US clinical-stage pharma Cempra will be celebrating news that its antibiotic Solitaire-Oral (solithromycin) achieved efficacy targets in a Phase III trial involving patients with difficult-to-treat community-acquired bacterial pneumonia.

The firm said data show that its drug - a next-generation macrolide - was statistically non-inferior in early clinical response (72 hours) compared to moxifloxacin, an older member of the popular macrolide class of antibiotics.

Safety profiles were also similar, with the most frequently reported adverse events for solithromycin and moxifloxacin being headache (4.5%, versus 2.5%), diarrohea (4.2% vs 6.5%), nausea (3.5% vs 3.9%), emesis (2.4% vs 2.3%) and dizziness (2.1% vs 1.6%). 

CABP is the number one cause of death from an infection, and one of the most commonly diagnosed bacterial infections in the US, with five to 10 million cases per year.

Treatment challenge

But despite many strains of the primary CABP pathogen being resistant to currently-approved macrolides, they are still one of the most commonly-used medicines for such infections, Cempra points out, noting that its drug has shown "potent activity" against most macrolide-resistant strains.

"The management of CABP remains a challenge for healthcare providers and I believe solithromycin has the potential to be a rational option for the treatment of this life threatening illness," said the firm's chief executive Prabhavathi Fernandes.

A Phase III trial of an intravenous form of the drug is also currently underway, as well as a Phase III trial pitting the effectiveness of an oral formulation against the standard of care (ceftriaxone/azithromycin) in patients with uncomplicated gonorrhea and chlamydia infections. A Phase Ib paediatric clinical study of solithromycin is also in the pipeline.