At IDWeek 2025, (the joint annual meeting of the Infectious Diseases Society of America, the Society for Healthcare Epidemiology of America, the HIV Medicine Association, the Pediatric Infectious Diseases Society and the Society of Infectious Diseases Pharmacists) held from 19 to 21 October in Atlanta, Georgia, Dr Reeti Khare of National Jewish Health presented the microbiological outcomes from a Phase II, randomised, placebo-controlled trial investigating oral omadacycline in adult patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) caused by Mycobacterium abscessus complex (MABc).
Exposure to NTM occurs on a daily basis as they are ubiquitous in the environment, particularly in water, soil and dust, but does not result in an infection for most healthy individuals. NTM are opportunistic pathogens responsible for causing infections in patients with pre-existing health conditions or compromised immune systems. The most frequent symptoms of NTM-PD are cough, fatigue, fever, loss of appetite, shortness of breath and weight loss. According to GlobalData, prevalent cases of pulmonary NTM are expected to increase by 7.2% in the seven major pharmaceutical markets (7MM: Germany, France, Japan, Italy, Spain, the UK and the US) between 2023 and 2033. The species most commonly responsible for NTM-PD infections is Mycobacterium avium complex (MAC). MABc is the second most common species responsible for NTM-PD infections.
Go deeper with GlobalData
Access deeper industry intelligence
Experience unmatched clarity with a single platform that combines unique data, AI, and human expertise.
The lack of NTM therapeutics is one of the biggest unmet needs within the NTM market. Nearly all of the drugs used to treat NTM infections are used off-label. Many of these drugs are broad-spectrum antibiotics that have been repurposed for the treatment of NTM. Paratek’s omadacycline, a novel tetracycline derivative, is already marketed in the US and China for the treatment of adults with community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections, under the brand name Nuzyra. Omadacycline is currently in the development pipeline for several other indications, including NTM-PD, for which it has fast-track designation from the US Food and Drugs Administration (FDA) and orphan drug designation from both the FDA and the European Medicines Agency.
The exploratory Phase II trial (NCT04922554) included 66 patients who were 18 years of age or older and had been diagnosed with NTM-PD caused by MABc per Infectious Diseases Society of America/American Thoracic Society guidelines. These patients were randomised into two groups: those receiving 300mg of oral omadacycline once daily for 84 days or those receiving an oral placebo once daily for 84 days. Bacterial cultures were taken from patients at their baseline visit, day 28 visit, day 56 visit and day 84 visit.
One way in which the sputum cultures were analysed was through a scoring system based on colony counts on an agar plate. At day 28, 56, and 84, the omadacycline cultures had a reduction in culture score, and therefore a reduction in colony forming units compared to the placebo cultures. Overall, 76.5% of patients treated with omadacycline experienced a decrease in their culture scores, compared to 45.8% of the placebo treated patients. Similar results were obtained from sputum cultures in liquid media; greater reductions in bacterial burden were observed in the omadacycline group. Of the omadacycline treated patients, 73.0% had sputum cultures with growth in liquid medium only, compared to 39.1% of the placebo treated patients, which is also indicative of a lower bacterial burden.
Overall, 53.8% of participants in the omadacycline treated group produced negative sputum cultures at day 84 of treatment, compared to 25.0% of participants in the placebo group. Further, minimum inhibitory concentrations evaluated for omadacycline did not change from baseline to day 84, therefore, there was no observed change in omadacycline susceptibility throughout the duration of the study.
US Tariffs are shifting - will you react or anticipate?
Don’t let policy changes catch you off guard. Stay proactive with real-time data and expert analysis.
By GlobalDataThe results of this Phase II study highlight omadacycline’s potential within the NTM market. Key opinion leaders (KOLs) interviewed by GlobalData have expressed positive opinions on the development of oral omadacycline for NTM-PD, particularly because this indication lacks novel, effective therapies. Several US KOLs have acknowledged that they utilise omadacycline off-label for the treatment of NTM-PD caused by MAC and MABc. The clinical success of omadacycline highlights its potential to fulfil a critical unmet need within the NTM market and possibly contribute to increased treatment success rates among NTM-PD patients.
