entospletinib (GS-9973)

Despite the investigation of inhibitors of SYK including fostamatinib, entospletinib, cerdulatinib, and TAK-659 for cancer therapy, their lack of specificity and potential off-target effects remain significant concerns...Rifabutin, darunavir, and sildenafil were found as promising SYK inhibitors, showing strong interactions and stable conformations...Our findings underscore the value of computational methods in drug discovery and advocate for further experimental validation of these compounds as SYK-targeted therapies. This study aims to advance the development of more effective and safer treatments for cancers associated with SYK overexpression.

Naive AML cells treated with entospletinib showed a strong downregulation of the same gene sets which were upregulated in the resistant state. Our data suggest that inflammatory signaling pathways play a role in entospletinib resistant AML cells.

This study investigates in vitro antiproliferative effects of SYK inhibitors on leukemia cells by analyzing 48 primary AML samples treated with five SYK inhibitors: fostamatinib, entospletinib, cerdulatinib, TAK-659, and RO9021. Gene set enrichment analysis further highlighted that high-sensitivity patient samples were upregulated in pathways associated with oxidative phosphorylation and MYC targets, whereas low-sensitivity patient samples showed enrichment in TGF beta signaling and IL6 JAK STAT3 signaling. These results identify gene expression profile signatures that may predict sensitivity to SYK inhibition and underscore the potential for personalized therapeutic strategies in AML.

P1, N=203, Terminated, Gilead Sciences | Active, not recruiting --> Terminated; The goal of the study was to improve tolerability while maintaining or increasing efficacy. The results of this study showed no efficacy advantage although the combinations were well tolerated.

P1, N=203, Active, not recruiting, Gilead Sciences | Trial completion date: Dec 2025 --> Dec 2024 | Trial primary completion date: Dec 2025 --> Dec 2024

Our study demonstrates that glioma cells can be activated by macrophages via SIRPB1, subsequently reprogramming the TME, suggesting that SIRPB1 could serve as a promising therapeutic target for gliomas.

This transporter-mediated restriction of brain penetration for both drugs could be almost fully inhibited by coadministration of the dual ABCB1/ABCG2 inhibitor elacridar, without signs of acute toxicity. This interaction was, however, unlikely to be mediated through any of the studied transporters or CYP3A. The obtained insights may perhaps help to further improve the safety and efficacy of entospletinib and lanraplenib.

Taken together, entospletinib abrogates dermal-epidermal separation, likely through inhibition of granulocyte responsiveness to deposited immune complexes. Entospletinib or other Syk inhibitors may provide therapeutic benefit in BP.

P1, N=203, Active, not recruiting, Gilead Sciences | Phase classification: P1b --> P1

Entospletinib (ENTO) and lanraplenib (LANRA) are inhibitors of spleen tyrosine kinase (SYK); the latter is a next-generation SYK inhibitor and is currently being evaluated in combination with gilteritinib (GILT) in patients with relapsed or refractory FLT3-mutated AML (NCT05028751)...Two different AML patient cohorts were assessed by ex vivo treatment with ENTO, LANRA and combinations of LANRA (trametinib, gilteritinib (GILT), aPD-1) over a range of time points (2h, 4h, 3d and 9d) and readouts for cellular phenotype (e.g., differentiation state, immune cell populations) and functional readouts (pSYK, viability) for each cohort were analyzed by HP-FC and sc-MI and associated with available mutation information (bulk gene and single cell RNA sequencing)...These support studies investigating the use of pSYK inhibitors in combination with other therapies to reduce tumor burden, and as an improved line of treatment for AML. Acknowledgements: We are appreciative of the patients and families for their time and participation.

In an orthotopic mouse model of FLT3-mutant AML, tuspetinib exhibited greater antitumor activity than gilteritinib, entospletinib, venetoclax (VEN), and azacitidine (AZA) and combined favorably with VEN and AZA individually. Tuspetinib was well-tolerated and delivered single agent clinical responses across four dose levels among diverse AML genotypes; with a RP2D of 80 mg chosen for future single agent studies. Although early, the VEN/TUS combination has been well tolerated with preliminary objective responses noted.