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Purpose Probing efficacy and safety of lusutrombopag in Chinese chronic liver disease (CLD) and severe thrombocytopenia (PLT 9/L) patients undergoing elective invasive procedures. Methods In this double-blind, parallel-group phase 3 study, 66 patients with CLD and severe thrombocytopenia were randomized 2:1 to lusutrombopag or placebo arm treatment regimens for seven days at 9 centers in China. Responders (PLT ≥ 50 × 109/L that increased to ≥ 20 × 109/L from the baseline and not received rescue therapy for bleeding) on Day 8 (the day after seven-day treatment) were assessed. PLT ≥ 50 × 109/L on or after Day 8 and within 2 days before invasive procedure (alternative criteria for not requiring platelet transfusion) were also analyzed. Adverse events (AEs) were recorded. Results The proportion of responders on Day 8 was evidently higher (p = 0.0011) in the lusutrombopag group (43.2%, 19/44) versus placebo (4.5%, 1/22). And 72.7% (32/44) patients receiving lusutrombopag met the alternative criteria for not requiring platelet transfusion, while 18.2% (4/22) in the placebo group. The median maximum PLT in lusutrombopag group increased to 80.5 × 109/L, and median time to reach maximum was 14.5 days. Compared with placebo, the lusutrombopag group had a lower incidence of bleeding events (6.8% versus 13.6%), and only one patient had thrombotic-related AE. Overall, the incidence of treatment-emergent AEs was comparable between two groups. Conclusions Lusutrombopag was effective in raising PLT, diminishing platelet transfusion requirement, and documented a safety profile like the placebo in CLD and severe thrombocytopenia patients in a Chinese cohort undergoing elective invasive procedures. Chinese clinical trial registration number: CTR20192384.

Mixed lineage kinase domain-like (MLKL) is widely accepted as an executioner of necroptosis, in which MLKL mediates necroptotic signaling and triggers cell death in a receptor-interacting protein kinase 3 (RIPK3)-dependent manner. Recently, it is increasingly noted that RIPK3 is intrinsically silenced in hepatocytes, raising a question about the role of MLKL in hepatocellular carcinoma (HCC). This study reports a previously unrecognized role of MLKL in regulating parthanatos, a programmed cell death distinct from necroptosis. In HCC cells with intrinsic RIPK3 deficiency, knockout of MLKL impedes the orthotopic tumor growth, activates the anti-tumor immune response and enhances the therapeutic effect of immune checkpoint blockade in syngeneic HCC tumor models. Mechanistically, MLKL is required for maintaining the endoplasmic reticulum (ER)-mitochondrial Mg2+ dynamics in HCC cells. MLKL deficiency restricts ER Mg2+ release and mitochondrial Mg2+ uptake, leading to ER dysfunction and mitochondrial oxidative stress, which together confer increased susceptibility to metabolic stress-induced parthanatos. Importantly, pharmacological inhibition of poly(ADP-ribose) polymerase to block parthanatos restores the tumor growth and immune evasion in MLKL-knockout HCC tumors. Together, our data demonstrate a new RIPK3-independent role of MLKL in regulating parthanatos and highlight the role of MLKL in facilitating immune evasion in HCC.