A Phase 2A Trial of the Safety and Tolerability of Increased Dose Rifampicin and Adjunctive Linezolid, With or Without Aspirin, for Human Immunodeficiency Virus–Associated Tuberculous Meningitis: The LASER-TBM Trial

Background: Drug regimens which include intensified antibiotics alongside effective anti-inflammatory therapies may improve outcomes in Tuberculous Meningitis (TBM). Safety data on their use in combination and in the context of HIV is needed to inform clinical trial design. Methods: We conducted a phase 2 open-label parallel-design RCT to assess safety of high-dose rifampicin, linezolid and aspirin in HIV-associated TBM. Participants were randomised (1.4:1:1) to three treatment arms (arm 1, standard of care (SOC); arm 2 SOC + additional rifampicin (up to 35mg/kg/day)) + linezolid 1200mg/day reducing after 28/7 to 600mg/day; arm 3, as per arm 2 + aspirin 1000mg/day) for 56 days, when the primary outcome of adverse events of special interest (AESI) or death was assessed. Results: 52 participants were randomised. 59% had mild disease (MRC Grade 1) vs 39% (Grade 2) vs 2% (Grade 3). 33% of participants had microbiologically-confirmed TBM; vs 41% possible or 25% probable. AESI or death occurred in 10/16 (arm 3) vs 4/14 (arm 2) vs 6/20 (arm 1) (p=0.083). The cumulative proportion of AESI or death (Kaplan-Meier method) demonstrated worse outcomes in arm 3 vs arm 1 (p=0.04), however only one event in arm 3 was attributable to aspirin and was mild. There was no difference in efficacy (Modified Rankin Scale) at day 56 between the three arms. Conclusions: High-dose rifampicin and adjunctive linezolid can safely be added to SOC in HIV-associated TBM. Larger studies are required to evaluate whether potential toxicity associated with these interventions, particularly aspirin, is outweighed by mortality or morbidity benefit.