And so there is a lot of room to continue to grow the overall size of the market. And with AYVAKIT getting, about 70% of those new starts, I think we’re very well positioned as the market continues to grow to continue to drive new patient starts on AYVAKIT.

51:28 So I continue to see both new starts, as well as treatment duration to be very important drivers for our ongoing growth. And in fact in the near-term, you know, I think new starts will be probably the more part of the two of them and we continue to see a lot of help there, expanding prescriber base, continuing theory even the last few months in Q1. And so I think we're well set up for this year after the steady growth that we expect.

David Lebowitz

51:55 Sure. Thank you for that. And we're looking at the claims data regarding systemic mastocytosis as a whole. How are those numbers actually determine? What factors goes into determining differentiating one patient versus another given that polypharmacy is a substantial issue, which could be hamper such analysis, many of the drugs often use or antihistamines things that actually don't require prescriptions? How do you break those numbers down?

Kate Haviland

52:30 Jenna can you talk that --

Jenna Cohen

52:33 Sure. Sorry, guys we're coordinating remotely, but Philina, maybe if you can take a stab and Christy please add color.

Christy Rossi

52:39 I'm happy to start. Yes, so thanks for that question. So first off, I would say we're fairly confident that these are indeed unique patients that we're looking at as we're able to follow their journeys through initial diagnosis and their health care utilization, which includes things like the treatments that they may use, as well as the different physician specialties that they're interacting with both for chronic care, as well as sort of acute or episodic care. And so some of the features that we're able to see are both the initial diagnosis of SM, as well as the SM diagnosis code associated with all of these care interactions along that journey.

David Lebowitz

53:23 Got it. And the last question is the denominator of those questions on the left of Slide 6, patients on polypharmacy, is the --

Kate Haviland

53:35 Yes.

David Lebowitz

53:36 Is that populate denominator essentially equivalent to this the population that's in the claims data or other differences in the sample?

Christy Rossi

53:43 Yes. That's a great question. They're actually a number of different publications on this topic and so some of these facts that we're showing on Slide six come from a touchstone survey that has been done with both patients living with non-advanced SM, as well as our immunologists and hematology, oncologists that are managing these patients. We also see though that these numbers correlate very well across a number of other published literature that surveys patient and provider health care population.

David Lebowitz

54:18 Thank you very much for taking my questions.

Operator

54:22 Thank you. Our next question comes from the line of Eun Yang from Jefferies. Please, Eun, the line is now open.

Eun Yang

54:30 Thank you. I have a questions on non-advanced SM. Previously you mentioned about 70,000 patients in major global markets. And based on the entry criteria, what percent of patients do you think would be realistically candidates for avapritinib? And if you are targeting majority of 70,000 patients, what do you think would there be a reasonable pricing for a rapid adoption? And the second question is, what percent of a target patient population in SM, would it be treated with a hematologists versus allergy specialists? Thank you.

Kate Haviland

55:17 So Philian can -- will take some of the first part of that question just around the addressable patient population. And then Christy, if you could weigh in on the pricing would be great.

Philina Lee

55:26 Yes, thanks for that question Eun. So just to kick it off, as we look across multiple data points suggest that 60% or more patients may ultimately be candidates for disease modifying therapy. So we've talked about the vast majority of these patients receiving polypharmacy, and despite there is still reporting significant impacts on their quality of life. For example, we hear that up to 50% of patients are reporting, potentially life-threatening anaphylaxis. And we've heard an example of a patient, who keeps an EpiPen in every room of her house. As we speak to allergists and hematologists-oncologists, they also share with us that they see 60% approximately of their patients being moderate to severe and really not well controlled on symptom directed therapies.

Kate Haviland

56:22 Okay. And Christy, do you want to weigh in on the pricing question from you?

Christy Rossi

56:27 Absolutely, so the context that we just shared about this disease, I think is important when we think about pricing. There are non-advanced SM that's clearly a much bigger indication versus advanced. However, it is still very much a rare disease. And it's a rare disease where patients are suffering from very severe morbidity impact on ability to work quality of life along the lives of cancer patients et cetera. As we've engaged with payers, they very much understand that context and impacts through our experience with the launch of AYVAKIT so far. We've had really no barriers to access from a payer perspective very rapid time to sell.

57:09 And we've seen some reimbursement impact as a non-advanced setting as well. And so our expectation is we go forward the AYVAKIT, we're on the market and price certainly in the US at all doses and would expect it to be able to continue to ensure patient access as we go forward into the non-advanced launch. So I don't really see price is being kind of a major driver of that launch. I think it's going to be much more about our continued engagement with healthcare providers and patients education around patient identification and testing and, of course, a very positive benefit risk profile that we're expecting to see from AYVAKIT in this syndication, particularly at the doses for non-advanced SM based on the data that we've seen so far from PIONEER in Part 1.

Kate Haviland

57:59 And Becker --

Eun Yang

58:01 In terms of population. Thank you.

Becker Hewes

58:04 Sure. Go ahead, go ahead.

Philina Lee

58:06 I’m Sorry, Eun what was that?

Christy Rossi

Sorry I missed that last part, I apologize, yes. Hematologist versus allergists, yes. So what we see is that non-advanced patients generally are managed by allergy primarily hematology is often involved in co-managing these patients and so we expect that our efforts will be primarily focused in an allergy, as well as making pathology call points that were already focused for the advanced patients.

Eun Yang

58:39 Can I ask you one more question to that then? Do you have to -- would you needed to add the sales reps to target allergy specialists?

Christy Rossi

58:51 So yes.

Philina Lee

58:52 Our expectation of that we may --

Christy Rossi

58:54 Okay, go ahead, Philina.

Philina Lee

58:56 Go ahead, Christy.

Kate Haviland

58:57 Go ahead, Christy.

Christy Rossi

58:59 Our expectation is that we may modify our commercial footprint as we go forward towards that non-advanced approval to make sure that we are really adequately directing these resources into the allergy space, but we don't expect those changes to be significant. This is a very tractable call point for a specialty commercial organization and kind of the context of a biotech company. And we are already quite adapt and skillful at utilizing some of the claims data that we've already been talking about to make sure that we're directing our efforts in really special way.

Eun Yang

59:32 Thank you very much.

Becker Hewes

59:34 Hey, Eun, this is Becker. I just wanted to make a point about the first part of your question. I think we need to think of these patients as having a chronic disease that does progress over time. The story that we've heard from patients has been that they may start out with mild symptoms, but they tend to get worse and worse over time become more and more debilitating. To-date we haven't had an option for these patients. So I think that what we're going to see is providers looking to understand the depth of the disease sometimes by trying the treatment that we know wiped out the clone and causes the disease and also starting to work with the community to understand the value of preventing the progression of the disease, even in the non-advanced setting. So I wouldn't think of patients showing up as a certain level of severity and simply staying there for good.

Operator

60:32 Thank you. At this time, we have run out of time for further questions. So I will turn the call over back to Katie Haviland for any final remarks.

Kate Haviland

60:41 Thank you, operator. Our strong performance in Q1 sets the foundation for us to achieve the priorities we've laid out as a company this year. AYVAKIT, as we just talked about, is off to a very strong start in its first full-year of launch with the opportunity to expand the non-advanced SM right around the corner. We are also maintaining our growth momentum with the execution of our pipeline to key data milestones this year and next. We look forward to talking with all of you on this continued progress very soon. So thank you for taking the time to join us today and thank you for your continued support of Blueprint Medicine.

Operator

61:16 This concludes today's conference call. Thank you so much for joining. You may now disconnect your lines.