Evaluation of Sulfasalazine As an Adjunctive Therapy in Treating Pulmonary Pre-XDR-TB: Efficacy, Safety, and Treatment Implication

Background: The rising prevalence and limited efficacy of treatments for pre-extensively drug-resistant tuberculosis (pre-XDR-TB) underscore an immediate need for innovative therapeutic options. A combination of host-directed therapy (HDT) and anti-TB treatment presents a viable alternative for pre-XDR-TB management. Sulfasalazine (SASP), by targeting the amino acid transport system xc (xCT), potentially reduces the intracellular Mycobacterium tuberculosis load and mitigates lung pathology, positioning it as a promising TB HDT agent. This study aims to assess the efficacy of SASP as a supplementary therapy for pre-XDR-TB.

Methods: A pilot study examined the safety and effectiveness of two 9-month short-course, all-oral regimens for pre-XDR-TB treatment: Bdq-regimen (consisting of Bdq, linezolid, cycloserine, clofazimine, and pyrazinamide) and SASP-regimen (comprising SASP, linezolid, cycloserine, clofazimine, and pyrazinamide). The primary endpoint was the incidence of unfavorable outcomes 12 months post-treatment.

Results: Of the 44 participants enrolled, 43 were assessable 12 months post-treatment. Culture conversion rates stood at 73.2% by Month 2 and escalated to 95.1% by Month 6. Overall, 88.4% (38/43) of the participants exhibited favorable outcomes, 85.2% (19/23) for the Bdq-regimen and 93.8% (14/15) for the SASP-regimen. The SASP-regimen group recorded no deaths or treatment failures.

Conclusion: Both 9-month short-course, all-oral regimens manifested commendable primary efficacy in treating pre-XDR-TB patients. The SASP-regimen emerged as effective, safe, well-tolerated, and cost-effective.