Slide 1: Bringing life into balance
Bringing life into balance Yarrow Bioscience Overview October 2026 1
Slide 2: Disclaimers
Disclaimers The information contained in this presentation has been prepared by Yarrow Bioscience, Inc. and its affiliates (“Yarrow” or the “Company”) and contains information pertaining to the business and operations of the Company. The information contained in this presentation: (a) is provided as
Slide 3: Yarrow Bioscience is seeking to bring life into balance for patients with Graves' Disease and TED
Yarrow Bioscience is seeking to bring life into balance for patients suffering with Graves’ Disease and TED 3
Slide 4: Yarrow is advancing YB-101, a potential first-in-class anti-TSHR antibody
Yarrow is advancing YB-101, a potential first-in-class anti-TSHR antibody, to redefine the treatment of Graves’ Disease and TED Yarrow: Aspiring to be a new leader in thyroid autoimmune disease • Founded in 2025 with the singular focus of developing novel therapies to treat thyroid autoimmune diseas
Slide 5: TSHR: the site of action in GD and TED
TSHR: the site of action in GD and TED Pathophysiology of both diseases converges at TSHR Ideal target for both diseases TSHR blockade designed to address both thyroidal and extra-thyroidal clinical manifestations of GD Directly disrupts the disease process Protects thyroid tissue TSHR is the
Slide 6: Opportunity to generate clinical data across both indications leveraging GenSci collaboration
Our opportunity with YB-101 is to generate clinical data across both indications, leveraging collaboration with GenSci • Accelerating to Phase 2 in GD in the US based on China Phase 1 data • Leveraging ongoing GenSci TED development to enable future global TED development after TED POC in China • Ca
Slide 7: Experienced leadership team and board with strong track record of value creation
Experienced leadership team and board with strong track record of value creation Rebecca V. Frey, PharmD | President and CEO Tyler Zeronda | Chief Financial Officer Lori Payton, PhD | Chief Development Officer Steve Ryder, MD | Chief Medical Officer Board of Directors • Bill Lundberg, MD, Board Chai
Slide 8: Significant unmet needs exist 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 and mortality risk
GD and TED are poorly treated diseases with significant morbidity and mortality risk Sleep disturbance, anxiety, mood alterations Bulging, swollen eyes, orbital Goiter thyroid storm, pain, visual disturbances Graves’ Disease: TSHR-stimulating thyroid cancer (TED) autoantibodies drive hyperthyroidism
Slide 10: Current GD and TED treatments remain inadequate
Current GD and TED treatments remain inadequate FIRST-LINE SECOND-LINE Graves’ Anti-thyroid drugs Ablative treatments Disease Methimazole, Propylthiouracil Radioactive iodine Risk of skin rash, nausea/vomiting, hepatitis, agranulocytosis, Radiation exposure, exacerbates TED, and possible risk of can
Slide 11: ATDs are suboptimal as first-line treatment for GD, and are not effective for TED
ATDs are suboptimal as first-line treatment for GD, and are not effective for TED Efficacy limitations Safety / tolerability risks Noncompliance Safety/tolerability concerns require Adherence challenges limit ATD 50% 50% monitoring and drive treatment treatment effectiveness – Remission rate after R
Slide 12: Yarrow's potential first-in-class anti-TSHR offers a highly differentiated approach
Yarrow’s potential first-in-class anti-TSHR offers a highly differentiated approach to treat GD and TED
Slide 13: YB-101 is a potent anti-TSHR antibody with the potential to redefine treatment
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 YB-101 POTENTIAL KEY VALUE DRIVERS Phase 2 clinical asset with first-in-class potential Directly disrupts central mechanism of both GD and TED Potential for rapid
Slide 14: Pathophysiology of GD and TED converges at TSHR
Pathophysiology of GD and TED converges at TSHR GD and TED are polyclonal Thyroid cell Orbital autoantibody-driven diseases fibroblast • Autoantibodies attack and Stimulating overstimulate TSHR autoantibodies • Autoantibodies are diverse but all (TRAb/TSI) bind to the same TSHR • Autoantibody attack
Slide 15: YB-101 is designed to directly disrupt the central mechanism of GD & TED
YB-101 is designed to directly disrupt the central mechanism of GD & TED by blocking autoantibody attack on TSHR Thyroid cell Orbital fibroblast YB-101 is designed to directly disrupt the autoantibody attack YB-101 Stimulating Blocks autoantibody autoantibodies (TRAb/TSI) attack and over-stimulation
Slide 16: GenSci Phase 1 SAD in TED: Study design and patient population
GenSci Phase 1 SAD in TED: Study design and patient population • SAD evaluated safety and efficacy of 270 mg five dose levels of YB-101 vs. placebo 180 mg N=8 in TED (6:2) 90 mg N=8 • Key inclusion criteria: active TED N=8 (6:2) (CAS >=3) 45 mg (6:2) N=8 • SC administration 15 mg (6:2) • Majority eu
Slide 17: GenSci Phase 1 SAD: Favorable safety data of YB-101 in active TED
GenSci Phase 1 SAD: Favorable safety data of YB-101 in patients with active TED ✓ All AEs mild or moderate in severity No severe adverse events reported across all cohorts ✓ Hearing impairment and hyperglycemia are known risks associated with drugs targeting No clinically meaningful hearing-related
Slide 18: GenSci Phase 1 SAD: Rapid, dose-dependent proof of mechanism and clinical responses in TED
GenSci Phase 1 SAD: A single dose of YB-101 produced rapid, dose-dependent proof of mechanism and meaningful clinical responses in TED FT3 and FT4 changes occurred rapidly: TSH also increased: • Rapid changes observed in FT3/FT4 FT3/FT4 declines TSH rises and TSH Starting on day 2-3 Starting on day
Slide 19: YB-101 potentially highly differentiated from emerging biologics for GD and TED
YB-101 has the potential to be highly differentiated from emerging biologics for GD and TED One potential solution for both diseases with a compelling target product profile Anti-FcRn IgG degraders Anti-IGF-1R YB-101 (Anti-TSHR) Specific against TSHR Addresses GD and TED TBD Rapid reversal of hypert
Slide 20: YB-101 offers the lowest dosing burden for GD among emerging biologics
YB-101 offers the lowest dosing burden for patients with GD among emerging biologics in development Convenient SC formulation with feasibility for pre-filled syringe and autoinjector P RODUCT STAGE NUM BE R OF DO SE S FO R P RIM ARY E NDP OINT (6 M ONTHS) YB-101 Initiating Phase Targeting SC adminis
Slide 21: Yarrow is 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: The shift to targeted biologics in GD and TED is expected to create a substantial new market
The shift to targeted biologics in GD and TED is expected to create a substantial new market — with Yarrow well-positioned to lead RECENT ANALOG: OUR OPPORTUNITY: OUR OPPORTUNITY: Myasthenia Gravis Graves’ Disease Thyroid Eye Disease Nonspecific symptom management Anti-thyroid drugs Steroids symptom
Slide 23: Large addressable population for YB-101 across GD and TED
Large addressable population for YB-101 across GD and TED Strong market potential for incident patients plus ~1M prevalent patients with GD on ATDs New GD cases 40% of patients w/GD develop TED 20-40 per 100K persons per year 84% of GD patients are prescribed ATDs 20-30% develop 75% remain on ATDs a
Slide 24: Yarrow is advancing the first anti-TSHR therapy into Phase 2 in GD
Yarrow is advancing the first anti-TSHR therapy into Phase 2 in GD YB-101 Phase 2a/2b study design: Phase 2a (Part 1), US and Australia Parallel cohorts 1 & 2 Parallel cohorts 3 & 4 n=8 per cohort n=8 per cohort YB-101 or PBO YB-101 or PBO 180 mg Q8W 400 mg Q8W R R Initiate 3:1 3:1 Part 2 YB-101 or
Slide 25: Yarrow GD Phase 2b expected to begin in 1H 2028
Yarrow GD Phase 2b expected to begin in 1H 2028 Part 2/Phase 2b design and endpoints aligned with FDA Key inclusion criteria: YB-101 Dose 1 • Confirmed GD, w/ or w/o TED n=50 • FT3+FT4 normal; TSH <ULN; thyroid autoantibodies >ULN YB-101 Dose 2 • Stable on ATD for >=3 mon n=50 R Long-term Extension
Slide 26: Yarrow is positioned to capture additional upside potential in TED
Yarrow is positioned to capture additional upside potential in TED Leveraging collaboration with GenSci for maximum efficiency YB-101 TED MAD (China) Study Design N=12 (5:1) per cohort • GenSci is conducting a randomized, double-blinded, placebo-controlled MAD in China 270 mg x 3 • Study is evaluati
Slide 27: Capital raised enables multiple clinical catalysts and cash runway into 2030
Capital raised enables multiple potential clinical catalysts and cash runway into 2030 Leveraging GenSci collaboration for efficient value creation across indications YB-101 Ant i ci pa t ed M i lest o nes 2026 2027 2028 Graves’ GD Ph 2a/2b initiated GD Ph 2a POC data Disease Q2 2026 2H 2027 Initiat
Slide 28: Capitalization following closing of merger with VYNE and September '26 financing
Capitalization following closing of merger with VYNE and September ‘26 financing Number of Shares Common stock Shares outstanding 11,473,285 Common stock equivalents Pre-funded warrants 23,745,610 Common stock & Total outstanding 35,218,895 common stock equivalents Cash balance of ~$108.8M as of Aug
Slide 29: YB-101 license: financial terms summary
YB-101 license: financial terms summary Yarrow Worldwide, excluding Greater China for all fields of use, Territory / rights including the treatment of GD and TED Upfront GenSci received $70M Development, regulatory, manufacturing and sales-based milestones payable up to $1.295B Milestones Inclusive
Slide 30: Thank you
Thank you 30 yarrowbioscience.com