Safety and tolerability of clofazimine as salvage therapy for atypical mycobacterial infection in solid organ transplant recipients

Abstract

Background: The treatment of Mycobacterium avium complex (MAC) requires prolonged, multidrug therapy, which is often not well tolerated. In solid organ transplant (SOT) recipients, drug-drug interactions complicate treatment further. Failure or intolerance requires the use of salvage regimens, and clofazimine is one of the drugs that can be used. No data are available on the safety and tolerability of clofazimine for the treatment of MAC in SOT recipients.

Methods: Retrospective review of all SOT recipients treated for MAC infection with clofazimine at a large transplant center between 2006 and 2013.

Results: Five SOT recipients received clofazimine as salvage therapy. Transplanted organs were lungs in 3 patients, and kidney and liver in 1 patient each. Infection was diagnosed at a median of 22 months (range 4-57) post transplant. Sites of infection were the lungs in 2 patients, and septic arthritis, mesenteric, and disseminated disease in 1 patient each. All patients received standard anti-MAC therapy for a median of 26 weeks (range 18-45) before starting clofazimine. Indications for use of clofazimine included a lack of response to previous therapy (3 patients), and poor tolerance of other regimens (3 patients). All patients received at least 2 additional drugs besides clofazimine. Median duration of clofazimine-containing regimen was 8 months (range 2-18). Clofazimine was discontinued because of gastrointestinal intolerance in 1 of the 5 patients. The most common adverse event from clofazimine was skin discoloration, in 60% of patients. No hepatotoxicity or hematologic toxicity occurred. Microbiological clearance and resolution of clinical disease was documented in 2 of 5 patients; and 2 of the 5 patients died of other causes while on therapy.

Conclusions: Clofazimine appears safe and may be considered as a salvage therapeutic option in SOT recipients with MAC infection who are intolerant or unresponsive to standard therapy. The small sample size does not allow conclusions regarding efficacy.

Keywords: MAC; NTM; clofazimine; mycobacteria; solid organ transplant.