YB-101 Market Summary

Key Factors Driving YB-101 Growth

1. First-in-Class Anti-TSHR Mechanism Targeting the Root Cause of Graves' Disease

YB-101 directly blocks the thyroid-stimulating hormone receptor (TSHR), the primary autoantigen responsible for Graves' disease. Unlike current anti-thyroid drugs, which suppress thyroid hormone synthesis without addressing the underlying autoimmune mechanism, YB-101 is designed to neutralize disease-driving TSHR autoantibodies. This mechanism also has the potential to improve both hyperthyroidism and associated Thyroid Eye Disease (TED), providing a differentiated therapeutic approach. Company presentations describe YB-101 as the first anti-TSHR antibody advancing into Phase II development for Graves' disease.

2. Large Addressable Patient Population Across Graves' Disease and TED

Graves' disease affects a substantial patient population globally. According to company materials supported by published epidemiologic literature, 20–40 new Graves' disease cases occur per 100,000 people annually, approximately 84% of patients receive anti-thyroid drugs (ATDs), and nearly 75% remain on ATDs after three months, highlighting the need for improved long-term therapies. Furthermore, 40% of Graves' disease patients develop TED, while 20–30% develop moderate-to-severe TED, creating an opportunity to address both diseases with a single biologic.

3. Potential Best-in-Class Dosing Convenience

YB-101 is being developed as a subcutaneous (SC) therapy with a target dosing interval of once every eight weeks, substantially reducing treatment burden compared with several emerging biologics that require weekly administration. The company is also evaluating administration through prefilled syringes and autoinjectors, which could improve patient adherence and support broader adoption if clinical efficacy is confirmed.

4. Advancement into Mid-Stage Clinical Development and FDA Fast Track Designation

Clinical development continues to progress. The U.S. FDA cleared the Investigational New Drug (IND) application in March 2026, enabling initiation of a randomized Phase IIa/IIb study in Graves' disease in the United States. The study is evaluating multiple SC dose regimens, with primary endpoints including safety and the proportion of patients achieving euthyroidism without anti-thyroid drugs. The program has also received FDA Fast Track Designation, which may facilitate regulatory interactions and accelerate development if clinical benefit is demonstrated. Top-line Phase IIa results are expected in the second half of 2027.

5. Opportunity to Expand into the High-Value TED Market

Beyond Graves' disease, YB-101 has potential in Thyroid Eye Disease, where the current commercial market is significant. Company disclosures note that the existing TED market, led by approved biologic therapy, exceeds US$2 billion annually, illustrating the commercial attractiveness of the indication. Because TSHR is a fundamental disease driver in both Graves' disease and TED, successful clinical development could allow YB-101 to compete across two closely related autoimmune disorders using a single mechanism.

YB-101 Recent Developments

In December 2025, VYNE Therapeutics Inc. and Yarrow Bioscience, Inc. announced that they have entered into a definitive merger agreement pursuant to which the companies will combine in an all-stock transaction (the “Merger”). Upon completion of the Merger, the combined company expects to operate as Yarrow Bioscience, Inc. and trade on Nasdaq under the ticker symbol “YARW”. Following completion of the Merger, the combined company plans to focus on advancing YB-101 (also known as GS-098), a clinical-stage, potentially first-in-class TSHR antibody for the treatment of GD and TED.

“YB-101 Sales Forecast, and Market Size Analysis – 2034” report provides comprehensive insights of YB-101 for potential indication like Graves’ disease and Graves ophthalmopathy in the 7MM. A detailed picture of YB-101’s existing usage in anticipated entry and performance in potential indications in the 7MM, i.e., the United States, EU4 (Germany, France, Italy, and Spain) and the United Kingdom, and Japan for the study period 2020 –2034 is provided in this report along with a detailed description of the YB-101 for potential indications. The YB-101 market report provides insights about YB-101’s sales forecast, mechanism of action (MoA), dosage and administration, as well as research and development including regulatory milestones, along with other developmental activities. Further, it also consists of historical and current YB-101 performance, future market assessments inclusive of the YB-101 market forecast analysis for potential indications in the 7MM, SWOT, analysts’ views, comprehensive overview of market competitors, and brief about other emerging therapies in respective indications. It also provides analysis of YB-101 sales forecasts, along with factors driving its market.

YB-101 Drug Summary

YB-101 (also known as GS-098) is an investigational, clinical-stage humanized monoclonal antibody targeting the thyroid-stimulating hormone receptor (TSHR) for the treatment of Graves' disease and Thyroid Eye Disease. The antibody is designed to selectively bind TSHR and block activation by pathogenic thyroid-stimulating autoantibodies, thereby directly inhibiting the autoimmune signaling pathway that drives hyperthyroidism and orbital inflammation. By targeting TSHR—the central disease-driving receptor in both conditions—YB-101 aims to provide a more disease-specific approach than therapies directed at downstream pathways such as IGF-1R. The drug is being developed as a subcutaneous biologic therapy, with early clinical studies evaluating its safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy. As of 2026, YB-101 is undergoing Phase I/II clinical development in Graves’ disease and thyroid eye disease, and remains investigational without regulatory approval. The report provides YB-101’s sales, growth barriers and drivers, post usage and approvals in multiple indications.

Scope of the YB-101 Market Report

The report provides insights into:

• A comprehensive product overview including the YB-101 MoA, description, dosage and administration, research and development activities in potential indication like Graves’ disease and Graves ophthalmopathy.
• Elaborated details on YB-101 regulatory milestones and other development activities have been provided in YB-101 market report.
• The report also highlights YB-101‘s cost estimates and regional variations, reported and estimated sales performance, research and development activities in potential indications across the United States, Europe, and Japan.
• The YB-101 market report also covers the patents information, generic entry and impact on cost cut.
• The YB-101 market report contains current and forecasted YB-101 sales for potential indications till 2034.
• Comprehensive coverage of the late-stage emerging therapies for respective indications.
• The YB-101 market report also features the SWOT analysis with analyst views for YB-101 in potential indications.

Methodology

The YB-101 market report is built using data and information sourced primarily from internal databases, primary and secondary research and in-house analysis by DelveInsight’s team of industry experts. Information and data from the secondary sources have been obtained from various printable and nonprintable sources like search engines, news websites, global regulatory authorities websites, trade journals, white papers, magazines, books, trade associations, industry associations, industry portals and access to available databases.

YB-101 Analytical Perspective by DelveInsight

• In-depth YB-101 Market Assessment

This YB-101 sales market forecast report provides a detailed market assessment of YB-101 for potential indication like Graves’ disease and Graves ophthalmopathy in the seven major markets, i.e., the United States, EU4 (Germany, France, Italy, and Spain) and the United Kingdom, and Japan. This segment of the report provides current and forecasted YB-101 sales data uptil 2034.

• YB-101 Clinical Assessment

The YB-101 market report provides the clinical trials information of YB-101 for potential indications covering trial interventions, trial conditions, trial status, start and completion dates.

YB-101 Competitive Landscape

The report provides Insights on competitors and marketed products within the domain, along with a summary of emerging products and their respective launch dates, posing significant competition in the market.

YB-101 Market Potential & Revenue Forecast

• Projected market size for the YB-101 and its key indications
• Estimated YB-101 sales potential (YB-101 peak sales forecasts)
• YB-101 Pricing strategies and reimbursement landscape

YB-101 Competitive Intelligence

• Number of competing drugs in development (pipeline analysis)
• YB-101 Market positioning compared to existing treatments
• YB-101 Strengths & weaknesses relative to competitors

YB-101 Regulatory & Commercial Milestones

• YB-101 Key regulatory approvals & expected launch timelines
• Commercial partnerships, licensing deals, and M&A activity

YB-101 Clinical Differentiation

• YB-101 Efficacy & safety advantages over existing drugs
• YB-101 Unique selling points

YB-101 Market Report Highlights

• In the coming years, the YB-101 market scenario is set to change due to strong adoption, increased prescriptions and broader uptake in multiple immunological indications; which would expand the size of the market.
• The YB-101 companies are developing therapies that focus on novel approaches to treat/improve the disease condition, assess challenges, and seek opportunities that could influence YB-101’s dominance.
• Other emerging products for Graves’ disease and Graves ophthalmopathy are expected to give tough market competition to YB-101 and launch of late-stage emerging therapies in the near future will significantly impact the market.
• A detailed description of regulatory milestones, and developmental activities, provide the current development scenario of YB-101 in potential indications.
• Analyse YB-101 cost, pricing trends and market positioning to support strategic decision-making in the immunology landscape.
• Our in-depth analysis of the forecasted YB-101 sales data uptil 2034 will support the clients in decision-making process regarding their therapeutic portfolio by identifying the overall scenario of YB-101 in potential indications.

Key Questions

• What is the class of therapy, route of administration and mechanism of action of YB-101? How strong is YB-101’s clinical and commercial performance?
• What is YB-101’s clinical trial status in each individual indications such as Graves’ disease and Graves ophthalmopathy and study completion date?
• What are the key collaborations, mergers and acquisitions, licensing and other activities related to the YB-101 Manufacturers?
• What are the key designations that have been granted to YB-101 for potential indications? How are they going to impact YB-101’s penetration in various geographies?
• What is the current and forecasted YB-101 market scenario for potential indications? What are the key assumptions behind the forecast?
• What are the current and forecasted sales of YB-101 in the seven major countries, including the United States, Europe (Germany, France, Italy, Spain) and the United Kingdom, and Japan?
• What are the other emerging products available and how are these giving competition to YB-101 for potential indications?
• Which are the late-stage emerging therapies under development for the treatment of potential indications?
• How cost-effective is YB-101? What is the duration of therapy and what are the geographical variations in cost per patient?