Doxycycline fails to effectively reduce exacerbation rate in COPD patients

James P Allinson and team recruited people with moderate to very severe COPD and an exacerbation history from 3 UK centres and randomised to 12-months doxycycline 100mg once daily or placebo. The primary study outcome was exacerbation rate per person year.

The key findings of the study are

• A total of 222 people were randomised. Baseline mean FEV1 was 1.35 (SD 0.35) L; 52.5 (SD 15.9) % predicted. Median number of treated exacerbations in the year before the study was 2 (1-4).

• 71% of patients reported ≥2 exacerbations. 81% were already prescribed inhaled corticosteroids at baseline.

• COPD exacerbation rate did not differ between the groups - doxycycline/placebo rate ratio 0.86 (0.67, 1.10); p=0.23.

• No difference was seen if only treated exacerbations or hospitalisations were considered. In pre-planned sub-group analysis, doxycycline appeared to better reduce the exacerbation rate among people with severe COPD (RR:0.36 (0.15, 0.85); p=0.019), and in those with an eosinophil count <300 cells/μL (RR:0.50 (0.29, 0.84); p=0.01).

• Health status measured by SGRQ was 5.2 points worse in the doxycycline group at 12-months (p<0.007).

Allinson and team concluded that “Doxycycline did not significantly reduce exacerbation rate, over 12-months, in participants with COPD, who exacerbated regularly, but may have benefitted those with more severe COPD or blood eosinophil counts <300 cells/μL.”

Reference: Allinson JP, Vlies BH, Brill SE, Law M, Burnside G, Finney LJ, Alves-Moreira L, Donaldson GC, Calverley PMA, Walker PP, Wedzicha JA. A Double-Blind, Randomised, Placebo-controlled Trial of Long-Term Doxycycline Therapy on Exacerbation Rate in Patients with Stable COPD. Am J Respir Crit Care Med. 2023 Jul 14. doi: 10.1164/rccm.202212-2287OC.