Clofazimine for Treatment of Mycobacterium abscessus Infections in Children

BACKGROUND: Mycobacterium abscessus infections are increasingly common and can be challenging to treat due to antimicrobial resistance. Clofazimine (CFZ), which is commonly used for treatment of leprosy, comes as a 50 mg capsule that must be swallowed whole. It has excellent in vitro activity against M. abscessus but there are limited reports of its use, particularly in children. During a healthcare associated outbreak of M. abscessus odontogenic infections, 27 children were treated with a CFZ containing regimen for several months. METHODS: Data was collected on all children who received CFZ for a proven or probable M. abscessus odontogenic infection via a Food and Drug Administration Investigational New Drug Application. Demographic, diagnostic and therapeutic information was evaluated, as were laboratory results, adverse events and clinical outcomes. RESULTS: Of 27 children who received CFZ, 13 were male, 22 were Hispanic and mean age at initial dosing was 5.8 years (range 3.0 – 9.4 years). Patients also received azithromycin, amikacin and either imipenem or cefoxitin, though the β-lactam was stopped an average of 31 days after CFZ started. All 27 children had osteomyelitis of the jaw and received aggressive surgical debridement; 10 had a positive stain for acid-fast bacilli (AFB) and 14 had a positive AFB culture (13 M. abscessus, 1 M. chelonae). Lung nodules were present in 16 children and granulomatous lymphadenitis requiring surgery in 10. Patients received a mean of 105.6 total days of CFZ therapy (range 84–164 days) with a mean weekly dose of 7.6 mg/kg and with dosing occurring a mean of 3 days a week. Every child was able to swallow the CFZ capsule. Minor skin discoloration was noted in 6 children, dry skin in 17, and gastrointestinal symptoms in 11. No child had a clinically significant change in corrected QT interval. All children showed evidence of jaw healing and resolution of lymphadenitis at the end of therapy, and 14 had resolved or improving lung nodules. CONCLUSION: This is the largest reported case series of children receiving clofazimine for reasons other than leprosy. It is also the largest report of clofazimine use for extra pulmonary M. abscessus infections. Clofazimine appears to be safe in children and may be an effective part of a surgical and multi-drug regimen for M. abscessus infections. DISCLOSURES: All authors: No reported disclosures.