Slides
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Advancing a leading autoimmune- focused company January 12, 2026
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2 Forward-looking statements Certain statements in this presentation, other than purely historical information, may constitute “forward-looking statements” within the meaning of the federal securities laws, including for purposes of the safe harbor provisions under the United States Private Securities Litigation Reform Act of 1995, express or implied statements regarding future plans and prospects, including statements regarding the expectations or plans for discovery, preclinical studies, clinical trials and research and development programs, in particular with respect to claseprubart and DNTH212, and any developments or results in connection therewith, including the target product profile and administration of claseprubart and DNTH212; the anticipated timing of the initiation and results from those studies and trials; expectations regarding the clinical trial designs or indications; expectations regarding the time period over which the Company’s capital resources are expected to be sufficient to fund its anticipated operations; and expectations regarding market size, patient population size, and potential opportunities for complement therapies, in particular with respect to claseprubart and DNTH212. Claseprubart and DNTH212 are investigational agents that are not approved as therapies in any indication in any jurisdiction worldwide. The words “opportunity,” “potential,” “milestones,” “runway,” “will,” “anticipate,” “achieve,” “near-term,” “catalysts,” “pursue,” “pipeline,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “possible,” “predict,” “project,” “should,” “strive,” “would,” “aim,” “target,” “commit,” and similar expressions (including the negatives of these terms or variations of them) generally identify forward-looking statements, but the absence of these words does not mean that statement is not forward looking. Actual results could differ materially from those included in the forward-looking statements due to various factors, risks and uncertainties, including, but not limited to, that preclinical testing of claseprubart and DNTH212 and data from clinical trials may not be predictive of the results or success of ongoing or later clinical trials, that the development of claseprubart or DNTH212 may take longer and/or cost more than planned, that the Company or its partner may be unable to successfully complete the clinical development of the Company’s compounds, that the Company or its partner may be delayed in initiating, enrolling or completing its planned clinical trials, and that the Company's compounds may not receive regulatory approval or become commercially successful products. These and other risks and uncertainties are identified under the heading "Risk Factors" included in the Company’s Annual Report on Form 10-K for the period ended December 31, 2024, and other filings that the Company has made and may make with the SEC in the future. Nothing in this presentation should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. Nothing in this Presentation should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. Dianthus undertakes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by law.
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3 Developing two autoimmune therapeutics with best-in-class, pipeline-in-a-product potential and targeting patient-friendly, infrequent S.C. self-administration Advancing a leading autoimmune-focused company • Highly potent, ~8-week half-life, classical pathway (CP) inhibitor targeting active C1s • Validated pipeline-in-a-product potential with positive Ph. 2 gMG results and clinical PoC for CP inhibition in CIDP and MMN • Clinical and in vitro head-to-head data support potential for a more effective and convenient biologic with no boxed warning/REMS • Targeting convenience of a single, self-administered S.C. 300mg/2mL autoinjector dosed every 2 or 4 weeks Claseprubart • Bifunctional BDCA2 and BAFF/APRIL inhibitor targeting two validated pathways • Potential for enhanced efficacy from complementary mechanisms targeting innate and adaptive immune systems • Demonstrated superior in vitro pDC depletion vs. litifilimab and superior serum Ig inhibition vs. povetacicept in NHPs • Pipeline-in-a-product opportunity across multiple diseases with potential for Q4W or less frequent S.C. self-administration DNTH212 (BDCA2 and BAFF/APRIL bifunctional fusion protein) Strong financial position with cash of ~$514M1 and runway into 2028 expected to fund multiple near-term catalysts Claseprubart (aC1s mAb) 1. Estimated cash includes preliminary and unaudited cash, cash equivalents and investments as of December 31, 2025 Claseprubart 2026 milestones: Ph. 3 gMG trial initiation (’26), Ph. 3 CIDP interim responder analysis (Q2’26) and Ph. 2 MMN top-line results (2H’26) DNTH212 2026 milestones: Update on indication prioritization (1H’26) and Ph. 1 healthy volunteer study top-line results (2H’26)
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4 Pursuing the power of consistent control…with one-click! Targeting a best-in-class, first-line biologic treatment for neuromuscular diseases CLASSICAL CONVENIENCE Upstream Inhibition of Classical Pathway Only <10-Second Autoinjector Targeting No Boxed Warning or REMS Self-Administered At Home or On-the-Go Potential to Preserve Immune Function One-Click Every 2 or 4 Weeks claseprubart CONFIDENCE Aim for Potent, Rapid, Consistent Efficacy Broad Potential in Neuromuscular Diseases Potential for Best-in-Class Profile Autoinjector image for illustration purposes only. Autoinjector for claseprubart administration is anticipated to be SHL Medical’s Molly technology, patented or patent pending in the US, China, India, Japan, Korea, Taiwan and at the European Patent Office. Claseprubart is an investigational agent that is not approved as a therapy in any indication in any jurisdiction worldwide.
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5 Claseprubart has opportunity to compete as a first-line biologic in large and growing US neuromuscular market >100K patients >140K patients >150K patients AChR+ gMG patients Positive Ph. 2 data reported Sept. ’25 >40K CIDP patients Ph. 3 interim responder expected in Q2’26 Ph. 2 top-line data expected in 2H’26 Large potential for US market growth as only <20% of AChR+ patients treated with biologics >10K MMN patients Potential for aC1s to prove equal or superior in efficacy to current SOC IVIG POC supporting classical pathway inhibition and limited competition gMG is just the first step in building a leading neuromuscular franchise with claseprubart Figures represent U.S. estimated patients only. gMG: >100,000 gMG U.S. patients from Komodo claims data accessed 2013-2025; approx. 85% of gMG patients have AChR autoantibody-driven disease https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7033452/# CIDP & MMN: Komodo claims data 2013-2025, adjusted to account for 70% capture of real-world patient counts for biologic treated patients; CIDP adjusted to account for 27% misdiagnosed
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Claseprubart: Opportunity to be a Best-in- Class, First-Line Biologic for Generalized Myasthenia Gravis
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7 Across key efficacy measures, claseprubart demonstrated robust and clinically meaningful responses Placebo Claseprubart 300mg/2mL Q2W Claseprubart 600mg/4mL Q2W Absolute Placebo- adjusted Absolute Placebo- adjusted MG-ADL mean change from baseline at Week 13 -2.8 -4.6 -1.8 (P=0.0113)* -5.4 -2.6 (P=0.0006)* QMG mean change from baseline at Week 13 -2.0 -4.4 -2.4 (P=0.0144)* -4.5 -2.5 (P=0.0111)* MSE at Week 13 14% 37% 23% (P=0.0550)* 27% 13% (P=0.1031) MGC mean change from baseline at Week 13 -3.1 -8.7 -5.6 (P=0.0008)* -8.6 -5.5 (P=0.0008)* MG-QoL-15r mean change from baseline at Week 13 -3.9 -6.1 -2.2 (P=0.0414)* -5.4 -1.5 (P=0.1122) *One-sided p-values are presented for comparisons of claseprubart vs placebo, with any p-value below 0.1 considered nominally statistically significant. Claseprubart 300mg/2mL Q2W treatment arm achieved statistical significance vs. placebo across all five key efficacy measures
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8 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 Baseline1 3 5 7 9 11 13 2 4 6 Weeks QMG MG-ADL OLE data support addition of 300mg/2mL Q4W in Ph. 3 Mean Change in PBO Patients’ MG-ADL and QMG Score from RCT Baseline to OLE Week 6 QMG: 14.2 RCT Period OLE Period PBO Patients Entering OLE Received 600mg/4mL Q2W w/ No Loading Dose • PK of ~65 µg/mL at week 4 after only two 600mg/4mL doses is substantially lower than steady state seen with 300mg/2mL dosing of ~100-120 µg/mL • Robust reductions in MG-ADL and QMG are achieved by week 4, after just two 600mg/4mL doses and remain stable in subsequent weeks • Growing external evidence further supports that lower levels of complement inhibition (<90%) may be sufficient for efficacy in gMG 1 Represents 600mg/4mL S.C. dose The change from RCT baseline in MG-ADL and QMG were separately analyzed using a mixed effect model for repeated measures (MMRM) with randomized treatment group, visit, randomized treatment by visit interaction, stratification factors, and baseline measure included. All patients received claseprubart in OLE. 1. https://newsroom.regeneron.com/node/31216/pdf 11.7 -2.5 -3.2-2.0 -3.6 MG-ADL: 8.5 5.7 -2.8 -2.5-1.7 -2.6 Estimated PK of ~65 µg/mL 3.1 8.1 PK levels approximately half of 300mg/2mL Q2W steady state resulted in robust reductions on MG-ADL & QMG
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9 Patients with QMG ≥10 Adding QMG screening criteria in Ph. 3, similar to zilucoplan Ph. 31, may better control for placebo response Claseprubart MG-ADL Change from Baseline P=0.0006* -3.0P=0.0113* -1.8 The change from baseline in ADL was analyzed using a mixed effect model for repeated measures (MMRM) with treatment group, visit, treatment by visit interaction, stratification factors, and baseline measure included. *One-sided p-values are presented for comparisons of claseprubart vs placebo, with any p-value below 0.1 considered nominally statistically significant. 1. Zilucoplan Ph. 3 MG trial had screening criteria of QMG ≥ 12 and MG-ADL ≥ 6 (https://clinicaltrials.gov/study/NCT04115293) Ph. 2 study did not include QMG inclusion criteria, similar to ravulizumab Ph. 3; post-hoc analysis of MaGic data demonstrates potentially best-in-class MG-ADL improvement in patients with QMG ≥10 Zilucoplan Ph. 3 MG-ADL Change from Baseline in Patients with QMG ≥12 -2.8 -4.6 -2.2 -5.2 -2.3 -4.4 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 Placebo (n=22) Claseprubart 300mg Q2W (n=21) Placebo (n=16) Claseprubart 300mg Q2W (n=18) Placebo (n=88) Zilucoplan (n=86) P=<0.001 -2.1 All Patients
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10 Potential for improved efficacy vs. C5 inhibitors with claseprubart may be due to upstream inhibition Upstream inhibition prevents the creation of pro-inflammatory C3a and C3b as well as MAC, potentially providing additional efficacy benefits for AChR+ gMG patients C3a Formation1 C3b Deposition2* 100 80 60 40 20 0 % of hRBC with C3b Deposition -12 -10 -8 -6 -4 Ab Concentration, log M Claseprubart Isotype Ravulizumab 0 -20 -40 -60 -80 -100 % Reduction in C3a 10 Ab Concentration, log M -12 -10 -8 -6 -4 Claseprubart Isotype Ravulizumab 1. C3a Formation Assay: Human C3a ELISA specific to C3a-desArg with no cross-reactivity to C3 (N=3) 2. C3b Deposition Assay: Ab-sensitized hRBC triggered by complement-positive sera to deposit C3b on the hRBC surface, measured by flow cytometry (N=3) *Enjaymo (sutimlimab) targets the C1s complement protein, which prevents C3b deposition on red blood cells, thereby stopping hemolysis and improving anemia in patients with cold agglutinin disease (Jager U, et al. Blood 2019;133:893–901) Claseprubart Prevents the Creation of Pro-inflammatory Split Products C3a and C3b vs. Ravulizumab
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11 Ph. 3 trial design to include additional Q4W arm, and new screening criteria of QMG >10 as well as MG-ADL >6 Potential to further enhance best-in-class differentiation on efficacy and dosing convenience with QMG screening criteria and 300mg/2mL Q4W dosing Final Ph. 3 trial design TBD after regulatory consultations Highlights • Design: Male and female subjects randomized to receive either claseprubart or placebo for TBD weeks • Inclusion: ≥18 years old with AChR antibody + gMG, MG-ADL of ≥6 and QMG of ≥10 • Dosing: I.V. Loading Dose followed by 300mg/2mL S.C. Q2W or Q4W starting Day 7 Endpoints • Primary: MG-ADL change from baseline • Secondary / Exploratory: Efficacy (QMG, MSE, MGC, MG-QoL-15r) Screening Period Open-Label Extension Claseprubart 300mg/2mL S.C. Q2W Claseprubart 300mg/2mL S.C. Q4W Placebo S.C. Treatment Period TBD After Consulting with FDA Loading Dose Randomization
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12 Achieving this profile could position claseprubart as a potential best-in-disease treatment for gMG Similar or superior MG-ADL to FDA- approved C5 inhibitors with continuous, effective symptom control C1s SAFETY (ENJAYM O) C5 OR SUPERIOR EFFICACY (ULTOMIRIS/SOLIRIS/ZILBRYSQ) AUTOINJECTOR CONVENIENCE (DUPIXENT) Comparable safety to FDA-approved C1s & Classical Pathway inhibitor, leaving the lectin and alternative pathways intact Comparable convenience to DUPIXENT with one-click, self- administered SHL-Molly autoinjector Claseprubart is an investigational agent that is not approved as a therapy in any indication in any jurisdiction worldwide. Safety and efficacy for claseprubart has not been evaluated in head-to-head comparative clinical studies. Autoinjector for claseprubart administration is anticipated to be SHL Medical’s Molly technology, patented or patent pending in the US, China, India, Japan, Korea, Taiwan and at the European Patent Office Targeting >2-point MG-ADL improvement vs. placebo Targeting no Boxed Warning & REMS Targeting single 300mg/2mL S.C. Q2W or Q4W
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Claseprubart: Opportunity to Change the Treatment Paradigm in Chronic Inflammatory Demyelinating Polyneuropathy
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14 The US CIDP market offers substantial growth given the high unmet need and limitations of the current standard of care Opportunity for an active C1s inhibitor with the target profile of claseprubart to replace the standard of care • Current Ig and biologics account for >$3.5B3,4,5 • Despite SoC, many (30-50%) patients are refractory, face risk of relapse, and confront adverse effects of long-term treatment 6-8 • FcRn is considered more of an alternative than improvement over IVIg 9 • Active C1s inhibition has demonstrated ~50% improvement in both SoC treated and SoC refractory patients 10 • Opportunity to replace SoC with a patient friendly and easy-to-use active C1s inhibitor US CIDP Market Opportunity 1. Komodo claims data 2013-2025, adjusted to account for 70% capture of real-world patient counts for biologic treated patients, adjusted to account for 27% misdiagnosed; 2. Other Tx: PLEX/Splenectomy/Thymectomy, Rituximab, Biologic; 3. Argenx Corp Pres – July 2025; 4. Fierce Pharma, CIDP Pricing; 5. CIDP - Intravenous Immunoglobulin Market Statistics. Grand View Horizon. 6. Mair D, et al. Novel therapies in CIDP. Journal of Neurology, Neurosurgery & Psychiatry 2025;96:38-46.; 7. Gogia B, et al. Chronic Inflammatory Demyelinating Polyradiculoneuropathy, StatPearls Publishing.; 8. Bus, S.R.M., et al. Clinical outcome of CIDP one year after start of treatment. J Neurol.; 9. Levine T, et al. Early deterioration of CIDP following transition from IVIG to FcRn inhibitor, Journal of the Neurological Sciences; 10. Novel therapies in CIDP, Journal of Neurology, Neurosurgery, and Psychiatry (2024). Claseprubart target profile Est. >$900M3,4 FcRn ~2,000 pts I.V., S.C., Oral QW S.C. PFS Rapid [<10s] Q2W S.C. Autoinjector CIDP Patients1 Opportunity to Reach More Patients Ig ~19,000 pts Steroids, ISTs, other2 ~10,000 pts Standard of care1 ~40,000 (~5% CAGR) + Steroids (~6,000 pts) *Patient numbers through end of 2024, except FcRn 1H 2025
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15 Neuromuscular indication with high unmet medical need Evidence supports classical complement role in disease Active C1s inhibition has demonstrated clinical POC with potential for equal or superior efficacy to current SOC IVIG Claseprubart target dose of 300mg/2mL S.C. every two weeks may offer more convenient, lower volume dosing for CIDP patients vs. riliprubart >40,000 patients in the U.S. and no approved targeted complement therapies riliprubart (active C1s inhibitor) recently reported positive interim efficacy results1 1 Riliprubart Phase 2 at PNS 2024 2 Pg 76: riliprubart patent filing Ph. 2 Riliprubart Data Validates Active C1s in CIDP1 but with High Volume, Weekly Dosing of 600mg/4mL2
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16 Claseprubart has superior affinity and potency vs. riliprubart Note: Riliprubart is produced using sequence from patent WO2018071676A1 1. Data shown is dissociation constant (KD) and the average of 3 different experiments performed at independent laboratories 2. Data is quantitative analysis of active C1s protease inhibition of cleaved C4 fragments in the presence of claseprubart or riliprubart 3. Data shown are the average of 3 experiments conducted for each of the functional assays (CH50 hemolysis, Wieslab and Liposome). CH50 and Wieslab were confirmed at independent laboratories DNTH103 riliprubart IC90 (nM) 0.47 3.69 C4 cleavage by human active C1s2 Enzymatic Assay Functional Assays of Classical Pathway Inhibition DNTH103 riliprubart IC90 (µg/mL) 0.45 5.4 Wieslab classical pathway Assay in human serum3 CH50 assay of RBC lysis in human serum3 DNTH103 riliprubart IC90 (µg/mL) 98 668 DNTH103 riliprubart Fold Improvement Binding Affinity to human active C1s (K D)1 KinExa 9pM 75pM ~8X SPR 8pM 35pM ~4X Affinity Assays Claseprubart consistently outperforms riliprubart in affinity and potency when compared head-to-head in multiple in vitro experiments 0.01 0.1 1 10 100 0 20 40 60 80 100 Ab Concentration (nM) % C4 cleavage Norm. to total Cleavage DNTH103 Riliprubart 0.001 0.01 0.1 1 10 100 1000 0 50 100 Ab Concentration (nM) % CCP Activity (BL) DNTH103 Riliprubart 1 10 100 1000 10000 0 50 100 Ab Concentration (nM) CH50 (U/ml) DNTH103 Riliprubart ~8X more potent at blocking complement cascade ~12X more potent at IC90 ~7X more potent at IC90 DNTH103 riliprubart IC90 (ug/mL) 14.7 39.8 Liposome lysis in human serum3 1 10 100 1000 10000 0 50 100 Ab Concentration (nM) % CCP activity (norm to NHS) DNTH103 Riliprubart ~3X more potent at IC90
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17 CIDP Ph. 3 pivotal trial includes open-label Part A testing the target dose of 300mg/2mL S.C. Q2W CIDP interim responder analysis with first 40 patients in Part A anticipated in Q2’26 Claseprubart 300mg/2mL S.C. Q2W (N=64) Placebo (N=64) Claseprubart 600mg/4mL S.C. Q2W (N=64) Screen PART A: Up to 13-Week Open-Label Claseprubart Only PART B: 52-Week Pbo- controlled RCT CIDP diagnosis confirmed by an Independent CIDP Review Panel (ICRP) Open-Label Extension: 104 Weeks Loading Dose Day 0 Interim Responder Analysis (N=40) Claseprubart 300mg/2mL S.C. Q2W CAPTIVATE Trial: https://clinicaltrials.gov/study/NCT06858579 Highlights • Design: All subjects receive claseprubart in Part A for up to 13 weeks. Only responders randomized to Part B for 52 weeks • Inclusion: ≥18 years old with confirmed CIDP, including SOC-refractory, SOC- stable or SOC-naïve • Dosing: I.V. loading dose followed by 300mg/2mL S.C. Q2W in Part A; followed by 300mg/2mL or 600mg/4mL or placebo in Part B Endpoints • Part A: Response as measured as ≥1 point decrease (improvement) in adjusted INCAT score compared to Part A baseline • Part B Primary: Efficacy (time to relapse) as measured as ≥1 point increase in adjusted INCAT Responders Randomized 1:1:1 to Part B Enrolling a broad patient population including SOC- refractory patients, in addition to SOC-stable and SOC-naïve patients All confirmed CIDP patients receive convenient 300mg/2mL S.C. Q2W dosing of claseprubart in Part A Only responders from Part A randomized into the double-blind, placebo-controlled Part B Single pivotal two-part, randomized withdrawal, double-blind, placebo- controlled trial designed to support BLA in adult patients with CIDP
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18 Key differences between ADHERE and CAPTIVATE trials make cross-trial comparisons challenging Source: Company filings, presentations and clinicaltrials.gov 1. ADHERE required removal of IVIG and evidence of clinically meaningful deterioration before dosing in Part A 2. Defined as a clinical improvement on the parameters that the participant worsened in during run-in (≥4-point increase in I-RODS and/or ≥8-kPa increase in mean grip strength) or clinical improvement (≥1-point decrease) in INCAT 3. Represents IMVT-1402, empasiprubart and riliprubart studies Considerations Efgartigimod (FcRn) S.C. QW Claseprubart (aC1s) 300mg/2mL S.C. Q2W Key Differentiators of CAPTIVATE Ph. 3 Study Populations Enrolling a broad population of CIDP patients, including SOC- Refractory IVIG Withdrawal Required Prior to Part A of Study 1 YES NO No requirement for IVIG withdrawal and disease worsening, consistent with ongoing FcRn and complement CIDP studies3 Study Endpoints / Results • Confirmed ECI 2 • Ph. 3 Stage A results: ‒66.5% ECI (wk 12) • ≥1-point aINCAT improvement • Part A expectations: ‒Targeting similar response in open-label Part A to riliprubart open-label Ph. 2 in SOC- Treated and SOC-Refractory arms Potential to show clinically meaningful improvement (similar to riliprubart) from baseline without first requiring IVIG withdrawal and disease worsening SoC-Treated Off Treatment SoC-Treated SoC-Refractory SoC-Naïve ~1/3 of pts did not return to pre-IVIG washout baseline No SOC-Refractory patients Patients must relapse before enrolling into Part A
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Claseprubart: Opportunity to be Best-in-Class in Multifocal Motor Neuropathy
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20 The US MMN market is underdiagnosed with a need for more effective and convenient treatment options US MMN Market Opportunity Opportunity for the target profile of claseprubart to become the new standard of care in MMN 1. 2024 patients projected from 2023 count due to unreliable 2024 data from the Change Healthcare cyber-attack; 2. Komodo claims data 2013-2025, adjusted to account for 70% capture of real-world patient counts; 3. Other Tx: CS, NSISTs, PLEX/Splenectomy/Thymectomy, RTX, Biologic; 4. MMN. National Organization for Rare Diseases (2025); 5. Schaik et al., Intravenous immunoglobulin for MMN. Cochrane Library (2005) • Market is growing ~11% per year with ~2K newly diagnosed patients each year2 • Despite standard of care, patients face progressive and disabling weakness 4 • Patients also supplement Ig treatment with steroids despite guidelines against use 5 • Opportunity for an effective and easy-to-use active C1s inhibitor to become the new SoC Claseprubart target profile I.V. , S.C., Oral Rapid [<10s] Q2W S.C. Autoinjector MMN Patients1,2 Opportunity to Reach More Patients Ig ~3,400 pts Standard of care2 ~10,000 pts (~11% CAGR) Steroids, ISTs, Other ~1,600 pts3 + Steroids (~800 pts) *Patient numbers through end of 2024
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21 Neuromuscular indication with high unmet medical need Evidence supports classical complement role in disease MMN is an attractive opportunity with clinical PoC demonstrated via classical pathway inhibition Phase 2 trial of claseprubart, a low-volume Q2W S.C., ongoing in MMN No approved targeted biologic therapies Empasiprubart (I.V., C2 inhibitor) reported efficacy signals1 MMN patient sera has been confirmed to activate complement >10,000 patients in the U.S. 1 https://argenx.com/content/dam/argenx-corp/events-presentations/argenx_RnD_Day_2024_Slides.pdf#/page=127 Empasiprubart (Q1-2W I.V., C2 inhibitor) Ph. 2 Data Demonstrating Efficacy Signals1 “We hypothesize that targeting the classical complement pathway is a potential therapeutic approach in MMN. We investigated the interaction of circulating anti- GM1 IgM from patients with MMN with complement in detail using iPSC-derived MNs. In this disease model for MMN, we evaluated the effects of ARGX-117, a novel monoclonal antibody that inhibits complement factor C2.” - Neurol Neuroimmunol Neuroinflamm. 2022 Jan; 9(1): e1107 PlaceboEMPA I.V.
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22 Claseprubart demonstrates superior classical pathway potency vs. empasiprubart Claseprubart Demonstrates Superior Classical Pathway Potency Head-to-head vs. Empasiprubart Using Same Assay claseprubart empasiprubart IC50 (µg/mL) 3.8 ± 0.8 22.1 ± 5.7 Empasiprubart Published Classical Pathway Potency Data Using the Quidel MicroVue CH501 ~6X more potent at IC50 Claseprubart and empasiprubart are investigational agents that are not approved as therapies for MMN or any indication in any jurisdiction worldwide. Head-to-head data shown are the average of 3 experiments conducted for claseprubart and 8 experiments conducted for empasiprubart. Empasiprubart in the head-to-head experiment is produced using the sequence published in the IMGT database (DB card 12277). EC50 and IC50 can be considered as interchangeable for this analysis 1. Journal of Allergy and Clinical Immunology, Volume 147, Issue 4, 1420 - 1429.e7 “ARGX-117 potently inhibited CP and LP (half-maximal effective concentration [EC50] = 30.5 ± 4.5 and 93.4 ± 10.4 μg/mL, respectively) in a concentration-dependent manner” – Journal of Allergy and Clinical Immunology
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23 Considerations Empasiprubart (C2)* Claseprubart (active C1s)* Key Differentiators of Claseprubart MMN is an IgM and classical pathway driven disease1 Published classical pathway3 EC50 = 30.5 ±4.5 µg/mL using Quidel MicroVue CH50 Claseprubart has demonstrated potent inhibition of classical pathway in multiple assays ~6x more potent than empasiprubart on IC50 in head-to-head in-vitro experiment using Quidel MicroVue CH50 Lectin pathway inhibition not required for efficacy in MMN Published lectin pathway 3 inhibition of EC50 = 93.4 ±10.4 µg/mL Does not inhibit lectin pathway Claseprubart preserves key bacterial killing role of lectin pathway2 Patients prefer convenient therapies I.V. Q4W Targeting Q2W self- administration via 300mg/2mL S.C. autoinjector More convenient by targeting infrequent, low volume, self- administered S.C. autoinjector Claseprubart has the potential to dominate the MMN market with its best-in-class target product profile Claseprubart has the potential to be the first-line targeted biologic treatment given its unique combination of classical pathway potency, preservation of the lectin pathway, and dosing convenience * Claseprubart and empasiprubart are investigational agents that are not approved as therapies for MMN or any indication in any jurisdiction worldwide. EC50 and IC50 can be considered as interchangeable for this analysis 1. Budding et al., (2021). Neurol Neuroimmunol Neuroinflamm.9(1):e1107; Vlam et al., (2015). Neurol Neuroimmunol Neuroinflamm. 2015;2(4):e119; 2. Ali et al., (2012). PLoS Pathog 8(7):e1002793 3. Journal of Allergy and Clinical Immunology, Volume 147, Issue 4, 1420 - 1429.e7.
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24 MMN Phase 2 top-line data anticipated 2H’26 A global, multicenter, randomized, double-blind, placebo-controlled study to evaluate the safety, efficacy, and PK / PD of claseprubart administered S.C. following initial loading dose Top-line data expected in 2H’26 MoMeNtum Trial: https://clinicaltrials.gov/study/NCT06537999 Highlights • Design: 36 participants randomized to receive either claseprubart or placebo for 17 weeks • Inclusion: ≥18 years old with MMN who are immunoglobulin responsive and dependent • Dosing: I.V. Loading Dose followed by 300mg/2mL or 600mg/4mL S.C. Q2W starting Day 7 Endpoints • Primary: Safety • Secondary: Efficacy (time to IVIg retreatment, time to relapse, grip strength and other muscle strength and motor function measurements) Screen & Ig Monitoring Day 0 Open-Label Extension: 52 Weeks Claseprubart 300mg/2mL S.C. Q2W (N=12) Claseprubart 600mg/4mL S.C. Q2W (N=12) Placebo (N=12) 17-Week S.C. Treatment Collect data for safety, PK, PD, time to IVIg retreatment, time to relapse, grip strength and other muscle strength and motor function measurements Loading Dose 1 Week Wait Before Randomization
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DNTH212: Potential Best-in-Class Bispecific Fusion Protein for Multiple Autoimmune Indications
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26 • Inhibiting BDCA2 reduces Type 1 interferon production from plasmacytoid dendritic cells (pDCs) • Single CRD2 domain of TACI designed to deliver robust B cell modulation via BAFF/APRIL inhibition DNTH212 targets both the innate and adaptive immune systems with complementary disease modifying mechanisms enabling potential best-in-class efficacy DNTH212 is a bifunctional BDCA2 and BAFF/APRIL inhibitor targeting two validated pathways Anti-BDCA2 Antibody Potent inhibition of Type 1 interferon TACI-CRD2 Domain Potent reduction of Ig levels via BAFF/APRIL inhibition Afucosylated Bifunctional Ab Enhanced ADCC on target cells leads to pDC depletion YTE Mutation on Fc Extended half-lifeDNTH212 Humanized monoclonal antibody targeting BDCA2 fused with TACI-CRD2
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27 DNTH212 TPP aims to deliver superior efficacy in a safe and well-tolerated therapy with patient friendly convenience Achieving the TPP would position DNTH212 as a first-line biologic across a range of indications Bifunctional approach has potential for superior efficacy in various disease states versus only targeting innate or adaptive immune system SAFETYEFFICACY CONVENIENCE Inhibiting Type 1 interferon or BAFF/APRIL has been generally safe and well tolerated Targeting patient friendly S.C. self-administration with Q4W or less frequent dosing
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28 Advancing a leading autoimmune-focused biotech with two- clinical stage programs Program Indication Ph. 1 Ph. 2 Ph. 3 Upcoming Milestones Claseprubart aC1s gMG >100,000 U.S. Patients • Expect to initiate Ph. 3 study in 2026 CIDP >40,000 U.S. Patients • Interim responder analysis expected in Q2’26 • Peer Catalyst: riliprubart Ph. 3 MOBILIZE and VITALIZE (H2H vs. IVIG) data expected by early ’273 MMN >10,000 U.S. Patients • Ph. 2 top-line results expected in 2H’26 • Peer Catalyst: empasiprubart Ph. 3 data in 2H’264 DNTH212 BDCA2 and BAFF/APRIL Multiple Autoimmune Diseases • Update on indication prioritization in 1H’26 • Ph. 1 HV top-line results expected in 2H’26 Healthy volunteers (Part A) SLE patients (Part B) Strong balance sheet with ~$514M1 of cash & runway into 2028 ~44.8M shares outstanding2 1. Estimated cash includes preliminary and unaudited cash, cash equivalents and investments as of December 31, 2025 2. Shares outstanding on a pro forma basis, which assumes the exercise of all outstanding pre-funded warrants 3. Based on Sanofi Q3’25 financial results conference call transcript 4. Based on publicly available information: https://argenx.com/content/dam/argenx-corp/media-documents/Earnings_press_release_HY.pdf.coredownload.inline.pdf
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Advancing a leading autoimmune- focused company January 12, 2026