Septerna Drops SEP-631 Urticaria Phase 2b Plan

The Tip Desk · August 11, 2026 · 3 min read

The company is weighing capital-efficient signal-finding studies in mast cell-driven diseases after Phase 1 data, with cash of $516.5 million expected to fund operations at least into 2029.

Septerna, Inc. (SEPN) is evaluating capital-efficient, signal-finding clinical studies in mast cell-driven diseases in lieu of the Phase 2b trial of SEP-631 in chronic spontaneous urticaria that it had planned for the second half of 2026.

The clinical-stage biotechnology company said the change follows March Phase 1 results for SEP-631, an oral small molecule MRGPRX2 negative allosteric modulator, that had supported Phase 2b development. Those results included a well-tolerated safety profile, pharmacokinetics supportive of once-daily oral dosing and robust, dose-dependent suppression of icatibant-induced skin wheal formation.

Chief Executive Officer Jeffrey Finer said the company is advancing SEP-479 and is “very pleased with the observed clinical half-life, which is at the longer end of our preclinical estimates.” He said the finding reinforces confidence in SEP-479 as a differentiated, once-daily oral treatment for hypoparathyroidism.

SEP-479 is a potent, selective oral small molecule PTH1R agonist. Its Phase 1 single-ascending-dose and multiple-ascending-dose study, initiated in April 2026, is evaluating safety, tolerability, pharmacokinetics and pharmacodynamics, including serum calcium and endogenous serum PTH, in healthy volunteers. Based on pharmacokinetic data from the ongoing trial, the observed elimination half-life of SEP-479 is approximately three to four days, which the company anticipates will support once-daily dosing. To characterize steady-state pharmacokinetics, dosing for the MAD cohorts will be extended to 14 days. The company expects to report Phase 1 data from both SAD and MAD cohorts in the first quarter of 2027.

During the quarter, Septerna presented the first detailed preclinical characterization of SEP-479 at ENDO 2026, highlighting data supporting its potential as a once-daily oral treatment for hypoparathyroidism.

The TSHR NAM program continues toward development candidate selection, with the goal of a potential disease-modifying oral treatment for Graves’ disease and thyroid eye disease. Discovery work continues under a global collaboration with Novo Nordisk on oral small molecule medicines for obesity, type 2 diabetes and other cardiometabolic diseases, as well as wholly owned programs using the Native Complex Platform.

Revenue from the Novo Nordisk collaboration was $26.7 million for the quarter ended June 30, 2026, compared with $0.1 million from Vertex a year earlier. That total included $14.6 million of amortization of a $195.0 million upfront payment, $0.9 million from the achievement of $4.0 million in research milestones and $11.2 million for research services.

Research and development expenses were $35.1 million, compared with $22.2 million a year earlier. General and administrative expenses were $8.5 million. Net loss was $13.0 million, or $0.29 a share, compared with $24.8 million, or $0.56 a share, a year earlier. Interest income and other expense, net, was $4.8 million.

Cash, cash equivalents and marketable securities were $516.5 million as of June 30, 2026, down from $522.1 million at March 31. The cash position is expected to support operating plans at least into 2029. Working capital was $316.8 million. Total stockholders’ equity was $386.7 million.

Finer said the company is progressing the TSHR program toward development candidate selection. The next scheduled clinical readout is SAD and MAD data for SEP-479 in the first quarter of 2027.