Phase 2
N=46
Study of XP-8121 For the Treatment of Adult Subjects With Hypothyroidism
Hypothyroidism
Bottom Line
View on ClinicalTrials.gov: NCT05823012 ↗Enrolled (actual)
46
Serious AEs
0.0%
Results posted
Jul 2025
Primary outcome: Primary: Dose Conversion Factor — 4.24 Ratio
Study Design & Population
- Study type
- Interventional
- Phase
- Phase 2
- Interventions
- levothyroxine sodium (Drug)
- Age
- Adult, Older Adult · 18+ yrs
- Sex
- All
- Sponsor
- Xeris Pharmaceuticals
- Primary completion
- Feb 2024
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Dose Conversion Factor |
4.24 | — |
| PRIMARY Tolerability Assessment: Modified Draize Scale - Erythema |
43; 3; 0; 0; 0; 41 | — |
| PRIMARY Tolerability Assessment: Modified Draize Scale - Edema |
44; 2; 0; 0; 0; 43 | — |
| PRIMARY Tolerability Assessments: Injection Site Discomfort Evaluation |
14; 32; 9; 34; 12; 31 | — |
| SECONDARY Proportion of Participants With Normalized TSH Throughout the Maintenance Period |
27; 27 | — |
| SECONDARY Proportion of Participants With Normalized TSH at End of Maintenance Period |
31; 31 | — |
| SECONDARY Thyroid Hormone Concentrations: Total Thyroxine |
103.68; 88.17; 89.68; 92.44; 94.26; 97.38 | — |
| SECONDARY Thyroid Hormone Concentrations: Free Thyroxine (fT4) |
14.60; 12.09; 11.69; 12.47; 12.84; 12.88 | — |
| SECONDARY Thyroid Hormone Concentrations: Thyroid Stimulating Hormone (TSH) |
1.958; 3.942; 6.534; 6.162; 6.397; 5.506 | — |
Summary
This is a non-randomized, open-label, single arm, self-controlled study of XP-8121 (levothyroxine sodium) to determine a target dose conversion factor from stably dosed oral levothyroxine to XP-8121 (levothyroxine sodium) in patients with hypothyroidism and to assess the safety and tolerability of XP-8121(levothyroxine sodium) after once weekly subcutaneous injections. This study includes the following periods: Screening, Titration Period, and Maintenance Period. The study will conclude with an End of Maintenance Visit or Early Termination (ET) Visit.
Eligibility Criteria
Inclusion Criteria
- Provide written informed consent.
- Male or female between the ages of 18 and 65 years (inclusive) at Screening, with chronic hypothyroidism and on a stable dose of oral levothyroxine (Synthroid or an FDA-approved generic equivalent to Synthroid) or, if in the pharmacokinetic substudy, Synthroid only for at least 3 months.
- Thyroid stimulating hormone (TSH) within the normal range at Screening (central laboratory) and at least 3 months prior to Screening (documented by local laboratory).
- Free thyroxine within the normal range at Screening (central laboratory).
Exclusion Criteria
- History of hypersensitivity to levothyroxine (any formulation).
- Current dose of oral levothyroxine, based on body weight >2 μg/kg/day.
- Current levothyroxine total daily dose either 375 μg.
- Current use of combined thyroid treatment (i.e., Synthroid plus liothyronine or Synthroid plus Armour Thyroid) and/or any other levothyroxine aside from those used in the study.
Data sourced from ClinicalTrials.gov (NCT05823012). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.