Dual PI3K/HDAC Inhibitor BEBT-908 Exhibits Potent Efficacy as Monotherapy for Primary Central Nervous System Lymphoma.

BACKGROUND: The efficacy of systemic treatment for primary central nervous system lymphoma (PCNSL) is limited because of the blood-brain barrier (BBB) and the ineffectiveness of chemotherapy. The dual PI3K/HDAC inhibitor BEBT-908 has exhibited favorable in vivo distribution and activity in various cancers. OBJECTIVES: The aims of this study were to assess the efficacy of BEBT-908 in brain orthotopic mouse models of hematological malignancies, to investigate its pharmacologic properties, and to elucidate the underlying mechanism of action. METHODS: We evaluated the anticancer activity of BEBT-908 in various hematological malignancies through cell viability assays. The impact of BEBT-908 on c-Myc expression and ferroptosis signaling pathways was assessed using Western blotting, qPCR, ROS detection, GSH/GSSG detection, and IHC. Pharmacokinetic and pharmacodynamic profiles were assessed through LC-MS/MS and Western blotting. The effects of BEBT-908 in vivo were examined using xenografts and brain orthotopic mouse models. RESULTS: Our findings demonstrate that BEBT-908 exhibits promising anti-tumor activity in vitro and in vivo across multiple subtypes of hematological malignancies. Furthermore, BEBT-908 exhibits excellent BBB penetration and inhibits tumor growth in a brain orthotopic lymphoma model with prolonged survival of host mice. Mechanistically, BEBT-908 downregulated c-Myc expression, which contributed to ferroptosis, ultimately leading to tumor shrinkage. CONCLUSION: Our study provides robust evidence for the dual PI3K/HDAC inhibitor BEBT-908 as an effective anti-cancer agent for PCNSL.

A Dual PI3K/HDAC Inhibitor Induces Immunogenic Ferroptosis to Potentiate Cancer Immune Checkpoint Therapy.

The capacity of targeted anticancer agents to exert immunomodulatory effects provides a strong rationale to develop novel agents suitable for combinatorial regimens with immunotherapy to improve clinical outcomes. In this study, we developed a dual-targeting PI3K and HDAC inhibitor BEBT-908 that potently inhibits tumor cell growth and potentiates anti-PD1 therapy in mice by inducing immunogenic ferroptosis in cancer cells. Treatment with BEBT-908 promoted ferroptotic cell death of cancer cells by hyperacetylating p53 and facilitating the expression of ferroptotic signaling. Furthermore, BEBT-908 promoted a proinflammatory tumor microenvironment that activated host antitumor immune responses and potentiated immune checkpoint blockade therapy. Mechanistically, BEBT-908-induced ferroptosis led to upregulation of MHC class I and activation of endogenous IFNγ signaling in cancer cells via the STAT1 signaling pathway. The dual PI3K/HDAC inhibitor BEBT-908 is a promising targeted therapeutic agent against multiple cancer types that promotes immunogenic ferroptosis and enhances the efficacy of immunotherapy. SIGNIFICANCE: The dual PI3K/HDAC inhibitor BEBT-908 elicits potent antitumor responses, effectively inducing immunogenic ferroptosis of tumor cells and potentiating cancer immunotherapy.

BEBT-109, a pan-mutant-selective EGFR inhibitor with potent antitumor activity in EGFR-mutant non-small cell lung cancer.

EGFR mutation-positive NSCLC tumors are highly heterogeneous, therefore, exploring an agent simultaneously targeting multiple EGFR mutations may be valuable for clinical practice. Compared with osimertinib, BEBT-109 shows more sensitive and extensive antitumor activity in EGFR mutant NSCLC, while sparing wild-type EGFR cell lines. Meanwhile, unlike the metabolite of osimertinib AZ5104, the main metabolites of BEBT-109 are found lacking in activity against wild-type EGFR cell lines. Preclinical and clinical studies demonstrate a unique pharmacokinetic profiles of BEBT-109 with rapid absorption and quick in vivo clearance without accumulation, which are conducive to minimizing the off-target toxicity of the covalent irreversible EGFR inhibitor. Oral administration of BEBT-109 induces tumor regression in EGFR exon 20 insertion xenografts, and even tumor disappearance in PC-9, HCC827 and H1975 xenograft models. Furthermore, in clinical trials, the objective responses were observed in NSCLC patients with EGFR T790M mutation in the first and second dosing cohorts. These findings demonstrate that BEBT-109, a potent pan-mutant-selective EGFR inhibitor with improved pharmacokinetic properties, might offer a promising new option for the treatment of multiple mutant-EGFR-driven NSCLC.