Two Weeks of Imipenem as Initial Induction Therapy for Disseminated Rapidly Growing Nontuberculous Mycobacterium Infections: A single Arm, Open-Label, Comparative Study with Historical Control 4-week Imipenem Therapy
Panuwat Napinkul, MD1, Piroon Mootsikapun, MD1
Affiliation : 1Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon kaen, Thailand
Background: Disseminated non tuberculous mycobacterium (NTM) infection is a recently emerging problem worldwide, particularly in Asian countries. It is a difficult to treat the infections and there are limited options of antibiotic therapy. Currently, there is no guideline available for treatment of disseminated NTM infection, particularly from rapidly growing nontuberculous mycobacteria (RPGM). The common antibiotic regimen usually begins with imipenem intravenously for 2 to 4 weeks, followed by only oral regimen with macrolide and quinolone combination. Relapses of clinical symptoms occur frequently. Some experts thought it was related to the duration of imipenem given and preferred prolonged imipenem infusion for 4 weeks, but had no supported evidence.
Objective: To compare the relapse rate of disseminated NTM with 2-week imipenem versus historical cohort data of 4-week imipenem as initial therapy.
Materials and Methods: A prospective open-label study was conducted at Srinagarind Hospital, Khon Kaen, Thailand between 1 January 2019 and 28 February 2021. The adult patients who had a diagnosis of disseminated NTM infection were screened. After inclusion and exclusion criteria were met, the patients were enrolled and received imipenem as an initial therapy. Imipenem was stopped after completion of a 2 weeks course. The patients who had imipenem continued was defined as treatment failure. The patients came for a 1-month follow-up for 3 months, and then a 3-month follow-up, and then they had regular visits according to routine care. The demographic data was collected and clinical relapse was recorded during the study period. Intent-to treat and as treated analysis were performed.
Results: A total of 26 cases of disseminated NTM infection were enrolled. The patients received a 2-week imipenem arm. There were 30 cases from a historical cohort who were treated with 4-weeks of imipenem. By intent-to-treat analysis, the relapse rate of 2-week imipenem therapy was not statistically different from the 4-week arm at 1 month (8.0% vs. 6.7%) (p=0.89) and at 3 months (53.8% vs. 33.3%)(p=0.67). By as-treated analysis, there was also no difference in the relapse rate between the 2-week arm and 4-week arm at 1 month (10% vs. 6.7%) (p=0.72) and 3 months (44.4% vs. 34.2%)(p=0.69) follow-up.
Conclusion: Initial treatment of disseminated NTM infection with imipenem for 2 weeks has no statistical difference in the relapse rate when compared with treatment of imipenem for 4 weeks.
Received 1 April 2025| Revised 21 August 2025 | Accepted 9 September 2025
Keywords : Disseminated rapidly growing nontuberculous mycobacterium; Nontuberculous mycobacteria; Imipenem
