What Arthrosi Therapeutics does

Arthrosi Therapeutics, Inc. was a privately held, late-stage clinical biotechnology company founded in 2018 and headquartered in San Diego, California. The company was established by former Ardea Biosciences executives — the team responsible for developing the first-generation URAT1 inhibitor lesinurad that culminated in Ardea's $1.26 billion acquisition by AstraZeneca — with the explicit mission of advancing a next-generation urate-lowering therapy for gout and tophaceous gout. Arthrosi's entire pipeline was built around a single proprietary drug candidate, pozdeutinurad (also designated AR882), a once-daily oral, highly potent and selective next-generation URAT1 (Urate Transporter 1) inhibitor designed to lower serum uric acid (sUA), dissolve tophi, and reduce gout flares while avoiding the renal safety issues that constrained first-line therapies. The asset advanced through multiple Phase 1 and Phase 2 studies demonstrating industry-leading efficacy (e.g., 93% of patients on the 50mg dose achieving sUA <5 mg/dL vs 11% on allopurinol and 33% on febuxostat in Phase 2a), and into two fully enrolled global Phase 3 trials (REDUCE 1 and REDUCE 2) with pivotal data expected in 2026. In August 2024 the FDA granted Fast Track Designation for AR882 in tophaceous gout.

Arthrosi operated as a clinical-development organization with no commercial revenue; its business model was to develop pozdeutinurad through regulatory approval and either commercialize directly or partner with a larger pharmaceutical company for launch. To that end, the company raised approximately $228M+ across disclosed institutional rounds (a $75M Series D in July 2023 led by Guangrun Health Industry and a $153M Series E in October 2025 led by Prime Eight Capital Limited), formed a Greater China joint venture (Guangzhou Ruianbo Pharmaceutical Technology) with ApicHope Pharmaceutical's Ruiao Biopharmaceutical subsidiary in 2021 to develop AR882 in Mainland China, Hong Kong, Macao, and Taiwan, and engaged scientific KOLs (Dalbeth, Pérez-Ruiz, Schlesinger, Terkeltaub) on its advisory board. In December 2025, Sobi (Swedish Orphan Biovitrum AB) agreed to acquire Arthrosi for up to $1.5 billion ($950M upfront plus up to $550M in milestones), and the transaction closed in February 2026, transferring pozdeutinurad into Sobi's gout franchise and ending Arthrosi's independent operating status. Post-acquisition, Sobi assumes responsibility for global commercialization of the asset.

Name

Arthrosi Therapeutics

Legal name

Arthrosi Therapeutics, Inc.

Website

https://arthrosi.com

Company type

Private

Founded year

2018

Operating status

Acquired

Headcount range

11–50 employees

Short description

Arthrosi Therapeutics was a San Diego-based, late-stage clinical biotech developing pozdeutinurad (AR882), a once-daily oral next-generation URAT1 inhibitor for gout and tophaceous gout. Acquired by Sobi in February 2026 for up to $1.5 billion.

Ownership category

akta.pro rank

Product category

Gout Therapeutics

NAICS

Biological Product (except Diagnostic) Manufacturing (325414), Pharmaceutical and Medicine Manufacturing (3254)

akta.pro primary industry

Nephrology & Urology Pharmaceuticals (HLAIAAAM)

akta.pro secondary industries

Rare Renal & Nephrology Disorder Therapies (HLAIAIAI), Nephrology & Urology Specialty Pharmaceuticals (HLAIACAH)

Keywords

• Gout therapeutics
• URAT1 inhibitor drugs
• Urate lowering therapy
• Clinical stage biopharmaceuticals
• Tophaceous gout treatment

Headquarters

HQ city

San Diego

HQ country

United States

HQ region

North America

Offices2 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Marketing or Sales

Revenue model

1. Drug development and commercialization: As a late-stage clinical biotech company, Arthrosi was focused on developing its lead drug candidate pozdeutinurad (AR882) through Phase 3 clinical trials with the goal of obtaining regulatory approval and commercializing the product. The company was acquired by Sobi in February 2026 for up to $1.5 billion, transferring commercialization rights to Sobi.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels4 records

Core offering

Arthrosi Therapeutics develops pozdeutinurad (AR882), a once-daily oral next-generation URAT1 inhibitor for the treatment of chronic and tophaceous gout. The drug candidate is designed to lower serum uric acid (sUA) levels, dissolve tophi, and reduce gout flares with a renal-safe profile. Arthrosi was advancing the asset through two pivotal Phase 3 clinical trials (REDUCE 1 and REDUCE 2) until the company was acquired by Sobi in February 2026 for up to $1.5 billion.

Product overview

Arthrosi Therapeutics is a late-stage biotechnology company focused on developing a single proprietary drug candidate, pozdeutinurad (AR882), a highly potent and selective next-generation URAT1 inhibitor. The product is designed to reduce serum uric acid (sUA) levels, flares, and dissolve tophi in patients with gout and tophaceous gout. The company has completed multiple Phase 1 and Phase 2 clinical studies demonstrating industry-leading efficacy rates and superior safety profiles, and is currently advancing pozdeutinurad through pivotal Phase 3 trials (REDUCE 1 and REDUCE 2) with pivotal data expected in 2026. The company was acquired by Sobi in December 2025.

Differentiator

Problem solved

Functional benefit

Products and services

• Pozdeutinurad (AR882) A next-generation, once-daily oral URAT1 inhibitor in development for the treatment of chronic and tophaceous gout. Designed to reduce serum uric acid levels, dissolve tophi, and lower gout flares with a renal-safe profile. Demonstrated industry-leading efficacy rates and superior safety profiles in Phase 1 and 2 trials; currently in two fully enrolled global Phase 3 studies (REDUCE 1 and REDUCE 2).

Quantifiable outcome

• 93% of patients achieved sUA <5 mg/dL with AR882 50mg vs 11% for allopurinol 300mg and 33% for febuxostat 40mg in Phase 2a study
• +5 more outcomes

Named customers1 record

Segments3 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature3 records

Partnerships

Three partnerships are on record, tiered flagship and core.

• Sobi (Swedish Orphan Biovitrum AB)flagshipStrategic or Co-development Partner · 9 February 2026Sobi completed acquisition of Arthrosi Therapeutics in February 2026 for up to $1.5 billion ($950 million upfront plus up to $550 million in milestones). Sobi acquired all outstanding shares to add pozdeutinurad (AR882) to its gout franchise.
• ApicHope PharmaceuticalcoreStrategic or Co-development Partner · 17 August 2021Established joint venture Guangzhou Ruianbo Pharmaceutical Technology Co., Ltd. in Guangzhou, China for development of AR882 in Greater China. ApicHope is also a significant investor through its subsidiary Reichstein Biotech.
• Ruiao Biopharmaceutical Technology Co., Ltd.coreStrategic or Co-development Partner · 17 August 2021Subsidiary of ApicHope Pharmaceutical; joint venture partner in forming Guangzhou Ruianbo Pharmaceutical Technology Co., Ltd. for AR882 development in China.

Scale indicators5 records

Recent moves7 records

Expansion highlights6 records

Direct peers

• Ironwood Pharmaceuticals: Developed and commercialized lesinurad (DUZOLLO), a first-generation URAT1 inhibitor for gout, making it the closest direct mechanistic peer to Arthrosi's pozdeutinurad in the same drug class. Ironwood's experience illustrates both the commercial potential and challenges of URAT1 inhibition in gout.
• Horizon Therapeutics (Amgen): Markets KRYSTEXXA (pegloticase), the leading biologic for chronic refractory gout. Directly competes for the same tophaceous/refractory gout patient segment that pozdeutinurad targets and serves as the primary comparator for value capture in hard-to-treat gout.
• Savient Pharmaceuticals: Originator developer of KRYSTEXXA (pegloticase), the first biologic approved for chronic refractory gout. Directly comparable as a small-cap biotech that developed and commercialized a refractory gout therapy, illustrating the commercialization pathway Arthrosi now follows via Sobi.

Broad incumbents

• AstraZeneca: Acquired Ardea Biosciences (where Arthrosi's founders built lesinurad) for $1.26B in 2012, inheriting the URAT1 inhibitor franchise. While AstraZeneca does not directly market a URAT1 drug today, it remains a relevant peer via the same gout R&D lineage and represents potential competition given its scale.
• Takeda Pharmaceutical: Markets ULORIC (febuxostat), a leading branded xanthine oxidase inhibitor for chronic gout, including the tophaceous sub-population. Represents the most relevant incumbent oral gout competitor and benchmark for the urate-lowering market pozdeutinurad will compete in.

Emerging players

• Selecta Biosciences: Developed SEL-212, a combination of pegloticase with ImmTOR immune tolerance platform for chronic refractory gout. Targets the same tophaceous/refractory population and is a key emerging competitor in the advanced gout treatment space.
• BioCryst Pharmaceuticals: Has historically pursued gout and hyperuricemia therapeutics (e.g., ulodesine) and operates as a small/mid-cap biotech in adjacent metabolic and inflammatory disease areas, making it a comparable late-stage development-stage peer.

Regional players

• Atom Therapeutics (Fuji Pharma / Mochida): Markets dotinurad (URECE), a next-generation URAT1 inhibitor approved in Japan and under development in China. Mechanistically the closest direct peer to pozdeutinurad and a credible regional competitor that could expand into Arthrosi/Sobi's target geographies.
• Teijin Pharma: Markets febuxostat in Japan as a branded urate-lowering therapy. Comparable as a regional gout therapeutics commercializer with overlapping product profile to the standard-of-care pozdeutinurad will challenge.

Others

• Sobi (Swedish Orphan Biovitrum): Acquired Arthrosi in February 2026 for up to $1.5B and now owns pozdeutinurad. Comparable as the existing gout/inflammation franchise holder (Kineret, prior SEL-212 work) that provides the commercial backbone for Arthrosi's asset.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/arthrosi-therapeutics-inc

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Subsidiaries1 record

Funding overview

Funding rounds8 records

Investors11 records

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M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Arthrosi Therapeutics