Use of a patch containing heat-labile toxin from Escherichia coli against travellers' diarrhoea: a phase II, randomised, double-blind, placebo-controlled field trial

BACKGROUND

Enterotoxigenic Escherichia coli (ETEC) is a major cause of travellers' diarrhoea. We investigated the rate of diarrhoea attacks, safety, and feasibility of a vaccine containing heat-labile enterotoxin (LT) from ETEC delivered to the skin by patch in travellers to Mexico and Guatemala.

METHODS

In this phase II study, healthy adults (aged 18-64 years) who planned to travel to Mexico or Guatemala and had access to a US regional vaccination centre were eligible. A centralised randomisation code was used for allocation, which was masked to participants and site staff. Primary endpoints were to investigate the field rate of ETEC diarrhoea, and to assess the safety of heat-labile toxins from E coli (LT) delivered via patch. Secondary endpoints included vaccine efficacy against travellers' diarrhoea and ETEC. Participants were vaccinated before travel, with two patches given 2-3 weeks apart. Patches contained either 37.5 mug of LT or placebo. Participants tracked stool output on diary cards in country and provided samples for pathogen identification if diarrhoea occurred. Diarrhoea was graded by the number of loose stools in 24 h: mild (three), moderate (four or five), and severe (at least six). Analysis was per protocol. The trial is registered with ClinicalTrials.gov, number NCT00516659.

FINDINGS

Recruitment closed after 201 participants were assigned patches. 178 individuals received two vaccinations and travelled and 170 were analysed. 24 (22%) of 111 placebo recipients had diarrhoea, of whom 11 (10%) had ETEC diarrhoea. The vaccine was safe and immunogenic. The 59 LT-patch recipients were protected against moderate-to-severe diarrhoea (protective efficacy [PE] 75%, p=0.0070) and severe diarrhoea (PE 84%, p=0.0332). LT-patch recipients who became ill had shorter episodes of diarrhoea (0.5 days vs 2.1 days, p=0.0006) with fewer loose stools (3.7 vs 10.5, p<0.0001) than placebo.

INTERPRETATION

Travellers' diarrhoea is a common ailment, with ETEC diarrhoea illness occurring in 10% of cases. The vaccine patch is safe and feasible, with benefits to the rate and severity of travellers' diarrhoea.

Efficacy and safety of grepafloxacin 600 mg daily for 10 days in patients with community-acquired pneumonia

The efficacy and safety of grepafloxacin in treating patients with community-acquired pneumonia (CAP) was assessed in an open-label, noncomparative study. Patients (N = 273) received grepafloxacin 600 mg QD for 10 days. A total of 237 patients (87%) completed the study. In assessable patients, the clinical success rate at follow-up (4 to 6 weeks after the last dose) was 89% (211/238 patients). In microbiologically assessable patients, the eradication rate at follow-up was 95% (86/91 isolates). Grepafloxacin was highly effective in the treatment of bacterial CAP caused by Streptococcus pneumoniae (irrespective of penicillin susceptibility), Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis, and Staphylococcus aureus and in the therapy of atypical pneumonia caused by Mycoplasma pneumoniae and Legionella pneumophila. Grepafloxacin was well tolerated, with the most frequently reported drug-related adverse events being taste perversion and nausea. Grepafloxacin 600 mg QD for 10 days was highly effective and well tolerated in the treatment of patients with CAP.