Chandipura Viral Glycoprotein (CNV-G) Promotes Gectosome Generation and Enables Delivery of Intracellular Therapeutics.

Overexpression of VSV-G elevates the secretion of EVs known as gectosomes which contain VSV-G. Such vesicles can be engineered to deliver therapeutic macromolecules. We investigated viral glycoproteins from several viruses for their potential in gectosome production and intracellular cargo delivery. Expression of the viral glycoprotein (CNV-G) from the human neurotropic pathogen Chandipura virus in 293T cells significantly augments the production of CNV-G-containing gectosomes. In comparison to VSV-G gectosomes, CNV-G gectosomes exhibit heightened selectivity towards specific cell types, including primary cells and tumor cell lines. Consistent with the differential tropism between CNV-G and VSV-G gectosomes, cellular entry of CNV-G gectosome is independent of the Low-density lipoprotein receptor (LDLR), which is essential for VSV-G entry, and shows varying sensitivity to pharmacological modulators. CNV-G gectosomes efficiently deliver diverse intracellular cargos for genomic modification or responses to stimuli in vitro and in the brain of mice in vivo utilizing a split GFP and chemical-induced dimerization system. Pharmacokinetics and biodistribution analyses support CNV-G gectosomes as a versatile platform for delivering macromolecular therapeutics intracellularly.

Transcranial Functional Ultrasound Imaging Detects Focused Ultrasound Neuromodulation Induced Hemodynamic Changes in Mouse and Nonhuman Primate Brains In Vivo.

Focused ultrasound (FUS) is an emerging noinvasive technique for neuromodulation in the central nervous system (CNS). To evaluate the effects of FUS-induced neuromodulation, many studies used behavioral changes, functional magnetic resonance imaging (fMRI) or electroencephalography (EEG). However, behavioral readouts are often not easily mapped to specific brain activity, EEG has low spatial resolution limited to the surface of the brain and fMRI requires a large importable scanner that limits additional readouts and manipulations. In this context, functional ultrasound imaging (fUSI) holds promise to directly monitor the effects of FUS neuromodulation with high spatiotemporal resolution in a large field of view, with a comparatively simple and flexible setup. fUSI uses ultrafast Power Doppler Imaging (PDI) to measure changes in cerebral blood volume, which correlates well with neuronal activity and local field potentials. We designed a setup that aligns a FUS transducer with a linear array to allow immediate subsequent monitoring of the hemodynamic response with fUSI during and after FUS neuromodulation. We established a positive correlation between FUS pressure and the size of the activated area, as well as changes in cerebral blood volume (CBV) and found that unilateral sonications produce bilateral hemodynamic changes with ipsilateral accentuation in mice. We further demonstrated the ability to perform fully noninvasive, transcranial FUS-fUSI in nonhuman primates for the first time by using a lower-frequency transducer configuration.

Expanding the flexibility of base editing for high-throughput genetic screens in bacteria.

Genome-wide screens have become powerful tools for elucidating genotype-to-phenotype relationships in bacteria. Of the varying techniques to achieve knockout and knockdown, CRISPR base editors are emerging as promising options. However, the limited number of available, efficient target sites hampers their use for high-throughput screening. Here, we make multiple advances to enable flexible base editing as part of high-throughput genetic screening in bacteria. We first co-opt the Streptococcus canis Cas9 that exhibits more flexible protospacer-adjacent motif recognition than the traditional Streptococcus pyogenes Cas9. We then expand beyond introducing premature stop codons by mutating start codons. Next, we derive guide design rules by applying machine learning to an essentiality screen conducted in Escherichia coli. Finally, we rescue poorly edited sites by combining base editing with Cas9-induced cleavage of unedited cells, thereby enriching for intended edits. The efficiency of this dual system was validated through a conditional essentiality screen based on growth in minimal media. Overall, expanding the scope of genome-wide knockout screens with base editors could further facilitate the investigation of new gene functions and interactions in bacteria.

Cell- and Serum-Derived Proteins Act as DAMPs to Activate RAW 264.7 Macrophage-like Cells on Silicone Implants.

Protein adsorption after biomaterial implantation is the first stage of the foreign body response (FBR). However, the source(s) of the adsorbed proteins that lead to damaged associated molecular patterns (DAMPs) and induce inflammation have not been fully elucidated. This study examined the effects of different protein sources, cell-derived (from a NIH/3T3 fibroblast cell lysate) and serum-derived (from fetal bovine serum), which were compared to implant-derived proteins (after a 30 min subcutaneous implantation in mice) on activation of RAW 264.7 cells cultured in minimal (serum-free) medium. Both cell-derived and serum-derived protein sources when preadsorbed to either tissue culture polystyrene or medical-grade silicone induced RAW 264.7 cell activation. The combination led to an even higher expression of pro-inflammatory cytokine genes and proteins. Implant-derived proteins on silicone explants induced a rapid inflammatory response that then subsided more quickly and to a greater extent than the studies with in vitro cell-derived or serum-derived protein sources. Proteomic analysis of the implant-derived proteins identified proteins that included cell-derived and serum-derived, but also other proteinaceous sources (e.g., extracellular matrix), suggesting that the latter or nonproteinaceous sources may help to temper the inflammatory response in vivo. These findings indicate that both serum-derived and cell-derived proteins adsorbed to implants can act as DAMPs to drive inflammation in the FBR, but other protein sources may play an important role in controlling inflammation.

LOGGIC/FIREFLY-2: a phase 3, randomized trial of tovorafenib vs. chemotherapy in pediatric and young adult patients with newly diagnosed low-grade glioma harboring an activating RAF alteration.

BACKGROUND: Pediatric low-grade glioma (pLGG) is essentially a single pathway disease, with most tumors driven by genomic alterations affecting the mitogen-activated protein kinase/ERK (MAPK) pathway, predominantly KIAA1549::BRAF fusions and BRAF V600E mutations. This makes pLGG an ideal candidate for MAPK pathway-targeted treatments. The type I BRAF inhibitor, dabrafenib, in combination with the MEK inhibitor, trametinib, has been approved by the United States Food and Drug Administration for the systemic treatment of BRAF V600E-mutated pLGG. However, this combination is not approved for the treatment of patients with tumors harboring BRAF fusions as type I RAF inhibitors are ineffective in this setting and may paradoxically enhance tumor growth. The type II RAF inhibitor, tovorafenib (formerly DAY101, TAK-580, MLN2480), has shown promising activity and good tolerability in patients with BRAF-altered pLGG in the phase 2 FIREFLY-1 study, with an objective response rate (ORR) per Response Assessment in Neuro-Oncology high-grade glioma (RANO-HGG) criteria of 67%. Tumor response was independent of histologic subtype, BRAF alteration type (fusion vs. mutation), number of prior lines of therapy, and prior MAPK-pathway inhibitor use. METHODS: LOGGIC/FIREFLY-2 is a two-arm, randomized, open-label, multicenter, global, phase 3 trial to evaluate the efficacy, safety, and tolerability of tovorafenib monotherapy vs. current standard of care (SoC) chemotherapy in patients < 25 years of age with pLGG harboring an activating RAF alteration who require first-line systemic therapy. Patients are randomized 1:1 to either tovorafenib, administered once weekly at 420 mg/m2 (not to exceed 600 mg), or investigator's choice of prespecified SoC chemotherapy regimens. The primary objective is to compare ORR between the two treatment arms, as assessed by independent review per RANO-LGG criteria. Secondary objectives include comparisons of progression-free survival, duration of response, safety, neurologic function, and clinical benefit rate. DISCUSSION: The promising tovorafenib activity data, CNS-penetration properties, strong scientific rationale combined with the manageable tolerability and safety profile seen in patients with pLGG led to the SIOPe-BTG-LGG working group to nominate tovorafenib for comparison with SoC chemotherapy in this first-line phase 3 trial. The efficacy, safety, and functional response data generated from the trial may define a new SoC treatment for newly diagnosed pLGG. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05566795. Registered on October 4, 2022.

The type II RAF inhibitor tovorafenib in relapsed/refractory pediatric low-grade glioma: the phase 2 FIREFLY-1 trial.

BRAF genomic alterations are the most common oncogenic drivers in pediatric low-grade glioma (pLGG). Arm 1 (n = 77) of the ongoing phase 2 FIREFLY-1 (PNOC026) trial investigated the efficacy of the oral, selective, central nervous system-penetrant, type II RAF inhibitor tovorafenib (420 mg m-2 once weekly; 600 mg maximum) in patients with BRAF-altered, relapsed/refractory pLGG. Arm 2 (n = 60) is an extension cohort, which provided treatment access for patients with RAF-altered pLGG after arm 1 closure. Based on independent review, according to Response Assessment in Neuro-Oncology High-Grade Glioma (RANO-HGG) criteria, the overall response rate (ORR) of 67% met the arm 1 prespecified primary endpoint; median duration of response (DOR) was 16.6 months; and median time to response (TTR) was 3.0 months (secondary endpoints). Other select arm 1 secondary endpoints included ORR, DOR and TTR as assessed by Response Assessment in Pediatric Neuro-Oncology Low-Grade Glioma (RAPNO) criteria and safety (assessed in all treated patients and the primary endpoint for arm 2, n = 137). The ORR according to RAPNO criteria (including minor responses) was 51%; median DOR was 13.8 months; and median TTR was 5.3 months. The most common treatment-related adverse events (TRAEs) were hair color changes (76%), elevated creatine phosphokinase (56%) and anemia (49%). Grade ≥3 TRAEs occurred in 42% of patients. Nine (7%) patients had TRAEs leading to discontinuation of tovorafenib. These data indicate that tovorafenib could be an effective therapy for BRAF-altered, relapsed/refractory pLGG. ClinicalTrials.gov registration: NCT04775485 .

Modulation of cardio-respiratory activity in mice via transcranial focused ultrasound.

OBJECTIVE: The objective of this study was to investigate the effect of FUS on autonomic nervous system activity, including heart and respiratory rates, and to separate the thermal modulation from combined thermal and mechanical FUS effects. METHODS: The thalamus and hypothalamus of wild-type mice were sonicated with a continuous-wave, 2 MHz FUS transducer at pressures of 425 and 850 kPa for 60 seconds. Cardiac and respiratory rates were monitored as signs of autonomic nervous activity. FUS-induced changes in autonomic activity were compared to FUS targeted to a spatially-distant motor region and to laser-induced heating. RESULTS: FUS delivered to the primary target over the thalamus and hypothalamus at 850 kPa reversibly increased the respiratory rate by 6.5±3.2 breaths per minute and decreased the heart rate by 3.2±1.8 beats per minute. No significant changes occurred in this region at 425 kPa or when targeting the motor regions at 850 kPa. Laser heating with the same temperature rise profile produced by 850 kPa sonication resulted in cardiorespiratory modulation similar to that of FUS. CONCLUSIONS: FUS is capable of reversibly and non-invasively modulating cardiorespiratory activity in mice. Localized changes in temperature may constitute the main cause for this activity, though further investigation is warranted into the distinct and complementary mechanisms of mechanically- and thermally-induced FUS neuromodulation. Close monitoring of vital signs during FUS neuromodulation may be warranted to monitor systemic responses to stimulation.

Paediatric Strategy Forum for medicinal product development of epigenetic modifiers for children: ACCELERATE in collaboration with the European Medicines Agency with participation of the Food and Drug Administration.

The fifth multistakeholder Paediatric Strategy Forum focussed on epigenetic modifier therapies for children and adolescents with cancer. As most mutations in paediatric malignancies influence chromatin-associated proteins or transcription and paediatric cancers are driven by developmental gene expression programs, targeting epigenetic mechanisms is predicted to be a very important therapeutic approach in paediatric cancer. The Research to Accelerate Cures and Equity (RACE) for Children Act FDARA amendments to section 505B of the FD&C Act was implemented in August 2020, and as there are many epigenetic targets on the FDA Paediatric Molecular Targets List, clinical evaluation of epigenetic modifiers in paediatric cancers should be considered early in drug development. Companies are also required to submit to the EMA paediatric investigation plans aiming to ensure that the necessary data to support the authorisation of a medicine for children in EU are of high quality and ethically researched. The specific aims of the forum were i) to identify epigenetic targets or mechanisms of action associated with epigenetic modification relevant to paediatric cancers and ii) to define the landscape for paediatric drug development of epigenetic modifier therapies. DNA methyltransferase inhibitors/hypomethylating agents and histone deacetylase inhibitors were largely excluded from discussion as the aim was to discuss those targets for which therapeutic agents are currently in early paediatric and adult development. Epigenetics is an evolving field and could be highly relevant to many paediatric cancers; the biology is multifaceted and new targets are frequently emerging. Targeting epigenetic mechanisms in paediatric malignancy has in most circumstances yet to reach or extend beyond clinical proof of concept, as many targets do not yet have available investigational drugs developed. Eight classes of medicinal products were discussed and prioritised based on the existing level of science to support early evaluation in children: inhibitors of menin, DOT1L, EZH2, EED, BET, PRMT5 and LSD1 and a retinoic acid receptor alpha agonist. Menin inhibitors should be moved rapidly into paediatric development, in view of their biological rationale, strong preclinical activity and ability to fulfil an unmet clinical need. A combination approach is critical for successful utilisation of any epigenetic modifiers (e.g. EZH2 and EED) and exploration of the optimum combination(s) should be supported by preclinical research and, where possible, molecular biomarker validation in advance of clinical translation. A follow-up multistakeholder meeting focussing on BET inhibitors will be held to define how to prioritise the multiple compounds in clinical development that could be evaluated in children with cancer. As epigenetic modifiers are relatively early in development in paediatrics, there is a clear opportunity to shape the landscape of therapies targeting the epigenome in order that efficient and optimum plans for their evaluation in children and adolescents are developed in a timely manner.

Accelerating Pediatric Cancer Drug Development: Challenges and Opportunities for Pediatric Master Protocols.

Although outcomes for children with cancer have significantly improved over the past 40 years, there has been little progress in the treatment of some pediatric cancers, particularly when advanced. Additionally, clinical trial options and availability are often insufficient. Improved genomic and immunologic understanding of pediatric cancers, combined with innovative clinical trial designs, may provide an enhanced opportunity to study childhood cancers. Master protocols, which incorporate the use of precision medicine approaches, coupled with the ability to quickly assess the safety and effectiveness of new therapies, have the potential to accelerate early-phase clinical testing of novel therapeutics and which may result in more rapid approval of new drugs for children with cancer. Designing and conducting master protocols for children requires addressing similar principles and requirements as traditional adult oncology trials, but there are also unique considerations for master protocols conducted in children with cancer. The purpose of this paper is to define the key challenges and opportunities associated with this approach in order to ensure that master protocols can be adapted to benefit children and adolescents and ensure that adequate data are captured to advance, in parallel, the clinical development of investigational agents for children with cancer.

Assessment of the drug interaction potential and single- and repeat-dose pharmacokinetics of the BRAF inhibitor dabrafenib.

The induction of CYP2C9 by dabrafenib using S-warfarin as a probe and the effects of a CYP3A inhibitor (ketoconazole) and a CYP2C8 inhibitor (gemfibrozil) on dabrafenib pharmacokinetics were evaluated in patients with BRAF V600 mutation-positive tumors. Dabrafenib single- and repeat-dose pharmacokinetics were also evaluated. S-warfarin AUC(0- ∞) decreased 37% and Cmax increased 18% with dabrafenib. Dabrafenib AUC(0- τ) and C(max) increased 71% and 33%, respectively, with ketoconazole. Hydroxy- and desmethyl-dabrafenib AUC(0-τ) increased 82% and 68%, respectively, and AUC for carboxy-dabrafenib decreased 16%. Dabrafenib AUC(0-τ) increased 47%, with no change in C(max), after gemfibrozil co-administration. Gemfibrozil did not affect systemic exposure to dabrafenib metabolites. Single- and repeat-dose dabrafenib pharmacokinetics were consistent with previous reports. All cohorts used the commercial capsules. More-frequent monitoring of international normalized ratios is recommended in patients receiving warfarin during initiation or discontinuation of dabrafenib. Substitution of strong inhibitors or strong inducers of CYP3A or CYP2C8 is recommended during treatment with dabrafenib.

Dose selection, pharmacokinetics, and pharmacodynamics of BRAF inhibitor dabrafenib (GSK2118436).

PURPOSE: Dabrafenib is a selective, potent ATP-competitive inhibitor of the BRAFV600-mutant kinase that has demonstrated efficacy in clinical trials. We report the rationale for dose selection in the first-in-human study of dabrafenib, including pharmacokinetics, tissue pharmacodynamics, 2[18F]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) pharmacodynamics, and dose-response relationship. EXPERIMENTAL DESIGN: Dabrafenib was administered orally once, twice (BID), or three times daily (TID). Selected dose cohorts were expanded to collect adequate data on safety, pharmacokinetics, or pharmacodynamics. A recommended phase II dose (RP2D) was chosen based on safety, pharmacokinetic, pharmacodynamic, and response data. RESULTS: One hundred and eighty-four patients were enrolled and treated with doses ranging from 12 mg once daily to 300 mg BID in 10 cohorts. Pharmacokinetic assessment of dabrafenib demonstrated a less-than-dose-proportional increase in exposure after repeat dosing above 150 mg BID. Similar to parent drug concentrations, exposure for all metabolites demonstrated less-than-dose-proportional increases. Predicted target inhibition of pERK (>80%) was achieved at 150 mg BID, with a similar magnitude of inhibition at higher doses in BRAFV600 mutation melanoma biopsy samples. Although there was large variability between patients, FDG uptake decreased with higher daily doses in patients with BRAFV600 mutation-positive melanoma. A favorable activity and tolerability profile was demonstrated at 150 mg BID. There was no improvement with TID dosing compared with BID dosing, based on FDG-PET and tumor response analyses in patients with melanoma. CONCLUSION: The RP2D of dabrafenib was determined to be 150 mg BID after considering multiple factors, including pharmacokinetics, tissue pharmacodynamics, FDG-PET pharmacodynamics, and the dose-response relationship. A maximum tolerated dose for dabrafenib was not determined.

Metabolism and disposition of oral dabrafenib in cancer patients: proposed participation of aryl nitrogen in carbon-carbon bond cleavage via decarboxylation following enzymatic oxidation.

A phase I study was conducted to assess the metabolism and excretion of [(14)C]dabrafenib (GSK2118436; N-{3-[5-(2-amino-4-pyrimidinyl)-2-(1,1-dimethylethyl)-1,3-thiazol-4-yl]-2-fluorophenyl}-2,6-difluorobenzene sulfonamide, methanesulfonate salt), a BRAF inhibitor, in four patients with BRAF V600 mutation-positive tumors after a single oral dose of 95 mg (80 µCi). Assessments included the following: 1) plasma concentrations of dabrafenib and metabolites using validated ultra-high-performance liquid chromatography--tandem mass spectrometry methods, 2) plasma and blood radioactivity, 3) urinary and fecal radioactivity, and 4) metabolite profiling. Results showed the mean total recovery of radioactivity was 93.8%, with the majority recovered in feces (71.1% of administered dose). Urinary excretion accounted for 22.7% of the dose, with no detection of parent drug in urine. Dabrafenib is metabolized primarily via oxidation of the t-butyl group to form hydroxy-dabrafenib. Hydroxy-dabrafenib undergoes further oxidation to carboxy-dabrafenib, which subsequently converts to desmethyl-dabrafenib via a pH-dependent decarboxylation. The half-lives for carboxy- and desmethyl-dabrafenib were longer than for parent and hydroxy-dabrafenib (18-20 vs. 5-6 hours). Based on area under the plasma concentration-time curve, dabrafenib, hydroxy-, carboxy-, and desmethyl-dabrafenib accounted for 11%, 8%, 54%, and 3% of the plasma radioactivity, respectively. These results demonstrate that the major route of elimination of dabrafenib is via oxidative metabolism (48% of the dose) and biliary excretion. Based on our understanding of the decarboxylation of carboxy-dabrafenib, a low pH-driven, nonenzymatic mechanism involving participation of the aryl nitrogen is proposed to allow prediction of metabolic oxidation and decarboxylation of drugs containing an aryl nitrogen positioned α to an alkyl (ethyl or t-butyl) side chain.

Concomitant oral and intravenous pharmacokinetics of dabrafenib, a BRAF inhibitor, in patients with BRAF V600 mutation-positive solid tumors.

Dabrafenib is an orally bioavailable, potent, and selective inhibitor of human wild-type BRAF and CRAF kinases as well as mutant forms of BRAF kinase. The aim of this phase 1, single-center, open-label study in four patients with BRAF mutation-positive solid tumors was to determine the absolute bioavailability of a 150 mg oral dose of dabrafenib. A microtracer study approach, in which a 50 µg radiolabeled intravenous (IV) microdose of dabrafenib was given concomitantly with a 150 mg oral dose, was used to simultaneously recover IV and oral pharmacokinetic parameters. The least squares mean (90% CI) absolute bioavailability of dabrafenib (HPMC capsules) was 94.5% (81.3%, 109.7%). Median T(max) after oral administration was 2.0 hours and the geometric mean terminal half-life was 4.8 hours. The geometric mean clearance and volume of distribution after IV administration were 12.0 L/h and 45.5 L, respectively. Human clearance and volume of distribution at steady state were in agreement with predictions made using allometric scaling of pharmacokinetic parameters from four preclinical species. In conclusion, dabrafenib absolute bioavailability was high, whereas first-pass metabolism was low. Furthermore, the microtracer approach provided an innovative and efficient method for assessing the absolute bioavailability of dabrafenib in patients with advanced cancer.

Effects of particle size, food, and capsule shell composition on the oral bioavailability of dabrafenib, a BRAF inhibitor, in patients with BRAF mutation-positive tumors.

Dabrafenib is a small-molecule inhibitor of BRAF kinase activity that is currently being developed for the treatment of BRAF V600 mutation-positive melanoma. This clinical, open-label, two-cohort (n = 14 per cohort), randomized study was designed to evaluate the effect of drug substance particle size, and food on the plasma pharmacokinetics of a single oral dose of dabrafenib in patients with BRAF V600 mutation-positive solid tumors. In addition, an exploratory cross-cohort comparison of the relative bioavailability of single-dose dabrafenib administered in gelatin and hydroxypropyl methylcellulose (HPMC) capsules was performed. Higher bioavailability was noted with nonmicronized drug substance (larger particle size), under fasting conditions, and with HPMC capsules. Initial dissolution results at pH 1.2 showed higher dissolution of gelatin relative to HPMC capsules inconsistent with clinical data. Subsequent in vitro dissolution studies were conducted in fasted-state simulated gastric fluid over a 24-h period and showed that HPMC capsules reached a higher percentage of dabrafenib dissolved than gelatin capsules. The presence of HPMC is believed to inhibit precipitation of dabrafenib as the freebase, thereby maintaining a supersaturated solution over an extended period of time. Dabrafenib has been administered in pivotal clinical studies on an empty stomach using micronized drug substance in HPMC capsules.

Dabrafenib in patients with melanoma, untreated brain metastases, and other solid tumours: a phase 1 dose-escalation trial.

BACKGROUND: Dabrafenib is an inhibitor of BRAF kinase that is selective for mutant BRAF. We aimed to assess its safety and tolerability and to establish a recommended phase 2 dose in patients with incurable solid tumours, especially those with melanoma and untreated, asymptomatic brain metastases. METHODS: We undertook a phase 1 trial between May 27, 2009, and March 20, 2012, at eight study centres in Australia and the USA. Eligible patients had incurable solid tumours, were 18 years or older, and had adequate organ function. BRAF mutations were mandatory for inclusion later in the study because of an absence of activity in patients with wild-type BRAF. We used an accelerated dose titration method, with the first dose cohort receiving 12 mg dabrafenib daily in a 21-day cycle. Once doses had been established, we expanded the cohorts to include up to 20 patients. On the basis of initial data, we chose a recommended phase 2 dose. Efficacy at the recommended phase 2 dose was studied in patients with BRAF-mutant tumours, including those with non-Val600Glu mutations, in three cohorts: metastatic melanoma, melanoma with untreated brain metastases, and non-melanoma solid tumours. This study is registered with ClinicalTrials.gov, number NCT00880321. FINDINGS: We enrolled 184 patients, of whom 156 had metastatic melanoma. The most common treatment-related adverse events of grade 2 or worse were cutaneous squamous-cell carcinoma (20 patients, 11%), fatigue (14, 8%), and pyrexia (11, 6%). Dose reductions were necessary in 13 (7%) patients. No deaths or discontinuations resulted from adverse events, and 140 (76%) patients had no treatment-related adverse events worse than grade 2. Doses were increased to 300 mg twice daily, with no maximum tolerated dose recorded. On the basis of safety, pharmacokinetic, and response data, we selected a recommended phase 2 dose of 150 mg twice daily. At the recommended phase 2 dose in 36 patients with Val600 BRAF-mutant melanoma, responses were reported in 25 (69%, 95% CI 51·9-83·7) and confirmed responses in 18 (50%, 32·9-67·1). 21 (78%, 57·7-91·4) of 27 patients with Val600Glu BRAF-mutant melanoma responded and 15 (56%, 35·3-74·5) had a confirmed response. In Val600 BRAF-mutant melanoma, responses were durable, with 17 patients (47%) on treatment for more than 6 months. Responses were recorded in patients with non-Val600Glu BRAF mutations. In patients with melanoma and untreated brain metastases, nine of ten patients had reductions in size of brain lesions. In 28 patients with BRAF-mutant non-melanoma solid tumours, apparent antitumour activity was noted in a gastrointestinal stromal tumour, papillary thyroid cancers, non-small-cell lung cancer, ovarian cancer, and colorectal cancer. INTERPRETATION: Dabrafenib is safe in patients with solid tumours, and an active inhibitor of Val600-mutant BRAF with responses noted in patients with melanoma, brain metastases, and other solid tumours. FUNDING: GlaxoSmithKline.

Phase I pharmacologic and pharmacodynamic study of the gamma secretase (Notch) inhibitor MK-0752 in adult patients with advanced solid tumors.

PURPOSE: Aberrant Notch signaling has been implicated in the pathogenesis of many human cancers. MK-0752 is a potent, oral inhibitor of γ-secretase, an enzyme required for Notch pathway activation. Safety, maximum-tolerated dose, pharmacokinetics (PKs), pharmacodynamics, and preliminary antitumor efficacy were assessed in a phase I study of MK-0752. PATIENTS AND METHODS: MK-0752 was administered in three different schedules to patients with advanced solid tumors. Hair follicles were collected at higher dose levels to assess a gene signature of Notch inhibition. RESULTS: Of 103 patients who received MK-0752, 21 patients received a continuous once-daily dosing at 450 and 600 mg; 17 were dosed on an intermittent schedule of 3 of 7 days at 450 and 600 mg; and 65 were dosed once per week at 600, 900, 1,200, 1,500, 1,800, 2,400, 3,200, and 4,200 mg. The most common drug-related toxicities were diarrhea, nausea, vomiting, and fatigue. PKs (area under the concentration-time curve and maximum measured plasma concentration) increased in a less than dose proportional manner, with a half-life of approximately 15 hours. Significant inhibition of Notch signaling was observed with the 1,800- to 4,200-mg weekly dose levels, confirming target engagement at those doses. One objective complete response and an additional 10 patients with stable disease longer than 4 months were observed among patients with high-grade gliomas. CONCLUSION: MK-0752 toxicity was schedule dependent. Weekly dosing was generally well tolerated and resulted in strong modulation of a Notch gene signature. Clinical benefit was observed, and rational combination trials are currently ongoing to maximize clinical benefit with this novel agent.

Metachronous mediastinal seminoma occurring after intracranial germinoma in an adolescent.

We report a case of a mediastinal seminoma occurring 19 months after the resolution of a pineal germinoma. A 15-year-old boy with headaches and visual changes was diagnosed with a pineal germinoma by biopsy and mildly elevated beta-human chorionic gonadatropin (beta-HCG) in serum and cerebral spinal fluid. Radiation therapy leads to the resolution of his pineal germinoma and normalization of the beta-HCG. A mediastinal seminoma (germinoma) was diagnosed nearly 2 years later because of rising serum beta-HCG. There was no evidence of recurrent central nervous system disease. The patient underwent systemic chemotherapy with the complete resolution of the mediastinal seminoma.

Prenatal diagnosis and subsequent treatment of an intermediate-risk paraspinal neuroblastoma: case report and review of the literature.

OBJECTIVES: Neuroblastoma is the most common extracranial solid tumor of childhood, and the most common malignancy diagnosed during infancy. In comparison, neonatal neuroblastoma is relatively rare. Improvements in prenatal imaging and widespread use of fetal ultrasonography have led to an increased rate of prenatal diagnoses. METHODS: Case report and literature review. RESULTS: We report a case of an intermediate-risk neuroblastoma, diagnosed at 36 weeks' gestation by ultrasound and subsequently visualized by fetal MRI, that resulted in spinal cord compression and decreased fetal movement. A multidisciplinary team approach resulted in rapid delivery, evaluation, biopsy, staging, and treatment implementation in a successful effort to preserve lower extremity function. CONCLUSION: Prenatal diagnosis of neuroblastoma, management and outcomes are reviewed. Prompt diagnosis can strongly influence perinatal management and improve prognosis.