[Abrupt Start] A press release with our second quarter business update and half year 2018 financial results became available earlier today and can be found on the News and Events section of the company's website at www.argenx.com. Before we start, I'd like to go to Slide 2 to remind you that forward-looking statements may be prevented during this call. This may include statements about our future expectations, clinical development and regulatory timelines, the potential success of our product candidates, financial projections and upcoming milestones. Actual results may differ materially from those indicated by these statements. argenx is not under any obligation to update statements regarding the future or to conform these statements in relation to actual results, unless this is required by law. I'm joined on the call today by Tim Van Hauwermeiren, CEO of argenx; and Eric Castaldi, CFO. On Slide 3, you'll see a brief agenda for the call. Tim will highlight recent updates from our efgartigimod ARGX-113 program, including the full data set we presented at the American Academy of Neurology Annual Meeting from our Phase II clinical trial in myasthenia gravis, feedback from the FDA around our upcoming planned Phase III trial in myasthenia gravis, initial data for our subcutaneous formulation of our ARGX-113 product candidate and the first cohort of patients in our Phase II proof of concept trial in pemphigus vulgaris. We will then move on to provide update from our other clinical programs, including ARGX-110, our collaborations and our productive Innovative Access Program that continues to feed our antibody pipeline. Eric will then provide financial results for the half year before we start the question-and-answer portion of the call. With that, I would now like to turn the call over to Tim.

Thank you, Beth, and welcome everyone. We would like to spend the majority of the call today highlighting the key progress we made in the second quarter in advancing ARGX-113 efgartigimod and supporting its potential across several autoimmune indications. We believe we have a pipeline and a product opportunity with efgartigimod, which is shown on Slide 4, and that we are taking steps towards becoming a leader in translating immunology breakthroughs into noJason Limel medicines. We are very excited about the growth potential of efgartigimod and recognize the growing interest across our industry of the neonatal Fc receptors as a therapeutic target. We have invested heavily in developing our fundamental understanding of FcRn biology and believe we are well positioned to translate these insights into the clinic on an ongoing basis. To that extent, we have also developed the largest clinical database we knew of to date supporting the mechanism of action of our FcRn antagonist into indications, myasthenia gravis and pemphigus vulgaris. As you will see on Slide 5, the FcRn receptor serves to rescue IgG from degradation through a recycling mechanism. We have shown that by blocking the FcRn receptors, efgartigimod prevents the natural recycling of IgGs leading to their elimination and degradation to the lysosome. The clinical data we have gathered from the Phase II trial in MG has correlated a reduction of total and pathogenic IgGs with a rapid and durable improvement in disease course. Thus, showing that by breaking the chain of recycling pathogenic antibodies we are able to change the chain of disease. In building our efgartigimod product candidate portfolio, we've taken a data-driven approach to choosing indications from the vast pool of possibilities that could benefit from a pathogenic IgG clearing mechanism. This is outlined on Slide 6. Myasthenia gravis and pemphigus vulgaris…

Thank you, Tim. So let's move to Slide 23. Our half year operating results are detailed in this morning's press release and filed with the requisite exchange agencies. Total operating income was €20.5 million for the 6 months ended June 30, 2018, compared to $23.9 million for the same period in 2017. The difference in operating income between the 2 period was driven primarily by reduced revenues in relation with the completion of the pre-clinical activities under our ongoing collaboration with LEO Pharma. Research and development expenses amounted to €34.4 million for the 6 months ended June 30, 2018, compared to €25.6 million for the same period in 2017. The increase in R&D expenses in 2018 was principally due to an increase of €4.4 million in share-based compensation expense linked to the grant of stock options to our R&D employees, an increase of €4 million in costs related to the advancement of the clinical equipment and manufacturing activities of ARGX-113 and ARGX-110. And also costs associated with the planned increase in research and development headcount. SG&A expenses totaled $11.5 million for the 6 months period ended June 30, 2018, compared to $5 million for the same period in 2017. The increase in 2018 is mainly due to an increase of $4.5 million in share-based compensation expense linked to the grant of stock options to our SG&A employees and total equipment of additional employees not only in our U.S. office to further strengthen our SG&A activities in order to support the growth as next stage clinical company. The company generated a total comprehensive loss of €20.1 million in the first half of 2018 compared to a loss of $8.2 million during the same period last year. Our cash position, including our cash, cash equivalents and current financial assets as of June…

Thank you, Erik. Look, we're very excited by all of our focus this past quarter highlighting the broad potential of our lead asset, efgartigimod, as a pipeline of product opportunity. This includes Phase II data in 2 indications, myasthenia gravis and pemphigus vulgaris, showcasing the breadth of inhibiting FcRn in severe autoimmune diseases; the productive meeting we held with the FDA and feedback on our planned pivotal Phase III program; and the viability of the subcutaneous formulation of efgartigimod. We are moving forward across the efgartigimod program and have the following upcoming milestones. We expect to report Phase II proof of concept data in ITP before the end of the third quarter, and then the full data set around ASH in December. We expect to launch the Phase III pivotal trial in MG before the end of this year. We expect to report data from the second and third cohorts in PV during the first half of 2019. We expect to continue to explore potential dosing schedules with our subcu product candidates and determine how to best move forward into clinical trials and ultimately, commercial use if approved. We remain focused on our data pipeline and expect to report the dose escalation data of ARGX-110 from our Phase I AML cohorts around ASH and continue enrolling the Phase II parts. We are confident in our ability to advance and grow our pipeline, taking assets against novel targets that stem from our SIMPLE Antibody platform and collaborations with leading researchers and moving them swiftly forward to the clinics to expand our leadership as antibody specialists. And with that, we'd now like to open the call for questions and answers. Operator?

[Operator Instructions] We will now take our first question from Yatin Suneja from SunTrust. Please go ahead.

Maybe I'll start with the AA-MG trial, the planned Phase III. Could you tell us what the dosing frequency might be? Have you disclosed the powering assumption or how have you used the Phase II to come to the powering assumption, specifically with regard to the placebo arm? And finally, on that trial, can you confirm the autoantibody negative patient that you will be enrolling in the trial, they are not part of the statistical plan. And then I have a question on ITP afterwards.

It is true that specific details of the trial design like the dosing, the powering, et cetera, has not been disclosed yet, and I would like to hold off addressing that question until the details have been made public. We're likely going to make details public when we launch the Phase III clinical trial. I can confirm to you that although we are including patients with autoantibodies against different components of the neuromuscular junction than the acetylcholine receptors, that we will not be dependent on these patients to achieve statistical significance in this clinical trial.

Now with regard to the ITP trial, can you help us understand what the bar there is for success? I mean, obviously, there is a competitor that has shown response rate in the 30-plus percent range? So what data set are you looking at that would compel you to move forward? So that's just one part of the question. And then just a broader question on the ITP, if you can maybe help us understand the positioning of your drug a little better relative to IVIG, maybe talk about the importance of fast onset of action, how critical that is, and/or is it durability that drives physicians' interest?

So in ITP, if you want to compare, of course, data across clinical trials, we have to make sure we compare apples with apples. So I think the devil is in the detail of how people define response, and you see the different players have defined response in slightly different ways. In our breakfast symposium with Dr. Broome, actually we have presented a slide with 2 accepted definitions on what a platelet response constitutes. Now just for the sake of clarity, we will be releasing the full platelet count data on our top line data so that everybody can look at these curves and decide for him or her what type of definition you would like to apply. Now where is that the bar for success? If you look at the products today, you will see anything between, roughly speaking, 18% and 50%, and we have seen very recently an approval for sunitinib with an 18% response, very broad label. And we have seen in the past, the TPO receptor agonist with short-term response of, let's say, 15% to 50%, but long-term response, we all know that it's around 40%. So I would say, that the bar of success is between 18% and 50%. The real question is also, of course, durability of response. And that goes to your second question, specifically in ITP. IVIG is really niched into rescue therapy. The onset of action of IVIG is fast. I think it's one of the fastest therapies out there. It's a matter of days to restore platelet counts. But we also know that IVIG is losing its effect really fast. So IVIG can only be used as kind of rescue therapy in an ITP setting. It's not really used in a maintenance setting. I think there, we need to look more at the TPO receptor agonist. So speed of onset of action is important. But I think what we hear from physicians and patients is that in the first place, response is important and durability of response. That is what people are really waiting for, and let's also not forget that the safety profile of the current medication is pretty brutal. So people are looking for safe, efficacious medication.

I have a question for Eric on the P&L side. Maybe can you help us model the R&D on your data going forward? We saw an uptick in Q2. Is that a good proxy for rest of the year? And could you also tell us what was the weighted number of share outstanding, either for the quarter or for the first half of the year, so that we can calculate the EPS.

I mean, we're going to see a significant increase in our R&D expenses as we move forward. And that will be when we're going to enter into Phase III, obviously, this year. So we expect our cost rate to increase moving forward. We had even a guideline and now that we have received the payment from AbbVie, the $10 million, so the new guidelines for development is between $70 million to €75 million for the year. And regarding the number of shares, just one sec, I can't tell you immediately, so it is 32,442,864 average. So it's the weighted average, yes, for the Q2 2018, 32,442,864.

We will now take the next question from Jason Butler from JMP Securities. Please go ahead.

I have two. First of all, just thinking about the open label retreatment P trial versus the changes you made in the maintenance phase now on the PV trial, do you think that you're coming to a convergence of long-term repeat duration or thinking to roll this? Is this something you're going to continue to meet with the traditional and functionally, you look at. And then second question, could you maybe talk a little bit more about how you see the integration of the subcu formulation into the development program? Could we start to see this built into the ongoing trials or the label extensions? Or a new set of trials we should be thinking about in the future?

Yes, so regarding your first question, Jason, this is an excellent question. I think it's too early to say whether we see convergence between different disease indications. We would need to look at the ITP data when they become available in September. We need to learn more about PV. But as a general rule, I would be very careful doing that. Myasthenia gravis is a disease in the muscle, at the neuromuscular junction. ITP is a disease, which plays in the blood compartment and the bone morrow compartment and pemphigus is a disease which plays in the skin compartment. And therefore, I believe that the longer-term dosing considerations for all 3 indications could be different. So we're learning across different indications, we need more data. But today, I would shy away from just blindly extrapolating from one indication to the other indication. Concerning your question in the subcu product, we're very excited about the subcu opportunity. We're certainly going to push it forward into later clinical development. What we have said today is that it's unlikely that we're going to do that in myasthenia gravis first. Myasthenia gravis, we believe, is an indication where we can go-to-market with an IV product first. But for sure, we will want to flank the IV product to the subcu product going forward. So expect in the future announcements on further clinical work where we will actually advance subcu to market.

We will now take our next question from Boris Peaker from Cowen. Please go ahead.

I'll start the move for the MG pivotal study, I'm just curious, how long do you anticipate the enrollment to take?

This is an excellent question. We don't know, of course. The only thing we can do is we can look at precedents. And I would say that the REGAIN trial is an interesting proxy. The REGAIN trial performed by Alexion, where they enrolled 125 patients, took them about 22 months. I think we are enrolling in a broader patient population, not just the refractory patients, but we're enrolling more patients, 150. So based on everything we know today, I think the 22 months would be a good proxy for the duration of the study.

And before you commence the study, are you waiting on any competitor data to inform your thoughts or decision or is it fully developed and irrespective of any competitor data that might come to market?

Correct. So we believe that we're ahead of the pack in MG, so we'll be not waiting for anybody else's data. Our strategy is speed to market, so basically, the time line is driven by internal clinical operation considerations.

So a quick question on the subcu formulation. What's the injection volume?

So the 300 milligram, which we have been applying in this Phase I study is sitting in a volume of 2 milliliters, that is pretty exciting because you have off-the-shelf systems with good patient acceptance in that order of magnitude, 2 milliliters, 2.5 milliliters. For example, ipilimumab from Sanofi-Regeneron, is an antibody with a very well accepted user profile. It's a subcu product, which is sitting at 2.5-milliliter volume, dosed in a subcu injection. So the 300 milligram nicely fits into a 2 ml volume.

And my last question, on 110, can you comment specifically how many patients worth of data we should we be expecting at ASH?

We would get 12 patients worth of data because we have not seen any dose-limiting toxicity, so we follow the classical 3 plus 3 design, that means you have 3 patients for each of the 4 dose cohorts.

We will now take our next question from Ted Tenthoff of Piper Jaffray. Please go ahead.

So a lot of questions answered here looking for the ITP data in the Phase III trial side. I wanted to come back to PV and sort of get a better sense of what next steps are there and how you'll kind of figure out past towards a registration trial.

Ted. I think we need to continue enrolling cohort II and cohort III and learn. So we need to learn what the performance profile is of this drug in this specific indication. What we learned is that we can knock down the pathogenic IgGs in exactly the expected fashion. The IgG follow down a curve -- follows exactly the IgG fall and down curve from the healthy volunteers in the MG patients. The big surprise in the study so far has been the fast onset of action. Experts find it intriguing that within 1 week we achieved disease control in 3 other sick patients and in 4 -- in the 4 patients within the first month. Now that is something which is very valuable in this indication because PV, of course, is a barrier defecet. I mean, you have a massive barrier defect exposing you to a higher rate of infection and also high mortality due to infection. So stopping formation of new lesions and closing existing lesions is very valuable, especially knowing that today rituximab has a very slow onset of action. It takes about 3 to 4 months for rituximab to start to show activity. And still, the relapse rates on rituximab continues to be high. So I think we're unraveling and learning about the strengths of the molecule and we should be patient and wait for these data until we can craft then the Phase III design in function of the proper positioning in these compelling markets.

Right. That makes a lot of sense. And then just I know a lot of people are asking about this, but when could we expect to hear more about the target and sort of development plan for 117?

There is a plan to organize an R&D Day in the first half of next year, and I think the purpose of the R&D Day amongst all this will be to give a deeper view or a more thorough view into the upstream part of the pipeline. So you can expect during that R&D day that we will be disclosing quite a few data on the more upstream assets, including ARGX-117, but probably also ARGX-118. We said today that we will communicate about ARGX-118 later this year.

We will now take our next question from Chris Parrish from Nomura. Please go ahead.

I was wondering if you could take a look at -- or could help understand your path forward at MG. AbbVie is enrolling MG or most patients, and those patients might be expected to benefit disproportionately from your drug. And have you looked at perhaps stratifying enrollment and perhaps your path to approval in some populations of MG. And then I've got a follow-up.

So I think the expected thing about the global registration trial which we're about to roll out is that we are going to enroll all generalized MG patients regardless of the type of autoantibody. So the study is really designed and powered around the acetylcholine receptor-positive patients that we had a constructive discussion with the FDA how we would go about the other patients which are, by the way, in even bigger medical need because nobody developing a drug for these patients. So I think we will try to test them all in 1 trial and then enter the discussion again with the FDA once we have the submission file in hand. So the idea would be to go for broad label in generalized MG patients. Basically, those patients, which are inadequately controlled by the standard of care. So it's a pretty ambitious target.

Understood. So it sounds to me like there might be a possibility based on your trial design to also win in-construct populations if the broad -- if the efficacy in the broad population doesn't hold up to what our expectations currently are. Is that a correct assumption?

This is what I said, Chris. What I said is that the heart of the study consist of the acetylcholine receptor autoantibody positive patients and we're kind of adding on the other patients as an extra, as a bonus. But the study will basically pivot on success in the acetylcholine receptor-positive patients. Is that sufficient for you?

And then, just - yes, no, that's clear. And then just with respect to, I guess, the other indications for the drug, any possibility that this -- that this drug, 113, could be approved on other indications here or ITP or others to the MG Phase III readout?

We will be concentrating in our strategy. What we always said is that success in the beachhead indication means that we can now start to open up that space and start to add indications and try to build a franchise. We have strong data in myasthenia gravis. So we are currently examining additional possible indications in the neuromuscular space, just like we will do that in the heme space in case we have positive ITP data. So the 3 beachhead indications are just the start. We are actively exploring possible additional indications.

[Operator Instructions] We will now take our next question from Sandra Cauwenberghs from KBC Securities. Please go ahead.

I have four small questions left on ARGX-117. So I understand we'll get more information on the R&D Update Day. But is it possible to give us a bit more with regard to when a possible Phase III could -- sorry, a Phase I could start? So is that possible early next year? With regard to ARGX-110, I had understood that this could be up for partnering at the end of the Phase II. So is this possible by year-end '19? A quick update on potential milestone payment that we could still expect in the second half of this year would be interesting and into 2019. And then with regard to the headcount increase with regard to R&D and administrative staff, so we got an update on the amount of staff that was hired, but could you elaborate on how many people you foresee to hire in the second half of '18 and the first half of '19?

So with regard to ARGX-117, when we launched the program, we said we were about 18 months away from clinic. So that means that an IND filing would rather happen towards the end of 2019, not towards the beginning. For ARGX-110, yes, it is true that we said that we would continue to execute the Phase II study as fast as we can on a stand-alone scenario. We also need to aim for an interaction with FDA on the regulatory path going forward in a registration file. And I think the Phase II data and the FDA interaction will guide us as a company in our decision-making whether we embark on a Phase III alone or whether we would look for strategic partnership on the molecules. I would say, stay with us whilst we navigate through data and FDA interaction, and we will certainly be happy to give updates during the course of the next years. With regard to milestone payments expected, I have to be short. We only allow them at our deals to talk about milestone payments if and when they happen. So we will certainly actively communicate about them. We have explained in the past what expected payments could be under the LEO collaboration, under an AbbVie collaboration, under a Shire collaboration. So any of these payments actually are possible, but we can only communicate if and when they happen. And with regard to headcount increase, it is clear, of course, that this company needs to scale. We have created quite a bit of optionality in our programs and in our pipeline. It turns out, of course, that most of the options continue to yield outstanding data and that means that if we want to credibly develop, then we will need to grow as an organization. As Eric explained, we're currently with a headcount of 108 people. With this type of pipeline, I can tell you that most of our peers are actually running with headcounts, which are double or triple of our headcount. So we will need to invest in capacity and bandwidth, and you will see a rather aggressive move on the recruitment front in the next year. So I don't think it's unrealistic, that this company will add 50% to 75% extra headcount in the next year to come.

We will now take our next question from [indiscernible]. Please go ahead.

I wanted to go further on the AML trial with 110. You mentioned in the press release and a couple of times before that you expect to go forward there with the 10 milligram dose. As you've seen no dose-limiting toxicity in the different cohorts, do you expect that you could even go to the 20 milligrams? Is that a possibility still at this time?

So doses have been a key question in this Phase I because we saw efficacy across the doses. We didn't see any dose-limiting toxicity, so how did we pick the 10 milligram per kilogram dose for the Phase II? Well, we did it based on the bone marrow PK assay. So we do know that distribution of therapeutic antibodies in the bone marrow compartment can differ fundamentally from the distribution in the circulation. And therefore, we collected bone marrow data, convincing us that at 10 milligram per kilogram, we achieve full saturation of the target at bone marrow level. So the target saturation in the bone marrow has been our guiding factor to determine to go for a 10 milligram per kilogram dose in the ongoing Phase II study. [Abrupt end]