DAR-901 vaccine for the prevention of infection with Mycobacterium tuberculosis among BCG-immunized adolescents in Tanzania: A randomized controlled, double-blind phase 2b trial. Issue 46 (27th October 2020)

• Record Type: Journal Article
• Authors: Munseri, Patricia; Said, Jamila; Amour, Maryam; Magohe, Albert; Matee, Mecky; Rees, Christiaan A.; Mackenzie, Todd; Tvaroha, Susan; Bailey-Kellogg, Chris; Maro, Isaac; Wieland-Alter, Wendy; Adams, Lisa V.; Horsburgh, C. Robert; Nakamura, Keiko; Arbeit, Robert D.; Pallangyo, Kisali; von Reyn, C. Fordham
• Is Part Of: Vaccine. Volume 38:Issue 46(2020)
• Page Start: 7239
• Page End: 7245
• Publication Date: 2020-10-27
• Subjects: DAR-901 -- Tuberculosis -- Vaccine -- BCG -- Interferon gamma release assay -- Tanzania; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2020.09.055
• Languages: English
• ISSNs: 0264-410X

Abstract

Abstract: Background: SRL172 prevented disease due to Mycobacterium tuberculosis in a Phase 3 trial. DAR-901 represents a scalable manufacturing process for SRL172. We sought to determine if DAR-901 would prevent infection with M. tuberculosis among BCG-primed adolescents age 13–15 years in Tanzania. Methods: Adolescents with a negative T- SPOT.TB R interferon gamma release assay (IGRA) were randomized 1:1 to three intradermal injections of DAR-901 or saline placebo at 0, 2 and 4 months. Repeat IGRAs were performed at 2 months, and at 1, 2, and 3 years. The primary efficacy outcome was time to new TB infection (IGRA conversion to positive); the secondary outcome was time to persistent TB infection (IGRA conversion with repeat positive IGRA). Results: Among 936 participants screened 667 were eligible and randomized to their first dose of vaccine or placebo (safety cohort). At 2 months, 625 participants remained IGRA-negative and were scheduled for the additional two doses (efficacy cohort). DAR-901 was safe and well-tolerated. One DAR-901 recipient developed a vaccine site abscess. Neither the primary nor secondary endpoints differed between the two treatment arms (p = 0.90 and p = 0.20, respectively). DAR-901 IGRA converters had median responses to ESAT-6 of 50.1 spot-forming cells (SFCs) vs. 19.6 SFCs in placebo IGRA converters (p = 0.03). Conclusions: A three-dose series of 1 mg DAR-901 was safe and well-tolerated but did not prevent initial or persistent IGRA conversion. DAR-901 recipients with IGRA conversion demonstrated enhanced immune responses to ESAT-6. Since protection against disease may require different immunologic responses than protection against infection a trial of DAR-901 to prevent TB disease is warranted. Trial Registration. The trial is registered at ClinicalTrials.gov as NCT02712424.