Study protocol for safety and efficacy of all-oral shortened regimens for multidrug-resistant tuberculosis: a multicenter randomized withdrawal trial and a single-arm trial [SEAL-MDR]

IntroductionThe urgent need for new treatments for multidrug-resistant tuberculosis (MDR-TB) and pre-extensively drug-resistant tuberculosis (pre-XDR-TB) is evident. However, the classic randomized controlled trial (RCT) approach faces ethical and practical constraints, making alternative research designs and treatment strategies necessary, such as single-arm trials and host-directed therapies (HDTs).MethodsOur study adopts a randomized withdrawal trial design for MDR-TB to maximize resource allocation and better mimic real-world conditions. Patients' treatment regimens are initially based on drug resistance profiles and patient's preference, and later, treatment-responsive cases are randomized to different treatment durations. Alongside, a single-arm trial is being conducted to evaluate the potential of sulfasalazine (SASP) as an HDT for pre-XDR-TB, as well as another short-course regimen without HDT for pre-XDR-TB. Both approaches account for the limitations in second-line anti-TB drug resistance testing in various regions.DiscussionAlthough our study designs may lack the internal validity commonly associated with RCTs, they offer advantages in external validity, feasibility, and ethical appropriateness. These designs align with real-world clinical settings and also open doors for exploring alternative treatments like SASP for tackling drug-resistant TB forms. Ultimately, our research aims to strike a balance between scientific rigor and practical utility, offering valuable insights into treating MDR-TB and pre-XDR-TB in a challenging global health landscape. In summary, our study employs innovative trial designs and treatment strategies to address the complexities of treating drug-resistant TB, fulfilling a critical gap between ideal clinical trials and the reality of constrained resources and ethical considerations.Trail registrationChictr.org.cn, ChiCTR2100045930. Registered on April 29, 2021.