MBX Biosciences — Third Quarter 2026 Earnings Summary

Financial Performance:

• Cash, cash equivalents, and marketable securities totaled $481.6 million as of September 30, 2026, up from $373.7 million as of December 31, 2025, reflecting $97.6 million in net proceeds from an at-the-market (ATM) stock sale.
• Research and development expenses for the three months ended September 30, 2026, were $32.0 million, an increase from $19.3 million in the same period of 2025.
• General and administrative expenses for the three months ended September 30, 2026, were $34.3 million, a significant increase from $4.7 million in the same period of 2025.
• Net loss for the three months ended September 30, 2026, was $62.4 million, compared to a net loss of $21.6 million for the same period in 2025.
• Net loss per common share (basic and diluted) was $1.29 for the three months ended September 30, 2026, compared to $0.63 in the same period of 2025.
• Total operating expenses for the nine months ended September 30, 2026, were $134.5 million, compared to $72.3 million for the same period in 2025.
• Net loss for the nine months ended September 30, 2026, was $123.0 million, compared to $64.9 million for the same period in 2025.
• Total assets were $500.6 million as of September 30, 2026, compared to $385.1 million as of December 31, 2025.
• Total stockholders' equity was $472.9 million as of September 30, 2026, compared to $369.2 million as of December 31, 2025.
• Accumulated deficit increased to $(347.5) million as of September 30, 2026, from $(224.5) million as of December 31, 2025.

Guidance and Future Outlook:

• The company expects its current cash balance to fund operations into 2029.
• Unblinded 12-week multiple ascending dose (MAD) data for MBX 4291 is on track for release in the fourth quarter of 2026.
• The pivotal Phase 3 oPTimize trial for canvuparatide is underway, with enrollment of approximately 160 adults expected to continue.

Business Segments and Product Lines:

• Canvuparatide (Hypoparathyroidism): The pivotal Phase 3 oPTimize trial initiated dosing of the first patient in August 2026; the trial is a global, randomized, double-blind, placebo-controlled study building on positive Phase 2 Avail results and one-year open-label extension data.
• MBX 4291 (Obesity): A GLP-1/GIP co-agonist prodrug designed for once-monthly dosing; Phase 1 Part C, Cohort 1 is evaluating a titration regimen of 30 mg weekly for four weeks followed by 120 mg and 180 mg monthly in participants with BMI ≥30 kg/m².
• MBX 5765 (Obesity): An amycretin prodrug combining GLP-1, GIP, glucagon, and dual amylin/calcitonin receptor agonist activity is in IND-enabling studies with a design for once-monthly dosing.
• MBX 6180 (Obesity): A GLP-1/GIP/GCG triple agonist prodrug designed for once-monthly dosing has preclinical pharmacokinetic data accepted for presentation at ObesityWeek 2026; IND-enabling studies are ongoing.
• PEP Platform: The company continues to advance its Precision Endocrine Peptide (PEP) platform, which is designed to provide extended time-action profiles, consistent drug concentrations, and less frequent dosing.

Market and Competitive Landscape:

• The company positions canvuparatide as a potential best-in-class PTH replacement therapy.
• MBX 4291 is designed to offer improved gastrointestinal tolerability compared to existing therapies.
• MBX 5765 is designed for potential superior efficacy and improved tolerability due to its differentiated mechanism.

Risks and Challenges:

• Forward-looking statements note risks related to research and development activities, regulatory approval timelines, and uncertainties in preclinical and clinical development.
• Risks include dependence on third parties for clinical trials, manufacturing, and commercialization, as well as the need for substantial additional funds to complete development and commercialization.
• Specific risks include the ability to attract and retain key personnel, regulatory developments by the FDA and foreign authorities, and maintaining intellectual property protections.

Management Commentary and Tone:

• CEO Steve Hoerter stated the third quarter marked an important milestone with the initiation of the pivotal Phase 3 oPTimize trial.
• Management expressed confidence in being well-positioned to advance canvuparatide through pivotal development while investing in the obesity portfolio, citing a strong balance sheet and cash runway into 2029.
• The tone indicates a focus on advancing a pipeline of novel candidates with clinically validated targets and significant unmet medical needs.

Other Key Points:

• Peter Radovich, President and COO of Mirum Pharmaceuticals, was appointed to the Board of Directors in October 2026.
• Jeff Held, J.D., was appointed Chief Legal Officer in September 2026.
• G&A expenses included $20.8 million in stock-based compensation expense related to the modification of awards for the Company's former chief executive officer.
• The increase in R&D expenses was driven by start-up costs for the canvuparatide Phase 3 trial, ongoing Phase 2 open-label extension studies, the MBX 4291 Phase 1 trial, and preclinical/IND-enabling activities for MBX 5765 and MBX 6180.
• The increase in G&A expenses was driven by higher personnel-related costs resulting from the expansion of the executive leadership team and general infrastructure.