NCT07526558

Mast Cell Treatment in Post-tick Bite Illness (PTBI)

A Phase II Pilot Study to Assess the Safety and Tolerability of Mast Cell Treatment in Post-tick Bite Illness

• Status: Not Yet Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 50 (estimated)
• Sponsor: University of North Carolina, Chapel Hill · Academic / Other
• Sex: All
• Age: 21 Years – 65 Years
• Healthy volunteers: Accepted

Summary

This is a Phase II double-blinded study to assess the safety, tolerability, and feasibility of the mast cell stabilizing medications ketotifen and cromolyn compared to participants receiving standard of care treatment with fexofenadine alone in participants who have persistent symptoms of mast cell activation following a documented tick-borne illness (Ehrlichiosis, Rocky Mountain Spotted Fever, Alpha-gal Syndrome).

Detailed description

This Phase II study is designed as a randomized, double-blind study to assess the safety, tolerability, and feasibility of mast cell-directed therapy using ketotifen, cromolyn and fexofenadine vs fexofenadine alone in participants who have post-tick bite illness. The study is a 2 arm, 4-month trial preceded by a 14 day run-in period of fexofenadine for all screened and consented participants. At the end of 14 days, participants will be re-administered the mast cell activation symptom screening questionnaire and those who have a greater than 20% increase in symptom improvement score during 14 days of fexofenadine will be considered meaningfully better and not be randomized due to not needing further treatment. Randomized participants (n=50) will be assigned 2:1 by study pharmacy to receive either fexofenadine 180mg daily or ketotifen 1 mg twice daily (starting dose) + cromolyn 200mg three times daily + fexofenadine 180 mg daily. After 30 days, ketotifen will be increased to 2 mg twice daily and remain at that dose until trial completion.

Conditions

• Post-tick Bite Illness
• Mast Cell Stabilizer

Interventions

Type	Name	Description
DRUG	Ketotifen	Ketotifen is a mast cell stabilizer and H1 antihistamine administered orally at 1 mg twice daily, with dose escalation to 2 mg twice daily after 30 days.
DRUG	fexofenadine	Fexofenadine is a second-generation H1 antihistamine administered orally at a dose of 180 mg once daily
DRUG	Cromolyn Sodium	Cromolyn sodium is a mast cell stabilizer administered orally at a dose of 200 mg three times daily.

Timeline

• Start date: 2026-04-30
• Primary completion: 2027-01-01
• Completion: 2027-01-01
• First posted: 2026-04-13
• Last updated: 2026-04-13

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study