Good day, ladies and gentlemen, and welcome to the REGENXBIO Inc. Fourth Quarter 2016 Earnings Conference Call. [Operator Instructions] As a reminder this conference is being recorded. I would now like to turn the call over to Mr. Patrick Christmas, Senior Vice President and General Counsel for REGENXBIO. Sir, you may begin.

Good afternoon and thank you for joining us today. With us are Ken Mills, REGENXBIO's President and Chief Executive Officer, and Vit Vasista, our Chief Financial Officer. Earlier this afternoon, REGENXBIO released financial and operating results for the three months and full-year ended December 30, 2016. The press release reporting our financial results is available on our website at www.regenxbio.com. Today's conference call will include forward-looking statements regarding our financial outlook in addition to regulatory and product development plans. These forward-looking statements are subject to risks and uncertainties that may cause actual results to differ from those forecasted and can be identified by words such as expect, plan, will, may, anticipate, believe, should, intend and other words of similar meaning. Any such forward-looking statements are not guarantees of future performance and involve certain risks and uncertainties. These risks are described in the risk factors and the management discussion and analysis section of REGENXBIO's annual report on Form 10-K for the fiscal year ended December 31, 2016 which is one file with the Securities and Exchange Commission and available on the SEC's website. Any information we provide on this conference call is provided only as of the date of this call, March 7, 2017, and we undertake no obligation to update any forward-looking statements we may make on this call on account of new information, future events or otherwise. Please be advised that today's call is being recorded and webcast. In addition, any unaudited or pro forma financial information that maybe provided is preliminary and does not purport to project financial positions or operating results of the Company. Actual results may differ materially. I will now turn the call over to Ken Mills, President and Chief Executive Officer of REGENXBIO.

Thank you Patrick and good afternoon everyone, thanks for joining us today. On today's conference call, we’ll provide a recap of our progress over the past year and update on our development program and financial results for the fourth quarter and full-year 2016. We will also review anticipated milestones for REGENXBIO over the next 12 months and then open up the call for any questions. At REGENXBIO, our mission is to improve lives through the curative potential of gene therapy based on our proprietary NAV Technology Platform. We are deeply committed to supporting the patient communities we work with and are engaged with several patient advocacy organizations to better understand the needs of their communities. The unique perspectives of patients and advocates help guide our development programs and we strive to be viewed as a trusted credible partners in the community. Our gene therapy product candidates are designed to deliver genes to cells to address genetic defects or to enable cells in the body to produce therapeutic proteins that are intended to impacted disease. Through a single administration, our gene therapy product candidates are designed to provide long lasting effects potentially significantly altering the course of disease and delivering improved patient outcomes. Internally, we are advancing a pipeline of product candidates based on our NAV Technology Platform for retinal, metabolic and neurodegenerative diseases. Areas where we believe our gene delivery vectors are uniquely suited to impact specific mechanisms of diseases for patient populations with significant unmet medical needs. We also selectively licensed elements of NAV Technology Platform typically single vectors used in single indication to third-party companies in the gene therapy space who share our vision. Our NAV Technology Platform consists of over 100 novel adeno-associated viral vectors or AAV vectors for short, including AAV7, AAV8, AAV9 and AAVrh10. These…

Thank you Ken, REGENXBIO ended the year on December 31, 2016 with cash, cash equivalents and marketable securities totaling $159 million as compared to $216.4 million of as of December 31, 2015, a decrease of $57.4 million. Research and development expenses were $16.1 million and $45.5 million for the three months and year ended December 31, 2016 compared to $4.8 million and $17.3 million during the same periods in 2015. The increased R&D expenses in the 2016 periods were primarily due to increased research and development personal cost due to growth with headcount and increases in preclinical research and development, manufacturing and clinical trial expenses. General and administrative expenses were $5.7 million and $23.6 million for the three months and year ended December 31, 2016 compared to $4.2 million and $11.9 million during the same period in 2015. The increased G&A expenses were primarily due to the growth of the G&A organization in establishing the infrastructure to meet the requirements of a public company and our business objectives. Our net loss was $19.6 million and $63.0 million or $0.74 and $2.38 per basic and diluted common share for the three months and year ended December 31, 2016 respectively, compared to a net loss of $5.2 million and $22.8 million or $0.20 and $2.59 for basic and diluted common share for the three months and year ended December 31, 2015 respectively. As of December 31, 2016, we had 26.5 million common shares outstanding. REGENXBIO reiterates that it expects full-year 2017 cash burn to be between $75 million and $85 million. With that I will turn the call back to Mr. Mills to review our upcoming 2017 milestones.

Thank you, Mr. Vasista. We expect 2017 will be a pivotal year for the continued clinical advancement in validation of REGENXBIO’s internal and partner pipeline candidates. With the recent initiation of the Phase I/II for RGX-501 for HoFH and with the Phase I trial for RGX-314 for wet AMD on track for enrollment by mid-2017, we expect to report our first interim trial updates for each trial by the end of year. Additionally, as I noted earlier, we are on track to file the IND for RGX-111 in MPS 1 in the first half of this year and we expect to begin enrolment in the phase I/II trial in the second half of 2017. We are also on track to file our IND for RGX-121 for MPS 2 in mid-2017 and manufacturing the material to support the planned RGX-121 trial is ongoing. With our strong cash position, we look forward to executing on the upcoming milestones and providing you all with further updates on patient enrolment and clinical data this year. With that, I'd like to open up the call for questions. Operator?

[Operator Instructions] Our first question comes from Ying Huang of Bank of America Merrill Lynch. Your question please.

Hi. Thanks for taking my questions. Maybe Ken, my first question has to do with the protocol for the AMD program. I think you are excluding some patients with the baseline AAV neutralizing antibodies. Can you talk about the screen failure rate for the enrollment of that trial?

Hi, Ying. Yeah. Thanks for the question. So just to clarify on RGX-314, which is the Phase I clinical trial in wet AMD, we actually don't have an exclusion criteria based on neutralizing antibodies. So it's not typical in AAV studies that use sub retinal treatment to exclude patients on the basis of neutralizing antibodies. So that -

Well, I guess, I was referring to the AMD trial? I am sorry, the HoFH trial.

Okay. I’ve got you. So in RGX-501, that is an exclusion criteria on the basis of neutralizing antibody titers and I think that what we've seen in the screening and enrolment process Ying is what's consistent with our expectations with respect to the epidemiology data and so I think for the AAV8 vector, we would predict or expect that on the order of 20% to 25% of patients might have neutralizing antibody titers that would exclude them from this trial at this time.

Got it. And then another question on the, well, I guess on the AMD trial, because with AGTC trial, I think there was a prophylaxis measure to prevent inflammation. Are you going to use similar measures for the AMD trial for 314?

So I want to make sure, Ying, I understand. With respect to prophylaxis, not sure I entirely know the AGTC study that you're referring to, but the RGX-314 study involves a sub retinal route of administration. And I think that route of administration is consistent with studies that have been run by groups like Spark with respect to their RPE65 program and I don't know of the use of any prophylaxis treatment to treat any kind of observed events associated with that route as administration. So I think that's consistent with our clinical implementation for a sub retinal route of administration.

Got it. Thanks. And then maybe just if I could squeeze a last one. For example, if you look at some of your sublicensees in the data reported, sometimes you see variability. For example, the Hemophilia B data from Dimension. Do you have any insight on that, why sometimes you will see this kind of variability, and how would you I guess prevent that from happening in your own trial? Thanks.

Sure. We don't have much insight beyond what's publicly available with respect to other people studies including with the NAV technology platform. We do think that there have been a number of studies that have reported really good results with respect to safety and dose response in clinical studies. With respect to our own internal programs, I think having achieved the milestone of first patient dosing in the RGX-501 study, we're going to continue to support what's needed for all the patients in those studies and the physicians that we work with as well as the investigators at the sites are certainly putting patient care first and at this point, we're just happy to have reported the first patient dosing.

Thank you. Our next question comes from Gbola Amusa with Chardan. Your question please.

Hi. Thanks for taking my call. Ken, on RGX-314, I have a couple questions, and then a question on manufacturing after that. For 314, are you able to say whether the antibody fragment encoded for in that product is Ranibizumab, or can you say when disclosure on the fragment might occur? And then on that program, other than the obvious look at safety, is there anything we could see on efficacy by the end of the year potentially, that could provide some proof-of-concept on RGX-314? And then on manufacturing, as you transition to being a clinical company on multiple fronts, could you provide a broad update on your progress for the internal programs, specifically with regard to any major milestones we can look to in 2017 to confirm things are on track? Thanks.

Sure. Thanks, Gbola. I think and thanks for the questions. I'll take them in order. So with respect to RGX-314, it is an antibody fab fragment that was developed in partnership with the preclinical partners at the University of Pennsylvania. It's a proprietary product. We're certainly filing intellectual property around the protection of the trans gene and the compositions of the product as well. So there won't be any additional disclosure on RGX-314 at this time other than to confirm that it is a monoclonal antibody fragment that is targeted at VEGF. With respect to the RGX-314 Phase I clinical trial, so certainly the Phase I study, the primary outcome as I alluded to is safety in patients at 24-weeks post the single administration of RG-314. We do have secondary outcomes including measures of best corrected visual acuity, central retinal thickness as measured by OCT and we also will be looking to make measures of expression of the protein product of RGX-314 in the eye over the course of the development. And with respect to the last question about manufacturing, really I think 2016 has been a fantastic year of growth of capabilities in terms of process development, analytics and manufacturing for REGENXBIO. And when you're in the process of having four clinical trials become active over the course of 12 to 18 months and then looking forward to plans for expectations of the outcomes of those studies, supporting additional manufacturing needs, it's an investment that we think is well supported with respect to the direction that the company is going. We have certainly been able to support all of the studies that are active and are on track to support all of the studies with respect to investigation material that's going to be needed over the course of this year and I think coming into 2018, continue through work in process development and improvements in analytics, both internal to REGENX as well as with partners to improve processes as we hope to take a step forward toward commercialization.

[Operator Instructions] I'm showing no further questions at this time. I would like to turn the call back over to Mr. Mills for closing remarks.

Thank you, operator and thank you all for joining us on the call this afternoon. We certainly have several important milestones and catalysts to come up over the next year and we look forward to progressing our pipeline and interacting and providing you with further updates. Have a great day.

Ladies and gentlemen, that does conclude today's conference. Thank you for your participation. You may now disconnect. Have a wonderful day.