Slide 1: Bringing life into balance: Yarrow Bioscience Overview
1 Bringing life into balance Yarrow Bioscience Overview September 2026
Slide 2: Disclaimers
2 Disclaimers The information contained in this presentation has been prepared by Yarrow Bioscience, Inc. and its affiliates (“Yarrow” or t he “Company”) and contains information pertaining to the business and operations of the Company. The information contained in this presentation: (a) is provided
Slide 3: Yarrow seeking to bring life into balance for Graves' Disease and TED
3 Yarrow Bioscience is seeking to bring life into balance for patients suffering with Graves’ Disease and TED
Slide 4: Yarrow advancing potential first-in-class anti-TSHR antibody
4 Yarrow is advancing YB - 101, a potential first - in - class anti - TSHR antibody, to redefine the treatment of Graves’ Disease and TED Yarrow in - licensed exclusive rights to YB - 101 for the treatment of GD and TED outside of greater China from Changchun GeneScience Pharmaceutical Company, Ltd.
Slide 5: TSHR: the site of action in GD and TED
5 TSHR: the site of action in GD and TED Sources: Furmaniak 2022, Hoermann 2009 GD=Graves’ disease; TED=thyroid eye disease; TSHR= thyrotropin receptor; RAI= radioactive iodine; ATD=anti - thyroid drug Directly disrupts the disease process x TSHR is the site of antibody attack in the thyroid and orb
Slide 6: Opportunity to generate clinical data across both indications with GenSci
6 Our opportunity with YB - 101 is to generate clinical data across both indications, leveraging collaboration with GenSci Yarrow in - licensed exclusive rights to YB - 101 for the treatment of GD and TED outside of greater China from Changchun GeneScienc e Pharmaceutical Company, Ltd. (GenSci) in D
Slide 7: Experienced leadership team and board
7 Experienced leadership team and board with strong track record of value creation Rebecca V. Frey, PharmD | President and CEO Lori Payton, PhD | Chief Development Officer Tyler Zeronda | Chief Financial Officer Rachael Alford, PhD | Chief Operating Officer Steve Ryder, MD | Chief Medical Officer Bo
Slide 8: Significant unmet needs in current management of Graves' Disease and TED
Significant unmet needs exist in current management of Graves’ Disease and TED
Slide 9: GD and TED are poorly treated diseases with significant morbidity
9 GD and TED are poorly treated diseases with significant morbidity and mortality risk Sources: 1. Grixti 2023; 2. Brandt 2013; 3. Chin 2020; 4. Boutzios 2014; 5. Kostopoulos 2024; 6. Okosieme 2019 CV=cardiovascular; GD=Graves’ disease; TED=thyroid eye disease; TSH=thyroid stimulating hormone; AF=at
Slide 10: Current treatments remain inadequate
10 Radioactive iodine Radiation exposure, exacerbates TED, and possible risk of cancer Current GD and TED treatments remain inadequate Sources: Yarrow market research, Lupo 2025; Sjolin 2019; Davies 2020; Momo 2026; Traisk 2009; Abraham 2010; Brito 2020; Methimazole Tablets, USP, Prescribing Informa
Slide 11: Emerging regulatory focus on ATD withdrawal endpoints creates opportunity
11 Emerging regulatory focus on ATD withdrawal endpoints creates a clear opportunity for anti - TSHR as a new standard of care with improved risk/benefit ATDs are suboptimal as first - line treatment for GD, and are not effective for TED Sources: Ross 2016; Otsuka 2012; Sjolin 2019; Abraham 2010; Ya
Slide 12: Yarrow's potential first-in-class anti-TSHR offers a differentiated approach
Yarrow’s potential first - in - class anti - TSHR offers a highly differentiated approach to treat GD and TED
Slide 13: Potent anti-TSHR antibody with potential to redefine treatment
13 YB - 101 is a potent anti - TSHR antibody with the potential to redefine the treatment of GD and TED Multiple ways to win in both indications IgG4 Composition - of - matter coverage through 2043; method - of - treatment patents through 2045; formulation patents through 2046 Phase 2 clinical asset
Slide 14: Pathophysiology of GD and TED converges at TSHR
14 Pathophysiology of GD and TED converges at TSHR Thyroid cell Orbital fibroblast Stimulating autoantibodies (TRAb/TSI) TSHR Thyroid hormone over - production and TSH suppression P roduction of cytokines & hyaluronic acid Differentiation into adipocytes and myofibroblasts Intracellular Extracellula
Slide 15: Designed to disrupt the central mechanism of GD and TED
15 YB - 101 is designed to directly disrupt the central mechanism of GD & TED by blocking autoantibody attack on TSHR Sources: Adapted from Davies 2020 and Lanzolla 2024 TRAb/TSI=thyroid receptor antibody/thyroid stimulating immunoglobulin; FT3=free triiodothyronine; FT4=free thyroxine; TSH=th yro i
Slide 16: GenSci Phase 1 SAD in TED: Study design and patient population
16 GenSci Phase 1 SAD in TED: Study design and patient population Sources: GenSci data on file TED=thyroid eye disease; SC=subcutaneous; SRC=safety review committee; SAD= single ascending dose; MAD=multiple ascending dos e; CAS=clinical activity score • SAD evaluated safety and efficacy of five dose
Slide 17: Safety and tolerability in Phase 1 SAD
17 ✓ No dose interruptions or study withdrawals due to AEs No deaths, no treatment - related SAEs All AEs mild or moderate in severity No severe adverse events reported across all cohorts No clinically meaningful hearing - related or hyperglycemia adverse events Hearing impairment and hyperglycemia
Slide 18: GenSci Phase 1 SAD: rapid, dose-dependent proof of mechanism and responses in TED
18 GenSci Phase 1 SAD: A single dose of YB - 101 produced rapid, dose - dependent proof of mechanism and meaningful clinical responses in TED Sources: GenSci data on file, TEPEZZA® (teprotumumab - trbw) Prescribing Information and Douglas et al. (2020) (6 - week time - point) . No head - to - head t
Slide 19: Potential to be highly differentiated from emerging biologics
19 YB - 101 has the potential to be highly differentiated from emerging biologics for GD and TED 1 Single case report from Biohaven, Ltd. Press Release, January 12, 2026; broader controlled data are not available. Attributes sh own for YB - 101 reflect (i) clinical observations from the GenSci Phase
Slide 20: Lowest dosing burden for GD patients among emerging biologics
20 YB - 101 offers the lowest dosing burden for patients with GD among emerging biologics in development Sources: VYVGART® Hytrulo (efgartigimod alfa and hyaluronidase - qvfc) Prescribing Information, Clinicaltrials.gov NCT07018323, NC T06727604, NCT06980649. 1 Q 8W regimen is target only; subject t
Slide 21: Yarrow positioned for a unique value creation opportunity
Yarrow is positioned for a unique value creation opportunity Pursuing rapid advancement of YB - 101 in GD with additional future upside in TED
Slide 22: Shift to targeted biologics expected to create a substantial new market
22 The shift to targeted biologics in GD and TED is expected to create a substantial new market — with Yarrow well - positioned to lead Sources: Gerischer 2025, Argenx Q4 and Full year Financial results dated February 26, 2026 and Company estimate; Amgen Q4 and Full Year 2025 Financial Result s date
Slide 23: Potential substantial new biologic market opportunity for GD
23 Potential to build substantial new biologic market opportunity for GD Large addressable population for YB - 101 across GD and TED Sources: Davies 2020, Villagelin 2024, Lupo 2025, Chin 2020, Gillespie 2012; Amgen Q4 and Full Year 2025 Financial Results dated February 3, 2026. GD=Graves’ disease;
Slide 24: Advancing the first anti-TSHR therapy into Phase 2 in GD
24 Yarrow is advancing the first anti - TSHR therapy into Phase 2 in GD Sources: Yarrow data on file DMC=data monitoring committee; PBO=placebo; TSHR= thyrotropin receptor; ULN=upper limit of normal; ATD=anti - thyroid drug; GD=Gra ves’ disease; TED=thyroid eye disease; PK=pharmacokinetics; TFT= thy
Slide 25: Yarrow GD Phase 2b expected to begin in 1H 2028
25 Yarrow GD Phase 2b expected to begin in 1H 2028 Sources: Yarrow data on file. GD=Graves’ disease; TED=thyroid eye disease; FT3= free triiodothyronine; FT4=free thyroxine; TSH=thyroid stimulating hormone; UL N=upper limit of normal; ATD=anti - thyroid drug; PK=pharmacokinetic; TFT=thyroid function
Slide 26: Positioned to capture additional upside potential in TED
26 Yarrow is positioned to capture additional upside potential in TED Sources: GenSci data on file, TEPEZZA® (teprotumumab - trbw) Prescribing Information. TED=thyroid eye disease; MAD=multi ascending dose; CAS=clinical activity score; SC=subcutaneous; TSHR= thyrotropin receptor; IGF 1R= insulin - l
Slide 27: $200M raised enables clinical catalysts and cash runway into 2028
27 $ 200M raised enables multiple potential clinical catalysts and cash runway into 2028 $200M raised includes $100M from Yarrow Pre - Closing Financing. Sources: VYNE’s SEC filings including VYNE/Yarrow S - 4 Registration Statement (2026) GD=Graves’ disease; TED=thyroid eye disease; MAD=multiple as
Slide 28: Capitalization following closing of merger with VYNE
28 Note: Cash and cash equivalent balance of $108.8M as of August 31, 2026 is preliminary, unaudited and is subject to change. Nu mber of shares are as of August 10, 2026 on an as - converted basis and following the 1 - for - 50 reverse stock split effected in connection with the merger. The post -
Slide 29: GenSci license: financial terms summary
29 Yarrow in - licensed exclusive rights to YB - 101 for the treatment of GD and TED outside of greater China from Changchun GeneScience Pharmaceutical Company, Ltd. ( GenSci ) in December 2025. Refer to VYNE and YARW SEC filings for additional information. GD=Graves’ disease; TED=thyroid eye diseas
Slide 30: Thank you
30 yarrowbioscience.com Thank you