Effects of baseline symptom burden on treatment response in COPD

Rationale: In symptomatic patients with COPD, the decision whether to initiate maintenance treatment with a single agent or a combination of long-acting bronchodilators remains unclear. Objective: To investigate whether baseline symptomatic status influences response to tiotropium/olodaterol treatment. Materials and methods: Post hoc analysis of the randomized OTEMTO® studies (NCT01964352; NCT02006732), in which patients with moderate-to-severe COPD received placebo, tiotropium 5 µg, tiotropium/olodaterol 2.5/5 µg, or tiotropium/olodaterol 5/5 µg once daily for 12 weeks via the Respimat® inhaler (Boehringer Ingelheim, Ingelheim am Rhein, Germany). Impact of baseline symptomatic status (modified Medical Research Council [mMRC] score) on response to treatment with tiotropium/olodaterol 5/5 µg, tiotropium 5 µg, or placebo at Week 12 was assessed by St George's Respiratory Questionnaire (SGRQ) total score and response rate, transition dyspnea index (TDI) focal score and response rate, and trough forced expiratory volume in 1 second response. Results: Tiotropium/olodaterol improved SGRQ total scores and response rates compared with placebo and tiotropium for patients with baseline mMRC scores 0-1 and ≥2. For tiotropium/olodaterol vs tiotropium, greater improvements were observed for patients with mMRC ≥2 (SGRQ score adjusted mean treatment difference -3.44 [95% CI: -5.43, -1.46]; P=0.0007; SGRQ response rate ORs 2.09 [95% CI: 1.41, 3.10]; P=0.0002). Dyspnea, measured by TDI score, was consistently improved with tiotropium/olodaterol vs placebo for patients with mMRC scores 0-1 and ≥2 (adjusted mean treatment difference 1.63 [95% CI: 1.06, 2.20]; P<0.0001 and 1.60 [95% CI: 1.09, 2.10]; P<0.0001, respectively). In patients with mMRC scores 0-1 and ≥2, tiotropium/olodaterol consistently improved TDI response rate and lung function vs placebo and tiotropium. Conclusions: Patients with COPD with more severe baseline dyspnea appear to derive greater health status benefit with tiotropium/olodaterol compared with tiotropium alone.