Solithromycin effective against M. pneumoniae in phase 3 trial

SAN DIEGO — A 5-day regimen of oral solithromycin was noninferior to a 7-day regimen of moxifloxacin for the treatment of community-acquired bacterial pneumonia and performed as well as or better than moxifloxacin in the subgroup of patients who had identified Mycoplasma pneumoniae infection, according to data presented at IDWeek 2015.

“M. pneumoniae is an underdiagnosed cause of (community-acquired bacterial pneumonia [CABP]) and can cause severe infection,” Brian D. Jamieson, MD, senior director of clinical research at Cempra, told Infectious Disease News. “There have been more and more case reports being published about severe outbreaks within the United States.”

Brian D. Jamieson

In June 2014, the CDC reported an outbreak of M. pneumoniae at a long-term care facility, which resulted in 55 illnesses, 12 hospitalizations and seven deaths. The pathogen infects up to 2 million people in the U.S. each year, according to Jamieson and colleagues.

In the phase 3 SOLITAIRE-Oral trial, researchers analyzed oropharyngeal swabs of 860 adults with confirmed CABP from 16 countries. The swabs were assessed by culture and/or quantitative PCR for the presence of M. pneumoniae. These data, along with conventional serologies, resulted in a diagnosis of M. pneumoniae in 9.2% of the 860 patients (mean age, 52 years). The incidence of M. pneumoniae by geographic region ranged from 5.9% in South Africa to 10.9% in Europe.

Patients with M. pneumoniae were randomly assigned solithromycin (CEM-101, Cempra) for 5 days followed by 2 days of placebo or moxifloxacin for 7 days. Solithromycin was dosed at 800 mg on the first day and 400 mg daily for the 4 subsequent days. Moxifloxacin was dosed at 400 mg daily for all 7 days.

According to the data, 83.3% of patients who received solithromycin had an early clinical response (on days 3 to 5) compared with 78.6% of those who received moxifloxacin. All patients were followed 5 to 10 days after therapy and demonstrated similar clinical success rates; 89.2% patients were cured with solithromycin and 90.5% were cured with moxifloxacin.

In January, Cempra reported that 78.2% of patients treated with solithromycin had early clinical response vs. 77.9% of those treated with moxifloxacin. A sub-group analysis showed the difference in treatment responses increased with age and favored solithromycin, according to a company press release.

“These data support a treatment strategy that includes empiric coverage for atypical pathogens in the treatment of CABP,” Jamieson and colleagues concluded. – by Stephanie Viguers

Reference:

Oldach D, et al. Abstract 893. Presented at: IDWeek; Oct. 7-11, 2015; San Diego.

Disclosure: Jamieson reports being a paid employee and shareholder of Cempra. Please see the full study for a list of all other authors’ relevant financial disclosures.