Safety, tolerability, pharmacokinetics and preliminary antitumour activity of an antisense oligonucleotide targeting STAT3 (danvatirsen) as monotherapy and in combination with durvalumab in Japanese patients with advanced solid malignancies: a phase 1 study.

OBJECTIVES: We assessed the safety, tolerability, pharmacokinetics, preliminary antitumour activity and pharmacodynamics of danvatirsen, an antisense oligonucleotide targeting signal transducer and activator of transcription 3 (STAT3), monotherapy and danvatirsen plus durvalumab, an antiprogrammed cell death ligand 1 monoclonal antibody, in patients with advanced solid malignancies. DESIGN: Phase 1, open-label study with two cohorts. SETTING: Two centres in Japan. PARTICIPANTS: Japanese individuals aged ≥20 years, with histologically confirmed solid malignancies, except for hepatocellular carcinoma, refractory to standard therapy. INTERVENTIONS: In cohort 1, patients received danvatirsen monotherapy; in cohort 2, patients received danvatirsen plus durvalumab combination therapy. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary endpoint was safety and tolerability based on adverse events (AEs). Secondary endpoints were pharmacokinetics, immunogenicity, antitumour activity and pharmacodynamics. RESULTS: Eleven patients were assigned to treatment and included in the analysis. Danvatirsen dose reductions were only required in cohort 2 for hepatic function abnormal (alanine aminotransferase (ALT)/ aspartate aminotransferase (AST)/gamma-glutamyl transferase (γGT) increased), neutrophil count decreased and platelet count decreased. One patient experienced grade 3 ALT/AST increased and new appearance of eosinophilia as a dose-limiting toxicity. AEs were reported in 90.9% (10/11) patients. Commonly reported AEs causally related to the danvatirsen were platelet count decreased (60% (3/5)) and ALT/AST/γGT increased (50% (3/6)) in cohorts 1 and 2, respectively; none was causally related to durvalumab. One serious AE occurred in cohort 1 (pancreatitis; unrelated to study treatment). One case of ALT/AST/γGT increased occurred in cohort 2, leading to discontinuation. No AEs led to death. Danvatirsen did not accumulate in plasma after multiple dosing. In cohort 2, three patients had disease control at 12 weeks and one had unconfirmed partial response. STAT3 expression tended to decrease regardless of monotherapy or combination therapy. CONCLUSIONS: Danvatirsen was well tolerated by Japanese patients with advanced solid tumours as monotherapy and combined with durvalumab. No new safety signals arose. TRIAL REGISTRATION NUMBER: NCT03394144; ClinicalTrials.gov.

Safety and Pharmacokinetics of Second-line Ramucirumab plus FOLFIRI in Japanese Patients with Metastatic Colorectal Carcinoma.

BACKGROUND: This phase Ib study evaluated the pharmacokinetic profile and safety of ramucirumab, a recombinant human IgG1 neutralizing monoclonal antibody specific for vascular endothelial growth factor receptor 2, in combination with irinotecan, levofolinate and 5-fluorouracil (FOLFIRI) in Japanese patients with metastatic colorectal carcinoma (mCRC). PATIENTS AND METHODS: Eligible patients had Eastern Cooperative Oncology Group performance status 0-1, and disease progression during or within 6 months following first-line therapy with bevacizumab, oxaliplatin and a fluoropyrimidine. Six enrolled patients received 8 mg/kg ramucirumab plus FOLFIRI every 2 weeks. RESULTS: One out of six patients experienced a dose-limiting toxicity (grade 2 proteinuria and grade 4 neutropenia, resulting in a dose delay >2 weeks). All patients experienced at least one grade 3 or higher adverse event: neutropenia (five patients, 83%), proteinuria (two patients; 33%) and anemia, thrombocytopenia and hypertension (one patient each, 17%). There were no serious adverse events or deaths. CONCLUSION: Ramucirumab plus FOLFIRI was well-tolerated in Japanese patients with mCRC, warranting further investigation of this combination therapy.

Pemetrexed and carboplatin followed by pemetrexed maintenance therapy in chemo-naïve patients with advanced nonsquamous non-small-cell lung cancer.

INTRODUCTION: This study prospectively evaluated the efficacy and safety of pemetrexed and carboplatin followed by maintenance pemetrexed in chemo-naïve patients with advanced nonsquamous non-small cell lung cancer (NSCLC). METHODS: A total of 109 patients received pemetrexed (500 mg/m(2)) and carboplatin (area under the curve = 6 mg/mL·min) every 21 days. For patients without disease progression after 4 cycles, pemetrexed was continued until disease progression or unacceptable toxicity. Pre-planned subgroup analysis results based on the presence of epidermal growth factor receptor (EGFR) mutations are also presented. RESULTS: The median number of treatment cycles was 5 (range: 1-30) in the entire study period. Most of the grade ≥ 3 toxicities observed were hematologic in nature, with no increase in the relative incidence associated with continuation maintenance therapy with pemetrexed. Among the 106 total patients assessable for efficacy, the objective response rate was 35.8 %, median progression free survival (PFS) 5.7 months, and median overall survival (OS) 20.2 months. Sixty patients received maintenance pemetrexed (median: 4 cycles, range: 1-26 cycles); median PFS from the beginning of induction treatment was 7.5 months. From the subgroup analysis for EGFR mutation status, the median OS of EGFR wild-type patients (n=61) was 20.2 months. CONCLUSIONS: Pemetrexed/carboplatin followed by pemetrexed was well tolerated and active for front-line treatment of advanced nonsquamous NSCLC. Encouraging survival outcomes were observed even in EGFR-wild type patients.

PRAK suppresses oncogenic ras-induced hematopoietic cancer development by antagonizing the JNK pathway.

The p38 mitogen-activated protein kinase (MAPK) pathway regulates multiple physiologic and pathologic processes, including cancer development. PRAK, a p38 substrate protein kinase, has previously been implicated in the suppression of skin carcinogenesis. In the current study, we show that PRAK deletion accelerates hematopoietic cancer development in a mouse model harboring an oncogenic ras allele, Eµ-N-Ras(G12D), specifically expressed in hematopoietic cells. Further investigation reveals that enhanced hematopoietic tumorigenesis by PRAK deficiency is associated with hyperactivation of the c-jun-NH(2)-kinase (JNK) pathway both in vivo and in primary hematopoietic cells isolated from spleens. In primary splenocytes, PRAK deficiency further enhanced oncogenic ras-induced cell proliferation and promoted ras-mediated colony formation on semisolid medium in a JNK-dependent manner. In addition, deletion of PRAK leads to abrogation of ras-induced accumulation of senescence markers. These findings indicate that PRAK suppresses hematopoietic cancer formation in this mouse model by antagonizing oncogenic ras-induced activation of the JNK pathway. Our results suggest that PRAK may function as a tumor suppressor in multiple types of cancers.

A novel function of p38-regulated/activated kinase in endothelial cell migration and tumor angiogenesis.

The p38 mitogen-activated protein kinase (MAPK) pathway has been implicated in both suppression and promotion of tumorigenesis. It remains unclear how these 2 opposite functions of p38 operate in vivo to impact cancer development. We previously reported that a p38 downstream kinase, p38-regulated/activated kinase (PRAK), suppresses tumor initiation and promotion by mediating oncogene-induced senescence in a murine skin carcinogenesis model. Here, using the same model, we show that once the tumors are formed, PRAK promotes the growth and progression of skin tumors. Further studies identify PRAK as a novel host factor essential for tumor angiogenesis. In response to tumor-secreted proangiogenic factors, PRAK is activated by p38 via a vascular endothelial growth factor receptor 2 (VEGFR2)-dependent mechanism in host endothelial cells, where it mediates cell migration toward tumors and incorporation of these cells into tumor vasculature, at least partly by regulating the phosphorylation and activation of focal adhesion kinase (FAK) and cytoskeletal reorganization. These findings have uncovered a novel signaling circuit essential for endothelial cell motility and tumor angiogenesis. Moreover, we demonstrate that the tumor-suppressing and tumor-promoting functions of the p38-PRAK pathway are temporally and spatially separated during cancer development in vivo, relying on the stimulus, and the tissue type and the stage of cancer development in which it is activated.

PRAK is essential for ras-induced senescence and tumor suppression.

Like apoptosis, oncogene-induced senescence is a barrier to tumor development. However, relatively little is known about the signaling pathways mediating the senescence response. p38-regulated/activated protein kinase (PRAK) is a p38 MAPK substrate whose physiological functions are poorly understood. Here we describe a role for PRAK in tumor suppression by demonstrating that PRAK mediates senescence upon activation by p38 in response to oncogenic ras. PRAK deficiency in mice enhances DMBA-induced skin carcinogenesis, coinciding with compromised senescence induction. In primary cells, inactivation of PRAK prevents senescence and promotes oncogenic transformation. Furthermore, we show that PRAK activates p53 by direct phosphorylation. We propose that phosphorylation of p53 by PRAK following activation of p38 MAPK by ras plays an important role in ras-induced senescence and tumor suppression.

Human immunodeficiency virus type 1 Vpr-dependent cell cycle arrest through a mitogen-activated protein kinase signal transduction pathway.

The human immunodeficiency virus type 1 (HIV-1) Vpr protein has important functions in advancing HIV pathogenesis via several effects on the host cell. Vpr mediates nuclear import of the preintegration complex, induces host cell apoptosis, and inhibits cell cycle progression at G(2), which increases HIV gene expression. Some of Vpr's activities have been well described, but some functions, such as cell cycle arrest, are not yet completely characterized, although components of the ATR DNA damage repair pathway and the Cdc25C and Cdc2 cell cycle control mechanisms clearly play important roles. We investigated the mechanisms underlying Vpr-mediated cell cycle arrest by examining global cellular gene expression profiles in cell lines that inducibly express wild-type and mutant Vpr proteins. We found that Vpr expression is associated with the down-regulation of genes in the MEK2-ERK pathway and with decreased phosphorylation of the MEK2 effector protein ERK. Exogenous provision of excess MEK2 reverses the cell cycle arrest associated with Vpr, confirming the involvement of the MEK2-ERK pathway in Vpr-mediated cell cycle arrest. Vpr therefore appears to arrest the cell cycle at G(2)/M through two different mechanisms, the ATR mechanism and a newly described MEK2 mechanism. This redundancy suggests that Vpr-mediated cell cycle arrest is important for HIV replication and pathogenesis. Our findings additionally reinforce the idea that HIV can optimize the host cell environment for viral replication.

An alternative transcript derived from the trio locus encodes a guanosine nucleotide exchange factor with mouse cell-transforming potential.

By screening cDNA expression libraries derived from fresh leukemic cells of adult T-cell leukemia for the potential to transform murine fibroblasts, NIH3T3, we have identified a novel transforming gene, designated Tgat. Expression of Tgat in NIH3T3 resulted in the loss of contact inhibition, increase of saturation density, anchorage-independent growth in a semisolid medium, tumorigenicity in nude mice, and increased invasiveness. Sequence comparison revealed that an alternative RNA splicing of the Trio gene was involved in the generation of Tgat. The Tgat cDNA encoded a protein product consisting of the Rho-guanosine nucleotide exchange factor (GEF) domain of a multifunctional protein, TRIO, and a unique C-terminal 15-amino acid sequence, which were derived from the exons 38-46 of the Trio gene and a novel exon located downstream of its last exon (exon 58), respectively. A Tgat mutant cDNA lacking the C-terminal coding region preserved Rho-GEF activity but lost the transforming potential, indicating an indispensable role of the unique sequence. On the other hand, treatment of Tgat-transformed NIH3T3 cells with Y-27632, a pharmacological inhibitor of Rho-associated kinase, abrogated their transforming phenotypes, suggesting the coinvolvement of Rho-GEF activity. Thus, alternative RNA splicing, resulting in the fusion protein with the Rho-GEF domain and the unique 15 amino acids, is the mechanism generating the novel oncogene, Tgat.