Extension Study to Evaluate the Long-Term Safety and Tolerability of MBX 2109 in Patients With Hypoparathyroidism

An Extension Study to Evaluate the Long-Term Safety and Tolerability of MBX 2109 in Patients With Hypoparathyroidism Who Completed the 12-Week Treatment Period in the Phase 2 Study, MBX-2H1002 Study (Avail-Ext)

The purpose of this study is to evaluate the long-term safety and tolerability of MBX 2109 in patients with hypoparathyroidism who completed the 12-week treatment period in the Phase 2 study, MBX-2H1002.

Study Overview

• Status: Active, not recruiting
• Conditions: Hypoparathyroidism
• Intervention / Treatment: Drug: 400 µg of MBX 2109 once-weekly by subcutaneous injection; Drug: 200-1600 µg of MBX 2109 once-weekly by subcutaneous injection

Detailed Description

This study is to investigate the long-term safety and tolerability of MBX 2109 administered once weekly to patients with hypoparathyroidism. Additionally, the ability of MBX 2109 to maintain serum calcium levels within the normal range without the need for active vitamin D and to reduce elemental calcium supplements to ≤600 mg/day.

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Phase 2

Contacts and Locations

Study Locations

• Argentina
  • Córdoba, Argentina, X5000AAW
    • MBX Biosciences Investigational Site
  • San Miguel de Tucumán, Argentina, T4000IEH
    • MBX Biosciences Investigational Site
  • Buenos Aires
    • Ciudad Autonoma de Buenos Aires, Buenos Aires, Argentina, C1012AAR
      • MBX Biosciences Investigational Site
    • Ciudad Autonoma de Buenos Aires, Buenos Aires, Argentina, C1425AGC
      • MBX Biosciences Investigational Site
  • Río Cuarto
    • Córdoba, Río Cuarto, Argentina, X5800AEV
      • MBX Biosciences Investigational Site
• Turkey (Türkiye)
  • Samsun, Turkey (Türkiye), 55270
    • MBX Biosciences Investigational Site
• United States
  • Florida
    • Miami, Florida, United States, 33033
      • MBX Biosciences Investigational Site
  • Georgia
    • Macon, Georgia, United States, 31210
      • MBX Biosciences Investigational Site
  • Mississippi
    • Jackson, Mississippi, United States, 39202
      • MBX Biosciences Investigational Site
  • Missouri
    • St Louis, Missouri, United States, 63110
      • MBX Biosciences Investigational Site
  • Nevada
    • Las Vegas, Nevada, United States, 89148
      • MBX Biosciences Investigational Site
    • Reno, Nevada, United States, 89511
      • MBX Biosciences Investigational Site
  • New York
    • Albany, New York, United States, 12203
      • MBX Biosciences Investigational Site
    • New York, New York, United States, 10032
      • MBX Biosciences Investigational Site
    • The Bronx, New York, United States, 10467
      • MBX Biosciences Investigational Site
  • Ohio
    • Columbus, Ohio, United States, 43201
      • MBX Biosciences Investigational Site
  • Texas
    • Dallas, Texas, United States, 75208
      • MBX Biosciences Investigational Site
    • El Paso, Texas, United States, 79935
      • MBX Biosciences Investigational Site
    • Fort Worth, Texas, United States, 76132
      • MBX Biosciences Investigational Site
    • Round Rock, Texas, United States, 78681
      • MBX Biosciences Investigational Site
    • San Antonio, Texas, United States, 78231
      • MBX Biosciences Investigational Site
    • Weslaco, Texas, United States, 78596
      • MBX Biosciences Investigational Site
  • Wisconsin
    • Madison, Wisconsin, United States, 53705
      • MBX Biosciences Investigational Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

1. Must have completed the Week 12 Visit in MBX-2H1002 Study.
2. Is an adult ≥18 years of age at the time of the Screening visit of this extension study.

3. Has a diagnosis of one of the following types of hypoparathyroidism for at least 26 weeks prior to the

   Screening visit:

   1. Postsurgical chronic hypoparathyroidism
   2. Idiopathic hypoparathyroidism
   3. Autoimmune hypoparathyroidism
4. Can comprehend and is willing to sign an informed consent form (ICF), and abide by the study restrictions, study visits, and procedures.
5. In the opinion of the investigator, must be able to successfully demonstrate reconstitution and self-administration of study drug.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 400 µg once-weekly by subcutaneous injection	Drug: 400 µg of MBX 2109 once-weekly by subcutaneous injection; Supplied as 1.5 mg per vial, to be reconstituted in 1.4 mL water for injection (diluent) to a concentration of 1.0 mg/mL. Patients who received Placebo in the Phase 2 MBX-2H1002 study, will initiate treatment with 400 µg subcutaneous MBX 2109 once-weekly
Experimental: 200-1600 µg once-weekly by subcutaneous injection	Drug: 200-1600 µg of MBX 2109 once-weekly by subcutaneous injection; Supplied as 1.5 mg per vial, to be reconstituted in 1.4 mL water for injection (diluent) to a concentration of 1.0 mg/mL. Patients treated with MBX 2109 in the Phase 2 MBX-2H1002 study will continue at the screening visit in the extension study on the same dose they were receiving at the Week 11 Visit in Study MBX-2H1002. The maximum allowed dose is 1600 μg weekly administered subcutaneously in the abdomen, rotating injection sites. Doses of MBX 2109 study drug greater than 1000 μg will be administered subcutaneously in two separate, equal injections.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To evaluate the long-term safety and tolerability of weekly MBX 2109 in patients with hypoparathyroidism.	Incidence of treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs).	104 weeks

Collaborators and Investigators

• Sponsor: MBX Biosciences

Study record dates

Study Major Dates

• Study Start (Actual): October 31, 2024
• Primary Completion (Estimated): May 27, 2027
• Study Completion (Estimated): May 27, 2027

Study Registration Dates

• First Submitted: July 16, 2024
• First Submitted That Met QC Criteria: July 30, 2024
• First Posted (Actual): August 1, 2024

Study Record Updates

• Last Update Posted (Estimated): October 28, 2025
• Last Update Submitted That Met QC Criteria: October 24, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Thyroid; Hypopara; Hypoparathyroid; MBX 2109
• Additional Relevant MeSH Terms: Endocrine System Diseases; Parathyroid Diseases; Thyroid Diseases; Hypoparathyroidism
• Other Study ID Numbers: MBX-2H1004

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No