Summary of MBX Biosciences Conference Call - September 22, 2025 Company Overview - **Company**: MBX Biosciences - **Ticker**: NasdaqGS:MBX - **Focus**: Development of once-weekly candiparatide for the treatment of hypoparathyroidism (HP) Key Industry Insights - **Hypoparathyroidism**: A chronic condition affecting over 250,000 people in the U.S. and EU combined, primarily caused by a deficiency of parathyroid hormone (PTH) due to surgical removal of parathyroid glands [6][7] - **Market Opportunity**: The U.S. and EU represent a multibillion-dollar market opportunity for treatments addressing HP [30] Core Findings from AVAIL Phase II Clinical Trial - **Positive Results**: The trial demonstrated that 63% of patients receiving once-weekly candiparatide achieved the primary composite endpoint at week 12, compared to 31% on placebo, indicating a statistically significant difference [5][15] - **High Patient Retention**: 94% of patients completed the 12-week study and chose to continue into the open-label extension, reflecting strong patient enthusiasm for the treatment [5][19] - **Durability of Response**: In the ongoing open-label extension, responder rates increased to 79% at six months, suggesting potential durability of the treatment effect [19] - **Calcium Balance Restoration**: Urine calcium excretion was reduced in candiparatide-treated patients, indicating the therapy's ability to help restore calcium balance [6][18] Safety Profile - **Well Tolerated**: Once-weekly candiparatide was well tolerated, with no treatment-related serious adverse events or discontinuations reported during the 12-week trial [6][25] - **Adverse Events**: Commonly reported adverse events included headaches, hypercalcemia, arthralgia, and nausea, with hypercalcemia occurring in approximately 13% to 31% of patients depending on the dose [26][27] Future Development Plans - **Phase III Preparation**: The company plans to schedule an end-of-Phase II meeting with the FDA and begin dosing patients in a global Phase III registration trial in 2026 [31][32] - **Upcoming Presentations**: Data will be presented at the International Hypoparathyroidism Conference in October 2025 and at a major medical conference [31] Additional Considerations - **Patient-Centric Approach**: The once-weekly dosing regimen is expected to be preferred by both healthcare providers and patients due to its convenience compared to daily injections [30][31] - **Sensitivity Analysis**: A sensitivity analysis indicated that excluding patients with higher baseline PTH levels resulted in a placebo response of 15%, reinforcing the efficacy of candiparatide [38] Conclusion - **Best-in-Class Potential**: The results from the AVAIL Phase II trial strongly support the potential of once-weekly candiparatide to become a new standard of care for patients with hypoparathyroidism, addressing significant unmet medical needs in this patient population [28][30]