Good afternoon ladies and gentlemen and welcome to the aTyr Pharma Second Quarter 2021 Conference Call. At this time, all participants are in a listen-only mode. Later, we will conduct a question-and-answer session and instructions will be given at that time. [Operator Instructions] As a reminder, this conference is being recorded for replay purposes. It is now my pleasure to hand the conference call over to Ashlee Dunston, aTyr's Director of Investor Relations and Corporate Communications. Ms. Dunston, you may begin.

Thank you, operator, and good afternoon everyone. Thank you for joining us today to discuss aTyr's second quarter 2021 operating results and corporate update. We are joined today by Dr. Sanjay Shukla, our President and CEO; and Ms. Jill Broadfoot, our CFO. On the call, Sanjay will provide an update on our corporate strategy, including our clinical program for ATYR1923; and our research and discovery programs in neuropilin-2, including our pre-clinical program for ATYR2810. Jill will review the financial results and our current financial positioning before handing it back to Sanjay to open up the call for any questions. Before we begin, I would like to remind everyone that except for statements of historical facts, the statements made by management and responses to questions on this conference call are forward-looking statements under the Safe Harbor provision of the Private Securities Litigation Reform Act of 1995. These statements involve risks and uncertainties that can cause actual results to differ materially from those in such forward-looking statements. Please see the forward-looking statement disclaimer in the company's press release issued this afternoon as well as the risk factors in the company's SEC filings and included in our most recent annual report on Form 10-K and quarterly reports on Form 10-Q. Undue reliance should not be placed on forward-looking statements, which speak only as of the date they are made, as facts and circumstances underlying these forward-looking statements may change. Except as required by law, aTyr Pharma disclaims any obligation to update these forward-looking statements to reflect future information, events, or circumstances. I will now turn the call over to Sanjay.

Thank you, Ashlee. Good afternoon everyone and thank you for joining us for our second quarter 2021 results conference call. As we make our way through 2021. We continue to make significant progress in our mission to translate novel biological pathways into innovative therapeutics for improved outcomes for patients. Notably, we recently completed the last subject visit in our Phase 1b/2a proof-of-concept study of our lead therapeutic candidate ATYR1923 or 1923 in pulmonary sarcoidosis, our lead interstitial lung disease or ILD indication. We expect to report results from this important study in mid September of this year. This is a significant milestone for ATYR and the upcoming readout represents a key inflection point for 1923 clinical program and tRNA synthetase biology platform. The clinical proof of mechanism for 1923 established from our Phase 2 study in COVID-19 patients and the favorable safety profile demonstrated to-date, along with the preclinical efficacy observed in multiple translational ILD models support the potential for 1923 as a new therapeutic approach for pulmonary sarcoidosis and possibly other forms of ILD. We believe 1923 could potentially offer an alternate to current treatments, such as steroids with improved efficacy and fewer side effects. In addition to finishing up the important work for our 1923 clinical program, we've continued to generate new data and publish research related to our preclinical program further strengthening our pipeline. As we begin today, I'll summarize a few additional highlights. Since we last spoke in May. We hosted a key opinion leader or KOL event on current treatment options for pulmonary sarcoidosis, featuring Dr. Daniel Culver, Chair of Pulmonary Medicine and Director of Diffuse Parenchymal Lung Disease at the Cleveland Clinic. Kyorin Pharmaceutical Company, our partner for the development and commercialization of 1923 for ILD in Japan completed a Phase 1 study in…

Thank you, Sanjay. Cash, cash equivalents and investments as of June 30 2021 were 44.1 million; research and development expenses were 7.7 million for the second quarter of 2021, which consisted primarily of 1923 and 2810. program costs, including increased manufacturing costs. General and administrative expenses were 2.8 million for the second quarter of 2021. We do expect expenses to continue to increase throughout 2021 as research and development of 1923 and 2810 progress, including additional manufacturing costs for both 1923 and 2810, to prepare for future clinical trials. However, we have sufficient capital to take us through the readout of our trial in pulmonary sarcoidosis and initiate a patient trial in cancer for 2810. Common shares outstanding were 16.9 million and fully diluted shares were 18.7 million as of August 9, 2021. Now I'd like to turn the call back over to Sanjay before we open it up to Q&A.

Thank you, Jill. We're highly encouraged by what we've been able to accomplish in the first half of 2021. And we are looking forward to the upcoming readout for our proof-of-concept study for 1923. We've taken a very methodical approach to the development for 1923. When you look at 1923s MoA, we've shown that 1923 downregulates innate and adaptive immune responses during active inflammation. We've shown 1920 rebind selectively to neuropilin-2 to a receptor that we've shown is upregulated on key immune cell during inflammation, including sarcoid granulomas. And now, based on data, we will present at ERS. We've shown that the active portion of 1923 has the ability to disrupt sarcoid granuloma formation in vitro. We've established a library of data demonstrating 1923s favorable clinical safety profile, which has consistently shown that 1923 is safe and generally well tolerated with no serious drug related adverse events. This now includes data from two Phase 1 studies in healthy volunteers. A Phase 2 study in COVID-19 patients and two independent data safety monitoring board reviews from our current study in pulmonary sarcoidosis patients. And finally, we've demonstrated potential efficacy which includes a robust portfolio of translational work demonstrating 1923, anti inflammatory and anti-fibrotic effects in multiple preclinical models of ILD and clinical proof-of-mechanism from our Phase 2 study in COVID-19, with biomarker data showing that 1923 reduced inflammatory cytokine levels in patients consistent with preclinical models, including cytokines that are directly implicated in sarcoidosis and other forms of ILD. Based on the totality of this data, we believe 1923 has the potential to be a transformative alternative to steroids and other available treatments with improved outcomes in patients with pulmonary sarcoidosis. This upcoming readout represents years of hard work and dedication to developing and advancing our tRNA synthetase biology platform to one that can generate new therapeutic targets and from which we can develop a new class of medicine. We look forward to sharing the results from this important study with you in mid-September. We appreciate your interest, continued support at this time. Jill and I will be happy to take your questions.

[Operator Instruction] Your first question comes from the line of Prakhar Agrawal of Jones Trading.

On 1923, I had a couple on the healthy volunteer trial update from Kyorin. Could you expand on what has been seen in the safety database? I understand there are no drug related assays. But on other adverse events. How did that compare with what has been seen with 1923 previously? Was there anything new? Secondly, as we think about the September readout, what data will be disclosed at the time of press release? What exploratory efficacy endpoints we might see and what endpoints we might need to wait. And then I had a follow up.

Sure. Thanks, Prakhar. So with respect to our partners trial, as I mentioned, this trial is complete, the 1923 tract well, very consistent to what we saw in our trial. No serious adverse events related to the drug effect, and generally safe and well tolerated. So very much consistent with the findings we saw several years ago with our Phase 1 trial. Those are the details that I can share with you about that trial. With regard to your second question around the readouts in September, we expect to not only report the primary objective, which is safety and tolerability of the trial, but we will be focusing on those key exploratory endpoints, namely around steroids, steroid burden, looking at pulmonary function tests, imaging, inflammatory biomarkers. So really, we're looking at the totality of all of that data, in an attempt to really get it all out really at once. I do not expect things to trickle in after that. We're looking to look at all the data here and read out all of the primary and secondary objectives of the trial.

Good. I think same question on NRP2, the antibody that -- the secondary antibody that blocks NRP2 interaction with Semaphorin and Plexin. Could you expand on how this could play a different role than 2810? And what are the potential next steps for this antibody? Thank you.

Yes. This is an early opportunity for us, 2810 emerged out of this suite of specific antibodies that block different epitopes of neuropilin-2. Our 2810 block VEGF signaling, this is the next opportunity that we're looking at blocking Semaphorin signaling. With regards to how tuning neuropilin biology could be different, it could be useful in some instances in cancer, we of course, are seeing some effects, rather early on with 2810. With regard to Semaphorin, they're broadly implicated a bit more with inflammation. So we now want to look at how that signaling could be useful either in cancer or inflammation. The idea here is by tuning neuropilin biology, our suite of antibodies could be useful, not only in cancer, but also potentially as a -- even a more targeted anti-inflammatory, when you think about Semaphorin biology. But again, the first thing we did there was to make sure that it's a good strong blocking antibody, we have observed that now we'll start to tease out a little bit more of our mechanistic understanding of that next generation antibody.

Your next question comes from the line of an Emanuela Branchetti of H.C. Wainwright.

Couple of for me. So with regards to the upcoming Phase 1 to readout, obviously, we are excited to see the potential for steroid targeting with this higher 1923. But in this regard, do you expect a certain level of variability in patients responses based, for example, on the length of treatment with steroids? And also, I guess, what would be the main drivers of these variability?

Okay. So your question is really about duration of prior steroid therapy, Emanuela?

Yes. Correct. I know that the inclusion criteria was at least four weeks on stable steroid doses, if I’ am correct?

That's right. That's right. And most of these patients, we can sometimes be on steroids for years. So this will be an important element for us to look at closely in our trial. What we understand from the experts, however, is, once you progress to meeting at least 10 milligrams of prednisone a day, upwards to 25 that's really what we've enrolled in our trial. You now have moderate disease and in many ways, these patients are similar, whether they've received therapy for six months, or sometimes for several years. But it is going to be an important characteristic for us to look at to determine whether or not duration of steroid burden contributed to any of the responsibility. But I think that's an open question. I will say though, one of the things we really look to do is to eliminate folks who have self-resolve. This is why we focused in on a population receiving a moderate to high dose of steroids in our trial to create a bit more homogeneity amongst the patients enrolled, but that will be important for us to look at for sure.

Got it. Got it. Thank you, that's very helpful. And also, it's nice to see the update on Kyorin Phase 1. But in this regard, I was wondering if you can provide more color on the strategy for the development of ATYR1923 with Kyorin. So should the ATYR1923 moves to pivotal, should we expect Kyorin to participate in a parallel development in sarcoidosis or would they focus on other ILDs?

So the plan at this moment is for Kyorin as our partner to potentially join our next trial if we are advancing this program forward. In addition, there is also the ability to move into other interstitial lung diseases with Kyorin, something that obviously we will sit down and map out that strategy. Kyorin has the ability to look at interstitial lung disease in Japan independently or together with us. So I think these readouts are going to solidify a little bit more of the strategy. But at this point, our aim here is to conduct potentially a worldwide trial next in which Kyorin can hopefully support us with Japanese experts and trial sites.

Your next question comes from the line of Hartaj Singh of Oppenheimer.

Great, thank you for the questions and nice update, Sanjay, looking forward to September. Just a couple of questions from my part -- from my end. One is, when I look at the secondary outcome measures, Sanjay, on ClinicalTrials.gov, their listed total cumulative steroid dose results in a number of patients who achieve and maintain the tapered dose. My question is, which of these would you consider more important? Is it trying to get the patient down that targeted tapered dose? Is it a total cumulative dose? I know also during Dr. Culver's presentation, he had some opinions there, just your thoughts there, and then I just have a couple of follow-ups?

Yes, great question, Hartaj. I think the way to think about this is we really are looking at steroid burden a couple of ways. First off, we want to be able to evaluate whether or not folks were able to maintain a response and response being able to be on five milligrams or less in our trial, I think that is a subtherapeutic dose, and if patients do well on our therapy and are able to maintain that kind of dose. Remember, these are patients that have had very difficult time even dropping one milligram, they've sort of landed somewhere between 10 milligrams to 25 milligrams sometimes for several years. So that's number one. Number two, looking at the total steroid dose over time over the six months with regard to what Dr. Culver talked about, this could be, obviously, have a big impact on that sort of toxic burden over time. And if we can show some differences between placebo and treated populations there, that could also be a nice win for us. So I think those are the kind of ways we're looking at this trial. Of course, we have the ability that if a patient was able to even taper to zero, I think Dr. Culver highlighted that, that would be a real outstanding finding if we were able to do that even in the short trial. These patients at the end of the day want to get off or on their way to getting off steroids. And if we're able to observe anything like that, I think that would be a real tremendous finding. With regard to some of the secondary endpoints, I think right now, we really are looking closely at some of those inflammatory biomarkers in addition to some of those other endpoints that you see on ClinicalTrials.gov. Biomarkers have become really important, in particular, after we demonstrated some nice improvement in COVID-19 patients.

Yes, no, that's very helpful, Sanjay. It would be great like you said in a 24-week trial to show these effects, that's not very long. What is -- the other question I had was, Sanjay, assuming you had a positive readout in mid-September, what would be the next step with regulators and the timing on that? And then in association, how important would your OSU collaboration are looking at what could be a potential diagnostic type or diagnostic strategy would be, how important would that be to that interaction with regulators? Thanks for the question.

Sure. So obviously, we would want to move really quick here. These are -- we're working in rare disease. These patients can't wait. So after these readouts, we would look to get aggressive -- have an aggressive timeline to get back to the FDA. Some of that will also involve us sitting down with the investigators of our trial and really mapping out their thoughts. But we would want to quickly get to the FDA, so that we could start a -- what's hopefully a single pivotal trial next year. Again, that's pending some of that FDA dialog, but our approach here would be that in rare disease, these patients can't wait. And our approach would be to really move forward with an aggressive regulatory strategy. With regard to your question around the OSU collaboration, absolutely, this could be a avenue for us to develop an ex vivo assay, which can effectively identify patients sensitive to 28 -- to 1923 prior to even dosing these patients. So I think as they -- as you point out kind of companion predictive diagnostic, this would be something that we would work towards and potentially use to, at a minimum, enrich our target population -- patient population for the next trial. So I think it sets us up really nicely to create even more homogeneity around those patients that respond to 1923.

Great, thank you, Sanjay.

Your next question comes from the line of Yale Jen of Laidlaw and Company.

Good afternoon and thanks for taking the question. My first question is that -- is a follow-up with the previous one, which is that in terms of the Japan study versus the study you have done in healthy volunteer, was there any PK differences between the Japanese and I guess, Americas or there's not much? And then I have other follow-ups?

Yes, hi, Yale. No, we saw consistent findings on half-life of our drug is somewhere between eight days or nine days, and those PK findings tracked in the Japanese population as well. So we more or less are in the same ballpark, which is one of the reasons you conduct this trial because there sometimes can be differences in PK between the populations.

Okay, great. And the second question is that in terms of the readout in mid-September, in what venue you think you will communicate to the Street? Would that be an analyst or investor call or other means just -- or just a press release?

We would plan to have a call certainly. This is an important inflection point for us. So we'll certainly want to get everybody on the line and go through the data with each of you.

Okay. And then maybe one more -- two more quick one. First one is that in the ClinicalTrials.gov, in terms of the secondary outcome measure, there's one thing called the incident and the titers of Anti-Jo-1 antibodies. Would you give a little bit more color on what that is, what is that?

Sure. So as we are working with a class of medicines coming from the tRNA synthetase world, there is an ultra-rare condition called antisynthetase syndrome. In this example, antisynthetase patients sometimes develop antibodies to a protein fragment of full-length of histidyl tRNA synthetase. So as we are working in the same class, part of our safety is to ensure that we do not develop any autoimmunity. These Jo-1 antibodies are something that we are going to be required to watch for. However, I will tell you that antisynthetase patients who develop antibodies to histidyl tRNA synthetase, they develop interstitial lung disease. So in many ways, we're dealing with patients that already have interstitial lung disease. And another way to think about this is those patients that where you knock out this clinical pathway around tRNA biology, in some ways, it demonstrates proof-of-concept, if you will, that this is an important pathway, this protein fragment is involved in regulating the development of interstitial lung disease. But as we are working with this class, the FDA, from a safety perspective, we have to monitor Jo-1 antibodies because we are a tRNA synthetase platform company.

Okay, great. Maybe the last question is a housekeeping one. So in terms of the licensing and the collaboration agreement revenues for the remaining of 2021, do you see any potential revenue inside in this timeframe or how should we think about that piece of the line?

Yes. Well, we haven't really disclosed when each of those milestones are. The majority of the remaining $165 million is geared towards development, but we did see the $2 million milestone received upon the last patient in for their trials. So you can basically kind of think of that as what we received from a Phase 1 perspective. So the next milestone would -- you can think of as coming in that next stage of development, which would not begin this year.

Okay. But the last patient in was not the one you completed the enrollment, right, completed treatment reported earlier this year?

Right. They had the last patient in, in December of last year, and we reset it in the first quarter of this year.

Your next question comes from the line of Zegbeh Jallah of ROTH Capital Partners.

Hi, thanks for taking my question. Just have a few. The first one is just on how many patients you plan to have for the biomarker data on COVID-19? And then since it will be presented before the pulmonary sarc data readout, how would you be comfortable with investors in faring from that data readout?

Sure, thanks, Zegbeh. So this was -- again, we presented this data earlier this year. There were 32 patients in that COVID-19 mechanistic proof-of-concept trial we ran. Previously it presented that over 80%, 82% of those inflammatory markers substantially declined when 1923 was used on top of dexamethasone. So this is a poster, which essentially brings all that data together. So there isn't exactly new information coming from that. We have previously released it to the Street, but we thought it would be useful and the community would like to see this in a medical conference. So that's really what that poster is about. Previously, we've highlighted this data with interferon gamma, IL6, MCP-1, significant knockdown in those COVID pneumonia patients. These are the same biomarkers that we saw really move significantly in our animal studies. So this poster basically gets its arms around all of that information that we presented back in Q1 and is being presented at European Respiratory Society, which happens to be as it turns out just in the short period right before we're about to announce data from sarcoidosis.

Thanks, Sanjay. And then just a follow-up regarding the pulmonary sarc data that's going to be coming out next month. Would it just be highlights or would it be full patient-by-patient detail?

We'd like to be as detailed as possible. There's no top-line, no interim. We're aiming for full results being able to look at not only all of the safety endpoints, but even those exploratory efficacy endpoints that we've highlighted.

Thank you. It's nice to hear. And then just a follow-up to that one actually, I was just also wondering with the small sample size, are there any data points where you would expect to see some variability and how do you plan to tackle that or leverage all the data points that kind of determine the go-forward strategy?

Yes. I think Dr. Culver highlighted this that pulmonary function tests sometimes can be perhaps most variable in this population. The way we look at it is we may be able to look at pulmonary function tests and stratify based on response. We may learn something there. Our current trial did not create a stratification or inclusion criteria around forced vital capacity. We were advised by the experts to -- as this endpoint is pretty variable to leave it alone. I think with regards to some of the lung imaging, of course, that's a unvalidated PET scans are a new biomarker being used out there. So we're going to learn -- that's why these are exploratory endpoints. I think the way that what we are really prioritizing is the safety, looking at steroid sparing effect and looking at those biomarkers. Patient reported outcomes are also going to be really important here. Cough, fatigue, shortness of breath are all areas that if patients are doing well and we're able to also see improvement in knocking down their steroids, well, then I think those two PD markers going the same direction, as Dr. Culver pointed out, could be really, really impactful.

Thanks, Sanjay. Looking forward to the better readout.

Thank you.

There are no further questions at this time. I will now turn the call over to Sanjay Shukla for closing remarks.

Great. Well, we thank everyone for their interest. Great questions today and looking forward to getting back to everyone very soon here in the near future. So thank you, everybody. Have a great day.

This concludes today's conference call. Thank you for participating. You may now disconnect. Presenters, please stay on the line.