Septerna, Inc. (NASDAQ:SEPN), a clinical-stage biotechnology company pioneering a new era of G protein-coupled receptor (GPCR) drug discovery, today announced that the first detailed preclinical characterization of SEP-479 has been accepted for an oral presentation at the 2026 Endocrine Society's Annual Meeting (ENDO 2026), taking place June 13-16, 2026, in Chicago.

The presentation will highlight the pharmacologic profile of SEP-479, a potent, selective small molecule PTH1R agonist being developed for the treatment of hypoparathyroidism, including robust in vitro and in vivo activity supporting its potential as an oral therapy. SEP-479 is currently being evaluated in an ongoing Phase 1 single-ascending dose and multiple-ascending dose study in healthy volunteers, with data expected in late 2026 or early 2027.

"SEP-479 highlights the ability of our Native Complex Platform^® to discover novel oral small molecules directed towards challenging GPCR targets," said Jeffrey Finer, M.D., Ph.D., chief executive officer and co-founder of Septerna. "The preclinical data that will be presented at ENDO further characterize SEP-479 and support its potential to functionally replace PTH with a once-daily oral therapy. We believe this approach has the potential to redefine the treatment landscape for patients with hypoparathyroidism, and we look forward to further evaluating SEP-479 in the clinic as we advance our ongoing Phase 1 study."

Presentation Details:

Title: Characterization of SEP-479, a Novel Oral Small Molecule PTH1R Agonist for the Treatment of Hypoparathyroidism

Abstract Number: ORF16-05

Session: Parathyroid Disease – Bone and Mineral Metabolism-02

Presenter: Jun Zhang, Ph.D., Senior Director of Translational Biology

Session Date and Time: June 13, 2026, 2:15-2:30 p.m. CT

Location: McCormick Place West, Room W187

About SEP-479

Septerna is developing SEP-479, a potent oral small molecule parathyroid hormone 1 receptor (PTH1R) agonist, for the treatment of patients with hypoparathyroidism. In preclinical studies, SEP-479 demonstrated activity comparable to PTH peptides in cell-based assays and in vivo models, normalized serum calcium in a rat model of hypoparathyroidism and increased serum calcium with reductions in endogenous PTH in a non-human primate PK/PD study. SEP-479 was generally well tolerated in 28-day GLP toxicology studies in rats, dogs and non-human primates.

About Septerna

Septerna, Inc. is a clinical-stage biotechnology company with a world-class team of GPCR experts and drug developers advancing cutting-edge science to unlock the full potential of GPCR therapies for patients with significant unmet needs. The company's proprietary Native Complex Platform^® is designed to enable new approaches to GPCR drug discovery and has led to the development of a diverse pipeline of novel oral small molecule drug candidates. Septerna is advancing programs in endocrinology, immunology and inflammation, metabolic diseases and additional therapeutic areas, both independently and with partners. For more information, please visit www.septerna.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, implied and express statements about Septerna's beliefs and expectations regarding: the potential of SEP-479 preclinical data to translate into similar clinical safety, pharmacokinetic, and pharmacodynamic findings; the estimated availability of SEP-479 Phase 1 clinical data in late 2026 or early 2027; the potential for SEP-479 to be a differentiated once-daily oral therapy for patients with hypoparathyroidism; the potential of its proprietary Native Complex Platform^®to discover novel oral small molecules; the size and growth potential of the markets for its current and future product candidates; its expectations regarding strategic plans for its business, product candidates, and technology; and the scope of protection it is able to establish and maintain for intellectual property rights covering its Native Complex Platform^® and its product candidates. The words "anticipate," "believe," "continue," "could," "estimate," "expect," "intend," "may," "might," "objective," "ongoing," "plan," "predict," "project," "potential," "should," "will," or "would," or the negative of these terms, or other comparable terminology are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.

Any forward-looking statements in this press release are based on management's current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation: the risk that SEP-479 preclinical data does not turn out to be predictive of future clinical outcomes for SEP-479; risks related to clinical development outcomes for SEP-479 including unexpected safety, pharmacokinetic, or pharmacodynamic findings; risks related to the actual timing of future availability of clinical data for SEP-479 including that the actual timing of enrollment and completion of the study may differ from management's current estimates; the scope of protection Septerna is able to establish and maintain for intellectual property rights covering its Native Complex Platform^® and its product candidates (including SEP-479); and general economic, industry and market conditions. These and other risks and uncertainties are described in greater detail in the section entitled "Risk Factors" in Septerna's Quarterly Report on Form 10-Q for the three months ended March 31, 2026, as well as any subsequent filings with the Securities and Exchange Commission. In addition, any forward-looking statements represent Septerna's views only as of today and should not be relied upon as representing its views as of any subsequent date. Septerna explicitly disclaims any obligation to update any forward-looking statements subject to any obligations under applicable law. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements.

View source version on businesswire.com: https://www.businesswire.com/news/home/20260608910791/en/

Investor Contact:

Renee Leck, THRUST

renee@thrustsc.com

Media Contact:

Carly Scaduto, THRUST

carly@thrustsc.com

Septerna to Present Preclinical Characterization of SEP-479, an Oral PTH1R Agonist for Hypoparathyroidism, at 2026 ENDO Annual Meeting