Sonnet Biotherapeutc Hldng Stock Price, News & Analysis
Company Description
Sonnet BioTherapeutics Holdings, Inc. (formerly trading on Nasdaq under the ticker SONN) is an oncology-focused biotechnology company. According to company disclosures and recent news, Sonnet develops immunotherapeutic biologic drugs that target the tumor microenvironment, with an emphasis on biologics that can act with single or bifunctional mechanisms. The company has operated as a clinical-stage developer of drug candidates for solid tumors and certain sarcomas and gynecologic cancers.
A central element of Sonnet’s approach is its proprietary FHAB (Fully Human Albumin Binding) platform. This technology uses a fully human single chain antibody fragment (scFv) designed to bind to human serum albumin (HSA). By “hitch-hiking” on albumin, FHAB-based constructs are intended to transport immune-modulating biologic drugs to target tissues. Company materials describe FHAB as being designed to specifically target tumor and lymphatic tissue and to offer an improved therapeutic window for immune-modulating biologic drugs. The FHAB platform is presented as a modular, plug-and-play construct that can be used with large molecule therapeutic classes such as cytokines, peptides, antibodies and vaccines.
Sonnet’s lead clinical program is SON-1010, also referred to as IL-12-FHAB. SON-1010 is described as a candidate immunotherapeutic recombinant drug that links unmodified single-chain human interleukin-12 (IL‑12) with the albumin-binding domain of a single-chain antibody fragment (A10m3). Company communications state that this fragment was selected to bind albumin at both normal physiological pH and the acidic pH typically found in the tumor microenvironment. SON-1010 is being evaluated for the treatment of solid tumors, certain types of sarcoma, and ovarian cancer.
In clinical development, SON-1010 is being studied in a global Phase 1b/2a multicenter, dose-escalation and randomized proof-of-concept trial known as SB221. This study assesses the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and efficacy of SON-1010 administered subcutaneously, either alone or in combination with atezolizumab (Tecentriq), an immune checkpoint inhibitor provided by Genentech, a member of the Roche Group. The SB221 trial focuses on adult patients with advanced solid tumors and platinum-resistant ovarian cancer (PROC). Company announcements report that the maximum tolerated dose of SON-1010 in combination with atezolizumab was set at 1200 ng/kg in PROC patients, with no dose-limiting toxicity or cytokine release syndrome observed at the evaluated dose levels.
Sonnet has also disclosed a monotherapy trial, SB101, in patients with advanced solid tumors. Dose escalation results from SB101, as described in company news, indicated a clinical benefit rate at the 1200 ng/kg dose level, including a partial response in a patient with soft tissue sarcoma. The company has reported that SON-1010 monotherapy and the combination regimen in SB221 have shown acceptable safety signals and evidence of clinical benefit in early-stage evaluation.
In addition to SON-1010, Sonnet is evaluating a second program, SON-1210, characterized as an IL12-FHAB-IL15 construct for solid tumors. Company announcements state that SON-1210 is being developed in collaboration with the Sarcoma Oncology Center, with plans for an investigator-initiated and funded Phase 1/2a study for the treatment of pancreatic cancer. Both SON-1010 and SON-1210 are based on the FHAB platform, which is intended to target tumor and lymphatic tissues and to allow dose sparing and potential improvements in safety and efficacy profiles for potent immunomodulators.
Sonnet’s disclosures describe the scientific rationale for its platform, noting that the FHAB technology targets tumor and lymphatic tissue and that binding to native albumin in serum can extend the half-life and bioactivity of linked cytokines such as IL‑12. Company materials explain that this targeting may help deliver IL‑12 to local tumor tissue, potentially turning immunologically “cold” tumors “hot” by stimulating interferon (IFN) production, activating innate and adaptive immune responses, and increasing expression of Programmed Death Ligand 1 (PD‑L1) on tumor cells. The company has also referenced tumor microenvironment proteins such as SPARC and gp60 as relevant to this targeting strategy.
Beyond its biotechnology operations, Sonnet has undergone a significant corporate transaction. According to a joint press release dated December 2, 2025, Sonnet BioTherapeutics Holdings, Inc. completed a previously announced business combination with Hyperliquid Strategies Inc. (HSI) and Rorschach I LLC. As a result of the closing, Sonnet became a wholly owned subsidiary of Hyperliquid Strategies Inc., which is described as a digital asset treasury company focused on accumulating HYPE, the native token of the Hyperliquid blockchain. The same announcement states that HSI’s common stock is expected to trade on the Nasdaq Capital Market under the ticker symbol PURR and that Sonnet’s common stock will no longer trade separately following the transaction.
Company communications around this transaction indicate that, in parallel with the new cryptocurrency treasury strategy at the parent level, Sonnet is expected to continue focusing on its existing biotechnology assets and business lines, including the development of SON-1010, while disposing of other assets. Certain Sonnet stockholders are expected to receive contingent value rights (CVRs) linked to potential future value from Sonnet’s biotech assets, as described in the Business Combination Agreement and related filings.
Sonnet’s corporate governance and shareholder matters are documented in its SEC filings, including annual meetings of stockholders, advisory votes on executive compensation, and the appointment of independent registered public accounting firms. The company has also reported financing activities such as private placements of preferred stock and warrants, and the issuance of convertible notes and associated warrants, which are described in detail in its Form 8‑K filings.
Business focus and technology
Oncology focus: Sonnet describes itself as an oncology-focused biotechnology company. Its programs target solid tumors, platinum-resistant ovarian cancer, certain sarcomas, and pancreatic cancer through immunotherapeutic mechanisms.
FHAB platform: The FHAB (Fully Human Albumin Binding) platform is presented as the foundation for Sonnet’s drug candidates. By using a fully human single chain antibody fragment that binds human serum albumin, FHAB constructs are designed to transport biologic drugs to tumor and lymphatic tissues and to optimize the therapeutic window of immune-modulating agents.
Pipeline highlights: SON-1010 (IL‑12‑FHAB) is the lead program, with clinical studies in advanced solid tumors and PROC, both as monotherapy and in combination with atezolizumab. SON-1210 (IL12-FHAB-IL15) is a second program aimed at solid tumors, including pancreatic cancer, in collaboration with an oncology center.
Corporate transformation and listing status
According to the December 2, 2025 business combination announcement, Hyperliquid Strategies Inc. (NASDAQ: PURR) is a digital asset treasury company whose primary focus is to maximize shareholder value through accumulating HYPE, the native token of the Hyperliquid blockchain. The transaction materials state that Sonnet BioTherapeutics Holdings, Inc. continues to operate as a wholly owned subsidiary of Hyperliquid Strategies Inc. Following the closing, HSI’s common stock is expected to trade under the ticker PURR, and Sonnet’s common stock will no longer trade as a separate listing.
Earlier filings and press releases describe the Business Combination Agreement among Sonnet, Rorschach I LLC, and Hyperliquid Strategies Inc., including the planned issuance of Pubco (HSI) common stock, the contribution of HYPE tokens and cash by investors, and the expectation that Sonnet’s legacy stockholders, including PIPE and bridge investors, would hold a minority interest in the combined company. These documents also outline that Sonnet would continue to manage its biotech assets within the new corporate structure.
Regulatory and shareholder information
Sonnet’s SEC filings, such as its Definitive Proxy Statement on Schedule 14A and various Form 8‑K reports, provide detail on shareholder meetings, board composition, executive compensation matters, auditor ratification, and financing transactions. An 8‑K dated July 25, 2025, for example, discusses the company’s response to a Nasdaq deficiency notice regarding minimum stockholders’ equity and subsequent confirmation of compliance after capital raises. Another 8‑K dated July 2, 2025 describes the issuance of convertible notes and warrants to accredited investors.
Through these filings, investors can review how Sonnet has structured its capital, the terms of its financing instruments, and the governance processes surrounding major corporate actions, including the business combination with Hyperliquid Strategies Inc.
FAQs about Sonnet BioTherapeutics Holdings, Inc. (SONN)
- What does Sonnet BioTherapeutics Holdings, Inc. do?
Sonnet is described in company communications as an oncology-focused biotechnology company. It develops targeted biologic drugs with single or bifunctional action, using its FHAB (Fully Human Albumin Binding) platform to deliver immune-modulating agents to tumor and lymphatic tissues. - What is the FHAB platform?
FHAB is Sonnet’s proprietary technology that uses a fully human single chain antibody fragment (scFv) to bind human serum albumin (HSA). According to company descriptions, this allows biologic drugs to “hitch-hike” on albumin for transport to target tissues, with the goal of improving the safety and efficacy of immune-modulating biologic drugs. - What is SON-1010?
SON-1010, also referred to as IL‑12‑FHAB, is Sonnet’s lead candidate immunotherapeutic drug. Company materials state that it links unmodified single-chain human IL‑12 with the albumin-binding domain of a single-chain antibody fragment. SON-1010 is in clinical development for solid tumors, certain sarcomas, and ovarian cancer, including platinum-resistant ovarian cancer. - What clinical trials are associated with SON-1010?
Sonnet has disclosed two main trials: SB101, a monotherapy trial in patients with advanced solid tumors, and SB221, a global Phase 1b/2a multicenter study evaluating SON-1010 alone and in combination with atezolizumab in advanced solid tumors and platinum-resistant ovarian cancer. The SB221 trial is designed to establish the maximum tolerated dose and assess safety, PK, PD, and preliminary efficacy. - What is SON-1210?
SON-1210 is described as an IL12-FHAB-IL15 construct for solid tumors. Company announcements indicate that it is being evaluated in collaboration with the Sarcoma Oncology Center, with plans for an investigator-initiated and funded Phase 1/2a study in pancreatic cancer. - What happened to the SONN stock listing?
A joint press release dated December 2, 2025, states that Sonnet BioTherapeutics Holdings, Inc. completed a business combination with Hyperliquid Strategies Inc. and Rorschach I LLC. As a result, Sonnet became a wholly owned subsidiary of Hyperliquid Strategies Inc., whose common stock is expected to trade on the Nasdaq Capital Market under the ticker symbol PURR. The same announcement notes that Sonnet’s common stock will no longer trade as a separate listing. - Does Sonnet still operate as a biotechnology company after the business combination?
According to transaction-related press releases, following the completion of the business combination, Sonnet is expected to operate as a wholly owned subsidiary of Hyperliquid Strategies Inc. and to continue focusing on its existing biotech assets and business lines, including the development of SON-1010, while disposing of other assets. - What is Hyperliquid Strategies Inc. (PURR) in relation to Sonnet?
Hyperliquid Strategies Inc. is described as a digital asset treasury company whose primary focus is to accumulate HYPE, the native token of the Hyperliquid blockchain. Following the business combination, Sonnet BioTherapeutics Holdings, Inc. is a wholly owned subsidiary of Hyperliquid Strategies Inc., and HSI’s common stock is expected to trade under the ticker PURR on Nasdaq. - Where can investors find official information about Sonnet’s corporate actions?
Investors can review Sonnet’s filings with the U.S. Securities and Exchange Commission, including Forms 8‑K, the Definitive Proxy Statement on Schedule 14A, and other periodic reports. These documents describe material agreements, shareholder votes, financing transactions, and details of the business combination with Hyperliquid Strategies Inc.