Current opinion in investigational drugs最新文献

STA-9090 is a second-generation Hsp90 inhibitor in clinical development by Synta Pharmaceuticals for the intravenous treatment of hematological and solid malignancies. It is a resorcinol-containing triazole compound, with a novel chemical structure that is unrelated to the geldanamycin class of Hsp90 inhibitors. STA-9090 binds to the ATP-binding domain at the N-terminus of Hsp90 and acts as a potent Hsp90 inhibitor by inducing degradation of multiple oncogenic Hsp90 client proteins including HER2/neu, mutated EGFR, Akt, c-Kit, IGF-1R, PDGFRα, Jak1, Jak2, STAT3, STAT5, HIF-1α, CDC2, c-Met, and Wilms' tumor 1. STA-9090, at low nanomolar concentrations, potently arrested cell proliferation and induced apoptosis in a wide variety of human cancer cell lines, including many receptor tyrosine kinase inhibitor- and tanespimycin-resistant cell lines. Moreover, administration of STA-9090 led to significant tumor shrinkage in several tumor xenograft models in mice and appeared to be less toxic. Furthermore STA-9090 demonstrated better tumor penetration compared with tanespimycin. In initial phase I clinical trials, STA-9090 was well tolerated and has demonstrated activity. The further development of this agent, and the other Hsp90 inhibitors, may be dependent on the tumor type and the primary oncogenic driving forces.

Bafetinib (NS-187, INNO-406) is a second-generation tyrosine kinase inhibitor in development by CytRx under license from Nippon Shinyaku for treating Bcr-Abl+ leukemia's, including chronic myelogenous leukemia (CML) and Philadelphia+ acute lymphoblastic leukemia. It is a rationally developed tyrosine kinase inhibitor based on the chemical structure of imatinib, with modifications added to improve binding and potency against Bcr-Abl kinase. Besides Abl, bafetinib targets the Src family kinase Lyn, which has been associated with resistance to imatinib in CML. In preclinical studies, bafetinib was 25- to 55-fold more potent than imatinib in vitro and ≥ 10-fold more potent in vivo. Bafetinib inhibits 12 of the 13 most frequent imatinib-resistant Bcr-Abl point mutations, but not a Thr315Ile mutation. A small fraction of bafetinib crosses the blood-brain barrier, reaching brain concentrations adequate for suppression of Bcr-Abl+ cells. Data from a phase I clinical trial conducted in patients with imatinib-resistant or -intolerant CML have confirmed that bafetinib has clinical activity in this setting, inducing a major cytogenetic response in 19% of those patients in chronic phase. Currently, bafetinib is being developed in two phase II clinical trials for patients with B-cell chronic lymphocytic leukemia and prostate cancer, and a trial is in progress for patients with brain tumors.

EC-145, under development by Endocyte, is a conjugate composed of desacetylvinblastine monohydrazide linked through a peptide spacer to the targeting moiety folic acid, for the potential intravenous treatment of folate receptor-overexpressing tumors, in particular ovarian and lung cancers. In vitro studies demonstrated that EC-145 selectively binds to cells that overexpress the folate receptor, causing dose-dependent cytotoxicity. Furthermore, coincubation of the KB human nasopharyngeal carcinoma cell line with EC-145 and doxorubicin resulted in synergistic antitumor activity. Experiments in mouse tumor xenograft models have confirmed the potency of EC-145 and the curative effects of the drug conjugate were demonstrated in an aggressive lymphoma xenograft model. In a phase I clinical trial in patients with advanced or metastatic solid tumors, adverse events were generally of moderate severity with the most frequent being fatigue, constipation and peripheral sensory neuropathy. Preliminary data from a phase II clinical trial in patients with advanced ovarian cancer demonstrated that third- or fourth-line treatment with EC-145 yielded better disease control than second- or third-line liposomal doxorubicin. Coadministration of EC-145 and liposomal doxorubicin produced a statistically significant increase in progression-free survival over standard therapy in patients with platinum-resistant ovarian cancer. Phase III clinical trials are expected to confirm these promising results.

AT-9283 has been identified and developed by Astex Therapeutics via structure-based optimization of a ligand-efficient pyrazole-benzimidazole fragment. AT-9283 inhibits several important kinases, including the Aurora kinase A, Aurora kinase B, Janus kinase (Jak)2, Jak3 and Abl kinase. Studies using multiple solid tumor and leukemia cell lines have demonstrated the ability of AT-9283 to inhibit growth and survival of tumor cells, and the direct inhibition of these kinases has been demonstrated in cell-based systems. The in vivo antitumor activity of AT-9283 has also been demonstrated in human tumor xenograft models. Based on these preclinical studies, several clinical trials have been conducted in patients with hematological malignancies, such as leukemias, myelodysplastic syndrome, myeloproliferative disease, chronic myeloid leukemia, lymphomas and multiple myeloma, and also in patients with solid tumors. Although phase II clinical trials have not been completed, AT-9283 demonstrated good safety and efficacy in phase I clinical trials. Thus, AT-9283 has potential as a therapeutic agent in several patient populations through its different inhibitory activities.

Disease Control Rate (DCR) and Clinical Benefit Rate (CBR) are defined as the percentage of patients with advanced or metastatic cancer who have achieved complete response, partial response and stable disease to a therapeutic intervention in clinical trials of anticancer agents. DCR and CBR are commonly reported in many clinical trials in abstracts, papers, meeting presentations and media releases. The frequent use of these measures of drug activity presents the question of whether DCR and CBR are useful additional endpoints in early clinical trials, and if they can reasonably predict the success of an agent in subsequent, adequately powered, randomized trials. There are no comprehensive analyses to demonstrate that CBR and DCR add to the value of traditional response/activity endpoints in early clinical trials. Data from phase II clinical trials in which the DCR or CBR are reported suggest that DCR or CBR provides ambiguous information that likely exaggerates the anticancer activity of the therapy. The terms 'disease control' and 'clinical benefit' in the context of non-randomized trials are themselves disingenuous because neither tumor regression nor stable disease, defined without any consideration of duration of effect or reduction of symptoms appropriate for the specific patient population, are evidence of these endpoints in an individual patient.

Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) are cytosolic pattern-recognition receptors that sense microbial invasion, cell stress and physiological perturbations, and elicit an inflammatory response to alert the system to the presence of danger. Most NLRs exert their functions by assembling inflammasomes that recruit and activate caspase-1, whereas a few engage the NFκB and MAPK pathways. In the past few years, significant insights have been gained into the regulatory mechanisms of these innate immunity effectors and their role in health and disease that, notably, have led to direct therapeutic applications in the clinic. This review discusses the biology of NLRs, focusing on recent advances in the field that indicate a broader role for these proteins than had been previously anticipated, such as in priming systemic innate immunity, driving adaptive immunity, maintaining tissue homeostasis and inducing tissue repair following injury.

Systemic lupus erythematosus (SLE) is an autoimmune disease that is associated with the production of autoantibodies, and with considerable morbidity and mortality. There has been much interest in developing more specific therapies for this disease, which is currently managed with immunosuppressive drugs, predominantly corticosteroids, azathioprine, methotrexate and cyclophosphamide, in combination with hydroxychloroquine. Mycophenolate mofetil has been demonstrated to be as efficacious as cyclophosphamide in patients with lupus nephritis, and is being used increasingly in the clinic despite not being licensed for this indication. Novel methods of reducing autoantibody formation in SLE include the use of mAbs that modulate and/or deplete B-cells (anti-CD22 and anti-CD20 antibodies, respectively), or that interfere with the stimulatory effects of the soluble factor B-lymphocyte stimulator (anti-BLys antibodies). Alternative approaches include the use of atacicept (Merck Serono), a transmembrane activator and calcium modulator ligand interactor (TACI)-Ig fusion protein, which inhibits B-cell stimulation by binding to BLys and a profileration-inducing ligand (APRIL), or toleragens such as abetimus. Blocking costimulatory molecule interactions, such as the CD40-CD40 ligand interaction with mAbs and the CD28-B7 interaction with a soluble cytotoxic T-lymphocyte antigen 4 (CTLA-4)-IgG1 construct (abatacept), has also been attempted as a therapeutic strategy for SLE. The most promising strategy for a new drug for SLE is belimumab (Human Genome Sciences/GlaxoSmithKline), an anti-BLys antibody, as two phase III clinical trials with this drug recently met their primary endpoints. In this review, these novel approaches to the treatment of SLE, including the potential of targeting cytokine pathways involved in autoimmunity, are discussed.

According to current concepts for multiple sclerosis (MS), a fundamental pathogenic role is played by T- and B-cells that inappropriately recognize self antigens and initiate a cell-mediated or humoral inflammatory reaction that injures myelin and axons, and results in neural dysfunction and loss. Transplantation of bone marrow-derived hematopoietic stem cells following high-dose immunosuppression is being evaluated as an experimental treatment for severe forms of immune-mediated disorders, including MS. The primary goal of this therapeutic approach is to induce medication-free remission from new disease activity by correcting the immune aberrations that promote the attack against self tissue; this approach is termed 'immune repair'. In this review, the clinical experience gained from the use of autologous hematopoietic stem cell transplantation in treating severe forms of MS are presented, and the current understanding of the mechanisms underlying the mode of action of this treatment, including depletion of disease-mediating immune cells, rejuvenation of the immune repertoire and improvement of regulatory cell function, is discussed.

Advances in immunology and genetics have identified new therapeutic targets to control inflammation and symptoms in patients with inflammatory bowel diseases (IBD). Despite the success of anti-TNF therapies in the treatment of IBD, a considerable proportion of patients are refractory to treatment, highlighting an unmet medical need for new therapies. Molecules that direct the trafficking of inflammatory cells, such as the α4β7 integrin, are attractive targets for new drug candidates. The α4β7 integrin is involved in lymphocyte recruitment to the normal and inflamed gut mucosa, and the lymphoid tissue. The pan-α4 integrin neutralizing mAb, natalizumab, is not gut-selective but has demonstrated efficacy in IBD. However, treatment was associated with the occurrence of progressive multifocal leukoencephalopathy, which has limited its use, especially in Europe. Vedolizumab (MNL-0002), Millennium Pharmaceutical's gut-specific, α4β7 integrin-neutralizing mAb, does not affect peripheral blood cell counts and appears to lack systemic effects. Data from phase II clinical trials of vedolizumab demonstrated efficacy with an attractive safety profile, especially in ulcerative colitis. Large phase III, multicenter trials in both ulcerative colitis and Crohn's disease will provide valuable data for the ongoing development of vedolizumab, which might evolve as a new anti-inflammatory treatment option for the management of therapy-refractory patients.

ACh, the main neurotransmitter in the neuronal cholinergic system, is synthesized by pre-ganglionic fibers of the sympathetic and parasympathetic autonomic nervous system and by post-ganglionic parasympathetic fibers. There is increasing experimental evidence that ACh is widely expressed in prokaryotic and eukaryotic non-neuronal cells. The neuronal and non-neuronal cholinergic systems comprise ACh, choline acetyltransferase and cholinesterase, enzymes that synthesize and catabolize ACh, and the nicotinic and muscarinic ACh receptors (nAChRs and mAChRs, respectively), which are the targets for ACh action. This review analyzes the participation of the cholinergic system, particularly through mAChRs, in inflammation, and discusses the role of the different mAChR antagonists that have been used to treat skin inflammatory disorders, asthma and COPD, as well as intestinal inflammation and systemic inflammatory diseases, to assess the potential application of these compounds as therapeutic tools.