The LTI-01-2001 phase 2a trial of intrapleural LTI-01 in patients with infected, non-draining pleural effusions.

Publication date: Jun 17, 2026

Single chain urokinase (LTI-01) intrapleural enzymatic therapy (IET) was safe and promising in a phase 1 clinical trial to overcome failed drainage in patients with pleural infection. The LTI-01-2001 phase 2a trial was a randomized, double-blind, placebo-controlled, multi-center, dose-ranging study in hospitalized subjects with infected, non-draining pleural effusions. LTI-01, in doses of 400,000, 800,000 or 1,200,000 Units, or placebo was administered intrapleurally once daily for up to 3 days. The primary efficacy endpoint was incidence of treatment failure within 7 days of starting study medication. Treatment failure was defined as requiring alternative pleural therapy irrespective of subsequent treatment. Pleural opacification was a secondary endpoint and was assessed by CT imaging of the change in opacified area expressed as a percentage of the ipsilateral hemithorax (relative change) or absolute change in pleural opacification volume expressed in liters. 40/43 enrolled patients received LTI-01 or placebo due to constraints of the COVID-19 pandemic. There was no significant difference in incidence of treatment failure between the LTI-01 and placebo groups (OR 1. 04, 95% CI 0. 24,4. 44, P = 0. 96) while two predetermined sensitivity analyses demonstrated trends of improved efficacy in the 400,000 U group (P = 0. 052 and 0. 147). The absolute (Liters; L) and relative change from baseline in opacity volume were - 0. 28 L (p=0. 035) and - 55. 8% (P = 0. 064) versus placebo in the 800,000 U group, with significant reduction in absolute opacification found in the 400,000 and all LTI-01-treated groups combined (P 

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