Cempra Inc., a clinical-stage pharma focused on the development of antibiotics for difficult-to-treat bacterial infectious diseases, announced positive results from a Phase 2 clinical trial on community-acquired bacterial pneumonia (CABP) testing the efficacy and safety of solithromycin.
The potent antibiotic is being developed in partnership with Toyama Chemical, for the Japanese market.
Solithromycin is a type of antibiotic called a macrolide that has shown potency against bacterial strains that are usually resistant to this class of antibiotics. Its potent activity results from solithromycin’s ability to interact with three sites on the bacterial ribosome, the sub-cellular structure responsible for protein synthesis, as opposed to general macrolides’ ability to interact with only one site.
The antibiotic has shown potent activity against Streptococcus pneumoniae, a bacterial pathogen responsible for up to 36% of adult CABP, according to the Centers for Disease Control and Prevention (CDC).
The Phase 2, multi-center, randomized and double-blind study evaluating the efficacy, safety and pharmacokinetics of solithromycin in Japanese patients was conducted by Toyama. The selected patients, with mild to moderate CABP, were randomized to receive either oral solithromycin or oral antibiotic levofloxacin for 5 days. Patients in the solithromycin group received 800 mg on the first day of treatment as a single dose (QD group) or as a divided dose (BID group), and 400 mg daily on the other days. Patients in the levofloxacin group received 500 mg once daily on days 1-5. The study was designed according to guidance from the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA).
Of the 154 enrolled patients, 135 received at least one dose of the study medication. Among these patients, Test of Cure success, evaluated 5 to 10 days after therapy completion, was achieved by 77.3 percent (34/44), 72.7 percent (32/44), and 61.7 percent (29/47) of the patients in the solithromycin once-daily and twice-daily, and levofloxacin groups, respectively.
In the pre-specified Per Protocol population, consisting of patients meeting key exclusion and inclusion criteria, success at the Test of Cure visit was achieved by 85.0 percent (34/40) in the solithromycin once-daily group, 77.5 percent (31/40) in the solithromycin twice-daily group, and 67.4 percent (29/43) in the levofloxacin group.
In terms of safety, the overall safety and tolerability profiles were found to be similar in the different treatment groups.
“I could not be happier to receive the results of this important study completed by our strong partner in Japan; the safety and efficacy outcomes further validate global Phase 3 trial data demonstrating the potential for solithromycin in the treatment of this serious infection,” said Dr. Prabhavathi Fernandes, president and CEO of Cempra, in a press release.
“The need for a new treatment for CABP in Japan is great as multidrug resistance to common CABP pathogens such as Mycoplasma and Haemophilus continues to rise, with pneumococcal resistance to older macrolides reaching 88 percent in Japan. Solithromycin has once again demonstrated robust activity in comparison to a potent fluoroquinolone, levofloxacin, one of the most widely prescribed agents to treat CABP,” Fernandes added.
