SON-1010

PRINCETON, N.J., May 01, 2025 (GLOBE NEWSWIRE) -- Sonnet BioTherapeutics Holdings, Inc. (NASDAQ:SONN) (the "Company" or "Sonnet"), a clinical-stage company developing immunotherapeutic drugs targeting the tumor microenvironment (TME), today announced it will present at the 6th Annual Cytokine-Based Drug Development Summit being held May 15-16, 2025 in Boston, MA. Details of the presentation are as follows: Title: Managing Toxicity Caused by The Over Expression of Cytokines to Widen the Therapeutic Window Session: Understanding Toxicity Challenges & Improving Safety Profiles to Widen the Therapeutic Window Speaker: Richard Kenney, M.D., Chief Medical Officer of Sonnet Date and Time: Thursday, May 15, 2025 at 11:15 AM ET As part of the session, Dr. Kenney will discuss: Exploring the strategy behind the introduction of receptor bias to reduce toxicity and improve efficacy; Key strategies for optimizing cytokine potency and mitigating their inherent toxicity while considering the role of the therapeutic index in determining the clinical efficacy and safety of cytokine-based therapies; and Examining whether toxicity is the primary limiting factor in achieving therapeutic benefit and considering alternative factors that may influence the ‘therapeutic window’. For more information, please visit the Summit website here. About Sonnet BioTherapeutics Holdings, Inc. Sonnet is an oncology-focused biotechnology company with a proprietary platform for developing targeted biologic drugs with single or bifunctional action. Known as FHAB (Fully Human Albumin-Binding), the technology utilizes a fully human single chain antibody fragment (scFv) that binds to and "hitch-hikes" on human serum albumin (HSA) for transport to target tissues. Sonnet's FHAB was designed to specifically target tumor and lymphatic tissue, with an improved therapeutic window for optimizing the safety and efficacy of immune modulating biologic drugs. FHAB platform is the foundation of a modular, plug-and-play construct for potentiating a range of large molecule therapeutic classes, including cytokines, peptides, antibodies and vaccines. Sonnet’s lead program, SON-1010, or IL-12-FHAB, is in development for the treatment of solid tumors, certain types of sarcoma, and ovarian cancer. SON-1010 is being evaluated in an ongoing Phase 1/2a study through a Master Clinical Trial and Supply Agreement, along with ancillary Quality and Safety Agreements, with Roche in combination with atezolizumab (Tecentriq®) for the treatment of platinum-resistant ovarian cancer (PROC) (NCT05756907). The Company is also evaluating its second program using this platform, SON-1210, an IL12-FHAB-IL15 for solid tumors, in collaboration with the Sarcoma Oncology Center to commence an investigator-initiated and funded Phase 1/2a study for the treatment of pancreatic cancer. Forward-Looking Statements This press release contains certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 and Private Securities Litigation Reform Act, as amended, including those relating to the outcome of the Company’s clinical trials, the Company's cash runway, the Company's product development, clinical and regulatory timelines, market opportunity, competitive position, possible or assumed future results of operations, business strategies, potential growth opportunities and other statements that are predictive in nature. These forward-looking statements are based on current expectations, estimates, forecasts and projections about the industry and markets in which we operate and management's current beliefs and assumptions. These statements may be identified by the use of forward-looking expressions, including, but not limited to, "expect," "anticipate," "intend," "plan," "believe," "estimate," "potential," "predict," "project," "should," "would" and similar expressions and the negatives of those terms. These statements relate to future events or our financial performance and involve known and unknown risks, uncertainties, and other factors which may cause actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Such factors include those set forth in the Company's filings with the Securities and Exchange Commission. Prospective investors are cautioned not to place undue reliance on such forward-looking statements, which speak only as of the date of this press release. The Company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events, or otherwise. Investor Relations Contact: JTC Team, LLC Jenene Thomas 908-824-0775 SONN@jtcir.com Released May 1, 2025

- Raghu Rao, Interim Chief Executive Officer and Dr. Richard Kenney, Chief Medical Officer, of Sonnet discuss the recently announced safety data related to SON-1010 - Watch the "What This Means" video here PRINCETON, N.J., April 16, 2025 (GLOBE NEWSWIRE) -- Sonnet BioTherapeutics Holdings, Inc. (NASDAQ:SONN) (the "Company" or "Sonnet"), a clinical-stage company developing immunotherapeutic drugs targeted to the tumor microenvironment (TME), today announced that members of the Sonnet management team participated in a Virtual Investor "What This Means" segment. As part of the segment, Raghu Rao, Interim Chief Executive Officer and Dr. Richard Kenney, Chief Medical Officer, discussed the recently announced positive safety results of SON-1010 (IL12-FHAB) at the highest dose combined with atezolizumab being evaluated in the Phase 1b/2a clinical trial in adult patients with advanced solid tumors or platinum-resistant ovarian cancer (PROC) (the SB221 study). Mr. Rao and Dr. Kenney also provided insight into next steps for the program. The Virtual Investor "What This Means" segment featuring Sonnet is now available here. About Sonnet BioTherapeutics Holdings, Inc. Sonnet is an oncology-focused biotechnology company with a proprietary platform for developing targeted biologic drugs with single or bifunctional action. Known as FHAB (Fully Human Albumin-Binding), the technology utilizes a fully human single chain antibody fragment (scFv) that binds to and "hitch-hikes" on human serum albumin (HSA) for transport to target tissues. Sonnet's FHAB was designed to specifically target tumor and lymphatic tissue, with an improved therapeutic window for optimizing the safety and efficacy of immune modulating biologic drugs. FHAB platform is the foundation of a modular, plug-and-play construct for potentiating a range of large molecule therapeutic classes, including cytokines, peptides, antibodies and vaccines. Sonnet’s lead program, SON-1010, or IL-12-FHAB, is in development for the treatment of solid tumors, certain types of sarcoma, and ovarian cancer. SON-1010 is being evaluated in an ongoing Phase 1/2a study through a Master Clinical Trial and Supply Agreement, along with ancillary Quality and Safety Agreements, with Roche in combination with atezolizumab (Tecentriq®) for the treatment of platinum-resistant ovarian cancer (PROC) (NCT05756907). The Company is also evaluating its second program using this platform, SON-1210, an IL12-FHAB-IL15 for solid tumors, in collaboration with the Sarcoma Oncology Center to commence an investigator-initiated and funded Phase 1/2a study for the treatment of pancreatic cancer. Forward-Looking Statements This press release contains certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 and Private Securities Litigation Reform Act, as amended, including those relating to the outcome of the Company’s clinical trials, the Company's cash runway, the Company's product development, clinical and regulatory timelines, market opportunity, competitive position, possible or assumed future results of operations, business strategies, potential growth opportunities and other statements that are predictive in nature. These forward-looking statements are based on current expectations, estimates, forecasts and projections about the industry and markets in which we operate and management's current beliefs and assumptions. These statements may be identified by the use of forward-looking expressions, including, but not limited to, "expect," "anticipate," "intend," "plan," "believe," "estimate," "potential," "predict," "project," "should," "would" and similar expressions and the negatives of those terms. These statements relate to future events or our financial performance and involve known and unknown risks, uncertainties, and other factors which may cause actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Such factors include those set forth in the Company's filings with the Securities and Exchange Commission. Prospective investors are cautioned not to place undue reliance on such forward-looking statements, which speak only as of the date of this press release. The Company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events, or otherwise. Investor Relations Contact: JTC Team, LLC Jenene Thomas 908-824-0775 SONN@jtcir.com Released April 16, 2025