Aclaris Therapeutics, Inc 8-K, filed Oct 27, 2026
Aclaris Therapeutics, Inc. (ACRS)
About this 8-K
Aclaris Therapeutics, Inc filed this 8-K on October 27, 2026.
Aclaris Therapeutics reported ATI-052 achieved 45% placebo-adjusted EASI improvement at day 57 in atopic dermatitis and 59% FeNO reduction at day 15 in asthma, and plans a Phase 2b eosinophilic esophagitis trial in early 2027. AI summary
Items reported
- Item 2.02: Financial results
- Item 7.01: Regulation FD disclosure
- Item 8.01: Other events
- Item 9.01: Financial statements and exhibits
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM
CURRENT REPORT
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Item 2.02 Results of Operations and Financial Condition.
The information disclosed under the heading “Cash, Cash Equivalents and Marketable Securities as of September 30, 2026” under Item 8.01 of this Current Report on Form 8-K is incorporated herein by reference.
Item 7.01 Regulation FD Disclosure.
On October 27, 2026, Aclaris Therapeutics, Inc. (the “Company”) issued a press release announcing primary analysis results from the Phase 1b proof-of-concept (“POC”) trials of its anti-TSLP/IL-4Rα bispecific antibody ATI-052 in atopic dermatitis (“AD”) and asthma (the “Results”). The Company also announced it would hold a webcast and conference call with slides related to the Results. A copy of the press release and the presentation that will accompany the webcast and conference call are furnished as Exhibit 99.1 and Exhibit 99.2, respectively, to this Current Report on Form 8-K.
In accordance with General Instruction B.2. of Form 8-K, the information in this Item 7.01 and Item 9.01 (including Exhibits 99.1 and 99.2) shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any of the Company’s filings under the Securities Act of 1933, as amended, or under the Exchange Act, whether made before or after the date hereof, regardless of any incorporation language in such a filing, except as expressly set forth by specific reference in such a filing.
Item 8.01 Other Events.
Cash, Cash Equivalents and Marketable Securities as of September 30, 2026
Based upon preliminary estimates and information available to the Company, it estimates that its cash, cash equivalents and marketable securities were approximately $204.6 million as of September 30, 2026. This amount has not been audited, reviewed, or compiled by the Company’s independent registered public accounting firm. The Company’s actual cash, cash equivalents and marketable securities as of September 30, 2026 may differ from this amount after it completes its comprehensive accounting procedures for the quarter ended September 30, 2026, and any such differences may be material.
Primary Analysis Results
The Results announced are summarized below.
Phase 1b POC Trial in AD
The randomized, double-blind, placebo-controlled Phase 1b trial evaluated the safety and tolerability of ATI-052 compared with placebo in 14 patients with severe AD. Patients were randomized 3:1 to receive five weekly doses of 480 mg of ATI-052 or placebo from weeks 0 through 4. Endpoints for the primary analysis were assessed at day 57.
Four patients were excluded from the prespecified per-protocol analysis for reasons defined before unblinding. Two patients in the ATI-052 arm were excluded because one received only two doses and one did not meet the eligibility criteria. Two patients in the placebo arm were excluded because they took rescue medication early in the study. The resulting per-protocol population consisted of nine patients in the ATI-052 arm and one patient in the placebo arm. Among per-protocol patients in the ATI-052 arm, 78% had severe disease at baseline, as defined by a score of 4 on the Validated Investigator’s Global Assessment (“vIGA”).
Primary analysis results from the AD trial included:
Eczema Area and Severity Index (“EASI”) Score:
| ● | Patients treated with ATI-052 experienced a 45% placebo-adjusted mean improvement in EASI score from baseline at day 57, reflecting a 58% mean improvement in the ATI-052 arm compared with a 13% mean improvement in the placebo arm. Patients treated with ATI-052 experienced a 62% mean improvement from baseline in EASI score at week 10 and EASI improvement was maintained through week 16, for the subset of patients with available data. |
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| ● | In post hoc analyses of patients treated with ATI-052, mean improvements from baseline in EASI score at week 10 were 82% among patients with a baseline vIGA of 3 and 56% among those with a baseline vIGA of 4. |
| ● | Patients treated with ATI-052 experienced a 78% placebo-adjusted EASI-50 at day 57. Of those, in a post-hoc analysis, 100% of patients with a baseline severity of vIGA 3 achieved placebo-adjusted EASI-50 at day 57 compared to 71% of patients with a baseline severity of vIGA 4. |
| ● | In a post-hoc analysis, 89% of subjects treated with ATI-052 achieved EASI-50 during the study. |
Peak Pruritus Numerical Rating Scale (“PP-NRS”):
| ● | Improvement in itch was observed in the first week and continued to deepen through week 10 in patients with available data. |
| ● | At week 4, patients that received ATI-052 experienced a 40% placebo-adjusted mean improvement from baseline and absolute mean improvement from baseline in PP-NRS. |
| ● | At day 57, patients that received ATI-052 experienced a 43% placebo-adjusted mean improvement in PP-NRS, reflecting a 38% mean absolute improvement in the ATI-052 arm compared with a 5% mean worsening in the placebo arm. |
| ● | At day 57, patients treated with ATI-052 achieved a placebo-adjusted response rate of 33% for a ≥4-point improvement from baseline in PP-NRS. |
Pharmacodynamic Results:
| ● | At day 57, patients treated with ATI-052 experienced a 95% overall improvement in the difference between lesional and non-lesional skin proteome. |
| ● | ATI-052 broadly downregulated inflammatory pathways, with modulation across multiple inflammatory mediators in AD, including Th1, Th2 and Th17/Th22, fibrosis/extracellular matrix remodeling and itch-associated molecular pathways. |
| ● | ATI-052 produced a pronounced reduction of established dupilumab-associated biomarkers and additionally suppressed Th1, Th17 innate and myeloid pathways. Endogenous serum biomarkers, including CCL17, IL-5, and blood eosinophils, were also reduced. |
Phase 1b POC Trial in Asthma
The randomized, double-blind, placebo-controlled Phase 1b trial evaluated the safety and tolerability of a single 480 mg dose of ATI-052 compared with placebo in 16 patients with mild-to-moderate asthma and baseline fractional exhaled nitric oxide (“FeNO”) of at least 35 parts per billion. Patients were randomized 3:1 to receive a single 480 mg dose of ATI-052 or placebo. Endpoints for the primary analysis were assessed through day 29. The analysis population consisted of 12 patients in the ATI-052 arm and four patients in the placebo arm.
Primary analysis results from the asthma trial included:
FeNO:
| ● | At day 15, patients that received ATI-052 experienced a 59% mean reduction from baseline in FeNO, representing a mean absolute reduction of 45 parts per billion, compared with a 15% mean reduction in the placebo arm. |
| ● | A 40% mean reduction from baseline in FeNO was observed at day 29 in patients that received ATI-052. |
| ● | At day 15, 58% of patients that received ATI-052 achieved FeNO normalization, defined as FeNO of 25 parts per billion or less. |
| ● | In a post-hoc analysis, at day 15, patients treated with ATI-052 experienced FeNO reductions of 60% in the eosinophil ≥300 subgroup (T2-high) and 58% in the eosinophil <300 subgroup (T2-low). |
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Forced Expiratory Volume in One Second (“FEV1”):
| ● | At day 15, patients that received ATI-052 experienced a 200 mL placebo-adjusted and absolute mean improvement in FEV1. |
| ● | In a post hoc subgroup analysis of patients with baseline pre-bronchodilator FEV1 of less than 80% predicted and qualifying reversibility, patients that received ATI-052 experienced a 350 mL mean improvement from baseline in FEV1 at day 15, compared with a 140 mL mean decrease from baseline in the placebo arm. |
| ● | In a post-hoc analysis, FEV1 improvement was also observed in T2-high and T2-low subgroup populations. |
Area Under Reactance Curve (“AX”):
| ● | In a post-hoc analysis, at day 15, patients treated with ATI-052 experienced a placebo-adjusted AX change of −28 cmH₂O·L⁻¹ in patients with baseline FEV1 <80% predicted and qualifying reversibility. |
Safety and Tolerability
ATI-052 was well tolerated across both trials and demonstrated a favorable safety profile. Treatment-emergent adverse events (“TEAEs”) were predominantly Grade 1. There were no Grade 3 or Grade 4 TEAEs, and no adverse events led to study discontinuation. Injection-site reactions were transient, almost exclusively Grade 1 and observed at a low frequency. No conjunctivitis was observed.
Pipeline Update
The Company intends to prioritize the clinical development of ATI-052 initially in eosinophilic esophagitis (“EoE”). The Company intends to initiate a Phase 2b trial of ATI-052 in EoE in early 2027 and expects to provide an update regarding plans for the potential development of ATI-052 in an additional indication in the near term.
Cautionary Note Regarding Forward-Looking Statements
This Current Report on Form 8-K contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Exchange Act, and such forward-looking statements are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements may be identified by words such as “anticipate,” “believe,” “expect,” “intend,” “may,” “plan,” “potential,” “will,” and similar expressions, and are based on the Company’s current beliefs and expectations. These forward-looking statements include expectations regarding the Company’s development plans for ATI-052, including its intention to prioritize development of ATI-052 initially in EoE, the timing to initiate a Phase 2b trial of ATI-052 in EoE and the timing and plans to pursue development of ATI-052 in additional indications, the therapeutic potential for ATI-052, and the Company’s preliminary estimate of its cash, cash equivalents and marketable securities as of September 30, 2026. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements. Risks and uncertainties that may cause actual results to differ materially include uncertainties inherent in the conduct of clinical trials, potential changes to interim, topline and preliminary data as more subject data become available, the Company’s reliance on third parties over which it may not always have full control, the Company’s ability to enter into strategic partnerships on commercially reasonable terms, the uncertainty regarding the macroeconomic environment and other risks and uncertainties that are described in the Risk Factors section of the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, and other filings the Company makes with the U.S. Securities and Exchange Commission from time to time. These documents are available under the “SEC Filings” page of the “Investors” section of the Company’s website at www.aclaristx.com. Any forward-looking statements speak only as of the date of this Current Report on Form 8-K and are based on information available to the Company as of the date of this Current Report on Form 8-K, and the Company assumes no obligation to, and does not intend to, update any forward-looking statements, whether as a result of new information, future events or otherwise.
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Item 9.01 Financial Statements and Exhibits.
(d) Exhibits
Exhibit |
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Number | Exhibit Description | |
99.1 | | |
99.2 | | |
104 | The cover page from Aclaris Therapeutics, Inc.’s Form 8-K filed on October 27, 2026, formatted in Inline XBRL. |
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SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
| | ACLARIS THERAPEUTICS, INC. |
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| By: | /s/ Kevin Balthaser |
Date: October 27, 2026 | | Kevin Balthaser |
| | Chief Financial Officer |
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Exhibit 99.1
Aclaris Therapeutics Announces Positive Phase 1b Proof-of-Concept Primary Analysis Results for its Anti-TSLP/IL-4Rα Bispecific ATI-052 in Atopic Dermatitis (AD) and Asthma
- Results Demonstrated Breadth and Rapidity of Response to ATI-052 in Heterogeneous Patient Populations; Pharmacodynamic Results Demonstrated Potential for Additivity/Synergy of Targeting TSLP and IL-4Rα -
- Rapid and Durable Improvement in Skin and Itch Observed in Severe AD Population with ATI-052; Single Dose Rapidly Improved Airway Inflammation and Lung Function in Diverse Asthma Population -
- ATI-052 Demonstrated Favorable Safety and Tolerability Profile Including No Observations of Conjunctivitis -
- Aclaris to Prioritize Development in Eosinophilic Esophagitis (EoE), Consistent with Development Strategy -
- Aclaris to Host Conference Call this Morning at 8:00 AM ET-
WAYNE, Pa., October 27, 2026 -- Aclaris Therapeutics, Inc. (NASDAQ: ACRS), a clinical-stage biopharmaceutical company focused on developing novel product candidates for immuno-inflammatory diseases, today announced positive primary analysis results from the Phase 1b proof-of-concept (POC) trials of its anti-TSLP/IL-4Rα bispecific antibody ATI-052 in atopic dermatitis and asthma. Both trials demonstrated strong proof-of-concept with rapid and broad responses to ATI-052, further validating the additive/synergistic potential of simultaneously targeting TSLP, IL-4, and IL-13 with a bispecific anti-TSLP/IL-4Rα antibody, and achieved the primary objective, showing a favorable safety profile including no observations of conjunctivitis. Slides accompanying this announcement will be available for download at the time of the conference call here.
Aclaris intends to prioritize Phase 2b development of ATI-052 initially in EoE, where the Company believes a focused development program is well aligned with its development strategy and disciplined capital management.
“These strong results convey ‘the art of the possible’ with this bispecific mechanism in heterogeneous diseases across diverse patient populations and support that this is a potent, broadly acting compound with potential best-in-class activity,” said Dr. Neal Walker, Chief Executive Officer of Aclaris. “Across heterogeneous patient populations, we observed breadth and depth of response, normalization of the immune proteome, encouraging early durability, evidence of potential synergy of targets, and a favorable safety profile associated with ATI-052 – all of which clarify its potential across indications. Consistent with our development strategy, we intend to prioritize initiating a Phase 2b trial in EoE early next year and provide an update on plans for a potential additional indication in the near term.”
Primary Analysis Results: Safety
ATI-052 was well tolerated across both trials and demonstrated a favorable safety profile. Treatment-emergent adverse events (TEAEs) observed in these POC trials were predominantly Grade 1. There were no Grade 3 or 4 TEAEs, and no adverse events led to study discontinuation. Injection site reactions (ISR) were transient, almost exclusively Grade 1, and observed at a low frequency. No conjunctivitis was observed.
Phase 1b POC Trial in Atopic Dermatitis (AD)
The randomized (3:1), double-blind, placebo-controlled Phase 1b trial evaluated the safety and tolerability of ATI-052 compared with placebo in 14 patients with severe AD. Enrolled patients received five weekly doses of 480 mg of ATI-052 or placebo from weeks 0 through 4, and endpoints for the primary analysis were assessed at day 57. Four patients were excluded from the prespecified per-protocol analysis for reasons defined before unblinding: Two in the
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ATI-052 arm (only two doses taken; eligibility criteria not met) and two in the placebo arm (both began rescue medication early on). Among per-protocol patients in the active arm, 78% had severe disease at baseline, as defined by a score of 4 on the Validated Investigator’s Global Assessment (vIGA), setting a high bar for success.
Primary Analysis Results: AD
Eczema Area and Severity Index (EASI) Score
· | Patients treated with ATI-052 experienced a 45% placebo-adjusted mean change in EASI score from baseline at day 57 (absolute change of 58% in the active arm vs 13% in the placebo arm). Responses were durable for the subset of patients with available data at week 16 (follow up ongoing). |
· | Patients treated with ATI-052 experienced a 78% placebo-adjusted EASI-50 at day 57. Of those, 100% of patients with a baseline severity of vIGA 3 achieved placebo-adjusted EASI-50 at day 57 compared to 71% of patients with a baseline severity of vIGA 4. |
Peak Pruritus Numerical Rating Scale (PP-NRS)
· | Itch relief emerged in the first week and continued to deepen through week 10 in patients with available data despite high baseline disease severity. At week 4, patients that received ATI-052 experienced a 40% placebo-adjusted and absolute mean improvement from baseline in itch (PP-NRS). |
· | Patients that received ATI-052 experienced a 43% placebo-adjusted mean improvement in itch (PP-NRS) at day 57 (38% absolute improvement in the active arm vs a 5% worsening in the placebo arm). |
· | At day 57, 33% of patients experienced a placebo-adjusted mean improvement of ≥4-points in itch (PP-NRS4). |
“These ATI-052 data in AD are very noteworthy, not only in strength of response at day 57 but also in rapidity and durability of response,” said Dr. Michael Cameron, M.D., FAAD, CEO of Equity Medical and Assistant Clinical Professor, Department of Dermatology at Mount Sinai in New York, and an investigator in the trial. “Given the mechanism of ATI-052, one would expect reductions in EASI and itch from baseline to be rapid and sustained due to blockade of IL-4 and IL-13 via their shared receptor IL-4Rα, and durable through blockade of the TSLP alarmin. This is consistent with my experience during the trial. For example, one of my longstanding refractory patients responded quickly to ATI-052 and had a durable response that lasted months beyond their last dose. This bodes well for the mechanism in future clinical trials.”
Pharmacodynamic (PD) Results
· | 95% normalization in the lesional skin proteome was observed at week 8 in patients that received ATI-052, with immune protein expression resembling that of non-lesional skin. |
· | ATI-052 broadly downregulated pathways, with modulation across multiple inflammatory mediators in AD, including Th1, Th2 and Th17/Th22, fibrosis/ECM remodeling, and itch-associated molecular pathways. |
· | ATI-052 produced a pronounced reduction of the established dupilumab biomarkers, additionally suppressing Th1, Th17 innate, and myeloid pathways, suggesting a potential best-in-class footprint. |
“These ATI-052 pharmacodynamic biomarker results in patients with AD are clear, and significantly correlated to the efficacy results,” said Emma Guttman, M.D., Ph.D., Waldman Professor of Dermatology and Immunology and Health System Chair of the Kimberly and Eric J. Waldman Department of Dermatology at the Icahn School of Medicine at Mount Sinai in New York City. “Among the most important findings were the overall improvements to the immune
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proteome in patients receiving ATI-052; key immune proteins were significantly downregulated by ATI-052 compared to placebo, potentially highlighting the contribution of added benefit of blocking TSLP in this indication, with the proteomic phenotype of lesional skin closely resembling that of non-lesional skin already at week 8. These results, including ATI-052’s ability to modulate all three T helper cell related markers, are suggestive of early potent anti-inflammatory clinical activity.”
Phase 1b POC Trial in Asthma
The randomized (3:1), double-blind, placebo-controlled Phase 1b trial evaluated the safety and tolerability of a single 480 mg dose of ATI-052 compared with placebo in 16 patients with mild-to-moderate asthma and baseline fractional exhaled nitric oxide (FeNO) of at least 35 parts per billion (ppb). Endpoints were assessed through day 29.
Primary Analysis Results: Asthma
Fractional Exhaled Nitric Oxide (FeNO)
· | Following a single dose of ATI-052, patients experienced a rapid 59% mean absolute reduction in FeNO (45 ppb) only 15 days after administration compared to 15% in the placebo arm, and a 40% reduction at day 29. |
· | 58% of patients on ATI-052 achieved FeNO normalization (≤25 ppb) at day 15 after a single dose, highlighting the rapid onset of response. |
Forced Expiratory Volume in One Second (FEV1)
· | Following a single ATI-052 dose, patients responded rapidly, experiencing a placebo adjusted and absolute mean improvement of 200 ml in FEV1 only 15 days after administration. |
· | In a post hoc subgroup analysis of the enrolled patients with FEV1 of <80% at baseline with reversibility, which models the typical Phase 2b/3 eligible population of patients, an absolute mean improvement in FEV1 of 350 ml from baseline was observed at day 15 compared to a worsening of FEV1 of -140 ml in the placebo arm. |
“In such a Phase 1b trial, the goals are to ensure safety and to develop some encouraging signals; in this case, the results are significantly better than encouraging,” said Dr. Chris Brightling, Clinical Professor in Respiratory Medicine at the University of Leicester and Deputy Director and Respiratory and Infection Theme Lead, NIHR Biomedical Research Centre: Leicester. “Of particular interest are the rapid improvements in the breath biomarker FeNO, both in the overall population and when stratified by baseline eosinophils, and the lung function test FEV1, with maximum effects that are at least as good if not improving on those seen by comparator compounds.”
Webcast and Conference Call
Aclaris will host a webcast and conference call with slides today at 8:00 AM ET to discuss the Phase 1b POC primary analysis results in asthma and AD. The live and archived webcast will be available on the Events page of the Company’s website: https://investor.aclaristx.com/events. The webcast will be archived on the same page for 30 days following the event. If you would rather access the call via telephone: To register and receive a dial in number and unique PIN to access the live conference call, please follow this link to register online. Upon registering you will receive the dial-in info and a unique PIN to join the call as well as an email confirmation with the details.
About ATI-052
ATI-052 is an investigational humanized anti-TSLP and anti-IL-4Rα bispecific antibody that simultaneously inhibits thymic stromal lymphopoietin (TSLP) and interleukin-4 receptor (IL-4Rα) with high affinity and potency. By targeting TSLP, which sits at the top of the inflammatory cascade, it inhibits a broad range of inflammation; by targeting IL-4Rα,
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it blocks downstream signaling of both IL-4 and IL-13, which are key cytokines involved in Th2-mediated inflammation and allergic diseases. The TSLP binding interface of ATI-052 allows it to extensively bind TSLP, uniquely binding all six light chain and heavy chain CDRs. ATI-052 demonstrates very slow dissociation kinetics from TSLP with a residence time up to 116x longer than comparator antibodies. It exhibits potential best-in-class potency and utilizes the same TSLP antigen-binding fragment (Fab) region as the Company’s monoclonal antibody bosakitug (ATI-045), retaining the dissociation kinetics, long residence time, and high potency advantages over comparator antibodies, but is engineered to bind more tightly to the neonatal Fc receptor (FcRn) to extend its half-life. ATI-052 has the potential to treat a variety of atopic, immunologic and respiratory diseases. Aclaris has the exclusive worldwide rights to ATI-052, excluding Greater China.
About Aclaris Therapeutics, Inc.
Aclaris Therapeutics, Inc. is a clinical-stage biopharmaceutical company developing a pipeline of novel product candidates to address the needs of patients with immuno-inflammatory diseases who lack satisfactory treatment options. The company has a multi-stage portfolio of product candidates powered by a robust R&D engine. For additional information, please visit www.aclaristx.com and follow Aclaris on LinkedIn.
Cautionary Note Regarding Forward-Looking Statements
Any statements contained in this press release that do not describe historical facts may constitute forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements may be identified by words such as “anticipate,” “believe,” “expect,” “intend,” “may,” “plan,” “potential,” “will,” and similar expressions, and are based on Aclaris’ current beliefs and expectations. These forward-looking statements include expectations regarding its development plans for ATI-052, including its intention to prioritize development of ATI-052 initially in EoE, the timing to initiate a Phase 2b trial of ATI-052 in EoE and the timing and plans to pursue development of ATI-052 in additional indications, the therapeutic potential for ATI-052, including the potential for ATI-052 to be best-in-class, the potential for ATI-052 to provide additive or synergistic activity through the simultaneous inhibition of TSLP and IL-4Rα, and the potential for ATI-052 to treat atopic, immunologic, and respiratory diseases. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements. Risks and uncertainties that may cause actual results to differ materially include uncertainties inherent in the conduct of clinical trials, risks associated with interim, topline and preliminary data, Aclaris’ reliance on third parties over which it may not always have full control, Aclaris’ ability to enter into strategic partnerships on commercially reasonable terms, the uncertainty regarding the macroeconomic environment and other risks and uncertainties that are described in the Risk Factors section of Aclaris’ Annual Report on Form 10-K for the year ended December 31, 2025 and other filings Aclaris makes with the U.S. Securities and Exchange Commission from time to time. These documents are available under the “SEC Filings” page of the “Investors” section of Aclaris’ website at www.aclaristx.com. Any forward-looking statements speak only as of the date of this press release and are based on information available to Aclaris as of the date of this release, and Aclaris assumes no obligation to, and does not intend to, update any forward-looking statements, whether as a result of new information, future events or otherwise.
Aclaris Therapeutics Contact:
Will Roberts
Senior Vice President
Corporate Communications and Investor Relations
(484) 329-2125
wroberts@aclaristx.com
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Exhibit 99.2
| EMPOWERING PATIENTS THROUGH THERAPEUTIC INNOVATION October 27, 2026 ATI-052 Phase 1b Primary Analysis Results Atopic Dermatitis and Asthma |
| 2 Any statements contained in this presentation that do not describe historical facts may constitute forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements may be identified by words such as “anticipate,” “believe,” “expect,” “intend,” “may,” “plan,” “potential,” “will,” and similar expressions, and are based on Aclaris’ current beliefs and expectations. These forward-looking statements include expectations regarding the therapeutic potential of ATI-052, an investigational bispecific antibody, including the potential for ATI-052 to be best-in-class and have best-in-class attributes, the potential to increase the efficacy ceiling and show superior activity compared to other therapies, the potential for ATI-052 to have up to quarterly dosing, the potential for synergy of TSLP and IL-4Rα, the market opportunity for ATI-052, and the development of ATI-052 and Aclaris’ other product candidates, including the potential targets and indications Aclaris may pursue, the timing and number of regulatory filings, the design of future clinical trials, the timing for the initiation of clinical trials, and the availability and timing of data from clinical trials. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements. Risks and uncertainties that may cause actual results to differ materially include uncertainties inherent in the conduct of clinical trials, potential changes to interim, topline and preliminary data as more subject data become available, Aclaris’ reliance on third parties over which it may not always have full control, Aclaris’ ability to enter into strategic partnerships on commercially reasonable terms, the uncertainty regarding the macroeconomic environment and other risks and uncertainties that are described in the “Risk Factors” section of Aclaris’ Annual Report on Form 10-K for the year ended December 31, 2025, and other filings Aclaris makes with the U.S. Securities and Exchange Commission from time to time. These documents are available under the “SEC Filings” page of the “Investors” section of Aclaris’ website at www.aclaristx.com. Any forward-looking statements speak only as of the date of this presentation and are based on information available to Aclaris as of the date of this presentation, and Aclaris assumes no obligation to, and does not intend to, update any forward-looking statements, whether as a result of new information, future events or otherwise. Tradenames, trademarks and service marks of other companies appearing in this presentation are the property of their respective owners. This presentation also contains estimates and other statistical data made by independent parties and by us relating to market size and other data about our industry. These data involve a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of the markets in which we operate are necessarily subject to a high degree of uncertainty and risk. All future development, clinical, and regulatory timelines are expectations, are based on current beliefs and assumptions, and are subject to change based on a variety of factors. Disclaimer and Cautionary Note Regarding Forward-Looking Statements |
| 3 4x More potent than dupilumab + tezepelumab combined $19B+1 In annual sales across the mechanisms it targets ATI-052: Potential Best-in-Class Bispecific mAb Phase 1b POC Results Validate Preclinical Potency Differentiation OVERVIEW: PROOF-OF-CONCEPT RESULTS 400+ hours Up to 116x longer residence time on TSLP than comparator antibodies Combines two significant mechanisms in one molecule: anti-TSLP, anti-IL-4Rα Demonstrated potential for additivity/synergy of targets Proof-of-Concept Achieved in Atopic Dermatitis (AD) & Asthma Modulated all three TH cell endotypes: Th1, Th2, Th17 Potential to raise efficacy ceiling + provide rapid response Favorable tolerability profile observed Up to Quarterly Dosing potential 1. Regeneron Pharmaceuticals, Q4 and Full Year 2025 Financial and Operating Results, Jan. 30, 2026 (FY’25 Dupixent® annual sales) and AstraZeneca, Full Year and Q4 2025 Results, Feb. 10, 2026 (FY‘25 Tezspire® annual sales). |
| 4 OVERVIEW: MECHANISM OF ACTION Two Validated Mechanisms A More Complete Approach to Inflammatory Disease ATI-052 Pathways Simultaneous control of upstream disease initiation and downstream Type 2 effector pathways ATI-052 IgG1 anti-TSLP / anti-IL-4Rα bispecific antibody Molecular architecture • Bivalent for both TSLP and IL-4Rα (four total binding sites) • Unique multi-paratopic TSLP binding • Potential best-in-class potency for TSLP with long retention time • YTE Fc mutation engineered for T1/2 extension Anti-IL-4Rα scFv Anti-IL-4Rα scFv Anti-TSLP Fab Anti-TSLP Fab YTE Mutation FcRn-mediated half-life extension |
| Individual Components of ATI-052 are Both Important ATI-052 Targets The Two Most Broadly Validated Nodes In Type 2 Disease: TSLP and IL-4Rα Approval Status by Indication/Mechanism TSLP IL-4Rα IL-13 EoE ✓ ✓ ✕ Asthma ✓ ✓ ✕ COPD ✕ ✓ ✕ CRSwNP ✓ ✓ ✕ AD ✓ ✓ Validated 3/5 5/5 1/5 ✓ Approved ✕ Not approved IL-13–selective antibodies have failed to show competitive efficacy to dupilumab in late-stage trials in asthma and EoE 0 of 8 IL-13–selective programs approved in asthma or EoE ASTHMA 6 programs, none approved ✕ Lebrikizumab Roche ✕ Tralokinumab AstraZeneca ✕ GSK679586 GSK ✕ Anrukinzumab Pfizer ✕ IMA-026 Pfizer ✕ Dectrekumab Novartis EoE 2 programs, none approved ✕ Dectrekumab Novartis ✕ Cendakimab BMS SOURCE: DUPIXENT, TEZSPIRE, ADBRY and EBGLYSS U.S. Prescribing Information; AstraZeneca. TEZSPIRE Phase III CROSSING trial in EoE. Press release, Oct. 20, 2026. OVERVIEW: TARGET BIOLOGY NOTE: Approved = FDA-approved. EoE = Eosinophilic Esophagitis; COPD = Chronic Obstructive Pulmonary Disease; CRSwNP = Chronic Rhinosinusitis with Nasal Polyps; AD = Atopic Dermatitis Blocking IL-4Rα blocks both IL-4 and IL-13 IL-4 biology is directly implicated in asthma and other Th2 diseases 5 NDA Filing Expected ✕ |
| Lebrikizumab: Absolute EASI Response (%) at Week 16 0 20 40 60 80 63.5 46.1 EASI ≤7 56.5 40.0 EASI ≤5 41.7 30.8 EASI ≤3 24.2 16.6 EASI ≤1 Moderate (IGA3) Severe (IGA4) Baseline Severity Impacts Response Rates PHASE 1b POC TRIAL I SIGNIFICANCE OF BASELINE SEVERITY IN AD % of patients Difficulty in Treating Severe AD Understanding Severity: • Two ways to determine severity: EASI and vIGA; both must be assessed • EASI incorporates both extent and severity; vIGA provides a direct measure of disease severity Absolute vs. Relative Reduction: • Patients with severe disease need a larger improvement in score than those with milder disease to reach the same target score. Severe AD represents a higher bar for success NOTE: EASI = Eczema Area and Severity Index; vIGA = Validated Investigator’s Global Assessment; PP-NRS4 = ≥4 points of reduction from baseline in weekly averages of Peak Pruritus Numerical Rating Scale SOURCE: Dupilumab: SOLO 1 and 2 pooled (Weidinger S, et al. JEADV Clin Pract. 2023;2:247–260). Lebrikizumab: Advocate trials 250 mg q2w (Thaçi D, et al. Acta Derm Venereol. 2026;106:0160). 50 59 40 24 36 36 0 20 40 60 80 vIGA 0/1 EASI-75 PP-NRS4 % of patients Dupilumab: Absolute Response Rate (%) at Week 16 Moderate (IGA3) Severe (IGA4) 6 |
| ATI-052 Positive Phase 1b Primary Analysis Results: AD Strong POC in Severe AD (78% vIGA4); Efficacy Signals Support Advancement to Phase 2 CLINICAL RESULTS OVERVIEW: AD Favorable safety profile with no conjunctivitis observed ATI-052 has the potential to set a new efficacy ceiling in AD and other Th2 driven diseases Measure (D57) ATI-052 Load-in Doses (480 mg) Placebo % Reduction from Baseline in EASI 58% 13% 45% EASI-50 78% 0% 78% % PP-NRS Reduction 38% -5% 43% NOTE: ATI-052 efficacy results presented on per-protocol population. Missing data were not imputed. Sample sizes vary by endpoint and visit. PBO = placebo; PP-NRS = Peak Pruritus Numerical Rating Scale; EASI = Eczema Area and Severity Index; PD = pharmacodynamic; vIGA = Validated Investigator’s Global Assessment Sustained skin improvement Encouraging Early Endpoints Itch Improvement PBO-Adj. Change Objective PD Biomarker Analysis Deep reduction of established AD biomarkers & suppression of Th1, Th2, Th17 and myeloid inflammatory pathways observed Evidence of Additivity / Synergy 7 Safety and Tolerability Strong tolerability profile |
| ATI-052 Positive Phase 1b Primary Analysis Results: Asthma Strong POC in Mild-to-Moderate Asthma; Rapid Response Supports Advancement to Phase 2 CLINICAL RESULTS OVERVIEW: ASTHMA Measure (D15) ATI-052 Single Dose (480mg) Placebo PBO-Adj. Change % Reduction in FeNO 59% 15% 44% 200 mL 0 mL 200 mL Increase in FEV1 (FEV1 <80% at BL) 350 mL -140 mL 490 mL NOTE: FEV1 <80% at BL = pre-BD FEV1 value of < 80% at baseline + post-BD reversibility of FEV1 ≥ 12% and ≥ 200 mL or documented history of post-BD FEV1 reversibility during last 12 months at screening. BD = bronchodilator; FEV1 = Forced expiratory volume in 1 second; PBO = placebo; BL = baseline; ITT = intent-to-treat; FeNO = fractional exhaled nitric oxide. Target Engagement Large Airway Improvement Objective 8 Increase in FEV1 (ITT) Favorable safety profile with no conjunctivitis observed Safety and Tolerability Strong Tolerability profile ATI-052 has the potential to set a new efficacy ceiling in asthma and other Th2 driven diseases |
| ATI-052 POC in Atopic Dermatitis (AD) Data cutoff date: August 20, 2026 |
| 10 Screening/ Washout Randomization 3:1 Active to Placebo Primary Endpoint Safety and tolerability Phase 1b POC Trial in Severe Atopic Dermatitis 14 AD Patients Placebo Q1wk (five doses) ATI-052 Q1wk (five doses, 480 mg) 12-week follow-up Day 57 (Week 8) Primary analysis Other Endpoints AD clinical efficacy assessments (EASI, PP-NRS, etc.) PD endpoints measured by assays including lesional and non-lesional skin tape strips CLINICAL STRATEGY: ATI-052 IN AD Location United States: Multi-site Strategy First signal-finding clinical trial to assess the efficacy of load-in doses only (no doses after week 4) in severe AD patient population Load-in Injections Wk0 Wk1 Wk2 Wk3 Wk4 NOTE: EASI = Eczema Area and Severity Index; PP-NRS = Peak Pruritus Numerical Rating Scale |
| Baseline Demographics and Disease Severity 11 PHASE 1b POC TRIAL I ATI-052 IN AD: BASELINE CHARACTERISTICS Increased Percentage of African American and vIGA 4 Provides a More Severe / Difficult-to-Treat Patient Population1 SOURCE: 1. Sanyal RD, Guttman-Yassky E, et al. Ann Allergy Asthma Immunol. 2019. NOTE: vIGA = Validated Investigator Global Assessment for Atopic Dermatitis; EASI = Eczema Area and Severity Index; PP-NRS = Peak Pruritus Numerical Rating Scale; BSA = Body Surface Area; NC = not calculable Characteristic ATI-052 (N=11) Placebo (N=3) Age, mean (SD), y 27.8 (6.0) 38.3 (13.1) Female, n (%) 6 (54.5) 1 (33.3) Weight, mean (SD), kg 82.4 (18.5) 102.0 (4.8) Duration of AD from diagnosis, mean (SD), y 21.8 (8.2) 23.1 (4.8) Race, n (%) White 4 (36.4) 2 (66.7) Black or African American 5 (45.5) 1 (33.3) Asian 2 (18.2) 0 Baseline EASI, mean (SD) 28.3 (7.5) 23.2 (0.8) Baseline vIGA=4, n (%) 9 (81.8) 1 (33.3) Baseline weekly PP-NRS, mean (SD) 6.7 (1.7) 7.1 (1.5) BSA affected, mean (SD) 41.4 (13.7) 35.0 (14.4) Reasons for Exclusion ATI-052 Placebo Received rescue medication 0 2 Took only 2 doses 1 0 Eligibility criteria not met 1 0 Per Protocol Analysis Population Defined prior to unblinding |
| ATI-052 Was Well Tolerated, With a Favorable Safety Profile 12 Safety Summary ATI-052 N=11 (%) Placebo N=3 (%) Patients reporting ≥1 TEAE 6 (54.5) 2 (66.7) Patients reporting ≥1 serious TEAE 0 0 Patients reporting ≥1 Grade 3 or 4 TEAE 0 0 Patients who discontinued due to TEAE 0 0 Patients reporting ≥1 TRAE (only ISRs) 2 (18.2) 1 (33.3) PHASE 1b POC TRIAL I ATI-052 IN AD: SAFETY AND TOLERABILITY • Tolerability similar between active and placebo arms • Injection site reactions (ISR) were transient, almost exclusively Grade 1, and observed only at two timepoints • Preliminary safety observed after Day 57 consistent with that observed through Day 57 • No conjunctivitis observed in the Phase 1a/1b ATI-052 program NOTE: Safety results presented for safety population. Data after Day 57 are preliminary and based on partial dataset. TEAE = Treatment emergent adverse event. TREA = Treatment related adverse event. ADA = anti-drug antibody |
| -80% -60% -40% -20% 0% Baseline Week 4 Week 5 Week 6 Week 8 Week 10 ATI-052 Placebo ATI-052 Demonstrated Robust EASI Improvement Enrolled a Challenging Population to Treat: 78% Baseline vIGA4 Mean % Change in Baseline EASI Over Time Mean % Change in Baseline EASI Week 10 -62% -82% -56% -15% -90% -70% -50% -30% -10% ATI-052 (All) vIGA 3 vIGA 4 Placebo (All) EASI Improvement Maintained in Severe Patient Population Through Week 16 after Load-In Doses Only Pbo-adjusted: -45% Last dose Week 4 13 Week 16 PHASE 1b POC TRIAL I ATI-052 IN AD: EASI Expected Phase 2b Repeat Dosing Window Mean % change from baseline in EASI NOTE: Efficacy results presented for per protocol population Missing data were not imputed; number of participants may vary by endpoint and visit. Data after Day 57 are preliminary and based on partial dataset. All subgroup analyses were conducted post hoc. PBO = placebo. Load-in doses Mean % change from baseline in EASI |
| Early Efficacy Signal In Severe Disease Supports Advancement to Phase 2b 45% 38% 33% 36% 0 10 20 30 40 50 ATI-052 Dupilumab Zumilokibart Lebrikizumab % Severe (vIGA 4) Subjects at Baseline 78% PHASE 1b POC TRIAL I ATI-052 IN AD: EASI 14 % Severe (vIGA 4) Subjects at Baseline 49% % Severe (vIGA 4) Subjects at Baseline 35% % Severe (vIGA 4) Subjects at Baseline 39% SOURCE: Dupilumab: SOLO 1/2, 300 mg q2w pooled, approx. (Thaçi D, Simpson EL, et al. J Dermatol Sci. 2019;94(2):266–275.). Zumilokibart: APEX Part A/B mid dose averaged (Apogee, APEX Part A 16- week data presentation July 7, 2025; APEX Part B 16-week data presentation, May 27, 2026). Lebrikizumab: ADvocate1/2, 250 mg q2w averaged, approx. (Silverberg, NEJM 2023;388:1080). NOTE: ATI-052 results presented for per protocol population. Missing data were not imputed. Sample sizes vary by endpoint and visit. Data are derived from different clinical trials conducted at different times, with differences in trial design and patient populations. As a result, cross-trial comparisons cannot be made, and no head-to-head clinical trials have been conducted. PBO = placebo. Mean Placebo-adj. Change from Baseline in EASI (%), Week 8 Mean Pbo-adjusted change from baseline in EASI (%) Active: N=564 PBO: N=287 Active: N=167 PBO: N= 129 Active: N=465 PBO: N=456 Active: N=9 PBO: N=1 |
| 15 ATI-052 Demonstrated Robust EASI-50 Response 100% 71% 42% ATI-052 (vIGA 3) ATI-052 (vIGA 4) Dupilumab SOURCE: Dupilumab: SOLO 1/2, 300 mg q2w pooled, approx. (Thaçi D, Simpson EL, et al. J Dermatol Sci. 2019;94(2):266–275). PHASE 1b POC TRIAL I ATI-052 IN AD: EASI Overall = 78% Pbo-adj. EASI-50 Response (%), Week 8 89% of ATI-052 Subjects Achieved EASI-50 During the Study1 NOTE: ATI-052 results presented for per-protocol population. Missing data were not imputed. Sample sizes vary by endpoint and visit. ATI-052 placebo-adjusted results use the overall placebo group as the comparator. All subgroup analyses were conducted post hoc. Data are derived from different clinical trials conducted at different times, with differences in trial design and patient populations. As a result, cross-trial comparisons cannot be made, and no head-to-head clinical trials have been conducted. PBO = placebo. 1. Post hoc analysis including unscheduled visits. Each subject counted once if the criterion was met at any visit. |
| -50 -40 -30 -20 -10 0 10 20 Baseline Week 1 Week 2 Week 4 Week 5 Week 6 Week 8 Week 10 Week 16 % change from baseline ATI-052 Placebo PHASE 1b POC TRIAL I ATI-052 IN AD: PP-NRS Rapid, Deep and Durable Reductions in Itch Observed Itch Relief Emerged Week One and Continued to Deepen Through Week 10 16 SOURCE: Dupilumab: SOLO 1/2, 300 mg q2w pooled, approx. (Thaçi D, Simpson EL, et al. J Dermatol Sci. 2019;94(2):266–275.). Zumilokibart: APEX Part A mid dose (Apogee, APEX Part A 16-week data presentation July 7, 2025). Pbo-adjusted: -43% Placebo-Adj. Change in PP-NRS (%), Week 8 43% 29% 23% 0% 20% 40% ATI-052 Dupilumab Zumilokibart Change From Baseline in PP-NRS (%) Over Time Last dose Week 4 Expected Phase 2b Repeat Dosing Window NOTE: ATI-052 results presented for per protocol population. Missing data were not imputed. Sample sizes vary by endpoint and visit. Data after Day 57 are preliminary and based on partial dataset. Data are derived from different clinical trials conducted at different times, with differences in trial design and patient populations. As a result, cross-trial comparisons cannot be made, and no head-to-head clinical trials have been conducted. Placebo-Adj. change from baseline in PP-NRS (%) Load-in doses |
| PHASE 1b POC TRIAL I ATI-052 IN AD: PP-NRS 17 SOURCE: Dupilumab: PP-NRS4 - SOLO 1/2, 300 mg q2w pooled, approx. (Thaçi D, Simpson EL, et al. J Dermatol Sci. 2019;94(2):266–275.). Zumilokibart: APEX Part B mid dose (Apogee, APEX Part B 16-week data presentation, May 27, 2026). Lebrikizumab: ADvocate1/2, 250 mg q2w averaged, approx. (Silverberg, NEJM 2023;388:1080). Tilrekimig: 400mg + 200 mg q4w averaged (Active: N=70, PBO: N=20) (EADV 2026, Vienna, Sept 30 to Oct 3, 2026). 33% 26% 20% 27% 25% ATI-052 Dupilumab Zumilokibart Lebrikizumab Tilrekimig % Severe (vIGA 4) at Baseline 78% % Severe (vIGA 4) at Baseline 35% % Severe (vIGA 4) at Baseline 49% % Severe (vIGA 4) at Baseline 37% % Severe (vIGA 4) at Baseline 39% Pbo-adj. PP-NRS4 Response (%), Week 8 ATI-052 Showed Clinically Meaningful Improvements in Itch Improved Placebo-Adjusted PP-NRS Response Observed NOTE: ATI-052 results presented for per protocol population. Missing data were not imputed. Sample sizes vary by endpoint and visit. Data are derived from different clinical trials conducted at different times, with differences in trial design and patient populations. As a result, cross-trial comparisons cannot be made, and no head-to-head clinical trials have been conducted. PBO = placebo; PP-NRS4 = ≥4 points of reduction from baseline in weekly averages of Peak Pruritus Numerical Rating Scale (PP-NRS). |
| Photographic Examples of Clinical Activity 18 PHASE 1b POC TRIAL I ATI-052 IN AD: SKIN CLEARANCE Baseline Week 8 ATI-052 Load-in doses only Subject #1 vIGA 3 at Baseline Subject #2 vIGA 4 at Baseline |
| Potential Best-in-Class Pharmacodynamic Profile TSLP + IL-4Rα | Evidence of Potential Additivity/Synergy Between Targets Broad Pathway Modulation Marked downregulation of inflammatory mediators pertinent to AD observed Pathways modulated Th1 Th2 Th17/Th22 Fibrosis Itch Normalization of Skin Proteome Immune protein expression in lesional skin closely resembled non-lesional skin Proteome shift Lesional → Non-lesional Pronounced Biomarker Reduction Pronounced reduction of established dupilumab biomarkers observed Additional suppression Th1 Th17 Myeloid 19 PHASE 1b POC TRIAL I ATI-052 IN AD: PD AND TAPE STRIPS DR. EMMA GUTTMAN LAB· MT SINAI Skin Tape Strip Analysis O-link proteomics (300+ analytes) INTERNAL ANALYSIS Endogenous Serum Biomarkers (MSD-Select) CCL17/TARC, IL-5 Innate |
| PHASE 1b POC TRIAL I ATI-052 IN AD: PD AND TAPE STRIPS ATI-052 Normalized Skin Proteome ATI-052 Activity in Lesional Skin | Potential for Disease Modification KEY RESULTS 95% overall improvement in LS vs. NL proteome observed by Week 8 66% overall improvement in LS vs. NL skin with dupilumab by Week 16 % IMPROVEMENT Percent Improvement (%) Placebo ATI-052 LS vs. NL Proteome, Week 8 PROTEOME HEATMAP Results provided validation of additive/synergistic activity of dual IL-4Rα + TSLP inhibition by ATI-052 NOTE: ATI-052 results presented for all patients who completed study through Week 8. *** p<0.001. Data are derived from different clinical trials conducted at different times, with differences in trial design and patient populations. As a result, cross-trial comparisons cannot be made, and no head-to-head clinical trials have been conducted. SOURCE: Dupilumab: 300 mg q2w (He H, et al. Front Immunol. 2020;11:1768). 20 Baseline NL LS Placebo W8 NL LS ATI-052 W8 NL LS n 13 13 3 3 10 10 Z-score 2 0 −2 LS: Lesional Skin NL: Non-Lesional Skin |
| ATI-052 Demonstrated Broad and Deep Biomarker Reductions Median % Change from Baseline, Week 8 −76 −45 −43 −4 −16 -100 -75 -50 -25 0 25 50 75 CCL17 IL-5 Eosinophils (Week 12) NOTE: Sample sizes vary by endpoint and visit. GSVA: patients completing Week 8. ** p≤0.01, *** p≤0.001; + p<0.1. Navy asterisks: Week 8 vs. baseline; orange: ATI-052 vs. placebo. NL = non-lesional; LS = lesional skin. PHASE 1b POC TRIAL I ATI-052 IN AD: PD AND TAPE STRIPS Median % change from baseline +176 21 PATHWAY DOWNREGULATION BY GSVA NL LS Placebo ATI-052 Th1 (CCL2, CXCL9, CXCL10, IL8, TNF, etc.) Placebo ATI-052 Th2 (IL13, CCL13, CCL17, CCL24, etc.) Placebo ATI-052 Th17/22 (TGFB1, IL17A, IL6R, S100A12, etc.) Placebo ATI-052 Pruritus (OSM, CTSS, etc.) Y-axis: lgFCH vs. baseline BIOMARKER REDUCTIONS ■ ATI-052 ■ Placebo Downregulation of Th1, Th2, Th17/22 and Pruritus Signatures Observed |
| ATI-052 POC in Asthma Data cutoff date: September 24, 2026 |
| 23 Placebo (single dose) ATI-052 (single dose, 480 mg) Screening/ Washout Six-week follow-up Randomization 3:1 Active to Placebo Primary analysis through Day 29 Primary Endpoint Safety and tolerability Phase 1b POC Trial in Asthma 16 Patients Key Clinical Efficacy Assessment: FEV1, AX Other endpoints PD assessments: FeNO, Blood Eos, TARC (CCL17), Periostin, Cytokines CLINICAL STRATEGY I ATI-052 IN ASTHMA Location United States and Europe: Multi-site Strategy Clinical trial to assess a single dose of ATI-052 in a mild-to-moderate asthma population NOTE: FEV1 = Forced Expiratory Volume in 1 Second; FeNO = Fractional Exhaled Nitric Oxide; AX = Area of Reactance. Single Injection |
| 24 Characteristic ATI-052 (N=12) Placebo (N=4) Age, mean (SD), y 44.4 (12.6) 39.8 (17.6) Female, n (%) 3 (25.0) 3 (75.0) Weight, mean (SD), kg 86.0 (12.8) 75.8 (23.2) Duration of asthma from diagnosis, mean (SD), y 23.6 (12.0) 22 (20.8) FeNO, mean (SD), ppb 72.3 (33.3) 97.3 (62.5) Blood eosinophil count, mean (SD), cells/µL 378.3 (227.6) 395.0 (183.6) <300 n (%) 5 (41.7) 2 (50.0) ≥300 n (%) 7 (58.3) 2 (50.0) FEV1, mean L, (SD) 2.85 (0.98) 3.16 (0.71) FEV1, mean % predicted, (SD) 75.6 (22.1) 98.7 (22.8) <80% n (%) 6 (50.0) 1 (25.0) ≥80% n (%) 6 (50.0) 3 (75.0) BASELINE CHARACTERISTICS I ATI-052 IN ASTHMA Baseline Demographics and Asthma Severity NOTE: FEV1 = Forced Expiratory Volume in 1 Second; FeNO =Fractional Exhaled Nitric Oxide |
| Strong Tolerability Profile Observed with ATI-052 Favorable Safety Profile 25 Safety Summary ATI-052 (N=12) Placebo (N=4) Patients reporting ≥1 TEAE, n (%) 6 (50) 1 (25) Patients reporting ≥1 serious TEAE, n (%) 0 0 Patients reporting ≥1 Grade 3 or 4 TEAE, n (%) 0 0 Patients who discontinued due to TEAE, n (%) 0 0 Patients reporting ≥1 TRAE, n (%) (ISR) 1 (8.3) 0 • ATI-052 was well tolerated with Grade 1 ISRs as the most frequent AE • No conjunctivitis observed in the Phase 1a/1b ATI-052 program PHASE 1b POC TRIAL I ATI-052 IN ASTHMA: SAFETY AND TOLERABILITY NOTE: TEAE = Treatment emergent adverse events; TRAE = Treatment related adverse events; ISR = injection site reaction |
| Rapid FeNO Suppression Observed from Single Dose of ATI-052 Maximum FeNO Reduction of 59% and 45ppb Validate Potency of ATI-052 26 -59% -70% -60% -50% -40% -30% -20% -10% 0% Day 0 Day 8 Day 15 Day 29 % change from baseline ATI-052 Placebo -50 -45 -40 -30 -20 -10 0 Day 0 Day 8 Day 15 Day 29 Absolute change from baseline ATI-052 Placebo Percent Change from Baseline in FeNO Absolute Change from Baseline in FeNO PHASE 1b POC TRIAL I ATI-052 IN ASTHMA: FeNO Rapidity and Depth of FeNO Suppression Observed After a Single Dose of ATI-052; Provides Strong Signal and Proof-of-Concept Single Injection Single Injection NOTE: Data from one placebo participant were excluded from the Day 29 analysis following investigation of a testing event that affected the measurement. FeNO =Fractional Exhaled Nitric Oxide; PPB = parts per billion. |
| -59% -31% -36% -80% -70% -60% -50% -40% -30% -20% -10% 0% ATI-052 (Day 15) Anti-TSLP / IL-4Rα Dupilumab (Week 2) Anti-IL-4Rα Tezepelumab (Week 4) Anti-TSLP Single Dose of ATI-052 Demonstrated Deep Reduction in FeNO PHASE 1b POC TRIAL I ATI-052 IN ASTHMA: FeNO Maximum Mean FeNO % Reduction, Through Week 4 27 NOTE: Data are derived from different clinical trials conducted at different times, with differences in trial design and patient populations. As a result, cross-trial comparisons cannot be made, and no head-to-head clinical trials have been conducted. 480mg 400/600mg (Loading) 210mg Maximum Mean FeNO % Reduction SOURCE: Tezepelumab: approx. (Menzies-Gow et al., N Engl J Med. 2021;384:1800-1809). Dupliumab: approx. (Pavord ID, et al. J Allergy Clin Immunol Pract. 2024;12(7):1763-177). Active: N=1,160 PBO: N=583 Active: N=528 PBO: N=531 Active: N=12 PBO: N=4 |
| Similar Results Observed in Both T2-Low and T2-High Sub-Populations PHASE 1b POC TRIAL I ATI-052 IN ASTHMA: FeNO & FEV1 28 NOTE: All subgroup analyses were conducted post hoc. T2-Low = <300 Eosinophils at baseline; T2-High = ≥300 eosinophils at baseline; PPB = parts per billion. 58% of ATI-052 Subjects Achieved FeNO Normalization (≤25 ppb) at Day 15 60% FeNO Reduction in Eos ≥300 Subgroup (T2-High) at Day 15 58% FeNO Reduction in Eos <300 Subgroup (T2-Low) at Day 15 FEV1 Improvement Was Also Observed in T2-High and T2-Low Sub-Populations |
| -200 mL -100 mL +0 mL +100 mL +200 mL Baseline Day 8 Day 15 Day 29 Mean pre-BD FEV1 change from baseline (mL) ATI-052 Placebo FEV1 Improvement Over Time FEV1 Improvement at Day 15 in Subjects with FEV1 <80% at Baseline +350 mL -140 mL -200 mL -100 mL +0 mL +100 mL +200 mL +300 mL +400 mL ATI-052 (FEV1 <80% at BL) Placebo (FEV1 <80% at BL) 29 NOTE: All subgroup analyses were conducted post hoc. FEV1 <80% at Baseline = pre-BD FEV1 value of < 80% at baseline + post-BD reversibility of FEV1 ≥ 12% and ≥ 200 mL or documented history of post-BD FEV1 reversibility during last 12 months at screening. BD = bronchodilator; FEV1 = Forced expiratory volume in 1 second; PBO = placebo; BL = baseline. FEV1 Improvement Aligned with FeNO Suppression; Strong Signal and Proof-of-Concept PHASE 1b POC TRIAL I ATI-052 IN ASTHMA: FEV1 Rapid FEV1 Improvement Observed Single Dose of ATI-052 Increased Absolute and Pbo-Adjusted FEV1 Pbo-adjusted: +200 mL Mean pre-BD FEV1 change from baseline (mL) |
| PHASE 1b POC TRIAL I ATI-052 IN ASTHMA: FEV1 SOURCE: Tezepelumab: approx. (Menzies-Gow et al., N Engl J Med. 2021;384:1800-1809). Dupilumab: approx.(Castro et al. N Engl J Med. 2018;378:2486-2496). NOTE: All subgroup analyses were conducted post hoc. FEV1 <80% at BL = pre-BD FEV1 value of < 80% at baseline + post-BD reversibility of FEV1 ≥ 12% and ≥ 200 mL or documented history of post-BD FEV1 reversibility during last 12 months at screening. BD = bronchodilator; FEV1 = Forced expiratory volume in 1 second; PBO = placebo; BL = baseline. Data are derived from different clinical trials conducted at different times, with differences in trial design and patient populations. As a result, cross-trial comparisons cannot be made, and no head-to-head clinical trials have been conducted. ATI-052 Improved FEV1 at Day 15 350 mL 280 mL 165 mL 490 mL 150 mL 112 mL 0 100 200 300 400 500 ATI-052 (FEV1 <80% at BL) Dupilumab (Week 2) Tezepelumab (Week 2) Mean pre-bronchodilator FEV1 change from baseline (mL) Mean FEV1 % Pred at Baseline 63% Mean FEV1 % Pred at Baseline 59% Mean FEV1 % Pred at Baseline 57% 480mg 600mg (Loading) 210mg Baseline lung function Dose Active: N=633 PBO: N=321 Active: N=528 PBO: N=531 Active: N=5 PBO: N=1 Absolute change Pbo-Adjusted change Absolute change Pbo-Adjusted change Absolute change Pbo-Adjusted change 30 |
| -28 -2 -35 -30 -25 -20 -15 -10 -5 0 ATI-052 (480mg) Dupilumab (600mg Loading; Week 4) Placebo-adjusted change from baseline in pre-BD AX at Day 15 (cmH O·L 2 −1 ) 31 PHASE 1b POC TRIAL I ATI-052 IN ASTHMA: AX ATI-052 Demonstrated Rapid Small Airway Disease (SAD) Improvement AX (Area Under Reactance Curve) as a Marker of SAD Improvement • Highly prevalent in asthma across GINA Steps • More than doubles exacerbation risk • Nearly 3X the risk when small airway disease is severe • 1 in 3 ‘well-controlled’ patients has hidden SAD NOTE: All subgroup analyses were conducted post hoc. FEV1 <80% at BL = pre-BD FEV1 value of < 80% at baseline + post-BD reversibility of FEV1 ≥ 12% and ≥ 200 mL or documented history of post-BD FEV1 reversibility during last 12 months at screening. BD = bronchodilator; FEV1 = Forced expiratory volume in 1 second; PBO = placebo; BL = baseline. Unit conversion: 1 kPa/L = 10.1972 cmH2O·L−1. Data are derived from different clinical trials conducted at different times, with differences in trial design and patient populations. As a result, cross-trial comparisons cannot be made, and no head-to-head clinical trials have been conducted. SOURCE: Dupilumab: (Washko GR, et al. J Allergy Clin Immunol. 2025). Galant S, et al. Lancet Respir Med. 2025;13:990–1000. Placebo-Adjusted AX Change at Day 15 in Subjects with FEV1 <80% at Baseline Active: N=5 PBO: N=1 Active: n=72 PBO: n=37 Small Airway Disease |
| Key Learnings Additivity/synergy potential demonstrated across preclinical, clinical, and PD measures Breadth and depth of response: • Clinical and PD evidence of activity against all 3 inflammatory endotypes in severe AD • Both FENO & FEV1 improvements in T2 high & T2 low asthma patients Strong evidence of TSLP involvement in AD • Complete normalization of skin proteome • Reduction in IL-5 and eosinophils Encouraging early durability in severe AD patients • Maintenance of response to at least week 16 (12 weeks after load in doses) • Maintenance dosing expected to be the same in asthma and AD Strong and potentially differentiated tolerability profile throughout the Phase 1 program including no conjunctivitis 32 ATI-052: Key Learnings and Next Steps Go Forward Plan ATI-052 is a potent, broadly acting compound with potential best-in-class activity Moving into staged Phase 2b program CORPORATE STRATEGY: COMMITMENT TO THERAPEUTIC INNOVATION Opportunity to raise the efficacy ceiling with ATI-052 for patients |
| Continued Clinical Momentum Through 2027 Bosakitug (ATI-045) Anti-TSLP monoclonal antibody Phase 2 top line results in AD: 4Q 2026 ATI-052 Anti-TSLP / Anti-IL4Rα bispecific antibody Phase 2b program: Eosinophilic Esophagitis Atopic Dermatitis Asthma Modzatinib (ATI-2138) ITK/JAK3 Inhibitor Lichen planus (Fast Track designation) Phase 2b trial start: 4Q 2026 Oral/Mucosal (Topline data 2027) Cutaneous Lichen planopilaris ATI-9494 ITK Inhibitor IND: 4Q 2026 Phase 1 start: 1Q 2027 Innovation Driven Patient Focused 33 All future development, clinical, and regulatory timelines are expectations, are based on current beliefs and assumptions, and are subject to change based on a variety of factors CORPORATE STRATEGY: COMMITMENT TO THERAPEUTIC INNOVATION NOTE: ITK = Interleukin-2-inducible T-cell kinase; JAK3 = Janus Kinase 3; IND = Investigational New Drug application |
| EMPOWERING PATIENTS THROUGH THERAPEUTIC INNOVATION October 27, 2026 ATI-052 Phase 1b Primary Analysis Results Atopic Dermatitis and Asthma |
