Thank you for standing by. Welcome to the Jasper Therapeutics Chronic Urticaria Data Update webinar. At this time, all attendees are in a listen-only mode. A question-and-answer session will follow the formal presentations. As a reminder, this call is being recorded, and a replay will be made available on the Jasper Investor Relations website following the conclusion of the event. I'd now like to hand the call over to Jasper's Head of Investor Relations, Alex Gray. Please go ahead, Alex.
Thank you, Tara, and thank you to those listening in today. Joining us for the prepared remarks are Jeet Mahal, CEO, and Daniel Edelman, Acting CMO. Also on the line is Herb Cross, CFO, who will be available during the Q&A session. We will be presenting slides on today's call, which are available via the webinar link and posted to our Investor Relations website. During today's event, we will be making forward-looking statements based on our estimates and assumptions and our current expectations and projections about future events. All statements other than statements of historical fact made during today's event are forward-looking statements. These statements are subject to a number of risks, assumptions, and uncertainties, any of which may be significant, and our actual results may differ materially and adversely from those stated or implied in any forward-looking statements.
For a description of risks and factors that could affect our future financial results and business, please refer to the disclosure in the accompanying slides, our most recent forms 10-K and 10-Q, and the reports that we have filed or may file on Form 8-K with the Securities and Exchange Commission. All of our statements are made as of today, January 8, 2026, based on information currently available to us. We can give no assurance that these statements will prove to be correct, and you should not rely on any forward-looking statements as predictions of future events. We undertake no duty to update any forward-looking statements except as required by law. I'll now hand the call over to Jeet Mahal. Jeet.
Good morning, and thank you for joining us this morning. We're excited to share updated data from our BEACON study in patients with chronic spontaneous urticaria and our open-label extension study in patients who have previously participated in either the BEACON study or in our SPOTLIGHT study evaluating patients with chronic inducible urticaria. First, I'd like to thank Ron Martell, Jasper's previous CEO, for his work at Jasper since he took on the role in 2022. Ron led the company through a pivotal period, refocusing briquilimab development into mast cell-driven diseases and helped us achieve positive proof of concept data in multiple patient populations, including CSU, CIndU, and allergic asthma.
Turning to today's data update, we are very pleased with the updated results in both the BEACON and the open-label extension study as briquilimab continues to demonstrate rapid onset of disease control, durable efficacy, and a safety profile favorable for chronic dosing. We believe this favorable efficacy and safety profile is driven by the unique properties of our antibody. Briquilimab binds to the KIT receptor with high affinity, directly blocking receptor signaling and triggering apoptosis of mast cells. The rapid and high Cmax following subcutaneous dosing leads to mast cell depletion, deep UAS7 score reduction, and disease control in the first two to four weeks. Drug clearance near the end of an eight-week dosing cycle allows for a reduction of KIT-related AEs and improved tolerability profile for patients.
Today's update includes data from eight additional patients in the BEACON study who were given an initial dose of 240 milligrams followed by 180 milligrams every eight weeks. Six of the eight patients received briquilimab, and two received placebo. Of the six patients in the active arm, five achieved complete response by week three, with four of six achieving a complete response at week 12. We have also enrolled two additional patients in the 240 milligram eight-week cohort, but those patients have not reached the 12-week primary efficacy endpoint, so no data will be reported on today. Today's update also includes data from 63 patients in our open-label extension study given 180 milligrams of briquilimab every eight weeks.
With median exposure of over 200 days, we are pleased to report that briquilimab has been efficacious and well tolerated, demonstrating a favorable chronic safety profile with low incidence of KIT-related adverse events. Overall, the data from BEACON and OLE support commencing a phase 2b study as part of the CSU registrational program expected to start in the second half of 2026. We expect this study to be conducted in approximately 75 to 100 adult patients with CSU evaluating two effective dose regimens versus placebo. I'll now hand it over to Dan to review the data in more detail.
Thank you, Jeet, and good morning. As Jeet noted, we are very pleased by the updated results we're presenting today. Among the additional patients enrolled in BEACON, we observed deep reductions in tryptase levels and meaningful clinical responses, with a mean reduction of UAS7 scores of 31 points at week 12. Additionally, onset of effect was rapid, with complete responses reported in the majority of patients by week two. Overall, five of six patients achieved a CR after initial 240 milligram loading dose, and four of six patients reported a CR at week 12 on the 180 milligram maintenance dose. In the CIndU portion of the open-label extension, we observed durable clinical responses following repeat dosing of briquilimab, where 65% of the CIndU patients achieved either a CR or a PR at week 16, which was eight weeks following the last dose.
In the CSU portion of the open-label extension, we saw progressive UAS7 reductions over time, supporting the possibility of 180 milligrams as a maintenance dose in CSU. Across both studies, briquilimab continues to demonstrate the potential for a differentiated safety profile. Lastly, and perhaps most importantly, we believe the data gathered to date are sufficient to enable final dose selection for our phase 2b study in CSU. Before reviewing the additional BEACON data in detail, I will provide a quick reminder on the trial design. The patients we are discussing today are from Cohort 9.1, in which the patients were administered a loading dose of 240 milligrams followed by 180 milligrams every eight weeks. There were eight additional patients enrolled in this cohort, six of whom received active drug and two received placebo.
We also enrolled two patients in cohort 8.1, evaluating a 240 milligram dose every eight weeks, but these patients have not yet reached the 12-week efficacy endpoint. Moving over to the pharmacodynamic results. As you can see, a rapid and deep reduction in tryptase levels was observed in these patients, which was consistent with what was observed in other cohorts. On this slide, we show weekly mean UAS scores through week 12 for cohort 9.1. At baseline, the patients in this cohort were highly symptomatic, as evidenced by the high mean UAS scores. As with the tryptase, the 240 milligram loading dose drove rapid and clinically significant reductions in UAS7 scores, and those reductions were largely sustained with a mean UAS7 drop of 31 points at week 12.
We show the corresponding response data for cohort 9.1, with the percentage of patients achieving complete responses defined as a UAS7 score equal to zero, shown in blue, and the percentage of patients achieving CR or well-controlled disease defined as a UAS7 score less than six in orange. Five of six patients achieved a CR by week three, with four of six reporting a CR at the week 12 endpoint. Moving on to safety, briquilimab was well tolerated and demonstrated a favorable safety profile in this cohort, shown here in the gray box. As the table shows, there were no dose-limiting toxicities reported and no discontinuations due to treatment-related adverse events among patients enrolled in this cohort. This slide shows safety and tolerability observations possibly related to KIT blockade.
In cohort 9.1, one patient experienced a taste change, and another experienced a neutrophil count decrease, which was transient and resolved while on study. KIT-related safety events remain generally limited to low-grade events, the majority of which resolved during repeat dosing, and none of which resulted in discontinuations or dose delays. The results give us confidence in the safety and tolerability profile of briquilimab and inform the dosing strategy for phase 2b, with the goal of minimizing the severity and duration of adverse events associated with KIT blockade. Moving to the open-label extension, this slide shows the design of the study. Following completion of their dosing and follow-up periods, patients enrolled in both the BEACON study and the SPOTLIGHT CIndU study were eligible to roll over to the open-label extension, evaluating briquilimab at 180 milligrams administered every eight weeks.
We're reporting the safety data from 63 patients and reporting efficacy data from the 53 patients who have completed at least 12 weeks on study. On this slide, we show the clinical responses for the 17 CIndU patients enrolled in the open-label extension. Of note, in the CIndU portion of the OLE, efficacy challenges were conducted at weeks two, 8, 16, and 24. With the exception of the week two assessment, all measurements were taken eight weeks following the last dose. In this study, we continue to see rapid onset of symptom control in CIndU, with 69% of patients achieving complete or partial responses at week two, and that effect was durable, with 65% of patients maintaining responses at week 16.
Moving to the CSU portion of the open-label extension, this slide shows UAS7 data for 36 patients through week 20 in the left panel and those achieving either a complete response or well-controlled disease in the right panel. As you can see, we continue to observe a progressive reduction in UAS7 scores over time. We will continue to see rapid onset of effect with responses observed as early as week one, and as indicated in the UAS7 data, these responses appear to increase over time, with 62% achieving a complete response at week 20, four weeks after the administration of the third dose. Finally, we have safety and tolerability data from the CSU and CIndU patients enrolled in the open-label extension. We now have 63 patients treated at 180 milligrams every eight weeks, with a median follow-up of over 200 days, and briquilimab continues to demonstrate a favorable safety profile.
As with Beacon and Spotlight, safety and tolerability observations possibly related to KIT inhibition were infrequent and generally limited to low-grade events, the majority of which resolved during repeat dosing. With that, I'll now hand the call back over to Jeet.
Thank you, Dan. Before we wrap up, I'll share a couple of brief thoughts on how we believe these data support a differentiated and competitive product profile for briquilimab in patients with CSU. As you can see, at 12 weeks, both the open-label extension study and the additional patients enrolled in the BEACON study show a robust rate of disease control after just a second dose of briquilimab. We believe that this data compares favorably to published data with other antibodies that bind to the KIT receptor. On this slide, we showed the weekly disease activity score for the additional BEACON cohort of nine patients described today, along with the previously shared BEACON 240 milligram and 360 milligram single-dose cohorts and the data from the CSU patients in the open-label extension.
Across these cohorts, we see a rapid and deep reduction in disease activity score two to three weeks after the initial briquilimab dose. We believe that this rapid efficacy is driven by briquilimab's unique mechanism of action, as well as briquilimab's ability to deliver a rapid and a high Cmax following subcutaneous dosing. Towards the end of the eight-week dosing cycle, we see some recovery of disease activity consistent with drug clearance based on briquilimab's half-life. We believe that this relaxation of KIT signal suppression allows us to dose briquilimab in a manner to minimize unwanted KIT-related adverse effects and potentially deliver improved tolerability profiles for patients with CSU or CIndU. To wrap up, I'd reiterate a few of our key takeaways from this update. First, briquilimab continues to demonstrate the ability to drive rapid, deep, and durable disease control, including clinical complete responses.
Second, we now have sufficient repeat dose safety data available to support a favorable chronic safety profile characterized by low frequency, low-grade, and transient KIT-related AEs. Third, we believe that the data are now sufficient to enable selection of two efficacious dose regimens for a phase 2b study in patients with CSU. We are targeting commencement of this study in the second half of 2026. Finally, we believe the totality of data from the BEACON, SPOTLIGHT, and open-label extension studies support a compelling product profile for briquilimab in chronic urticarias, with briquilimab's unique drug properties delivering rapid disease control while minimizing KIT-related AEs. With that, we'd like to open the meeting to questions. Operator?
Great. Thank you, Jeet. So at this time, we will be conducting a question-and-answer session with our speakers. To our analysts that are joining us live, we kindly ask that you limit your question to one. So please hold for a brief moment while we poll for questions. So our first question comes from Yaron Werber at TD Cowen. Please go ahead, Yaron. Yaron, you might be on mute.
Yep. Can you guys hear me okay?
Yes, we can.
Great. Thank you. Thanks so much, and Jeet, congrats on the promotion. Maybe I know you want to limit to one, but if you don't mind, I'm going to ask more than one because this is just a bit important. Maybe can you just give us a little bit of a sense with the change in CEO at this point? What was the thinking behind it and why do it now, so to speak? And then, secondly, as you think about the dose selection for the phase 2b, do you have any sense what doses you are going to take forward? Because one of the slides does show that at eight weeks, there is sort of a rebound of efficacy. So, was Q8-week the right dosing? And then finally, the phase 2b start keeps on getting pushed out.
What gives you confidence that you really can hit the second half guidance? Thank you.
Thanks, Yaron. Let me start with the timing and rationale behind the change of the CEO. Yeah, this was a decision driven by the Jasper Board, looking at the development stage of the company and the next stage of leadership needed to move the program forward into phase 2b and pivotal studies. So the board asked that I become the CEO, given my track record in development of multiple therapeutics from phase one or phase two through BLA or NDA submission. With regards to the phase 2b dose selection, this data is really fresh. I think it's a little premature to comment on specific doses, but needless to say, we'll be taking all of this data along with the previous data, updating our models, our pharmacometric and pharmacodynamic models, our disease response models, and looking forward to dose regimens for the next study.
We will come back to you and others when we have a better idea of what those are. We don't think that will take too long, but we want to make sure we get it right. Finally, your question about starting the study in the second half of 2026, part of that is driven by the timeline it took to generate this data and the timing we need to analyze that data to be confident that we are selecting the right doses and then having those discussions with the regulatory bodies. We believe that we're in good shape for starting the study later this year as we have sufficient drug supply at this point to run the study, and we have the operations in place to get it off the ground.
Great. Thank you for the questions, Yaron. Our next question comes from Gavin Clark-Gartner at Evercore. Please go ahead, Gavin.
Hey, guys. Thanks for taking the questions. I just wanted to ask, on the path forward for the phase 2b, is the plan still to run an adaptive phase 2b/3 type of design, or are you planning to run a separate phase 2b and then go into phase 3 after that? And also, what's the capital requirements or timing to reach that phase 2b data portion? Thank you.
Yeah, thanks, Gavin. Yeah, right now, the protocol is still an operationally adaptive phase 2b/3. Now, where we are today, we want to make sure that we have adequate time between the 2b and 3 portions to make sure that we're making the right dose selection. But in any case, that can be done in a single protocol with minimal breakage in time between the 2b results and the start of the phase 3. That would also require us to need to run a separate phase 3 once we start the phase 3 portion of that first study in order to have two well-controlled or two adequately controlled studies for registration. With regards to capital requirements, I'll pass that to herb.
Yeah, thanks for the question, Gavin. I think from a phase 2b perspective, we haven't given kind of specific guidance on that. Suffice it to say our current guidance is that existing capital gets us through the middle of this year and into the third quarter of this year. So there will be a need to raise capital, but we're not giving specific guidance on what those capital requirements are at this point.
All right, great. Thanks, guys.
Sure.
Thanks for the questions, Gavin. Our next question comes from Matt Phipps at William Blair. Please go ahead, Matt.
Thanks, guys, for taking my questions. Hey, Jeet, congrats. Happy for you to get this promotion to CEO. I was wondering if you could give us maybe some context on how meaningful a UAS7 rebound from, say, five to 10 is in that later weeks versus having less on-target adverse events like hair color change and taste change for a patient. And then I guess, at what point or maybe when do you think about potential partnerships to help fund some of the phase 2b and into phase 3? Thank you.
So let me answer the question about partnerships, and then I'll pass it over to Dan about the question regarding UAS7 disease activity return, balancing that versus the AE profile. Yeah, look, in terms of partnerships, this is, I think, a very compelling product that could really benefit from a larger partner looking at multiple indications. We've done the proof of concept studies here in CSU and CIndU, previously reported the allergic asthma data, and have previously reported proof of concept data in the Jasper mast model across multiple other diseases. So Jasper, I think, is in good shape to start the phase 2b for CSU, but really to pursue all of those indications in a broad life cycle plan would take the resources of a larger organization. So I think whenever that may occur, that is something that the company would take very seriously.
With that, I'll pass it over to Dan.
So Matt, thanks for the question. Really, it comes down to the question of the return of symptoms as indicated by UAS7 that goes from, say, less than six up to somewhere around 10 in a patient. And is this worth the trade-off for reduction of those undesirable on-target effects, KIT effects? And I think each individual patient has to ultimately be the judge of that. A lot of these patients are starting off with UAS7s in the 20s and 30s and even maybe sometimes low 40. And so a reduction of symptoms down to less than six is incredible relief. Many of them see flares of their disease almost on a daily basis.
And so a return of symptoms from, say, one, two, three, or four up to 10, followed by another dose and a reduction is probably a huge improvement in the quality of life over what they had prior to treatment. And if you can reduce things like the undesirable KIT inhibition effects, it's probably worth it. But as I said at the very beginning, each individual patient is going to have to be the judge for that.
Great. Thanks for the questions, Matt. Our next question comes from Josh Worman at Citizens JMP. Please go ahead, Josh.
Hi. Thanks for taking my question. This is Josh on for Silvan. Congrats, Jeet, on the promotion, and thanks for taking my question. Maybe just on the phase 2b trial, maybe can you discuss what sort of the gating factors are in that direction? And then also, what are the processes or first of how many sites will need to be activated in order to run that study? And then sort of what will be the processes in site selection going forward to ensure that you enroll the patient population that will be effective? Thank you.
Thank you, Josh. Maybe Dan, you want to take on the questions about process selection, and then I can talk about the operational issues.
Sure. And did you say patient selection or?
Site selection.
Site selection. So we are going to be looking at sites where we have investigators who have significant experience in the management of patients with CSU, preferably those who've participated in clinical trials previously. But we will be looking exclusively at allergists and dermatologists who have significant experience in the management of patients with CSU. That's first and foremost. And that's critically important to make certain that we are enrolling patients who, in fact, have CSU. That being said, as we've mentioned previously, even the very best of the key opinion leaders in the management of CSU will sometimes get the diagnosis wrong up to 20%-30% of the time. But we want to make certain that we minimize the number of patients who are enrolled who don't have CSU. So that's how we're going to be selecting our sites.
As far as the number of sites, one of the things that we will go through in our operations group is feasibility assessments for each of these sites, and then that will help us determine the number of patients that we can expect to be enrolled per site per month, and then we will determine the number of total sites.
Yeah. And Josh, in terms of the gating factors, of course, it's a pretty complex path to get a multi-country, multi-site phase 2b study off the ground with a high degree of quality. This is such an important step for the company. And there's a number of items. We don't wait to do them all in serial. When possible, we do as many of them parallel as possible. But some of them are in order, right? So one of our first things we need to do here is analyze the data that we presented today in more detail in order to drive dose selection, which would then allow us to finalize protocols, submit to regulatory authorities, start the kitting, the manufacturing.
As Dan also noted, there's going to be a lot of focus on making sure that we have the right processes in place to drive quality site selection and patient inclusion and exclusion criteria. We think that it's better to be a bit more careful on the front end in order to ensure high-quality conduct and results by the time the study is over.
Great. Thank you.
Thanks for the questions, Josh. Our next question comes from Emily Bodnar at H.C. Wainwright. Please go ahead, Emily.
Hi. Good morning. Thanks for taking the questions. Looking at the most recent cohort 9.1, it looks like maybe the first dose with the 240 mg had a better CR rate than once patients kind of transitioned to the 180 mg. So curious to get your thoughts on how you're expecting the 240 mg Q8 weekly dose to perform based on these initial results?
Dan, you want to give some thoughts, and I'll add if needed?
Emily, thanks for the question. It's far more complicated than you might imagine because some of these patients may be quite heavy. Some of them might be quite light. And I think one of the things that we're going to have to do before we finalize our dose selection for phase 2b is to see on a weight-adjusted exposure basis where the optimal dose might actually be. And so while I think we are pretty clear that the 240 is a decent loading dose, we may need to make some adjustments for patients who are heavier or patients who are considerably lighter. And as you can see, while we did have some return of the UAS7 increasing towards the end of the dosing interval with subsequent doses at 180, the UAS7 nadirs kept progressively going down.
As Jeet has mentioned previously, we have to do a lot of clear modeling and analytics of the current data prior to landing on what our final dose selections will be for the phase 2b.
Got it. Thank you.
Thanks for the question, Emily. Our next question comes from Justin Zelin at BTIG. Please go ahead, Justin.
Thanks for taking our question, and congrats, Jeet. So you outlined the phase 2b as a 75-100 patient study with two active dose regimens versus placebo. And you also mentioned that there's a known 20%-30% misdiagnosis rate in CSU. So I just was curious on how you're thinking about powering assumptions for the phase 2b, and as well as based on the data you presented today, how are you currently thinking about incorporating a loading dose into the phase 2b design?
I'll take the powering one and then pass the question about loading dose over to Dan. As you know, the primary efficacy endpoint for regulators is a change in the UAS7 score. For the BEACON study here, we picked 12 weeks, right? We already have quite a bit of data to analyze the doses that we've studied. Importantly, as Dan mentioned, the exposure levels versus placebo. We can model various efficacy rates with regards to the UAS7 changes versus placebo. We can model and do sensitivity analysis on misdiagnosis rates or inclusion of patients without mast cell-driven CSU. Those are all the pieces that we take into account when looking to adequately power a phase 2b study. Right now, the 75-100 is a preliminary estimate. We don't expect that to change significantly, but maybe plus or minus a bit.
With that, I'm going to ask Dan to weigh in on the concept of an initial or loading dose versus maintenance doses.
Yeah. For the phase 2b, we anticipate and nothing is finalized at this point, but what we're anticipating is that we will have a three-arm study, two different dose regimens, and then a placebo group. One of those dose regimens is likely to be a load followed by maintenance, and the other is likely to be a steady fixed dose on an eight-week dosing interval. As Jeet mentioned, we still have a lot of work to do analyzing the data that we have, as well as do some modeling to really ultimately land on the final selection. That being said, we do have enough data to be able to make an informed choice of those two active dosing regimens and will be more forthcoming with that once we've completed our analysis.
As far as dealing with the 20%-30% that's baked into who may not have CSU, that's going to be baked into our power calculations.
Thanks for taking the question.
Thank you for the questions, Justin. So this concludes today's Q&A session and today's event. We thank you for joining. You may now disconnect.