Macrolide therapy for community-acquired pneumonia due to atypical pathogens: outcome assessment at an early time point.

BACKGROUND: Therapy directed against atypical pathogens in patients with community-acquired pneumonia (CAP) is often recommended. This post-hoc analysis evaluated the effect of addition of a macrolide to ceftaroline fosamil or ceftriaxone treatment in atypical CAP.

METHODS: Two phase 3, double-blind, comparative safety and efficacy studies of ceftaroline fosamil vs. ceftriaxone, FOCUS 1 and FOCUS 2, enrolled adults with CAP. Only FOCUS 1 included 24-h adjunctive clarithromycin therapy for all patients on day 1. Day 4 and test-of-cure (TOC) outcomes were compared for adjunctive vs. no adjunctive therapy.

RESULTS: Of 1240 enrolled patients, 130 patients with CAP due to atypical pathogens alone were included (FOCUS 1, n = 64; FOCUS 2, n = 66). Among patients infected with Mycoplasma pneumoniae and/or Chlamydophila pneumoniae alone, a higher clinical response rate was observed with clarithromycin plus ceftaroline fosamil or ceftriaxone compared with treatment without additional clarithromycin at day 4 [38/49 (77.6%; FOCUS 1) vs. 24/43 (55.8%; FOCUS 2)], but not at the TOC assessment [42/49 (85.7%; FOCUS 1) vs. 41/43 (95.3%; FOCUS 2)]. In patients infected with Legionella pneumophila alone, a higher clinical response rate with adjunctive clarithromycin therapy was observed at the TOC assessment alone [12/12 (100%; FOCUS 1) vs. 14/19 (73.7%; FOCUS 2)]. The unadjusted odds ratio of a favourable clinical response at day 4 with adjunctive clarithromycin vs. no adjunctive clarithromycin was 2.4 (95% confidence interval 1.1-5.1; P = 0.0299) for all pathogens combined.

CONCLUSIONS: These results suggest that empirical antibiotic therapy against atypical pathogens may improve early clinical response rate. This hypothesis is best evaluated in a prospective trial.