Good afternoon, everyone, and welcome to Shattuck Labs Second Quarter Financial Results and Business Updates Call. Today’s call is being recorded. At this time, I would like to turn the call over to Conor Richardson, Senior Director of Finance and Investor Relations of Shattuck Labs.

Thank you, operator. Good afternoon, everyone, and welcome to the Shattuck Labs conference call to discuss our second quarter financial results and business updates. The press release for our financial results was issued after market close this afternoon and can be found on the Events and Presentation section of our website shattucklabs.com. During this afternoon’s call, the Shattuck team will provide a business overview of the second quarter of 2021, including an update to our clinical development plans for SL-172154 and SL-279252. A Q&A session will follow our prepared remarks. Joining me on the call today are Dr. Taylor Schreiber, our Chief Executive Officer; Dr. Lini Pandite, our Chief Medical Officer; Andrew Neill, our Chief Financial Officer; and Casi DeYoung, our Chief Business Officer. Before we begin, I would like to remind you that today’s webcast contains forward-looking statements within the meaning of Safe Harbor provisions of the Private Securities Litigation Reform Act of 1995. Such statements represent management’s judgment as of today, and may involve certain risks and uncertainties that could cause actual results to differ materially from those expressed in or implied by these statements. For more information on these risks and uncertainties, please refer to our most recent Annual Report on Form 10-K for the year ended December 31, 2020, and our other filings with the SEC, which are available from the SEC’s website or on our corporate website shattucklabs.com. Any forward-looking statements represent our views as of today, August 11, 2021. With that, I will now turn the call over to Taylor Schreiber, our Chief Executive Officer. Taylor?

Thank you, Conor. Good afternoon, everyone, and thank you for joining us. Today’s earnings call is the first since our initial public offering in October of 2020 and I am exceptionally proud of the milestones. Our team has achieved since that time. Our clinical team has done an outstanding job of advancing the clinical development of both SL-172154 and SL-279252 our clinical stage Agonist Redirected Checkpoint or ARC compounds. As a reminder, 172154 is a SIRPα-Fc-CD40L bi-functional fusion protein currently in two different Phase 1 clinical trials, one for patients with advanced ovarian cancer and another for patients with squamous cell carcinoma of the head and neck or skin. Our second clinical stage compound 279252 a PD1-Fc-OX40L bi-functional fusion protein is being developed in collaboration with Takeda Pharmaceuticals and is in Phase 1 development for patients with advanced solid tumors. Both of our ARC product candidates are first-in-class compounds that entered the clinic in less than four years since our founding due to the pioneering work of our scientific manufacturing and regulatory teams. We are currently generating clinical data to validate the concept behind the ARC platform. And we are particularly excited to share this clinical progress with you in just a few months time. Specifically, we have submitted our clinical data from the monotherapy dose escalation portion of our Phase 1 clinical trials for 172154 and 279252 to the Society for Immunotherapy of Cancer also known as SITC for presentation at its annual meeting on November 10 through 14. Emerging data has guided us to amend and expand our clinical trials. And today, we will provide some context for those expansions in addition to our general corporate update. During 2021, we’ve made steady progress towards advancing the dose escalation cohorts for 172154 in patients with relapsed/refractory ovarian cancer. We…

Thank you, Taylor, and good afternoon, everyone. First, I would like to discuss our lead clinical programs SL-172154, which is a SIRPα-Fc-CD40L bi-functional fusion protein. As a reminder, SL-172154 contains the extra cellular domain of the human SIRPα protein, which directly binds to and inhibits CD47. In addition, SL-172154 also contains the extra cellular domain of the human CD40 ligand protein to simultaneously and directly activate the CD40 receptor. As most of you know, we are currently exploring SL-172154 in two ongoing Phase 1 clinical trials. Our first clinical study of SL-172154 is a multicenter open label dose escalation trial intended to assess the safety, tolerability, pharmacokinetics, anti-tumor activity, and pharmacodynamic effects of intravenous administration of SL-172154 as monotherapy in patients with relapsed/refractory ovarian cancer. Enrollment in the monotherapy dose escalation cohorts has progressed smoothly. We are currently completing enrollment at the fourth dose level of 3 milligrams per kilogram and we plan to proceed to the next dose level of 10 milligrams per kilogram thereafter. Our second clinical trial of SL-172154 is an ongoing multi-center open-label dose escalation clinical study intended to assess the safety, tolerability, pharmacokinetics and tumor activity and pharmacodynamic effects of intratumoral administration of SL-172154 as monotherapy in patients with relapsed/refractory squamous cell carcinoma of the head and neck or skin. We remain on track to present initial data from this study in the first half of 2022. Overall, we are very pleased with the emerging profile of SL-172154. To date no dose limiting toxicities have been observed in either clinical trial. And we are encouraged by our ability to dose in the higher dose level cohorts, because SL-172154 contains both CD47 inhibitory and CD40 agonist domains, the safety data should be considered in the context with prior CD47 inhibitors and CD40 agonists. On the CD47…

Thank you, Lini, and good afternoon, everyone. As Conor mentioned, the full financial results for the second quarter of 2021 are available in our earnings press release and our forthcoming 10-Q. Today, I would like to focus on a few key points from our disclosures. We are fortunate to be well positioned financially. As of June 30, 2021, we have cash and cash equivalents and short-term investments of approximately $304.8 million. Revenue for the second quarter ended June 30, 2021 was negative $4.2 million compared to $3.2 million for the second quarter ended June 30, 2020. All revenue to-date is generated solely from our collaboration agreement with Takeda, the negative revenue for the second quarter of 2021 was driven by increased expected costs required to complete our performance obligations in the collaboration agreement. As a result of the modifications to our clinical development plan for SL-279252. The negative revenue does not affect our cash position. In the second quarter of 2021, our research and development expenses were $14.9 million compared to $7.8 million for the second quarter of 2020. In the second quarter of 2021, our general and administrative expenses were $5.4 million compared to $1.7 million for the second quarter of 2020. Our net loss for the second quarter of 2021 was $23.6 million or a loss of $0.56 per basic and diluted share compared to a net loss of $6.2 million for the second quarter of 2020 or $0.81 per basic and diluted share. Now turning to our financial guidance for 2021 and beyond. Our financial guidance remains unchanged from the guidance given in connection with our initial public offering in October 2020. Importantly, expansion of SL-172154 into clinical trials in patients with AML and high-risk MDS does not change our current cash runway guidance, because the operating expenses associated with these trials were included in our internal forecasts. Based on our current and planned operations, our expected cash runway remains through year end 2024. And with that, I will now turn the call back over to Taylor. Taylor?

Thank you, Andrew. Over the past year, Shattuck has made tremendous progress and we are learning how to best apply the ARC platform for the benefit of patients with advanced cancers with the learnings from our first two clinical trials. SL-172154 and SL-279252 have been very well tolerated in humans to-date, which bodes well for the ARC platform as a whole. In addition, we have observed an escalating linear relationship between the dose of ARC administered and the corresponding pharmacodynamic responses to SL-172154 and SL-279252. We believe these observations validate one of the central hypotheses to the ARC platform that hexameric compounds like ARCs will engage TNF receptors in a fundamentally different manner than monoclonal IgG antibodies. Our progress with SL-279252 has been exciting, and we believe that the data collected from additional dose escalation cohorts will allow us to fully characterize the pharmacokinetic profile and to identify the dose at which the pharmacodynamic effects of OX40 stimulation reach maximum levels. We began this study in a PD-L1 unselected and highly heterogeneous patient population in order to proceed quickly through dose escalation. Now that we are within an immunologically active dose range, it is now appropriate to enrich for patients with PD-L1 positive tumors. It is not yet clear, however, whether OX40 stimulation will increase response rates beyond what is expected of a PD-1 inhibitor in a PD-1 or PD-L1 antibody experienced patient population. And the path forward for SL-279252 will depend upon observing monotherapy activity in PD-1 or PD-L1 antibody refractory patients at these higher dose levels. An enormous opportunity remains to address the unmet need in PD-1 and PD-L1 experience patients and we are excited to further characterize SL-279252 at higher dose levels in a PD-L1 selected patient population. We are also highly encouraged by the early data…

[Operator Instructions] Our first question comes from Marc Frahm from Cowen. You may begin.

Hi, thank you for taking the call. This is Ernie Rodriguez for Marc. Congratulations on the progress. We just have a question a follow-up on your commentary regarding the receptor occupancy for the CD47 and SL-172154. Have you discussed what level of receptor occupancy you have achieved? And if this ladle is above what others have seen or experienced that anemia on Shattuck?

Sure. Hi, Ernie, and thank you for the questions. This is Taylor. We will be disclosing that specific receptor occupancy levels at SITC. However, I can put the dose levels into a little bit more context with what has been reported with some of the other CD47 targeted agents. And with an antibody like magrolimab for example, that antibody began to see early receptor occupancy on CD47 expressing red blood cells, and then saw saturation of CD47 expressing leukocytes. But that didn’t occur until they reached those levels of roughly 20 milligrams per kilogram. In contrast some of the SIRPa-Fc fusion proteins have been shown to achieve a full occupancy and with different Fc fusion proteins, full occupancy can mean different things at levels of between 1 and 3 milligrams per kilogram. Our impression of the reason why some of the SIRPa-Fc fusion proteins have not reported a 100% occupancy on CD47 positive leukocytes is not that you cannot achieve 100% occupancy on leukocytes is that some of the lower affinity or lower avidity, SIRPa-Fc fusion proteins have a faster off rate and fall off CD47 on leukocytes faster than either high avidity or high affinity SIRPa fusion proteins. So hopefully, that provides a bit of context.

That’s very helpful. Thank you.

Our next question comes from the line of Jonathan Miller from Evercore ISI. You may begin.

Hi guys. Thanks for taking my question. And I’m really looking forward to seeing from the significant clinical data. But what we will look forward to that, I mean, it seems like, escalation on SL-172154 so far has been very supportive on safety agency, which both programs, but no responses yet. So now as we’re entering the immunologically active dose range, what are the key biochemical signals we’re going to get at certainly that’ll get us comfortable with activity given we’re sort of just entering that active dose range. And then secondly, as we turn to heme indications, as soon as you’re planning to pursue combo trials, obviously you are starting to mono there. Competitors have all moved robustly to combo trials for further development. Do you have any expectations of a meaningful monotherapy activity rate or development in that direction?

Sure. Thank you, Jon. I’ll take the first part of the question and then Lini to take the second. So in turn and she can elaborate on my response in the first as well. What you should expect to see at SITC with both programs is all of the patient characteristics and safety data to date at the various dose levels. The pharmacokinetic profile of the compound across the dose ranges, and then the pharmacodynamic effects that will include receptor occupancy as Lini mentioned for the OX40 engaging compound SL-279252 margination of OX40 positive lymphocytes, the various dose levels. And then for both compounds immunophenotypic data and a term cytokine analysis, as well as the antitumor activity. And I will ask Lini to take the second half of your question there regarding AML and MDS.

Thank you for the question. With the AML and MDS monotherapy portion of this is a very short monotherapy. That’s our plan to go into the combination very quickly. So we are bringing an immunologically active dose. We are bridging that dose from the Phase 1 ovarian study. And our plan is to go quickly into the combinations that I mentioned with azacitidine, venetoclax and with azacitidine monotherapy, it’s a azacitidine and azacitidine, venetoclax.

Okay. So I think that there’s no expectation of seeing substantial monotherapy activity there or developing in that direction…

If you don’t mind, Jon, I’ll just make one quick comment on that point. And our guidance around monotherapy antitumor activity for SL-172154 is based upon two things. It’s based upon what is known clinically about the expected monotherapy activity of the CD40 agonist, as well as what is known clinically about the expected activity of an FC silent CD47 inhibitor. And our interpretation of the 20-plus years experience we have the CD40 agonist antibodies in human clinical studies that, while some agents have shown sporadic monotherapy activity in tumors like melanoma, renal cell carcinoma and lymphoma, there is no consistent pattern of monotherapy activity, at least with the CD40 agonist antibodies. And because of that, we don’t feel that it’s appropriate to frame efficacy expectations around any CD40 agonist agents. On the CD47 side, the only agents that have shown monotherapy activity are those that have residual function in the Fc domain. CD47 inventory agents, which lack that function do not have monotherapy activity and they also don’t have tox. And so what that tells you with the CD47 inhibitors as a class is that the Fc domain and the characteristics of the Fc domain are in and of themselves sufficient to drive toxicity. However, what you notice about all CD47 inhibitors, regardless of whether the Fc domain is active or inactive, is that they are all pursuing registrational pathways in combination either with certain chemotherapies or ADCP-competent tumor targeted antibodies. And so you can then extend the conclusion a bit from there and say that while the Fc domain is sufficient for tox and sporadic monotherapy activity, it is insufficient to drive registration. And so with this agent, we are, again, framing expectations based upon SL-172154 being a CD47 inhibitor with an inactive Fc domain.

Great. Thank you. I think that’s very responsible. Maybe turning SL-279252, can you speak a little bit to the clinical relevance of OX40 stimulation pushing details into the periphery or out of the blood? Are there other signs of T-cell activation that go along with that? And granted, it’s tough to disambiguate what’s going on given the lack of PD-L1 positivity in many of these patients, but I’m trying to focus specifically on OX40 access PD and what that can tell us about successful immunostimulation.

Yes, thanks for the question, Jon. So OX40 is an antigen dependent CD4 specific T-cell co-stimulator. And so you expect the pharmacodynamic, at least the direct pharmacodynamic effects of OX40 stimulation to be centered on that T cell population. And more specifically to a subset of CD4 positive OX40 positive T cells that are actively encountering in this case tumor antigens. And in that subset of cells, you may expect those cells to rapidly carry, SL-279252 from the peripheral blood into tissues. And if that includes tumor tissues, then that could provide a means of actively transporting SL-279252 out of the blood and into peripheral tissues including tumors. And if those cells are being activated, then you would expect to see some signs of that. That could come in the form of changes to the immunophenotypic profile of those cells and patterns of activation markers or it could come in other forms. But it’s hard to say for sure because the human experience with OX40 antibodies contains very, very little in the way of convincing pharmacodynamic activity to date. And so I think we are in somewhat uncharted territory here for OX40 agonists, and therefore, we want to be sure that we fully explore the dose levels here and identify a dose level at which our OX40 biology at least as far as we can measure it has been maximized.

Great. Makes sense. Thank you very much.

Our next question comes from the line of Gil Blum from Needham. You may begin.

And congrats on all the progress. It looks like the both programs seem to be very safe. But as you dose escalate, do you expect at some point to start seeing some level of immune mediated tox, the sort of low grade rash, low grade CRS that are seeing sometimes with the immuno-oncology agents?

Sure. Thanks for the question. I’ll ask Lini to take this one.

Yes. As we dose escalate, given that we do have an agonist and to this molecule as well. We would expect to see some degree of talks. What we are very encouraged is that we are able to dose escalate through the lower doses, especially in the CD40 targeted with CD40 antibodies dose-limiting toxicity has picked you that dose escalation beyond a 0.3 milligrams per kilogram. We’ve been able to dose escalate to – we are currently at 3 milligrams per kilogram. And so it gives us an opportunity to dose escalate to the point that we have receptor occupancy on both CD40, as well as CD47 and be able to saturate those receptors. So I think we’re encouraged by this dose escalation that we’re able to do. But as you said, suddenly, I mean, we suddenly monitor our patients with a view to the fact that there could be toxicity at higher doses.

Okay. And on 252, just to clarify that I understood this correctly. So we’re discussing enrichment for patients who are PD-1 positive and PD-1 refractory following PD-1based therapy. Is that correct?

Yes, that’s correct. That’s correct. So the reason for that in dose escalation up to now, we did not really select for patients who are PD-L1 positive. We started at the very low dose and we wanted to get to the dose escalation as efficiently as possible to a point that we had an immunologically active dose range. And currently we are at that dose range. So moving forward, our plan is to select patients with no PD-L1 positivity. And the reason for that is that one end of our molecule bind PD-L1. And so it would make sense to actually select for that. Now we certainly acknowledged that these are patients who have failed PD-L1, PD-1 therapies, and have other mechanisms of resistance that may preclude them from responding to agents such as this.

Okay. That makes a lot of sense. And maybe a last one on the chip digit program, which we haven’t discussed too much today, following kind of the results in the space, ARC’s and others, has there been any additional disclosures regarding whether we’re going with an Fc active or an FC inactive here?

There has not been any additional disclosure yet, but we will be providing additional guidance around the next ARC program to enter the clinic later this year.

Okay, excellent. And we all definitely look forward for your results at SITC. Thank you for taking our questions.

Thanks for the questions.

And our last question will come from the line of Zhiqiang Shu from Berenberg. You may begin.

Hi, good afternoon. Thanks for taking my question. So on your first 154 program, the current dose is 3 milligram per kilogram. You – the next one is 10, it seems to be a big junk, I guess what gives you the level of comfort, you can dose escalate to more than two, three times at that, that you kind of dose. Curious you have to…

Sure. Hi Zhiqiang, thanks for the question. I’ll ask Lini to take that one as well.

We often dose escalate in this oncologist studies and half log increase. So that 3 to 10 is a reasonable increase. That’s a half log increase. And so depending on what we see, at 10, then we’ll determine whether we need to go higher or not. But right now that’s actually a very reasonable increasing.

Got it. And then in terms of next step, when you select a recommended Phase 2 dose and moving to the combination study as combination phase of the study, I guess what are the gating factors you’re looking for when you select dose – at a dose and when you want to combine with the rituximab in the trial?

Sure. So in general, what we’re looking for in identifying a recommended Phase 2 dose is to find a dose, which is well tolerated, where we see saturation of both targets of ARC compounds. So in the case of 172154 that will mean saturation, both CD47 and CD40. And where we see that, there has been a continued escalation and the on target pharmacodynamic effects that we expect to see downstream of that engagement. And wherein those pharmacodynamic effects have escalated up to a point and then reached a plateau, presumably after not every patient will reach maximum pharmacodynamic activation of CD40 or OX40 at the exact same dose. And so identification of a maximum plateau may improve the probability there’ll be selected dose, which maximizes the biology for all patients we might treat. Of course then, observation of anti-tumor activity is important. And then e should’ve mentioned this earlier, but also in narrowing the dose and schedule, we’ll be looking as well at the PK profile and ensuring that not only do we achieve full occupancy of the targets, but that there is sufficient free drug in the system to maintain full occupancy through the dosing interval. So collectively those are our – the vectors that we’re triangulating to pick a dose going into subsequent studies.

Great. Thanks, Taylor.

Sure. Thanks for the question.

Thank you. That’s all the time we have for today’s Q&A session of the call. At this time, I’d like to turn the call back over to Taylor Schreiber, Chief Executive Officer of Shattuck Labs for closing remarks.

Thank you, operator, and thank you all for joining the Shattuck Labs second quarter financial results and business updates conference call. We appreciate your continued interest in Shattuck, and we look forward to updating you on our milestones throughout the remainder of this year. Thanks very much.

This concludes today’s conference call. Thank you for participating. You may now disconnect. Have a wonderful day.