Abstract
Background
The safety, tolerability, efficacy, and pharmacokinetics of tirabrutinib, a second-generation, highly selective oral Bruton’s tyrosine kinase inhibitor, were evaluated for ...relapsed/refractory primary central nervous system lymphoma (PCNSL).
Methods
Patients with relapsed/refractory PCNSL, Karnofsky performance status ≥70, and normal end-organ function received tirabrutinib 320 and 480 mg once daily (q.d.) in phase I to evaluate dose-limiting toxicity (DLT) within 28 days using a 3 + 3 dose escalation design and with 480 mg q.d. under fasted conditions in phase II.
Results
Forty-four patients were enrolled; 20, 7, and 17 received tirabrutinib at 320, 480, and 480 mg under fasted conditions, respectively. No DLTs were observed, and the maximum tolerated dose was not reached at 480 mg. Common grade ≥3 adverse events (AEs) were neutropenia (9.1%), lymphopenia, leukopenia, and erythema multiforme (6.8% each). One patient with 480 mg q.d. had grade 5 AEs (pneumocystis jirovecii pneumonia and interstitial lung disease). Independent review committee assessed overall response rate (ORR) at 64%: 60% with 5 complete responses (CR)/unconfirmed complete responses (CRu) at 320 mg, 100% with 4 CR/CRu at 480 mg, and 53% with 6 CR/CRu at 480 mg under fasted conditions. Median progression-free survival was 2.9 months: 2.1, 11.1, and 5.8 months at 320, 480, and 480 mg under fasted conditions, respectively. Median overall survival was not reached. ORR was similar among patients harboring CARD11, MYD88, and CD79B mutations, and corresponding wild types.
Conclusion
These data indicate favorable efficacy of tirabrutinib in patients with relapsed/refractory PCNSL.
Trial registration
JapicCTI-173646.
Primary central nervous system lymphoma (PCNSL) is a rare malignancy confined to the central nervous system (CNS), and majority of PCNSL is pathologically classified as diffuse large B-cell lymphoma ...(DLBCL). We have now performed whole-exome sequencing for 41 tumor tissues of DLBCL-type PCNSL and paired normal specimens and also RNA-sequencing for 30 tumors, revealing a very high frequency of nonsynonymous somatic mutations in
PIM1
(100 %),
BTG2
(92.7 %), and
MYD88
(85.4 %). Many genes in the NF-κB pathway are concurrently mutated within the same tumors. Further, focal deletion or somatic mutations in the
HLA
genes are associated with poor prognosis. Copy number amplification and overexpression of genes at chromosome 7q35 were both found to predict short progression-free survival as well. Oncogenic mutations in
GRB2
were also detected, the effects of which in cultured cells were attenuated by inhibitors of the downstream kinases MAP2K1 and MAP2K2. Individuals with tumors positive for
MYD88
mutations also harbored the same mutations at a low frequency in peripheral blood mononuclear cells, suggesting that
MYD88
mutation-positive precancerous cells originate outside of the CNS and develop into lymphoma after additional genetic hits that confer adaptation to the CNS environment.
Purpose
Measuring serum and cerebrospinal fluid human chorionic gonadotropin (hCG) is essential for the diagnosis of intracranial germ cell tumors. There are three types of hCG-related markers in ...clinical use: hCGβ, intact hCG, and total hCG. The best marker for the diagnosis of intracranial germ cell tumors, especially germinoma, is currently unknown. This study aimed to evaluate the usefulness of these hCG-related markers.
Methods
We investigated 19 serum samples obtained from 6 patients with histologically diagnosed germinoma treated in our institute. Serum hCGβ, intact hCG, and total hCG values were measured before, during, and after treatment. Samples with hCG values above the lower limits were considered positive.
Results
The positivity rates of serum hCGβ, intact hCG, and total hCG were 6% (1/17), 47% (7/15), and 42% (8/19), respectively, with the latter two having significantly higher positivity rates than hCGβ (
p
= 0.041). Both intact and total hCGs showed similar values. The median values of hCGβ, intact hCG, and total hCG before treatment were 0.1 ng/mL, 4.6 mIU/mL, and 4.5 mIU/mL, respectively.
Conclusion
Serum intact and total hCGs have higher detection rates than hCGβ in patients with germinoma using available commercial measurement tools.
Podoplanin (aggrus), a transmembrane sialoglycoprotein, is involved in tumor cell-induced platelet aggregation, tumor metastasis, and lymphatic vessel formation. However, the mechanism by which ...podoplanin induces these cellular processes including its receptor has not been elucidated to date. Podoplanin induced platelet aggregation with a long lag phase, which is dependent upon Src and phospholipase Cγ2 activation. However, it does not bind to glycoprotein VI. This mode of platelet activation was reminiscent of the snake toxin rhodocytin, the receptor of which has been identified by us as a novel platelet activation receptor, C-type lectin-like receptor 2 (CLEC-2) (Suzuki-Inoue, K., Fuller, G. L., Garcia, A., Eble, J. A., Pohlmann, S., Inoue, O., Gartner, T. K., Hughan, S. C., Pearce, A. C., Laing, G. D., Theakston, R. D., Schweighoffer, E., Zitzmann, N., Morita, T., Tybulewicz, V. L., Ozaki, Y., and Watson, S. P. (2006) Blood 107, 542–549). Therefore, we sought to evaluate whether CLEC-2 serves as a physiological counterpart for podoplanin. Association between CLEC-2 and podoplanin was confirmed by flow cytometry. Furthermore, their association was dependent on sialic acid on O-glycans of podoplanin. Recombinant CLEC-2 inhibited platelet aggregation induced by podoplanin-expressing tumor cells or lymphatic endothelial cells, suggesting that CLEC-2 is responsible for platelet aggregation induced by endogenously expressed podoplanin on the cell surfaces. These findings suggest that CLEC-2 is a physiological target protein of podoplanin and imply that it is involved in podoplanin-induced platelet aggregation, tumor metastasis, and other cellular responses related to podoplanin.
Palliative care and advance care planning (ACP) from the first diagnosis of glioblastoma are important. This questionnaire survey was conducted to understand the current status of palliative care for ...brain tumors in Japan. Representative characteristics of Japan in comparison with Western countries (P <0.01) are described below: (1) Gender ratio of male in physicians who treat brain tumors in Europe and the United States/Canada are about 70%, but 94% in Japan. (2) The specialty is predominantly neurosurgeon (93%) in Japan. The ratio of neurologists is predominantly 40% in Europe. In the United States/Canada, neurologist (27%) and neurosurgeon (29%) are main parts. (3) Years of medical experience over 15 in physicians is 73% in Japan. Proportions of those with over 15 years are 45% in Europe and 30% in the United States/Canada. (4) In practicing setting, the rate of academic medical centers is about 80% in Europe and the United States/Canada, and ~60% in Japan. Representative differences compared with past domestic data (2007) (p<0.01): (1) In glioblastoma, the rate of explaining about median survival time increases from 39% (2007) to 80% (2018). Explanation about medical conditions to the patient himself with his family increases from 20% (2007) to 39% (2018). (2) Place of death: The rate at hospital is decreasing from 96% (2007) to 79% (2018) and at home is increasing from 3% (2007) to 10% (2018) (3) The rate of ventilator in adult has decreased from 74% (2007) to 54% (2018), but nasal tube feeding has remained unchanged from 62% (2007) to 60% (2018). These results will be shared with physicians to make better care systems for patients with brain tumors.
Intracranial germ cell tumors (iGCTs) are the second most common brain tumors among children under 14 in Japan. The World Health Organization classification recognizes several subtypes of iGCTs, ...which are conventionally subclassified into pure germinoma or non-germinomatous GCTs. Recent exhaustive genomic studies showed that mutations of the genes involved in the MAPK and/or PI3K pathways are common in iGCTs; however, the mechanisms of how different subtypes develop, often as a mixed-GCT, are unknown. To elucidate the pathogenesis of iGCTs, we investigated 61 GCTs of various subtypes by genome-wide DNA methylation profiling. We showed that pure germinomas are characterized by global low DNA methylation, a unique epigenetic feature making them distinct from all other iGCTs subtypes. The patterns of methylation strongly resemble that of primordial germ cells (PGC) at the migration phase, possibly indicating the cell of origin for these tumors. Unlike PGC, however, hypomethylation extends to long interspersed nuclear element retrotransposons. Histologically and epigenetically distinct microdissected components of mixed-GCTs shared identical somatic mutations in the MAPK or PI3K pathways, indicating that they developed from a common ancestral cell.
Pineal parenchymal tumors (PPTs) are clinically rare and a biopsy is often required for a definitive diagnosis. To improve the accuracy of histological assessment of PPTs, we examined the ...proliferative capacity of PPT cells and investigated DICER1 expression and
KBTBD4
mutations. This study included 19 cases of PPTs 3 pineocytomas (PCs), 10 PPTs of intermediate differentiation (PPTID), and 6 pineoblastomas (PBs). Immunohistochemistry for Ki-67, PHH3, and DICER1, as well as Sanger sequencing analysis for
KBTBD4
mutations, was performed using formalin-fixed paraffin-embedded tissue specimens that were resected during surgery. Tumor cell proliferation was quantified using an image analysis software. For the PHH3 and MIB-1 indices, a significant difference was observed between the PPTIDs and PBs (
P
< 0.05). Loss of DICER1 was not specific for PB; 0/3 PCs (0.0%), 2/9 PPTIDs (22.2%), and 2/4 PBs (50.0%).
KBTBD4
mutations were detected in 1/3 PCs (33.3%), 6/9 PPTIDs (66.7%), and 0/4 PBs (0.0%). Thus, combined application of the proliferative marker index and
KBTBD4
mutation analysis may be useful for the differential diagnosis of PPTs. Furthermore, detection of
KBTBD4
mutations using Sanger sequencing analysis may support the diagnosis of PPTID.
Podoplanin (aggrus) is a mucin-like transmembrane sialoglycoprotein that is expressed on lymphatic endothelial cells. Podoplanin is putatively involved in cancer cell migration, invasion, metastasis, ...and malignant progression and may be involved in platelet aggregation. Previously, we showed upregulated expression of podoplanin in central nervous system (CNS) germinomas, but not in non-germinomatous germ cell tumors, except for parts of immature teratomas in limited numbers. However, little information exists about its role in CNS astrocytic tumors. In this study, 188 astrocytic tumors (30 diffuse astrocytomas, 43 anaplastic astrocytomas, and 115 glioblastomas) were investigated using immunohistochemistry with an anti-podoplanin antibody, YM-1. In 11 of 43 anaplastic astrocytomas (25.6%) and in 54 of 115 glioblastomas (47.0%), podoplanin was expressed on the surface of anaplastic astrocytoma cells and glioblastoma cells, especially around necrotic areas and proliferating endothelial cells. However, the surrounding brain parenchyma was not stained by YM-1. On the other hand, podoplanin expression was not observed in diffuse astrocytoma (0/30: 0%). Furthermore, we investigated the expression of podoplanin using quantitative real-time PCR and Western blot analysis in 54 frozen astrocytic tumors (6 diffuse astrocytomas, 14 anaplastic astrocytomas, and 34 glioblastomas). Podoplanin mRNA and protein expression were markedly higher in glioblastomas than in anaplastic astrocytomas. These data suggest that podoplanin expression might be associated with malignancy of astrocytic tumors.
Two hot spot mutations (C228T, C250T) in the telomerase reverse transcriptase (
TERT
) gene are frequently identified in glioblastoma and oligodendroglioma.
TERT
mutations predicts an aggressive ...clinical course in isocitrate dehydrogenase (
IDH
) wild-type astrocytic tumors. Therefore, it is important to accurately detect
TERT
promoter mutations in glioma. Sanger DNA sequencing is the currently standard method for analyzing
TERT
mutations. However, PCR amplification in the first step of the sequencing has proven technically difficult because of the high GC content around the
TERT
mutation. In this report, we described a novel droplet digital PCR (ddPCR) assay to evaluate
TERT
hot spot mutations in fresh frozen and formalin-fixed paraffin-embedded (FFPE) specimens of glioma and verified the difference in results from the Sanger DNA sequencing results. We obtained the mutant allele fraction for
TERT
mutations of in a single ddPCR run in all cases, including the micro-dissected FFPE sections. On the contrary, up to twice the DNA sequences were required from fresh frozen tissue to obtain the results, consistent with ddPCR assay. When FFPE specimens were used, more time was required to evaluate
TERT
mutations through DNA sequencing. DdPCR is an effective and sensitive assay compared to the conventional standard Sanger DNA sequencing.
Glioblastoma (GBM) inevitably recurs due to a resistance to current standard therapy. We showed that the antidiabetic drug metformin (MF) can induce the differentiation of stem-like glioma-initiating ...cells and suppress tumor formation through AMPK-FOXO3 activation. In this study, we design a phase I/II study to examine the clinical effect of MF. We aim to determine a recommended phase II MF dose with maintenance temozolomide (TMZ) in patients with newly diagnosed GBM who completed standard concomitant radiotherapy and TMZ. MF dose-escalation was planned using a 3 + 3 design. Dose-limiting toxicities (DLTs) were assessed during the first six weeks after MF initiation. Three patients were treated with 1500 mg/day MF and four patients were treated with 2250 mg/day MF between February 2021 and January 2022. No DLTs were observed. The most common adverse effects were appetite loss, nausea, and diarrhea, all of which were manageable. Two patients experienced tumor progression at 6.0 and 6.1 months, and one died 12.2 months after initial surgery. The other five patients remained stable at the last follow-up session. The MF dose of up to 2250 mg/day combined with maintenance TMZ appeared to be well tolerated, and we proceeded to a phase II study with 2250 mg/day MF.
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