Preclinical characterization of WB737, a potent and selective STAT3 inhibitor, in natural killer/T-cell lymphoma.

Natural killer/T-cell lymphoma (NKTL) is an uncommon malignancy with poor prognosis and limited therapeutic options. Activating mutations of signal transducer and activator of transcription 3 (STAT3) are frequently found in patients with NKTL, suggesting that targeted inhibition of STAT3 is a potential therapeutic option for this disease. Here, we have developed a small molecule drug WB737 as a novel and potent STAT3 inhibitor that directly binds to the STAT3-Src homology 2 domain with high affinity. In addition, the binding affinity of WB737 to STAT3 is 250-fold higher than STAT1 and STAT2. Interestingly, WB737 is more selective for NKTL with STAT3-activating mutations in terms of growth inhibition and apoptotic induction when compared with Stattic. Mechanistically, WB737 inhibits both canonical and noncanonical STAT3 signaling via suppression of STAT3 phosphorylation at Tyr705 and Ser727, respectively, thereby inhibiting the expression of c-Myc and mitochondria-related genes. Moreover, WB737 inhibited STAT3 more potently than Stattic, resulting in a significant antitumor effect with undetectable toxicity, followed by almost complete tumor regression in an NKTL xenograft model harboring a STAT3-activating mutation. Taken together, these findings provide preclinical proof-of-concept for WB737 as a novel therapeutic strategy for the treatment of NKTL patients with STAT3-activating mutations.

[Clinical Efficacy of High Dose Methotrexate, Temozolomide and Rituximab in the Treatment of Patients with Primary Central Nervous System Lymphoma].

OBJECTIVE: To investigate the clinical efficacy of high dose methotrexate (HD-MTX), temozolomide (TMZ), and rituximab (R) in the treatment of patients with primary central nervous system lymphoma (PCNSL). METHODS: Clinical data of patients with PCNSL diagnosed and treated in Guangdong Provincial People's Hospital from February 2010 to May 2017 were collected. First, patients were given 6-8 cycles of MTX (3.5 g/m2) for induction treatment, and then 12 cycles of TMZ (150 mg/m2) for maintenance treatment. The day before induction treatment, patients were given rituximab 375 mg/m2 according to their economic status. A retrospective cohort study was performed on patients receiving HD-MTX+TMZ or HD-MTX+TMZ+R to analyze the efficacy and survival. RESULTS: There were 42 patients enrolled in the study, 17 cases in HD-MTX+TMZ group and 25 cases in HD-MTX+TMZ+R group. The median PFS and OS times in HD-MTX+TMZ+R group were 56.7 months and N/A, respectively, while, 7.3 months and 34.7 months in HD-MTX+TMZ group, respectively. In addition, there was no significant difference in median survival between patients who received TMZ maintenance therapy and those who were only actively monitored. During the induction period, all the patients had grade 1-2 nausea and vomiting, while in the consolidation treatment period, no grade 3/4 toxicity was observed. CONCLUSION: The combination of HD-MTX+TMZ+R in the treatment of PCNSL patients shows a definite short-term effect, which can increase the survival rate of the patients. The side effects are mild, and the patients can generally tolerate.

CREBBP cooperates with the cell cycle machinery to attenuate chidamide sensitivity in relapsed/refractory diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) exhibits frequent inactivating mutations of the histone acetyltransferase CREBBP, highlighting the attractiveness of targeting CREBBP deficiency as a therapeutic strategy. In this study, we demonstrate that chidamide, a novel histone deacetylase (HDAC) inhibitor, is effective in treating a subgroup of relapsed/refractory DLBCL patients, achieving an overall response rate (ORR) of 25.0% and a complete response (CR) rate of 15.0%. However, the clinical response to chidamide remains poor, as most patients exhibit resistance, hampering the clinical utility of the drug. Functional in vitro and in vivo studies have shown that CREBBP loss of function is correlated with chidamide sensitivity, which is associated with modulation of the cell cycle machinery. A combinatorial drug screening of 130 kinase inhibitors targeting cell cycle regulators identified AURKA inhibitors, which inhibit the G2/M transition during the cell cycle, as top candidates that synergistically enhanced the antitumor effects of chidamide in CREBBP-proficient DLBCL cells. Our study demonstrates that CREBBP inactivation can serve as a potential biomarker to predict chidamide sensitivity, while combination of an AURKA inhibitor and chidamide is a novel therapeutic strategy for the treatment of relapsed/refractory DLBCL.

Clinicopathological Characteristics and Mutational Profiling of Adult T-Cell Lymphoblastic Lymphoma in a Chinese Population.

PURPOSE: The purpose of this study is to perform a retrospective analysis of disease outcomes and mutational profiles in patients with adult T-cell lymphoblastic lymphoma (T-LBL). PATIENTS AND METHODS: A total of 43 patients were treated over a 9-year period at a single institution. The study examined treatment outcomes, clinical characteristics, and the use of circulating tumor DNA (ctDNA) and mutational profiling for patient diagnosis. RESULTS: The estimated overall survival (OS) and progression-free survival (PFS) time for all patients was 37.0 (95% CI: 17.7-56.2) and 28.1 (95% CI: 0.9-55.4) months, respectively. Chidamide maintenance was used in five patients exhibiting unfavorable genetic alterations, with no evidence of relapse. Next-generation sequencing of pretreatment tumor tissue was undertaken for 15 patients. NOTCH1 mutations were the most frequent genetic alterations, followed by mutations in PHF6, TP53, JAK1, JAK3, PTEN, and DNM2. The genetic profile of the blood was similar to that of the tumor. Kappa coefficient analysis (14 patients, 56 time points, kappa = 1.0, p = 0.00) indicated a 92.6% agreement between ctDNA response and tumor volume measurements at post treatment when compared with baseline. Detection of ctDNA predicted disease relapse in two patients. CONCLUSION: The prognosis of patients with adult T-LBL remains very poor. Detection of tumor-associated sequences in ctDNA may be an effective method for diagnosing T-LBL and measuring treatment efficacy. Incorporation of new drugs such as histone deacetylase inhibitors (HDACi)has the potential to improve outcomes in these patients.

Clinical outcomes of newly diagnosed primary CNS lymphoma treated with ibrutinib-based combination therapy: A real-world experience of off-label ibrutinib use.

Ibrutinib-based combination therapy with high-dose methotrexate (HD-MTX) has recently shown clinical activity against relapse/refractory (R/R) primary central nervous system lymphoma (PCNSL). Herein, we report our real-world experience of treating 11 newly diagnosed PCNSL patients with the ibrutinib/MTX combination. HD-MTX was given at 3.5 g/m2 every 2-week for eight doses. Ibrutinib was held upon HD-MTX infusion until clearance and was administered daily post-induction until disease progression, intolerable toxicity, or death. Nine out of 11 patients completed the induction phase and received ibrutinib as maintenance therapy. An objective response rate (ORR) of 82% (9/11) was observed including complete response (64%) and partial response (18%). The median progression-free survival (PFS) was 7.4 months while the median overall survival (OS) was not reached. The ibrutinib/MTX combination was well tolerated in these treatment-naïve PCNSL patients with an acceptable safety profile. Moreover, the longitudinal analysis of cerebrospinal fluid (CSF) circulating tumor DNA (ctDNA) revealed that CSF ctDNA detection was closely associated with tumor response, and sustained tumor responses correlated with the clearance of ctDNA from the CSF. In sum, our data not only demonstrated the clinical benefit of the ibrutinib and HD-MTX combination regimen in treating newly diagnosed PCNSL patients in a real-world setting, but also highlighted the significance of liquid biopsy including CSF ctDNA in tracing tumor burden and assessing treatment response.

Angiopep-2 conjugated nanoparticles loaded with doxorubicin for the treatment of primary central nervous system lymphoma.

Primary central nervous system lymphoma (PCNSL) is a rare brain tumor. Its therapeutic efficacy is much lower than that of traditional lymphoma, largely due to the presence of the blood-brain barrier (BBB), which hinders the effective drug delivery and deposition on the disease site. Angiopep-2 (ANG) can target low-density lipoprotein receptor-related protein (LRP) on the surface of brain capillary endothelial cells (BCECs) and exhibits high BBB transport capability. In this study, we designed an ANG conjugated poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) (APP) nanoparticle to deliver doxorubicin (DOX) for the treatment of PCNSL. Our data indicated that the targeted APP nanoparticles showed significantly increased cellular uptake by BCECs compared with the control nanoparticles. In the intracranial SU-DHL-2-LUC lymphoma xenograft mice model, APP enhanced drug deposition in tumor tissues, and DOX-loaded APP (APP@DOX) exhibited a better therapeutic effect than free DOX and nontargeted PP@DOX, which significantly prolonged the survival time of mice.