D107-10 Immune Checkpoint Inhibitors and Non-tuberculous Mycobacterial Infections: A Case Series

Abstract Introduction Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy through enhancing T-cell-mediated immune responses but have also been associated with immune-related adverse events. Emerging literature suggests a potential association between ICI therapy and the development or reactivation of tuberculous mycobacterial infections. It is unclear whether ICI therapy is also linked to an increased risk of non-tuberculous mycobacterial (NTM) infections, though case reports are rapidly accumulating. We aim to better elucidate the potential association between ICIs and NTM infections through a case series. Case Series This series includes patients at Mayo Clinic who were diagnosed with active NTM infection during or after ICI use from January 1, 2012 to December 31, 2024. Data including demographics, malignancy details, ICI regimen and duration, timing and site of NTM infection, microbiologic findings, antimycobacterial therapy, and clinical outcomes were evaluated. There were seven patients with positive testing for NTM during or after ICI therapy. Two had one colony of M. gordonae on cultures which were determined by Infectious Disease to be contaminants. One case had a reported culture positive for M. franklinii at an outside hospital without further details available and thus was excluded from analysis. Chart review was performed for the remaining four patients with active NTM infection during or after ICI therapy. Two of the patients had underlying chronic obstructive pulmonary disease with a smoking history; these same two had primary lung malignancy. The other two patients had no known underlying lung disease or malignancy lung involvement (primary or metastatic). ICI therapies included PD-1, PD-L1, and CTLA-4 inhibitors. All four NTM infections predominant had lung involvement and were all different species; two were diagnosed while the patient was actively receiving ICI therapy and two were diagnosed several months after ICI discontinuation. Of the two receiving ICI therapy at the time of diagnosis, the ICI was held for 101 days for one patient and the other continued the ICI without interruption. Three received multi-agent therapy while the fourth declined treatment and died of malignancy complications soon after. The other three were alive at one year after NTM diagnosis and completed approximately one year of antimycobacterial therapy. Conclusions Tuberculous and non-tuberculous mycobacterial infections are increasingly seen after immune checkpoint inhibitor therapy. We present a series of four cases of NTM infections after or during ICI therapy for various types of malignancy with good outcomes after approximately one year of treatment. This abstract is funded by: None