Trial Outcomes & Findings for Study 3: Minocycline Decreases Microglia Activation (NCT NCT02213575)
NCT ID: NCT02213575
Last Updated: 2025-07-01
Results Overview
This outcome represents the change in PET signal intensity in the bilateral paraventricular nucleus before and after minocycline treatment. PET imaging was performed using the radiotracer \[¹¹C\]PBR28, which binds to the Translocator Protein (TSPO), a marker of activated microglia and neuroinflammation. To ensure accurate anatomical localization, each participant's PET scan was co-registered with a high-resolution T1-weighted MRI. Regions of interest (ROIs) were manually drawn on the MRI and applied to the PET images to extract PET signal from the same brain structures. The signal was quantified as non-displaceable binding potential (BP\_ND). The change in signal is calculated as the average change in BP\_ND at baseline minus the average change in BP\_ND after treatment. A positive value indicates that the PET signal decreased following treatment, reflecting a reduction in microglial activation and suggesting a favorable anti-inflammatory response to minocycline.
COMPLETED
PHASE2
5 participants
Change in Baseline to 26 weeks
2025-07-01
Participant Flow
Participant milestones
| Measure |
Minocycline Treatment Group
Participants with neurogenic treatment-resistant hypertension who meet inclusion/exclusion criteria will receive minocycline at a dose determined to be most effective in lowering blood pressure (based on results from Study 1).
Participants will undergo brain imaging with MRI and PET at baseline and 26 weeks.
Intervention:
Drug: Minocycline Dose: 50, 100, or 200 mg/day (based on optimal BP-lowering dose from Study 1) Frequency: Administered orally twice daily (BID) Duration: 26 weeks
Minocycline: Subjects will receive the dose of Minocycline determined to best lower BP and will undergo baseline and 26 week follow-up MRI and PET scans for changes in the paraventricular nucleus.
|
Control
Patients without a diagnosis of neurogenic (treatment-resistant) Hypertension and have not been treated with minocycline will be recruited. These participants will undergo one-time brain imaging visit (MRI and PET)
|
|---|---|---|
|
Overall Study
STARTED
|
5
|
0
|
|
Overall Study
COMPLETED
|
5
|
0
|
|
Overall Study
NOT COMPLETED
|
0
|
0
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
Study 3: Minocycline Decreases Microglia Activation
Baseline characteristics by cohort
| Measure |
Minocycline Treatment Group
n=5 Participants
Participants with neurogenic treatment-resistant hypertension who meet inclusion/exclusion criteria will receive minocycline at a dose determined to be most effective in lowering blood pressure (based on results from Study 1).
Participants will undergo brain imaging with MRI and PET at baseline and 26 weeks.
Intervention:
Drug: Minocycline Dose: 50, 100, or 200 mg/day (based on optimal BP-lowering dose from Study 1) Frequency: Administered orally twice daily (BID) Duration: 26 weeks
Minocycline: Subjects will receive the dose of Minocycline determined to best lower BP and will undergo baseline and 26 week follow-up MRI and PET scans for changes in the paraventricular nucleus.
|
Control
Patients without a diagnosis of neurogenic (treatment-resistant) Hypertension and have not been treated with minocycline will be recruited. These participants will undergo one-time brain imaging visit (MRI and PET)
|
Total
n=5 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Continuous
|
69.20 Years
STANDARD_DEVIATION 3.70 • n=5 Participants
|
—
|
69.20 Years
STANDARD_DEVIATION 3.70 • n=5 Participants
|
|
Sex: Female, Male
Female
|
3 Participants
n=5 Participants
|
—
|
3 Participants
n=5 Participants
|
|
Sex: Female, Male
Male
|
2 Participants
n=5 Participants
|
—
|
2 Participants
n=5 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=5 Participants
|
—
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Asian
|
0 Participants
n=5 Participants
|
—
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=5 Participants
|
—
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Black or African American
|
0 Participants
n=5 Participants
|
—
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
White
|
5 Participants
n=5 Participants
|
—
|
5 Participants
n=5 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=5 Participants
|
—
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=5 Participants
|
—
|
0 Participants
n=5 Participants
|
|
Region of Enrollment
United States
|
5 participants
n=5 Participants
|
—
|
5 participants
n=5 Participants
|
PRIMARY outcome
Timeframe: Change in Baseline to 26 weeksPopulation: One subject was identified as a slow metabolizer of \[¹¹C\]PBR28 and therefore their data could not be used.
This outcome represents the change in PET signal intensity in the bilateral paraventricular nucleus before and after minocycline treatment. PET imaging was performed using the radiotracer \[¹¹C\]PBR28, which binds to the Translocator Protein (TSPO), a marker of activated microglia and neuroinflammation. To ensure accurate anatomical localization, each participant's PET scan was co-registered with a high-resolution T1-weighted MRI. Regions of interest (ROIs) were manually drawn on the MRI and applied to the PET images to extract PET signal from the same brain structures. The signal was quantified as non-displaceable binding potential (BP\_ND). The change in signal is calculated as the average change in BP\_ND at baseline minus the average change in BP\_ND after treatment. A positive value indicates that the PET signal decreased following treatment, reflecting a reduction in microglial activation and suggesting a favorable anti-inflammatory response to minocycline.
Outcome measures
| Measure |
Minocycline Treatment Group
n=4 Participants
Participants with neurogenic treatment-resistant hypertension who meet inclusion/exclusion criteria will receive minocycline at a dose determined to be most effective in lowering blood pressure (based on results from Study 1).
Participants will undergo brain imaging with MRI and PET at baseline and 26 weeks.
Intervention:
Drug: Minocycline Dose: 50, 100, or 200 mg/day (based on optimal BP-lowering dose from Study 1) Frequency: Administered orally twice daily (BID) Duration: 26 weeks
Minocycline: Subjects will receive the dose of Minocycline determined to best lower BP and will undergo baseline and 26 week follow-up MRI and PET scans for changes in the paraventricular nucleus.
|
Control
Patients without a diagnosis of neurogenic (treatment-resistant) Hypertension and have not been treated with minocycline will be recruited. These participants will undergo one-time brain imaging visit (MRI and PET)
|
|---|---|---|
|
PET Changes in the Paraventricular Nucleus From Baseline to 26 Weeks.
|
0.0350 Binding Potential (non-displaceable)
Standard Deviation 0.0292
|
—
|
Adverse Events
Minocycline Treatment Group
Control
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place