gdc-0449 and Brain-Neoplasms

During the past several years, targeted therapies have significantly improved outcomes in advanced basal cell carcinoma, psoriasis, and metastatic melanoma. This article reviews how advances in our understanding of the molecular pathogenesis of these diseases led to the development of targeted therapies and how these therapies are improving outcomes. Research is ongoing to address continuing challenges of drug resistance, adverse effects, and how best to use the new medications.

Topics: Adult; Anilides; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Azetidines; Brain Neoplasms; Carcinoma, Basal Cell; Dermatologic Agents; Dermatology; Etanercept; Female; Humans; Imidazoles; Indoles; Interleukin-17; Male; Melanoma; Middle Aged; Molecular Targeted Therapy; Oximes; Piperidines; Proto-Oncogene Proteins B-raf; Psoriasis; Pyridines; Pyridones; Pyrimidinones; Skin Neoplasms; Sulfonamides; Tumor Necrosis Factor-alpha; Ustekinumab; Vemurafenib

Two phase II studies assessed the efficacy of vismodegib, a sonic hedgehog (SHH) pathway inhibitor that binds smoothened (SMO), in pediatric and adult recurrent medulloblastoma (MB).. Adult patients enrolled onto PBTC-025B and pediatric patients enrolled onto PBTC-032 were treated with vismodegib (150 to 300 mg/d). Protocol-defined response, which had to be sustained for 8 weeks, was confirmed by central neuroimaging review. Molecular tests to identify patterns of response and insensitivity were performed when tissue was available.. A total of 31 patients were enrolled onto PBTC-025B, and 12 were enrolled onto PBTC-032. Three patients in PBTC-025B and one in PBTC-032, all with SHH-subgroup MB (SHH-MB), exhibited protocol-defined responses. Progression-free survival (PFS) was longer in those with SHH-MB than in those with non-SHH-MB, and prolonged disease stabilization occurred in 41% of patient cases of SHH-MB. Among those with SHH-MB, loss of heterozygosity of PTCH1 was associated with prolonged PFS, and diffuse staining of P53 was associated with reduced PFS. Whole-exome sequencing identified mutations in SHH genes downstream from SMO in four of four tissue samples from nonresponders and upstream of SMO in two of four patients with favorable responses.. Vismodegib exhibits activity against adult recurrent SHH-MB but not against recurrent non-SHH-MB. Inadequate accrual of pediatric patients precluded conclusions in this population. Molecular analyses support the hypothesis that SMO inhibitor activity depends on the genomic aberrations within the tumor. Such inhibitors should be advanced in SHH-MB studies; however, molecular and genomic work remains imperative to identify target populations that will truly benefit.

Topics: Adult; Anilides; Brain Neoplasms; Female; Hedgehog Proteins; Humans; Male; Medulloblastoma; Middle Aged; Pyridines; Young Adult

Gliomagenesis and resistance of glioblastoma (GBM) are believed to be mediated by glioma stem cells (GSC). Evidence suggests that SHH signaling promotes GSC proliferation and self-renewal.. ABTC-0904 was a two-arm, multicenter phase 0/II study of GDC-0449, an oral inhibitor of Smoothened (SMO) in patients undergoing resection for recurrent GBM. All patients (Arms I and II) had surgery and received drug post-operatively. Only patients in Arm I received drug prior to surgery. The primary objective was to determine 6-month progression free survival (PFS-6). Secondary endpoints include median PFS (mPFS) and overall survival (mOS), response rate, and toxicity. Correlative studies included bioanalysis of GDC-0449, and inhibition of SHH signaling, GSC proliferation and self-renewal.. Forty-one patients were enrolled. Pharmacokinetics of GDC-0449 in plasma demonstrated levels within expected therapeutic range in 75% of patients. The proportion of tumorcells producing CD133. GDC-0449 was well tolerated, reached tumor, and inhibited CD133

Topics: Antineoplastic Agents; Brain Neoplasms; Glioblastoma; Glioma; Hedgehog Proteins; Humans; Neoplasm Recurrence, Local; Neoplastic Stem Cells

The hedgehog (Hh) signaling pathway is activated in many types of cancer and therefore presents an attractive target for new anticancer agents. Here, we show that mebendazole, a benzamidazole with a long history of safe use against nematode infestations and hydatid disease, potently inhibited Hh signaling and slowed the growth of Hh-driven human medulloblastoma cells at clinically attainable concentrations. As an antiparasitic, mebendazole avidly binds nematode tubulin and causes inhibition of intestinal microtubule synthesis. In human cells, mebendazole suppressed the formation of the primary cilium, a microtubule-based organelle that functions as a signaling hub for Hh pathway activation. The inhibition of Hh signaling by mebendazole was unaffected by mutants in the gene that encodes human Smoothened (SMO), which are selectively propagated in cell clones that survive treatment with the Hh inhibitor vismodegib. Combination of vismodegib and mebendazole resulted in additive Hh signaling inhibition. Because mebendazole can be safely administered to adults and children at high doses over extended time periods, we propose that mebendazole could be rapidly repurposed and clinically tested as a prospective therapeutic agent for many tumors that are dependent on Hh signaling.

Topics: Anilides; Animals; Antineoplastic Agents; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Drug Repositioning; Drug Synergism; Female; Hedgehog Proteins; HEK293 Cells; Humans; Mebendazole; Medulloblastoma; Mice; Mice, Nude; Mutation; NIH 3T3 Cells; Pyridines; Receptors, G-Protein-Coupled; Signal Transduction; Smoothened Receptor; Xenograft Model Antitumor Assays

The Hedgehog (Hh) signaling pathway is inappropriately activated in certain human cancers, including medulloblastoma, an aggressive brain tumor. GDC-0449, a drug that inhibits Hh signaling by targeting the serpentine receptor Smoothened (SMO), has produced promising anti-tumor responses in early clinical studies of cancers driven by mutations in this pathway. To evaluate the mechanism of resistance in a medulloblastoma patient who had relapsed after an initial response to GDC-0449, we determined the mutational status of Hh signaling genes in the tumor after disease progression. We identified an amino acid substitution at a conserved aspartic acid residue of SMO that had no effect on Hh signaling but disrupted the ability of GDC-0449 to bind SMO and suppress this pathway. A mutation altering the same amino acid also arose in a GDC-0449-resistant mouse model of medulloblastoma. These findings show that acquired mutations in a serpentine receptor with features of a G protein-coupled receptor can serve as a mechanism of drug resistance in human cancer.

Topics: Amino Acid Sequence; Amino Acid Substitution; Anilides; Animals; Antineoplastic Agents; Brain Neoplasms; Cell Line, Tumor; Cinnamates; Drug Resistance, Neoplasm; Hedgehog Proteins; Humans; Medulloblastoma; Mice; Molecular Sequence Data; Mutant Proteins; Mutation, Missense; Neoplasm Metastasis; Patched Receptors; Protein Conformation; Pyridines; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Signal Transduction; Smoothened Receptor; Veratrum Alkaloids

Topics: Adult; Anilides; Animals; Antineoplastic Agents; Benzimidazoles; Brain Neoplasms; Carcinoma, Basal Cell; Drug Resistance, Neoplasm; Hedgehog Proteins; Humans; Male; Medulloblastoma; Mice; Point Mutation; Protein Binding; Pyridines; Receptors, G-Protein-Coupled; Signal Transduction; Skin Neoplasms; Smoothened Receptor