Efficacy and safety of an all-oral delamanid-containing regimen in the treatment of multidrug-resistant pulmonary tuberculosis complicated by extrapulmonary tuberculosis: Four case reports and review of the literature.

Background: Multidrug-resistant tuberculosis (MDR-TB) complicated by extrapulmonary TB (EPTB) poses significant therapeutic challenges. While delamanid (DLM) demonstrates extensive tissue penetration, clinical evidence supporting its use specifically for MDR-TB with EPTB remain limited. This report evaluates an all-oral DLM-containing regimen for this complex presentation. Case Presentation: Four patients (aged 35, 24, 47, 4 years; 3 females, 1 child) with molecularly confirmed MDR pulmonary TB (MDR-PTB) and concurrent EPTB (spinal, central nervous system, breast, lymph node) received individualized all-oral regimens. Regimens combined DLM with bedaquiline (BDQ), linezolid (LZD), fluoroquinolones, and companion drugs for ≥ 15 months. Follow-up imaging demonstrated significant lesion resolution in all cases, including the pediatric lymph node involvement (first reported in China). Twenty-four adverse events occurred (15 Grade 1, 6 Grade 2, 3 Grade 3), primarily corrected QT interval prolongation (5 events, one > 500 ms). Most events (21/24, 87.5 %) resolved following dose adjustments or supportive care. No serious adverse events or deaths occurred. Conclusion: In this small case series of patients with MDR-TB and diverse extrapulmonary manifestations, an all-oral DLM-containing regimen was associated with significant lesion regression and demonstrated a manageable safety profile. QT prolongation was the primary adverse event, reversible with intervention. These findings-representing China's first systematic report of this regimen for multisite EPTB, including the pediatric case-align with WHO guidance and suggest DLM's potential utility based on its extensive tissue penetration. Further validation in larger multicenter studies is warranted.