Kristin Hodous – Investor Relations Jeff Albers – Chief Executive Officer Andy Boral – Chief Medical Officer Mike Landsittel – Vice President, Finance Marion Dorsch – Chief Scientific Officer.

Terence Flynn - Goldman Sachs Eric Schmidt - Cowen and Company Sarah Frank - Raymond James Dane Leone - BTIG Carmen Augustine - Jefferies Mike King - JMP Securities Arlinda Lee - Canaccord.

Good day, ladies and gentlemen, and welcome to the Q3 2017 Blueprint Medicines Corp. Earnings Conference Call. [Operator Instructions] As a reminder, this conference maybe recorded. I would like to introduce your host for today's conference, Kristin Hodous. You may begin..

Thank you, operator. Good morning. This is Kristin Hodous of Blueprint Medicines and welcome to Blueprint Medicines third quarter 2017 financial and operating results conference call. This morning we issued a press release which outlines the topics that we plan to discuss today.

The release is available on the Investors section of our Web site at www.blueprintmedicines.com. Today on our call, Jeff Albers, Chief Executive Officer, will discuss Blueprint Medicines’ third quarter 2017 business highlights. Marion Dorsch, our Chief Scientific Officer will provide an update on our research portfolio.

And Mike Landsittel, Vice President of Finance, will review our third quarter financial results. We will then open the call for your questions. Dr. Andy Boral, our Chief Medical Officer, is also on the call and will be available for Q&A.

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 our most recent Quarterly Report on Form 10-Q filed with the SEC and any other filings that we may make with the SEC.

In addition, any forward-looking statements made on this call represent 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 statements. Now, here is our CEO, Jeff Albers..

Thanks, Kristin, and good morning everyone. Throughout 2017 we have made excellent progress across our portfolio towards the goal of delivering transformative, highly selective kinase medicines to patients with genomically defined diseases.

We expect this progress to culminate in an extremely productive fourth quarter marked by additional data disclosures for BLU-285 in gastrointestinal stromal tumors or GIST, and in systemic mastocytosis.

Importantly, we also continue to advance and expand a differentiated research pipeline with the potential to fuel our continued growth for years to come. As we work to haul Blueprint Medicines into a fully integrated commercial stage company, we are guided by four core principles. First, continued rigorous science. Second, rapid clinical development.

Third, disciplined portfolio management, and fourth, an unyielding focus on patients. On today's call we will highlight our continued clinical momentum and provide an update on our growing research pipeline.

Our clinical progress is highlighted by the presentation of updated data for our highly selective FGFR4 inhibitor, BLU-554, in patients with advanced hepatocellular carcinoma or HCC at ESMO in September. There are several key takeaways from the presentation that I want to call to your attention.

First, the new data demonstrated compelling clinical activity for BLU-554 in heavily pre-treated patients with FGFR driven HCC. With objective responses seen in 16% of patients and radiographic tumor reductions in nearly half of the patients.

Second, the data supported our patients selection approach and established FGFR4 pathway activation as a driver of disease in a biomarker defined subset of HCC patients.

Third, the data provided encouraging preliminary evidence of prolonged disease control in a small group of patients who had not received prior treatment with the TKI such as sorafenib.

Overall, the data supports further exploration of BLU-554 and FGFR4 driven HCC, both in the TKI-naïve patient population and in combination with an immune checkpoint inhibitor. As we generate additional data for BLU-554 over the course of 2018, we plan to initiate interactions with regulatory authorities on potential pathways towards approval.

Turning to our broader pipeline. We continue to make important progress with BLU-285, our potent and highly selective KIT and PDGFRα inhibitor. We plan to report updated data from our ongoing studies in advanced GIST as well as in systemic mastocytosis before the end of the year.

The first of these disclosures will be for GIST at the 22nd Annual Connective Tissue Oncology Society meeting on Friday, November 10. We expect this presentation will be an incremental update from our last disclosure to ASCO based on continued enrollment of the expansion portion of the ongoing Phase 1 clinical trial.

As we disclosed in June, BLU-285 received FDA breakthrough therapy designation for the treatment of patients with advanced GIST, harboring PDGFRα D842V mutations.

In addition, based on encouraging, progression free survival data shared at ASCO, we are on track to initiate a global randomized Phase 3 clinical trial of BLU-285 versus regorafenib in the third line setting in the first half of 2018. This will support development of BLU-285 in a broader populations of patients with KIT-driven GIST.

For systemic mastocytosis update, we will share updated safety data and importantly we will assess the data based on the IWG response criteria, which comprises the most rigorous approach to assessing response in advanced systemic mastocytosis.

The disclosure will include full escalation data along with any early expansion data that we may have available. I also want to highlight our selective RET inhibitor, BLU-667. As you may know, RET activating fusions and mutations are key drivers to these drivers in multiple cancers.

Last weekend we shared pre-clinical data for BLU-667 at the Molecular Targets or Triple meeting in Philadelphia. These data show that BLU-667 is highly potent against RET fusions including KIF5B, in non-small lung cancer as well as against predicted resistant mutations including gatekeeper mutations.

Earlier this year we initiated a Phase 1 trial of BLU-667 in patients with non-small cell lung cancer, medullary thyroid cancer and other advanced solid tumors. We continue to be pleased with trial enrollment and the enthusiasm of our investigators and we are on track to share initial clinical data from this program in the first half of 2018.

Finally, building a cohesive and strong team has always been a key focus for us at Blueprint Medicines. In October, we were thrilled to welcome Dr. Chris Murray as Senior Vice President of Technical Operations, who brings extensive strategic and operational experience to our management team.

Chris joins us from ARIAD Pharmaceuticals where he oversaw all aspects of clinical and commercial manufacturing including the late stage development, regulatory review and commercial launch for ponatinib and brigatinib.

We look forward to his contributions as we expand clinical activities for our most advanced investigational therapeutic and develop plans to meet potential future commercial supply needs. Now I would like to turn the call over to our Chief Scientific Officer, Marion Dorsch, to discuss our research portfolio in more depth.

Marion?.

Thanks, Jeff, and good morning, everyone. I want to start by discussing our overall therapeutic discovery strategy before providing some key updates on our research portfolio. As you know, we take great pride in our scientific platform and research capability which have enabled us to develop a robust pipeline of highly selective kinase medicines.

All of our current therapeutic candidates were internally discovered and developed by scientists at Blueprint Medicine. The foundation of our research program is a proprietary liability of chemical compounds which was built over several years following the foundation of the company.

What distinguishes our library from other libraries is that each chemical compound is fully annotated against the human kinome.

This detailed analysis of individual compounds enables us to bypass traditional and inefficient therapeutic screening techniques by providing improved starting points for the development of highly selective therapeutic candidates.

Furthermore, our carefully designed library has enabled us to pursue kinases that have been historically difficult to target. I am excited that just last week, our team identified potent and selective starting points for a well validated kinase that has been on my radar for nearly two decades but has proven difficult to track.

In general, our approach to therapeutic discovery first focuses on identification of an abnormally activated kinase in a defined subset of patients with severe cancer or rare disease. We then develop a therapeutic candidate that is highly selective for the target kinase to maximize target inhibition and to limit off target activity.

When combined with patient selection, this approach has the potential to achieve rapid proof of concept, importantly, we continuously evaluate opportunities to expand our therapeutic discovery capability.

For example, under our collaboration with Roche, we are working to identify targetable immunokinases that have the potential to elicit or enhance immune response against cancer.

Our strong technology platform combined with our talented and highly motivated scientists have the potential to unlock a broad range of development opportunities and we recognize we have a responsibility to deploy resources carefully.

We are committed to discipline the management of our portfolio and prioritization of our program with the creative potential to transform patient care. Consistent with this approach, we are providing three important updates on our research portfolio today.

First, I am extremely pleased that we are planning to prioritize continued advancement of our research program targeting the ALK2 kinase for the treatment of fibrodysplasia ossificans progressiva or FOP. Our scientific leader for this program referred to FOP as a catastrophic disease.

FOP is a severe, ultra rare disorder of the connective tissue characterized by the abnormal transformation of skeletal muscle, ligaments and tendons into bone.

Beginning in early childhood before age ten, patients experienced loss of joint function, progressive disability and ultimately premature death at a medium age of 40 typically due to restrictive pulmonary disease. The cause of FOP is a mutation international the ALK2 gene, which results in abnormal kinase activity.

Our research program seeks to identify a therapeutic candidate that can selectively inhibit ALK2 and treat the underlying cause of the disease.

As you know, in July Alexion informed us of their decision to exit our collaboration on this program following a strategic portfolio review and decision to focus their resources on certain core therapeutic areas.

In October, the termination because effective which enabled us to complete the transition of the program back into our portfolio as a wholly-owned program. As a result of the termination, we no longer have any exclusivity obligations to Alexion. We also don’t have any current or future payment obligation to Alexion.

We are currently evaluating a limited number of well-designed compounds with the goal of identifying a therapeutic candidate to move into the clinic. Importantly, we want to thank Alexion for productive partnership over the last two years and their support on a seamless transition.

Second, we plan to de-prioritize our research program targeting the PRKACA kinase for the treatment of fibrolamellar carcinoma or FLC, a rare sub-type of liver cancer that typically effects young adults. Here we have encountered scientific challenges to advancing our preliminary research due to the lack of suitable efficacy models of FLC.

We plan to share our learnings with the FLC community and may consider opportunities to further advance this program based on future potential developments in the field. Third, we have nominated an additional wholly-owned research program for an undisclosed kinase target.

Combined with the FOP program and another research program for an undisclosed kinase target nominated in 2016, we now have three wholly-owned programs in our research portfolio. Our initial work on the two undisclosed programs will focus on validating the target biology and identifying selective compounds for further development.

As these programs progress, we look forward to sharing more information. We also recognize the important role that partnerships play in disciplined portfolio management. We continue to make significant focus on our cancer immunotherapy collaboration with Roche.

We remain very pleased with the progress we are making together and we are grateful for Roche's expertise and contributions to the advancement of the collaboration program. We will continue to evaluate potential additional partnership opportunities that may similarly enable the acceleration and expansion of our ongoing R&D efforts.

I will now turn the call over to Mike to review our financial results from the third quarter..

Thanks, Marion. Blueprint Medicines continues to maintain a strong balance sheet and we are well positioned to execute on the development activities both clinical and pre-clinical that Jeff and Marion just outlined. Let me start by walking you through our third quarter P&L.

Collaboration revenues were $8.1 million for the third quarter of 2017, compared to $6.2 million for the same period in 2016. This increase was primarily due to revenue recognized under the Alexion collaboration as we began the transition of the FOP program back to Blueprint Medicines.

As Marion just pointed out, as a result of the discontinuation of our collaboration with Alexion, we will not receive any additional milestone payments from them and will no longer be entitled to reimbursement for certain R&D expenses related to the FOP program.

Research and development expenditures were $39.3 million for the third quarter of 2017, compared to $18.2 million for the same period in 2016.

The increase in R&D spending was primarily attributable to increased clinical and manufacturing expenses associated with advancing our ongoing clinical trials for BLU-285, BLU-554, and BLU-667, as well as increased personal related expenses.

General and administrative expenses were $7.4 million for the third quarter of 2017 compared to $4.9 million for the same period last year. The increase in G&A spending is primarily due to increased personnel expenses related to an increase in headcount, as well as increased professional fees.

Net loss for the quarter was $37.7 million or $0.96 per share compared to a net loss of $16.8 million or $0.62 per share for the same period in 2016. Now turning to our balance sheet. We ended the quarter with cash, cash equivalents and investments totaling $390.7 million, compared to $268.2 million as of December 31, 2016.

The increase in cash was primarily due to the net proceeds of $215.6 million from our follow-on offering that closed in April 2017, partially offset by cash used to fund operations.

Based on our current plans, we continue to expect that our existing cash, cash equivalents and investments excluding any potential option fees and milestone payments under our collaboration with Roche, will enable us to fund our operating expenses and capital expenditure requirements into the second half of 2019.

And as I discussed last quarter, as we refine our regulatory path for BLU-285 in advanced GIST, we are ramping up our clinical development and early pre-commercial activities.

This includes beginning to build the infrastructure to support the planned global Phase 3 clinical trial of BLU-285 in third line GIST, expanding manufacturing activities to provide clinical and commercial drug supply and preparing to expand our ongoing efforts with BLU-554 to include an additional arm of TKI-naïve patients to our ongoing trial.

We expect that our operating expenses will continue to increase in subsequent quarters as we continue to execute on our vision of building a fully integrated biopharmaceutical company. With that we would now like to open up the call for your questions.

Operator?.

[Operator Instructions] And our first question comes from the line of Terence Flynn from Goldman Sachs. Your line is now open..

Maybe, Jeff, as you guys look out to the 285 SM data, just wondering how you think about differentiating versus Midostaurin in the advanced setting and can you help us think about if there is a potential accelerated path to market for this indication. Thanks..

Thanks, Terence. So as we mentioned, we are still on track to share data for BLU-285 from our study in advanced systemic mastocytosis by year-end. And I actually think both part of your questions, both in terms of how we differentiate as well as the regulatory path, are best answered at the time we share that data.

As we have disclosed before, we won't be providing a regulatory update at that time but we will talk about what our plans are going forward in terms of next steps..

Okay. Thanks. And maybe just one follow-up. Will we get IWG response data for the expansion cohort? I know it sounds like for the dose escalation we will but the expansion cohort, will you have enough follow up to assess IWG response. Thanks..

No. For the expansion portion, there will not be sufficient time, you are correct.

Because of the criteria the follow-up necessary, I suppose there is perhaps one or two patients can fit into that but I would say the expectations should be that the data that we share in the IW and the patients for which we can share an IWG response, will all be from the escalations portion of the study..

Thank you. And our next question comes from the line of Eric Schmidt from Cowen and Company. Your line is now open..

Congrats on all the progress. Maybe another similar line of questioning around 285 and SM. I know you are going to be limited on what you can say, Jeff and Andy.

But I was hoping if you could give us a little bit more flavor for the type of data set that we are going to see in terms of number of patients either in the dose escalation and/or the three cohort expansions.

The duration of follow-up and it sounds like you might have patients across each of those three cohort expansions, is that correct?.

It's Andy. Eric, I will take that. So we prefer to present the data and you will see it soon at the end of the year and we don’t plan to get into a lot of detail about what it will look like.

But just to reiterate, the focus is definitely on the updated, both activity including IWG response criteria as Jeff said and safety on the escalation part of the study. And available data from the expansion part of the study and we will present as off they are and as we think there is sufficient information to refer to.

But I guess I do ask you to wait for the presentation for the details..

Okay. Maybe another forward looking question on the RET inhibitor. Andy, can you give us a sense of enrollment is going? What cohorts you might be up to and when we might see data there? Thank you..

Yes. So I will say this, it's accruing as anticipated and we do expect to share data in the first half of 2018 next year. Our preference has always been to share Phase 1 data after we have results available across a range of dose levels and in enough patients to make meaningful statements about safety and potential activity.

So, again, we will update you when we have a bit more say..

Thank you. And our next question comes from the line of Laura Chico from Raymond James. Your line is now open..

This is Sarah Frank on for Laura Chico. So now that you guys are progressing with the ALK2 program. Could you talk a little bit further about what you have seen in the data that’s compelling and also how do you think about the competitive landscape and what you all need to demonstrate in terms of clinical efficacy. Thank you..

Thanks, Sarah. This is Jeff. I will take the first portion of that question and then I will have Marion talk a bit about the competitive landscape.

So, obviously, we have just been going through the process of unwinding the collaboration with Alexion and really encouraged by how smoothly that went and the fact that we are now in a position where we can just evaluate the program as any other wholly-owned Blueprint program.

In terms of what we have seen to date or a stage we have not provided any updates similar to other Blueprint programs historically. What we will look to do is provide a more comprehensive update at a scientific conference as we move the program forward. So giving more detail at this time feel preliminary.

And maybe the competitive landscape, Marion?.

Yes. I just to reiterate. I mean FOP is a rare genetic disease whose underlying cause is an abnormally activated kinase and as such, a great match with Blueprint's strength in kinase discovery in genetically defined diseases. Our strategy is to develop a candidate that selectively targets the ALK2 kinase, the underlying cause of FOP.

And given the central role that the ALK2 kinase plays in this disease, we believe that ALK2 inhibition has the potential to be truly transformative for patients. The current clinical stage approaches in development use alternate mechanisms.

Clementia is pursuing retinoic acid receptor gamma agonist which will modulate the differentiation of [contracytes] [ph] to bone and Regeneron is pursuing an antibody against one of the many ligands of ALK2.

So we feel that our approached to go after the driver of the disease really has a great potential and is differentiated enough from the existing trials or agents in trials..

Okay.

Can I squeeze one more? Can you confirm if the advanced SM data for BLU-285 will be released at ASH?.

This is Jeff. We cannot confirm that. We will present data, we will share data by the end of this year..

Thank you. And our next question comes from the line of Dane Leone from BTIG. Your line is now open..

So I guess on FOP, I think, I know what we are trying to get out is understanding your team. From the messaging today it sounds like you are very committed to developing something here.

I guess, a, is that correct versus just evaluating it in October, taking the program back from Alexion and understanding where the progressing is where it currently sits. And then b, you have three people kind of going after this market.

As you just outlined, how large of a market opportunity do you think FOP is? I think from a lot of our understanding, it's a pretty rare disorder, so I think a lot of us trying to understand the ROI from going down that road.

And then I have one follow up that’s I guess maybe a little bit more boring, but you did talk about wrapping some late stage efforts for a number of the programs that are moving into later clinical efforts.

I was just wondering if you could give us a few more details in terms of infrastructure you are actually putting in place and what we should expect going into 2018 about commercial clinical manufacturing and other facets of the company that you guys are building up. Thank you..

So this is Jeff. I will take the first option and then maybe I will parse your question into three different parts and pass it along to the other members of the team here. So your first portion question went to our internal enthusiasm for the ALK2 program. And I guess I would say, yes, you characterize that correctly.

This has been a program from very early days that we at Blueprint Medicines were enthusiastic about.

The notion of identifying a kinase driver of disease, in a rare genetic disease, is certainly a rare opportunity and as we advanced that program along with Alexion and increasingly because confident that we could create a highly selective and potent ALK2 inhibitor, that enthusiasm has grown.

Now as within the other preclinical program, there are risks along the way and I have often talked about on past calls that part of our team's job is to stop programs or slow programs when appropriate.

So there are still those hurdles with this program as with any other Blueprint program that we always think about what's the next study, what's the next experiment that we can do to stop a program. So this one is no different.

But at this moment, we think it's a really unique opportunity and we feel quite fortunate to have had the unwinding of the Alexion of the agreement take place over the last couple of months.

Maybe, Marion you want to hit the competitive landscape again?.

Yes. As I mentioned earlier, I mean we feel our approach to after the underlying cause of this disease which is the kinase mutated in ALK2 has the potential to have a truly transformative potential.

And we feel that compared to the other approaches, we have differentiated enough compared to Clementia that is pursuing RA gamma agonist approach that enters much later in the disease process.

And compared to Regeneron whose approach is a little bit more similar to ours but is targeting it from a different angle and going after one of many ligands of ALK2..

Yes. And this is Jeff, maybe I will just add that any time you have a differentiated approach, regardless of the size of the opportunity, if we think we have the opportunity to have a transformative impact on the disease, we will take that program forward.

As our lead biologist on this program often talks about FOP is a catastrophic disease and if we can have a positive impact or a role whether complementary to those other programs or differentiated from those programs, we think that’s a opportunity worth pursuing if we have got chemical matter and a sound biological rationale to progress.

And maybe, Mike, I will have you take the third portion of the question which is the ramping up activities..

Yes. Just across the portfolio as molecules advance, I think we are now taking steps in a particularly, to continue to build out the clinical organization as we gear up for the Phase 3 trial in third line GIST which we expect to initiate the first part of next year.

And then with the manufacturing organization as well, we are increasingly planning not just for clinical supply but also for commercial supply. So starting to look at registration stability batches and in the future initiation of commercial validation batches. And so that is where we are kind of focusing a lot of in the infrastructure build.

And then on the commercial side, we are kind of in the pre-commercial planning phases as we begin to assess what the organizations look like as we move forward..

Thank you. And our next question comes from the line of Carmen Augustine from Jefferies. Your line is now open..

So there was some data from a competitive RET program earlier this month. I was curious if you have any views on the dataset despite it being kind of a small cut of data in terms of read through to the 667 program..

This is Jeff. Maybe I will take the initial stab at the question and then ask Andy to add color. But, obviously, we saw the data, it was not surprising to us. We think the notion of developing a highly selective and potent RET inhibitor ought to confer a benefit to patients, in the study patient population.

The approach is very similar to what we have done. So in terms of read through, I think that’s always challenging from our perspective is that the rationale for why we always announce [partly] [ph] when starting trials that we want to have a sufficient amount of data in the way we define it, whether right or wrong.

It's completing 20 plus patients, so you can start to get a sense of safety and efficacy. We think that’s still appropriate for Blueprint Medicines and we will look forward to sharing that data in the first half of next year..

Okay. Thanks. And then just another quick one. Do you have any updated thoughts around pursuing into an SM indication for BLU-285. Thanks..

Sure.

Andy, why don’t you take that question?.

Yes. So we remain very interested in pursuing into an SM or earliest evaluating into an SM with BLU-285. As we showed at ASH last year and we are very encouraged by the activity with BLU-285.

Really the first two dose levels, both in terms of bone marrow and mast cell reductions and tryptase reductions, as well as evidence of clinical improvements in the setting of a very good safety profile. So we think that really opens the door potentially for developing BLU-285 both in advanced disease but also in the more [indiscernible] population.

And we have been, over the course of the year we have been very actively pursuing those leads.

We have a mastocytosis patient registry and we continue to get a lot of very important data from that registry particularly regarding impact of ISM on patients and this helps us think about potentially regulatory endpoints because it's all about symptoms and impact on patients' lives, really what you get from registry in many ways.

Better than from lab tests. We have been working over the last few months with external collaborators to develop an indolent systemic mastocytosis specific patient reported outcome tool. We think that something like that will likely end up being a primary endpoint in a study in indolent mastocytosis. So we are actively developing that.

And we have been meeting with clinicians over the past month to care for these patients. A bit of a different group than we typically work. These are usually allergists and dermatologists and they have been helping us develop, we think we will be a pretty good protocol for evaluating 285 in the disease.

And certainly when we update in our ongoing advanced SM study later this year, we will provide more information regarding plans for ISM..

Thank you. And our next question comes from the line of Mike King from JMP Securities. Your line is now open..

Most of my questions have been answered.

Jeff, I may have missed it, but have you said what your strategy is going to be for the first line PDGFRα patients with GIST?.

This is Jeff. We have communicated that previously our path forward with PDGFRα was based on the back of receiving FDA breakthrough designation and then coming to agreement on a potential registration path forward in that patient population.

So we expanded our current Phase 1 study, the expansion arm to 50 patients there and we believe that that dataset, if the data matures in the way consistent with what we have shared previously, most recently at ASCO and at the upcoming CTOS conference next week, that that could form the basis of a registration in the front line setting of PDGFRα driven GIST..

Okay. I am sorry, I misunderstood. I though the CTOS was going to be in the relapse refractory KIT population.

Correct?.

So recall that the study, it's a single study. There are two arms in the phase. The PDGFRα arm and then the KIT refractory arm which requires matnib and at least one other TKI. So the data that we will share will be an update of both of those arms.

As we moved into -- if you recall, we had started the expansion phase of that study in March, so the time we shared data at ASCO was a limited data set. So this will be a more robust set of data from the early expansion phase of both arms of that study..

Okay. Great. And then just on the other programs that you de-prioritized.

Have you given any thought to potentially out-licensing those programs or will we never, they will never see light of day again?.

This is Jeff. So as Marion mentioned that we will look to make the data that we have in our learning to date available to collaborators and we certainly could explore opportunities with third parties but I think at this time we look at the therapeutic window in FLC in particular is quite narrow.

So unless there is additional learnings in those discussions with collaborators we learn something that expands the opportunity, I think that a partnership on that specific program would be unlikely..

[Operator Instructions] And our next question comes from the line of Arlinda Lee from Canaccord. Your line is now open..

I have a couple. On 285 with respect to additional indications, the presenting author for your ASH 16 suggested that there might be additional utility on some subsets of AML.

And I was curious if there are any plans for that?.

Arlinda, it's Andy. I will take that one. So, yes, as with all our compounds, we try to do a pretty broad, thorough search of potential indications even beyond the initial primary, what we see as the primary, quickest registration opportunity.

And with 285 we are looking broadly at other diseases that are potentially driven by KIT activated KIT, KIT expression, PDGFRα activation or expression. AML is a pretty interesting example.

There is a subset of AML that’s called core binding factor AML and I think it's about a quarter to a third of those cases actually contain activated mutations in KIT often in [indiscernible] 17. And so we are certainly talking to collaborators in some of our mastocytosis folks in particular who see these patients to think about paths forward.

Similarly, we are looking for other opportunities in PDGFRα diseases. I think we don’t have any specific plans. It would be premature to give you any specific details on what we will be doing there..

Okay. Great. Thanks. And then maybe a follow up on 285. Have you mentioned at ASCO that you were expecting completion of enrollment for the PDGFRα arm in mid-18.

I guess maybe we will get an update at CTOS next week but are you going to be providing an update on that?.

This is Jeff. So we are still on track to complete that in mid-'18, and I guess that is the update. You will see more of it at CTOS but that’s the update. We are still on track..

Okay. And then I guess the last question is maybe more strategic and maybe a little bit of a housekeeping question. I guess, a few of the [KOLs] [ph] were talking about that there is room for multiple players and given that it's competitor is doing a natural history study and you guys have been committed to being expeditious with your program.

I guess I am kind of curious what are your strategic plans in terms of moving this forward or moving it forward and then maybe getting a collaborator later on to help expedite the process. Just curios on your big picture thoughts for that..

So this is Jeff. I think that level of detail is premature. I think suffice to say, right now the ALK2 program has become like any other wholly-owned Blueprint program that we see the task at hand is to continue to evaluate the molecules we have pre-clinically and move into the clinic as quickly as possible.

And as with any other program, we will always think about the potential for partnering if we believe a partner brings expertise that could allow us to expand or accelerate that development..

Okay. And the just for clarification.

Are you guys still maintaining your goal of one new IND into the clinic or one new program into the clinic a year?.

Yes. So I don’t know if we continue to say it that way. I guess, I haven't said it that way since some time. What we continue to do is invest in our pipeline both in construct of newly or wholly-owned new programs that Marion alluded to. So one last year and again one this year.

As well as in the contract of collaboration, so most notably with the Roche collaboration where we have, we are working up to five targets. There is nothing that has slowed or narrowed our discovery efforts and if anything, as I think about this moment in time and the process we went through just to select this most recent program.

Perhaps the novel targets and discovery efforts are more robust than at any other time that I have been at Blueprint Medicines..

Thank you. And I am showing no further questions over the phone lines at this time. I would like to turn the call back over to Jeff Albers for closing remarks..

Thank you, operator. So I think about the opening statements and then the flow of questions that came through from all the analysts. There are really three things to take away from this call.

I would think about them as, one is, our research pipeline continues to grow and identify interesting targets that can make an impact in patient lives, specifically in genomically defined subsets of patients. Two, we will be sharing update data from BLU-285 in both GIST and systemic mastocytosis by year-end.

So we appreciate your patience in waiting till we provide those updates, to answer some of the questions that we heard.

And that third, we continue to operate from a very strong position that allows us to accelerate or de-prioritize programs in a way that we think is, which is a long term development of Blueprint Medicines and allows us to work on programs in a very responsible, financially responsible manner.

So with that, I want to thank you all again for your continued support and interest in the Blueprint story and we look forward to providing you with an update again very soon. Thanks for your time and have a great day. Bye, bye..

Ladies and gentlemen, thank you for your participation in today's conference. This concludes the program and you may now disconnect. Everyone have a great day..