MBX Biosciences FY Conference Summary Company Overview - **Company**: MBX Biosciences (NasdaqGS:MBX) - **Focus**: Pioneering Precision Endocrine Peptides (PEPs) for treating endocrine and metabolic disorders [1][4] Key Updates and Expectations for 2026 - **Pivotal Year**: 2026 is expected to be crucial with significant milestones across three clinical stage programs and advancements in obesity discovery and preclinical development [1] - **Cash Runway**: The company has a cash runway extending into 2029, providing flexibility in advancing its pipeline [3] Clinical Programs Canvuparatide - **Phase II Meeting**: An end-of-phase II meeting with the FDA is scheduled, with updates on study design for phase III expected [2] - **Phase II Update**: One-year data will be released in Q2, with a global registrational phase III study initiation planned for Q3 [2] - **Response Rate**: A 63% response rate was observed in a 12-week placebo-controlled study, with 79% of patients responding during the open-label extension [9][10] Obesity Portfolio - **MBX-4291**: A once-monthly GLP-1/GIP co-agonist with anticipated 12-week data from a multiple ascending dose study [2] - **New Candidates**: Two additional candidate selections targeting amylin and glucagon are expected in Q2 and Q3 [2] Imapextide - **Phase IIa Study**: A pharmacodynamic study is underway for post-bariatric hypoglycemia, with results expected in Q2 2024 [24][25] Technology and Differentiation - **PEP Technology**: The proprietary PEP technology allows for slow release and steady exposure, improving tolerability and reducing side effects associated with traditional therapies [4][19] - **Best-in-Class Potential**: The company aims to develop best-in-class drugs, with positive feedback from the physician community regarding their clinical data [12][15] Market Opportunity - **Hypoparathyroidism**: The disease has a prevalence of over 250,000 in the US and EU, with current treatments being inadequate [7] - **Obesity Treatment**: The company recognizes obesity as a heterogeneous disease requiring diverse therapeutic options, with a focus on improving tolerability and adherence [18] Financial Position - **Cash Balance**: Year-end cash balance of $373 million, projected to increase to $460 million post recent stock sale, supporting operations through 2029 [34][35] - **Commercialization Plans**: Preparations for the commercialization of canagliflozin are underway, with a focus on recruiting a Chief Commercial Officer [36] Conclusion - **Growth Potential**: MBX Biosciences is positioned for a catalyst-rich year with multiple data releases and a strong pipeline aimed at addressing significant health issues in endocrine and metabolic disorders [33][36]

Summary of MBX Biosciences Conference Call Company Overview - **Company**: MBX Biosciences - **Focus**: Building a leading biopharmaceutical company focused on endocrine and metabolic diseases with three clinical-stage programs aimed at multi-billion dollar markets [2][44] Key Programs and Developments - **Canvuparatide**: - Recently released outstanding phase two data for a once-weekly PTH replacement therapy in hypoparathyroidism [2] - Anticipated end of phase two meetings with FDA and EMA in Q1 2024 [3] - Phase three registration study initiation expected in Q3 2024 [3] - **MBX 4291**: - A GLP-1 GIP coagonist prodrug with a potential once-monthly dosing schedule for obesity [3][4] - 12-week MAD results expected in Q4 2024, aiming to demonstrate better tolerability and weight loss compared to competitors [5][10] - Unique PK profile with a flat peak-to-trough ratio observed in non-human primate studies, suggesting improved tolerability [9][10] Market Position and Strategy - **Obesity Market**: - The obesity candidate MBX 4291 is positioned to leverage the growing demand for once-monthly dosing in the obesity treatment landscape [4][5] - The company aims to address adherence challenges seen with current incretin therapies, which have high discontinuation rates [17][18] - **Competitive Landscape**: - The company is focused on differentiating its products through better tolerability and convenience, which are critical for chronic use [17][18] - Market research indicates that a well-tolerated drug with comparable weight loss could be considered best in class [18][37] Financial and Operational Outlook - **Funding**: - The company has secured funding into 2029, supporting ongoing clinical trials and pre-commercial activities [3][46] - **Regulatory Strategy**: - Plans to engage with regulatory agencies to discuss trial designs and endpoints, including stratification for PTH levels and urine calcium changes [31][32] Other Programs - **Imapextide and PBH Program**: - Phase two study focusing on pharmacodynamic effects, aiming to increase glucose nadir while reducing insulin peak [40] - Safety profile indicates benign nature of injection site reactions, which are not expected to impede prescribing if approved [41][42] Underappreciated Aspects - **Platform Technology**: - The potential of MBX's clinically proven platform technology for gradual controlled release is highlighted as a key differentiator [44][46] - **Pipeline Value**: - The company emphasizes the value inflection points across its pipeline programs, positioning itself favorably in the market [46] Conclusion - MBX Biosciences is poised for significant developments in 2024, with multiple catalysts expected across its pipeline, particularly in obesity and endocrine therapies. The focus on tolerability and convenience in drug administration is central to its strategy in a competitive market.

As filed with the Securities and Exchange Commission on September 22, 2025. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 MBX Biosciences, Inc. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Delaware 2834 84-1882872 (Primary Standard Industrial Classification Code Number) MBX Biosciences, Inc. 11711 N. Meridian Street, Suite 3 ...