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Editas Medicine, Inc. (EDIT -3.74%)
Q1Â 2019 Earnings Call
May. 7, 2019, 5:00 p.m. ET
Contents:
- Prepared Remarks
- Questions and Answers
- Call Participants
Prepared Remarks:
Operator
Good afternoon, and welcome to Editas Medicine's First Quarter 2019 Conference Call. All participants are now in listen-only mode. There will be a question-and-answer session at the end of this call. Please be advised that this call is being recorded at the company's request.
I would now like to turn the call over to Mark Mullikin, Vice President of Finance and Investor Relations at Editas Medicine.
Mark Mullikin -- Vice President of Finance and Investor Relations
Thank you, operator. Good afternoon, everyone, and welcome to our first quarter 2019 conference call. Shortly after the market closed, we issued a press release providing our financial results and corporate updates for the first quarter of 2019. A replay of today's call will be available on the Investors & Media section of our website approximately two hours after its completion. After our prepared remarks, we will open the call for Q&A.
As a reminder, various remarks that we make during this call about the company's future expectations, plans, and prospects constitute forward-looking statements for purposes of the Safe Harbor provisions under the Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including those discussed in the Risk Factors section of our most recent quarterly report on Form 10-Q, which is on file with the SEC.
In addition, any forward-looking statements 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, even if our views change.
Now, I will turn the call over to our Interim Chief Executive Officer, Cindy Collins.
Cindy Collins -- Interim Chief Executive Officer
Thanks Mark. Good afternoon everyone, and thanks for joining us for our first quarter 2019 corporate update. In addition to Mark, I'm joined today by several members of our executive team, including Charlie Albright, our Chief Scientific Officer; Vic Myer, our Chief Technology Officer; Eric Ek, our Interim Chief Financial Officer; and Tim Hunt, our Senior Vice President of Corporate Affairs.
Thanks to the hard work of our dedicated team of Editas. 2019 is off to a strong start with tangible progress on several of the goals we outlined on our last call. In the first quarter, we expanded and accelerated our development of universal allogeneic cell medicines for cancer through a newly formed collaboration with BlueRock Therapeutics.
We initiated IND-enabling activities for a potentially best-in-class medicines for sickle cell disease and beta-thalassemia. And we made progress in collaboration with our partner, Allergan toward dosing patients with Edit-101 for LCA10 in the second half of the year. Edit-101 is the first in vivo CRISPR medicine approved for human dosing and represents the translation of years of clinical research and scientific advancement into a potentially transformative treatment for patients. We are confident and we are at a tough stands today, capitalizing on the strong start to the year and anticipating numerous upcoming milestones.
Now let me turn the call over to our Chief Scientific Officer, Charlie Albright to discuss our pipeline in greater detail.
Charlie Albright -- Chief Scientific Officer
Thanks, Cindy. It is a great time for the company and I'm happy to be here to update you on our pipeline of transformative genomic medicines.
Let's start with our development of engineered cell medicines. We are excited to begin work with BlueRock Therapeutics to develop universal allogeneic cell medicines to treat cancer using the complementary technologies of CRISPR gene editing and induced pluripotent stem cell. In particular, gene-edited iPSC derived, allogeneic cell medicines represent truly universal, off-the-shelf treatments that can be mass produced with superior quality, greater scale and lower cost than autologous or donor-derived therapies. Further, we believe that the highly edited medicines will be possible with iPSC-derived cell will be required to unlock the full potential of cellular medicines, particularly in solid tumors are the greatest unmet need exist.
The combination of our unparalleled CRISPR gene editing platform and BlueRock's expertise in stem cell development of differentiation brings together two leaders in their respective fields. In this collaboration, we retain rights to edited cells develop for the use in the field of oncology, including T-cells, NK-cells, macrophages and other immune effector cell.
The technological complementarity distinct therapeutic areas of focus desire for collaboration make BlueRock a great partner, we look forward to productive collaboration. The BlueRock collaboration builds on our existing efforts in oncology. In particular, we have wholly owned efforts in NK-cells in a partnership with Celgene for engineered T-cell medicines for solid tumors and hematologic malignancies. Our work with Celgene and BlueRock are the two examples of how we are expanding and accelerate our oncology cell medicine platform, as we look to drive the next-generation cancer therapies.
We've also made significant progress toward developing an engineered cell medicine for sickle cell disease and beta-thalassemia. We believe we have a potentially best-in-class treatment for the severe diseases utilizing CRISPR to edit the beta-globin locus. This editing directly increases fetal hemoglobin and it's differentiated from others that targets the BCL11A enhancer site that indirectly upregulate fetal hemoglobin.
In December, we presented data at the American Society of Hematology demonstrating some of the reasons, we believe we can develop a superior medicine. Since that time, we have -- our confidence has continued to build, based on our work. We have finalized the design of the clinical candidate and started IND-enabling activities with an experimental medicines. We look forward to providing updates on medical conferences through the remainder of the year.
Now transitioning to our in vivo CRISPR medicines, our lead program Edit-101 for LCA10 is poised to be the first in vivo CRISPR medicine administered patients in history. The partnership with Allergan, we are conducting an open label dose escalation study to evaluate the safety and efficacy of Edit-101, in approximately 18 patients in the U.S. and Europe.
We remain on track to screen patients mid-year and dose in the second half. Concurrently our natural history study of LCA10 patients is ongoing. The natural history study helps us identify clinical endpoint measures, while also serving to strengthen ties to ophthalmology centers of excellence and introduce Editas to the liver patient community. Initial data were presented by the principal investigator, Dr. Eric Pierce of Massachusetts Eye and Ear at the Retinal Cell and Gene Therapy Innovation Summit last week.
Following Edit-101, we are advancing additional genomic medicines for serious ocular diseases, starting with Usher syndrome 2A or USH2. Our development of USH2 built-in the work we've done with the LCA10 program. Like LCA10, USH2 is a genetic disease that affects ciliary proteins and photoreceptors.
In vivo (inaudible) have been promising and we are developing a treatment Usher patients that leverages the same AAV vector, promoter and Cas9 enzyme as for Edit-101. In particular, USH2A medicine differs only in the guide RNAs specific to the USH2A gene and represents the power of our platform to accelerate the development.
Our academic collaborators from Massachusetts Eye and Ear presented preclinical in vivo proof-of-concept of our approach last week at the American Society of Gene and Cell Therapy Annual Meeting. In this work, the researchers demonstrated the CRISPR gene editing of exon 13 of the human USH2A gene can rescue the retinal phenotype and restore auditory function in a mouse model. Based on this data, we are optimizing a lead candidate are on track to be ready for IND-enabling studies this year.
Our ocular programs are the most advanced programs within our in vivo pipeline and we look forward to expanding efforts in additional therapeutic areas, that leverage this work. Our industry-leading platform including our exclusive access to Staph aureus Cas9, an extensive capabilities translating science into treatments for patients makes us enthusiastic about the potential to target additional genetic diseases.
Now let me turn the call over to our Interim Chief Financial Officer, Eric Ek to discuss our progress in building the business and review our financial results.
Eric Ek -- Chief Financial Officer
Thanks, Charlie. It's my pleasure to update you on key developments we have had over the past quarter and to summarize the financial results we are reporting today.
As Charlie mentioned, we have formed a research collaboration and entered into a non-exclusive cross license agreement with BlueRock Therapeutics. In each of their respective fields, Editas medicine gains non-exclusive rights to BlueRock's iPSC and cell differentiation technology and intellectual property, while BlueRock gains non-exclusive rights to Editas medicines, CRISPR technology and intellectual property. Each party is responsible for the payment of milestones and royalties to the respective partner for any licensed engineered cell medicine developed in their respective field.
Turning to the numbers, we summarized our financial results for the first quarter in the press release that we issued an hour ago and full details will be available in our Form 10-Q. Our cash, cash equivalents and marketable securities decreased $27 million in the first quarter to $342 million, as of March 31, 2019, from $369 million as of December 31, 2018. Our uses of cash totaled $30 million and include cash operating expenses of $29 million and capital expenditures of $1 million.
Key non-cash items recorded in our income statement include $8 million of stock-based compensation, $1 million of depreciation and a $5 million increase in our working capital. Our sources of cash totaled $3 million and consisted of $1 million of interest income and $2 million of stock option exercises by our employees. We believe our cash, cash equivalents and marketable securities of $342 million as of March 31, 2019, provides at least 24 months of capital to fund our business.
And with that, I will hand it back to Cindy.
Cindy Collins -- Interim Chief Executive Officer
Thank you, Eric. As part of our EM22 long range goals, we talk openly about our Inspiritas culture at Editas Medicine. In Q1, we marked progress on EM22 by rolling out what we call our elements of Inspiritas, which is an initiative to highlight and shape the outstanding culture we have here at Editas. We will talk more about our elements of Inspiritas in the future, but in short Inspiritas captures Editas at its best, a place where revolutionary finance happens daily and our employees, editors are driven to tackle yet unfold medical challenges, while being part of a community working for the common goal of serving patients.
At Editas, it is truly an exciting time for the company. We are on the verge of treating the first patient ever with an in vivo CRISPR gene-editing medicine. We are advancing best-in-class medicines that may revolutionize the treatment of cancers, sickle cell disease and other serious intractable diseases. And we are working to further extend the reach of gene-editing, as we tackle new indication, explore new targets and expand our platform to deliver on the promise of CRISPR technology.
We look forward to continuing to forge this journey in partnership with the broader community, patients, clinicians, employees and investors.
With that, we thank all of you for your interest and support and are happy to take your questions. Operator?
Questions and Answers:
Operator
(Operator Instructions) Our first question comes from the line of Amanda Murphy with William Blair. Your line is now open.
Amanda Murphy -- William Blair -- Analyst
Hi, good afternoon. First I had a few on the BlueRock collaboration iPSC in general. I guess, just starting out with BlueRock, not sure if you can share or how much you can share. I was just curious sort of why you selected them and what they bring to the table, specifically in terms of reprograming and building a cell line if you will?
Charlie Albright -- Chief Scientific Officer
Sure, Amanda. This is Charlie. So, we with BlueRock was going to be a great partner and we just had the kickoff meeting yesterday and are really excited about it. They bring both proprietary and non-proprietary research really with how to take the differentiated cells and iPSCs. It's an incredibly complementary partnership, because we're interested in oncology and they're interested in cardiovascular, neurology and immunosuppressive mechanisms. And so, and we think the two technologies of gene-editing and iPSC derived cells are really kind of create a powerful partnership.
Amanda Murphy -- William Blair -- Analyst
And then I'm not going to ask your timing or anything like that. But it is the right way to think about any candidates that emerged from the partnership is more of a longer term part of the pipeline? And then thinking about you mentioned solid tumors, but also that I think it's also covers heme. So, would you consider going after some low-hanging fruit initially with, some of heme cancers or how should we think about the evolution?
Charlie Albright -- Chief Scientific Officer
Yeah. We have rights to all oncology indications and all cell types, which is really powerful. So, we obviously have some ideas about what we're going to do here. We haven't shared them more broadly and yes, all the things you mentioned are on the table. I do also say that all cell types focus on oncology on the table as well. So, that's part of the reason we're really thrilled with the deal, because it really gives us the ability to work broadly in the space that around, which we're trying to build the business.
Amanda Murphy -- William Blair -- Analyst
Again and just last one. I think you mentioned it was not exclusive, so I just with curious if you had thought about exclusivity just on both sides in iPSC's and then with CRISPR from your side?
Charlie Albright -- Chief Scientific Officer
We decided to do a non-exclusive deal, I think I said both parties, the option to go and work with additional parties in our field of interest, which I think is also quite powerful. All part of what we thought it was a great deal.
Amanda Murphy -- William Blair -- Analyst
Got it. Okay, thanks very much.
Operator
Our next question comes from the line of Matthew Harrison with Morgan Stanley. Your line is now open.
Connor Meehan -- Morgan Stanley & Co. -- Analyst
Hi, everyone, thanks for taking my question. This is Connor Meehan on for Matthew Harrison. We're just looking to hear a little bit about your sickle cell approach and sort of what you guys think differentiates your program clinically? And then just a quick follow up afterwards.
Charlie Albright -- Chief Scientific Officer
Sure. We have two bases for differentiation. One of them, we discussed at length at the ASH meeting, American Society of Hematology Meeting last December and we were awarded one of the best in ASH hosters for the work. And so that, in that study, we showed that cells edited at the beta-globin locus, which is where we're editing reconstitute the hemato -- the erythroid lineage normally.
In contrast cells edited as BCL11A enhancer locus, which is what all of our competitors are doing had a significant decrease in the cells for erythroid lineage in mice. Obviously if this translated into humans, this could be a significant safety and efficacy issues. So, that's the first basis for differentiation. That the slides and related items to that can be found on our website and we're happy to go into more details somewhat complicated story.
And then we're also excited about the amount of fetal hemoglobin we can induce. We'll be having more to say about that in upcoming scientific meetings later this year. That's obviously also key to driving the efficacy of the product.
Connor Meehan -- Morgan Stanley & Co. -- Analyst
Got it. Thank you. I will definitely follow-up with some the PowerPoints on your website. Would be possible to just comment quickly on IND-enabling steps, you guys need to take. And I guess maybe a quick comment on the expected duration as well.
Charlie Albright -- Chief Scientific Officer
We haven't provided guidance on the timing. And I think it's like as usual the IND-enabling activities are not atypical and to put it in a positive way, they're typical for a cell-based medicine in this field and we'll obviously be discussing those with regulators along the way to make sure that we're all happy about those.
Connor Meehan -- Morgan Stanley & Co. -- Analyst
Thank you.
Operator
Our next question comes from the line of Steven Seedhouse with Raymond James. Your line is now open.
Steven Seedhouse -- Raymond James -- Analyst
Hi, great thank you. So, I know there's a lot of features of Edit-101 that can be leveraged in USH2A and other eye indications. But how much of the know-how and tools that you developed are applicable to non-rental programs? How much time, could you save on subsequent on non-retinal indications?
Charlie Albright -- Chief Scientific Officer
I think a much of what we learned with that Edit-101 is going to be useful in other in vivo editing indication. So, we do think AAV delivery in general is the, it's a preferred way to deliver these agents. And the work we've done with that Edit-101 enable that. So, you probably realize, we have exclusive access to Staph aureus Cas9, which allows us to make an all in one AAV with two guide RNAs. That's unique to Editas and we are obviously going to take that learnings.
And so basically, we believe, anywhere where you can deliver AAV, we're going to be able to deliver the editing machinery and so we are in the process of evaluating other indications that where the unmet need in the other aspects of disease selection makes sense, and we'll have more about to say about that in the future.
Steven Seedhouse -- Raymond James -- Analyst
Okay, thanks. And then, Charlie, regarding the sickle cell and beta-thal program. So, given what you just mentioned you presented at ASH last year regarding BCL11A versus beta-globin locus. I think if I'm remembering correct that was sort of a single time point that you showed. I'm curious what happens over time in the mice?
Does the proportion of edited cells those are fetal hemoglobin fraction decrease over time after engraftment and is it any different, when you edit at the beta-globin locus?
Connor Meehan -- Morgan Stanley & Co. -- Analyst
It's -- we had, I think we presented data from both 8 weeks and 16 weeks last year. And 16 weeks is kind of the standard time, where things have reached a steady state and so the -- and there were marked differences at both time points between editing into BCL11A enhancer and editing at the beta-globin locus. I can't recall there was a difference between 8 weeks and 16 weeks on either one of them.
Steven Seedhouse -- Raymond James -- Analyst
Okay. And the data presentation that you have this year for the hemoglobinopathy program, is that more data comparing these methods? Or is it some other experiments?
Charlie Albright -- Chief Scientific Officer
We're actually in the process of figuring that out right now.
Steven Seedhouse -- Raymond James -- Analyst
Okay, thanks. One quick question on the BlueRock collaboration. Is this basically a way to regain sort of more favorable economics on an allogeneic CAR-T platform? Is that a fair way to characterize the deal?
Charlie Albright -- Chief Scientific Officer
Right now, as part of our Celgene relationship, we're not allowed to work on T-cells and engineered T-cells in oncology. We are allowed to work on non-T-cells in oncology. And so that could be a way to think about things in the short run. And we have indicated that we're interested in NK-cells. And I think in the long run, our interests are obviously broader.
Steven Seedhouse -- Raymond James -- Analyst
Okay. So, you're not able to develop CAR-T as part of that, BlueRock collaboration what you say?
Charlie Albright -- Chief Scientific Officer
Not as long as we had -- because the current relationship with Celgene is intact and that research portion of that expires in May 2020.
Steven Seedhouse -- Raymond James -- Analyst
Understood. Okay, thank you. And one last question. I just wanted to ask about going back to the mouse studies of Edit-101 in the LCA10 preclinical model. So, this is in the Nature Medicine publication, but also like for example you presented at the ASGCT recently. You get about 20% as I think just above within 8 weeks and then it doesn't increase of anything it drops back down to about 10% over time out to week 40. I'm just curious, is there turnover or you know decline of the actual sales that have been edited? Are they going dying turning over in the odd?
Charlie Albright -- Chief Scientific Officer
No. We have no evidence of that and we don't think there is a decrease between the time points you mentioned. And it's also important that's, that editing is not corrected for the frequency of the retina that was transduced. So, that really -- if you look at the dose response curve from that last presentation that leveled off at 50% productive editing, which is essentially the maximum you can get it and we think it gets there and then stays there.
Steven Seedhouse -- Raymond James -- Analyst
Okay. Appreciate that. All right, thank you. Thanks for taking my questions.
Charlie Albright -- Chief Scientific Officer
Sure.
Operator
Our next question comes from line of Phil Nadeau with Cowen & Company. Your line is now open.
Phil Nadeau -- Cowen & Company -- Analyst
Good afternoon. Thanks for taking my question. I apologize for background noise. First, on the natural history study in a LCA, can you talk about how that study dovetails with your efforts in your clinical trial? Is it possible that you can use that study to identify patients and speed the screening portion of the study along?
that you can use that study to identify patients and speed the -- portion of the study along.
Charlie Albright -- Chief Scientific Officer
Yes, is the short answer. So, that study does several things for us. It gives us familiarity with the scales, it helps to set up the sites. It's essentially the sites are being used in the natural history study or the same sites that -- many of the same sites that will be used in the interventional study and they'll be patients that are enrolling in the natural history study. We obviously -- it's their decision in consultation with their primary care physician as to what they -- would they enroll in the interventional study or not, but clearly they'll have familiarity with the -- with both the site and the study and then they can make their own informed decision.
Phil Nadeau -- Cowen & Company -- Analyst
That's helpful. Then second, a follow-up question on the Celgene collaboration. Do you have any visibility into Bristol-Myers desire to continue that collaboration? Or maybe more broadly, is there any update on the progress of the collaboration toward the clinic?
Charlie Albright -- Chief Scientific Officer
We have -- we can only say a limited things now that we are -- that the collaboration is part of Celgene, as you can appreciate with a larger pharma partner there, interest in disclosure is not the same as our -- as it was with which you know. All we know is what's been stated publicly, which was that the cell-based medicines part of the Celgene acquisition is an important part of the DMS strategy going forward and their efforts, and particularly in liquid tumors synergizes very nicely with the BMS' focus on solid tumors.
And I think it's from the outside I think it represents a very interesting merger of two complementary portfolios, both of which have a large focus on oncology. So, for those reasons, we're optimistic that the merger actually will bring good things with respect to the collaboration.
Phil Nadeau -- Cowen & Company -- Analyst
And any sense of timing, when we could see IND-enabling studies?
Charlie Albright -- Chief Scientific Officer
We can't say anything at this point.
Phil Nadeau -- Cowen & Company -- Analyst
Fair enough. Thanks for taking my question.
Charlie Albright -- Chief Scientific Officer
Sure.
Operator
Our next question comes from the line of Gena Wang with Barclays. Your line is now open.
Xiaobin Gao -- Barclays Capital -- Analyst
Hey, this is Xiaobin Gao for Gena. Thank you so much for taking our questions. Maybe just a follow-up on the Edit-101 question. And with the natural history data, would you be able to refine more about the enrollment criteria regarding like patient age or visual acuity?
And then that second question would be just what additional step are you taking so to activite the size? And then last one, it's based on the kinetics of the gene-editing, what do you sort of speculate on the timeline that we can see initial efficacy?
Charlie Albright -- Chief Scientific Officer
Let me start with the last question and then, I'm not sure I got the second one and I'll hit the natural history one. So, in mice and non-human primate, editing was completed in 6 weeks. The after editing, you need to reexpress the CEP290 method, the CEP290 protein and rebuild the outer segments. We believe that will be sufficient to allow light to be detected, and then from that you need to activate the visual pathways to establish vision. So, that there's a good reason to believe that we could potential -- patients could potentially see benefit in a few months, is the answer.
When we will disclose clinical data, which is probably what you're actually want to know is an entirely different question, and that will depend very much on the results we see in our consultations with our collaborators, Allergan.
The natural history study will potentially led us to refine both entry criteria and the endpoints that we look at in the patient group, that's all part of -- was all part of the objectives of running a natural history study. And so, yes, it has the potential to alter that. I won't sure I caught the middle question.
Xiaobin Gao -- Barclays Capital -- Analyst
Yeah, just more asking about sort of what left to start the clinical to dose for the first patient is that part of the site activation?
Charlie Albright -- Chief Scientific Officer
Right. And so all the usual things to activate the site IRB approval, institutional safety approval, delivering the drug product to the site. We plan to enroll patients in the middle of the year. So, we're virtually -- in the middle of the year based on that our definition of second and third quarter. And so will start enrolling patients and then somewhat in the second half of the year.
Xiaobin Gao -- Barclays Capital -- Analyst
Got it. Thank you.
Operator
Our next question comes from the line of Cory Kasimov with JP Morgan. Your line is now open.
Matthew Holt -- JP Morgan -- Analyst
Hi guys, thanks for taking my questions. And this is Matthew on for Cory. So, the first one I wanted to follow-up on the previous questions for your sickle cell disease and beta cell program. In referring to as best-in-class, can you expand on that a little bit, especially as it compares to non-gene editing approaches. Basically, I'm wondering if you're confident here is mostly based on fetal hemoglobin levels.
Charlie Albright -- Chief Scientific Officer
Yes. And so it's a little bit hard to do that comparison with -- in the database, where they were willing to disclose at this point, because your -- it basically you're doing different things. The gene therapy approaches, you have what I mean by that is, in the gene therapy approaches you are expressing beta globin, but it has to outcompete the endogenous sickle beta globin. And so, it's actually not clear how that competitions going to go.
In our case, we're actually doing two things. We're turning on fetal hemoglobin and we're turning off the sickle globin. So, doing that pharmacologic comparison is actually quite challenging, suffice it to say that, that we do believe that the combination of what we're doing is, has the potential to be best-in-class and part of that as well, is based on the human genetics. As you recall, the patients with elevated levels of fetal hemoglobin can reach a available fetal hemoglobin and actually suppresses the sickle cell symptoms. And so this is the mechanism that the nature has taught us kind of actually rescue the disease.
Matthew Holt -- JP Morgan -- Analyst
Got it. And then I guess just based on what you just said, what's your like broad level strategy to demonstrate this clinically?
Charlie Albright -- Chief Scientific Officer
We're going to go into patients and fetal hemoglobin levels and symptoms that come from that.
Matthew Holt -- JP Morgan -- Analyst
Got it. And then just one follow-up. Can you provide an update to the CEO search.
Cindy Collins -- Interim Chief Executive Officer
Sure. Our researches are well under way and we're really looking forward to hiring excellent executives to help us lead the company through the next phase of growth as we move into the clinic. So, no comment on timing, we will update you when the timing is right, but those searches are quite active at this point.
Matthew Holt -- JP Morgan -- Analyst
Great. Thanks for taking my questions.
Operator
Our next question comes from the line of Peter Lawson with SunTrust Robinson Humphrey. Your line is now open.
Peter Lawson -- SunTrust Robinson Humphrey -- Analyst
Hi, thanks for taking my questions. Just on LCA10, how long, should we think about the period, it takes to identify screen and dose the patients? And then if any of the patients are on the natural history consented to be part of the interventional study?
Charlie Albright -- Chief Scientific Officer
We can't comment on whether anybody, you basically asking anybody's enrolled yes, we can't comment on that. Clearly, we hope and believe that the natural history study will aid in the enrollment in the LCA10 interventional study. As with any Phase I gene therapy like study, there will be an interval between dosing the first patient and dosing subsequent patients and.
And we haven't provided the details for that. I would just say these are typical intervals of the gene therapy development space right now.
Peter Lawson -- SunTrust Robinson Humphrey -- Analyst
That's it. Thank you. And then just on the number of sites this is rollover from the natural history study, but how many sites do you have and how many others, would you add? And what's the timing around that?
Charlie Albright -- Chief Scientific Officer
Yeah, we have four sites in the U.S. and three sites in Europe is my recollection. You guys are testing my memory of all the numbers today. And we have an IND approved right now. So, the sites in the U.S. will be open first, and we feel those will be sufficient to get us well started on the clinical trial, and we'll work on opening Europe and the European sites, because we do believe we need in the long run the patients from the Europe. But we're good in the short run.
Peter Lawson -- SunTrust Robinson Humphrey -- Analyst
Got you. Thank you. And then, when do you think you could start the sickle cell trial?
Charlie Albright -- Chief Scientific Officer
We haven't provided that guidance yet, but you'll be the first one I'll call, Peter.
Peter Lawson -- SunTrust Robinson Humphrey -- Analyst
Thank you and take care.
Operator
(Operator Instructions) Our next question comes from the line of Whitney Ijem with Guggenheim Securities. Your line is now open.
Whitney Ijem -- Guggenheim Securities -- Analyst
Hi, this is Whitney. Thanks for taking the questions. Well, actually just one. So, on USH2A, you mentioned that there some additional optimization ongoing there. So, wondering is, sorry if I missed it, but wondering if you can give us any color on the optimization that you're working through?
Charlie Albright -- Chief Scientific Officer
Actually, there is nothing, nothing unusual of that . We're finishing up the pharmacology package that supports the nomination of a development candidate, which will put us in a position to be the IND -- ready for IND-enabling studies at the end of the year. So, we're on track for that.
Whitney Ijem -- Guggenheim Securities -- Analyst
Okay. Got it, thanks.
Operator
And I'm showing no further questions in queue at this time, I'd like to turn the call back to Cindy Collins for closing remarks.
Cindy Collins -- Interim Chief Executive Officer
Great. So with that, we thank all of you for participating in today's call and for your support, as we work to bring transformative new medicines to patients. Have a great evening.
Operator
Ladies and gentlemen, this concludes today's presentation. Thank you once again for your participation. You may now disconnect.
Duration: 35 minutes
Call participants:
Mark Mullikin -- Vice President of Finance and Investor Relations
Cindy Collins -- Interim Chief Executive Officer
Charlie Albright -- Chief Scientific Officer
Eric Ek -- Chief Financial Officer
Amanda Murphy -- William Blair -- Analyst
Connor Meehan -- Morgan Stanley & Co. -- Analyst
Steven Seedhouse -- Raymond James -- Analyst
Phil Nadeau -- Cowen & Company -- Analyst
Xiaobin Gao -- Barclays Capital -- Analyst
Matthew Holt -- JP Morgan -- Analyst
Peter Lawson -- SunTrust Robinson Humphrey -- Analyst
Whitney Ijem -- Guggenheim Securities -- Analyst
