CHINA: Study on Doxycycline for Mild TAO

In a recent study released in JAMA Ophthalmology, it was reported that patients with mild TAO who took oral doxycycline 50 mg once a day saw higher relief from TAO-related symptoms after 12 weeks compared to those who took a placebo.

Although thyroid-associated ophthalmopathy is an autoimmune disorder, the exact cause of the condition is unknown. The quality of life is significantly impacted by mild thyroid-associated ophthalmopathy (TAO), however, there are no clinical recommendations for treatment. For the patient with mild TAO, waiting it out is the best course of action. In addition to its antibacterial activities, doxycycline exhibits a potent anti-inflammatory and immunomodulatory effect. Doxycycline can be used to treat mild TAO, according to the available research.

The researchers intended to assess doxycycline's short-term (12 weeks) effectiveness in treating mild TAO.

For this purpose, 148 patients had their eligibility for this placebo-controlled, multicenter, randomized, double-masked trial evaluated. Following exclusions, 100 patients with mild TAO (mildly impacted orbicular soft tissue) at 5 locations in China were enrolled and followed up with for 12 weeks. A total of 75 participants (75.0%) were female, and 100 (100.0%) were Asian. The mean (SD) age was 36.7 (9.1) years. Participants' medication compliance was examined by interviews and a count of extra tablets. For 12 weeks, participants were randomized to receive either doxycycline (50 mg) or a placebo. 50 subjects were given doxycycline, while 50 received a placebo. The main result was the rate of progress from baseline to 12 weeks as measured by a composite indicator of ocular motility (increase of ≥ 8°), eyelid aperture (reduction of ≥ 2 mm), proptosis (reduction of ≥ 2 mm), and Graves ophthalmopathy-specific quality-of-life (GO-QOL) scale score (increase of 6 points). Unfavorable events were noted.

Key Results of the Trial

• In the intention-to-treat population, the improvement rate at week 12 was 22.0%; 95% CI, 5.0-39.0; P =.01 in the doxycycline group and 16.0% (8 of 50) in the placebo group.
• Similar findings were obtained from the per-protocol sensitivity analysis (39.6% [19 of 48] vs 16.0% [8 of 50]; difference, 23.6%; 95% CI, 6.4-40.8; P =.009).
• Other than one episode of moderate gastric acid regurgitation, neither group experienced any negative effects.

The data support the use of doxycycline for moderate TAO, but caution should be exercised given the cohort size and very little follow-up, concluded the authors.

Reference

Pan Y, Chen Y, Zhang J, et al. Doxycycline vs Placebo at 12 Weeks in Patients With Mild Thyroid-Associated Ophthalmopathy: A Randomized Clinical Trial. JAMA Ophthalmol. Published online September 29, 2022. doi:10.1001/jamaophthalmol.2022.3779