Sironax
Waltham, US Β· Founded 2017 Β· 65 employees on LinkedIn Β· 20 known investors
Sironax is a biopharmaceutical company focused on the discovery and development of therapies for neurodegenerative, inflammatory and immunological, metabolic, and rare diseases. Its research targets conditions affecting longevity, those requiring supportive care, and certain rare diseases.
Also known as Sironax, Inc.
Founders & leadership
Sironax was founded in 2017 by Dr. Xiaodong Wang and Dr. Zhiyuan Zhang.
Investors Β· 20
Also in the syndicate Β· 8
Funding
SEC filings, press & company announcements$200M disclosed across 1 of 4 rounds Β· 2019β2025
- Undisclosed amountSeries BSep 2025Source β
- $200MSeries BAug 2022 Β· 2 sources
Gaorong Capital (lead), Yunfeng Capital (lead), Abu Dhabi Investment Authority (ADIA), ARCH Venture Partners, CBC Group, Eight Roads, F-Prime Capital, Future Innovation Fund, Invus, K2 Venture Partners, Long River Investments, LSV Capital, MSA Capital, Superstring Capital, Temasek
Source β
Source: company announcements and press reports β follow each round's link for the claim.
Company profile
researched Aug 2026Sironax is a clinical-stage biotechnology company developing therapies for neurodegenerative, inflammatory and immunological, metabolic, and rare diseases. Its scientific approach targets what it describes as underlying contributors of degeneration β disrupted energy homeostasis, dysregulated cell death, and uncontrolled inflammation β across multiple organs and tissues, with stated clinical directions in neurodegenerative disease, inflammatory and immunological disease, metabolic disease, and rare disease.
The pipeline combines small molecules with large-molecule therapeutics enabled by a proprietary Brain Delivery Module (BDM) blood-brain-barrier crossing platform. Three programs are in Phase 1b/2: SARM1 inhibitor SIR2501 (chemotherapy-induced peripheral neuropathy, ALS and other neurodegenerative diseases), NAMPT activator SIR4156 (neuronal, muscular degenerative and metabolic diseases), and RIPK1 inhibitor SIR9900 (inflammation and immunological diseases, traumatic CNS conditions). Preclinical assets include SIR8752 (inflammation and immunology), SIR0811 (neurodegenerative diseases) and BDM-enabled therapeutic payloads, alongside undisclosed discovery-stage programs. Earlier company communications from 2022 described early clinical studies with SIR0365 and SIR2446 and framed the focus as age-related degenerative diseases.
The company reports more than 170 employees with operations in the United States (Waltham, Massachusetts), China (Beijing and Shanghai), Switzerland (Basel), and Australia (Sydney). Leadership referenced in sources includes President and CEO Dr. Shefali Agarwal (2025) and, at the time of the Series B, CEO Dr. Aaron Ren.
Founding story
Sironax was founded in 2017 in the Cayman Islands by Dr. Xiaodong Wang and Dr. Zhiyuan Zhang. Investor commentary at the time of the Series B credited Dr. Wang's roughly two decades of programmed cell death research, which identified mechanisms relevant to aging and degenerative disease, as the scientific foundation of the company.
Business model
Sironax discovers and develops proprietary drug candidates in-house and advances them through clinical development, while also monetizing platform technology through partnerships β as illustrated by the 2025 agreement granting Novartis an exclusive option to acquire the Brain Delivery Module platform, with Sironax retaining rights to develop selected therapeutic assets on the platform.
Sources describe potential payments from partnering rather than product revenue: under the Novartis agreement Sironax is eligible to receive up to $175 million in upfront and near-term payments, with Novartis acquiring full global rights to the BDM platform upon option exercise. No product sales or other revenue is disclosed in the sources.
Traction
Three clinical-stage assets (SIR2501, SIR4156, SIR9900) are in Phase 1b/2 studies after completing Phase 1 healthy-volunteer trials; SIR2501 received FDA Fast Track Designation in CIPN in May 2026 and had an abstract selected for the 2026 ASCO Annual Meeting. Three abstracts were selected for Neuroscience 2025. The company has raised over $300 million to date and reports more than 170 employees.
Latest developments
In May 2026 the FDA granted Fast Track Designation to SIR2501 in CIPN. In April 2026 an SIR2501 abstract was selected for the 2026 ASCO Annual Meeting; in March 2026 the company announced a poster presentation on NAMPT activation and appointed Clive Wang to its Board of Directors. Throughout 2026 the company is advancing Phase 1b/2 studies of SIR2501, SIR4156 and SIR9900.
βΈFull profile β market position, technology, go-to-market, geography, history, risks & controversies
Market position
Sironax describes itself as an emerging leader and a global clinical-stage biotechnology company in neurodegenerative, inflammatory/immunological, metabolic and rare diseases. It was named to the 2025 Endpoints 11 list of promising biotech startups, and its Series B drew a syndicate including sovereign wealth and specialist life-science investors.
Sironax positions its pipeline as first-in-class and potentially best-in-class, citing a first-in-class allosteric SARM1 inhibitor and a first-in-class NAMPT activator, plus a differentiated blood-brain-barrier crossing BDM platform applicable across modalities. Novartis's neuroscience head described effective delivery across the blood-brain barrier as a major drug discovery challenge.
Technology
The company's science centers on pathways contributing to degeneration: disrupted energy homeostasis (addressed via NAMPT activation), dysregulated cell death (SARM1 inhibition in axonal degeneration; RIPK1 inhibition), and uncontrolled inflammation. It also operates a proprietary Brain Delivery Module (BDM) platform, a blood-brain-barrier crossing technology intended to enhance brain delivery of therapeutics across multiple modalities, including large molecules.
Go-to-market
The company advances candidates through its own clinical programs, initially conducting early-phase studies including in Australia, and pursues strategic agreements with large pharmaceutical companies for platform assets.
Patients with neurodegenerative diseases (including chemotherapy-induced peripheral neuropathy and ALS), inflammatory and immunological diseases, traumatic CNS conditions, metabolic and muscular degenerative diseases, and certain rare diseases; pharmaceutical partners such as Novartis for platform technology.
Geography
Operations in the United States (headquarters in Waltham, Massachusetts), China (Beijing Changping, downtown Beijing, and Shanghai), Switzerland (Basel), and Australia (Sydney). The entity was founded in the Cayman Islands.
History
Following its 2017 founding, Sironax established an R&D facility in Beijing in 2018, set up clinical operations in Australia and secured Series A funding in 2019, and opened a Shanghai research facility in 2021. In 2022 it closed a $200 million Series B and nominated brain-penetrant RIPK1 inhibitor SIR9900 as a preclinical candidate. In 2023 it nominated allosteric SARM1 inhibitor SIR2501 and completed the SIR9900 Phase 1 healthy-volunteer study; in 2024 it nominated NAMPT activator SIR4156 and completed SIR2501 Phase 1. In 2025 the company established its U.S. headquarters and European operations in Switzerland, formed a strategic asset agreement with Novartis, initiated the SIR2501 Phase 1b/2 patient study, and completed SIR4156 Phase 1. In 2026 it is advancing Phase 1b/2 studies of SIR2501, SIR4156 and SIR9900, and SIR2501 received FDA Fast Track Designation in CIPN.
Risks & controversies
The Novartis agreement is an option, not a completed transaction: payments of up to $175 million are contingent on evaluation and option exercise, and the associated press release notes forward-looking statements subject to technical, regulatory and market risks. All disclosed clinical programs remain in early-stage (Phase 1b/2 or earlier) development. Descriptions of the company's focus and named clinical assets have shifted between 2022 (SIR0365 and SIR2446, age-related degenerative diseases) and current materials.
Compiled by commissioned research from 8 cited public sources β announcements, filings, and press listed under research sources below.
Key figures
latest reportedCompany-reported or press-reported figures, each dated to when it was claimed β not independently audited.
Competitors Β· 4
by search overlap
Companies competing with Sironax for the same Google search keywords, organic and paid, via search-intersection analysis.
Timeline Β· 15
launches, deals, and filingsSironax announced that the U.S. Food and Drug Administration granted Fast Track Designation to its SARM1 inhibitor SIR2501 for chemotherapy-induced peripheral neuropathy (CIPN).
Sironax granted Novartis an exclusive option to acquire its proprietary Brain Delivery Module (BDM) blood-brain-barrier crossing platform. Novartis evaluates the platform during an option period and, upon exercise, would acquire full global rights; Sironax retains rights to continue developing selected therapeutic assets using the platform and is eligible for up to $175 million in upfront and near-term payments.
$175M source β
Company timeline records establishment of U.S. HQ and Swiss operations, formation of the strategic asset agreement with Novartis, initiation of the SIR2501 Phase 1b/2 patient study, and completion of the SIR4156 Phase 1 healthy volunteer study.
Dated company events from announcements, filings, and press; legal rows summarize public dockets and regulator releases.
In the news
βΈResearch sources Β· 8
primary sources listed
- Sironaxsironax.com Β· web
8 public sources were cited for this profile; the first-party ones are listed here.
Frequently asked questions
- What does Sironax do?
- Clinical-stage biotech developing therapies for neurodegenerative, inflammatory, metabolic and rare diseases.
- Who founded Sironax?
- Sironax was founded by Dr. Xiaodong Wang, Dr. Zhiyuan Zhang in 2017.
- Who are Sironax's investors?
- Sironax's investors include ARCH Venture Partners, F-Prime Capital, YuanBio Venture Capital, CBC Group, Eight Roads Ventures, Future Innovation, Gaorong Capital, Invus and 4 more.
- How much funding has Sironax raised?
- Sironax has disclosed $200M raised across 1 of its 4 known rounds.
- Where is Sironax headquartered?
- Sironax is headquartered in Waltham, US.