Safety and efficacy of the addition of bevacizumab (BV) to temozolomide (TMZ) and radiation therapy (RT) followed by BV, TMZ, and irinotecan (CPT-11) for newly diagnosed glioblastoma multiforme (GBM)

2015

Background: Standard GBM treatment includes TMZ and RT, and results in a median progression-free survival and median survival of 6.9 and 15.8 months, respectively. GBM have high concentrations of vascular endothelial growth factor (VEGF), higher levels are associated with poorer prognosis. BV is a humanized antibody to VEGF with activity in recurrent GBMs. This study aims to improve the survival of newly diagnosed GBM patients by incorporating an anti-angiogenic agent with RT and TMZ, and adding a topoisomerase I inhibitor, and an anti-angiogenic agent to TMZ post-RT therapy. Methods: Patients received standard RT and TMZ at 75 mg/m2/day, with BV at 10 mg/kg every 14 days beginning a minimum of 28 days post-operatively. Following the completion of RT, patients received 6 cycles of BV, TMZ and CPT-11. Each cycle was 28 days. BV was given at a dose of 10 mg/kg on days 1 and 15, TMZ at 200 mg/m2 on days 1–5 and CPT-11 on days 1 and 15 at 125 mg/m2 for patients not on an enzyme inducing anti-epileptic drug (EIAED) and 340 mg/m2 for patients on an EIAED. The study was designed to differentiate between a 16-month survival rate of 45% and 60% with type I and II error rates of 0.05. Results: 75 patients were enrolled between 8/07 and 9/08. All the patients have completed RT; 40 patients continue to receive BV, TMZ, and CPT-11. Twenty-two patients have completed 6 cycles of BV, TMZ, and CPT-11; 17 of them had a cold PET One patient developed a CNS hemorrhage (grade 2) necessitating stopping BV. Five patients developed thrombocytopenia for which TMZ was held (grade 3, n = 1; grade 4, n = 4). There were no other ≥ grade 3 toxicities, including no wound dehiscence during RT. Twelve patients had tumor progression, and 14 stopped because of toxicity, including: 6 with fatigue; 3 with PEs; 2 with grade 4 thrombocytopenia; the patient with CNS hemorrhage, and one each with a rectal abscess and sepsis. There have been 7 deaths: 5 from tumor progression; one each from sepsis and PEs. At a median follow-up of 9 months, 81% remain alive and progression-free. Conclusions: Adding BV to TMZ and RT followed by BV, TMZ with CPT-11 is tolerable and efficacious.

No significant financial relationships to disclose.

An efficient strategy for the determination of the three-dimensional architecture of ribonucleoprotein complexes by the combination of a few easily accessible NMR and biochemical data: intermolecular recognition in a U4 spliceosomal complex

Ribonucleoprotein (RNP) complexes are involved in several cellular processes, including RNA processing, transcription and translation. RNP structures are often dynamic in nature, undergoing significant remodeling during the course of their function. Visualization of the three-dimensional arrangement of single components in the complex and characterization of the intermolecular interactions are essential for understanding the mechanisms of operation. Crystallization either is not always achievable for these highly dynamic RNP particles or requires trimming the complex to a stable, well-structured core that lacks the flexible, regulatory domains. Alternative techniques that can provide structural information for complexes in solution under native conditions, where they retain their natural dynamic properties, are needed. In this study, we explored the possibility of using a combination of NMR, biochemical data and molecular modeling to generate an accurate high-resolution model of RNP complexes. We applied this strategy to the ternary hPrp31 (human Prp31)-15.5K-U4 5'-SL (stem-loop) spliceosomal complex, which, due to its large size and instability and because of the difficulty in obtaining isotopically labeled hPrp31, is not amenable to complete structure determination by NMR. We designed a protocol where the protein-protein interaction surface is defined for 15.5K by NMR data, while the relative orientations of the U4 RNA and the hPrp31 protein are described by mutational and cross-linking data. Using these data in a restrained ensemble docking protocol, we obtained a model for the ternary complex that reveals a novel rationale for the hierarchical assembly of the complex. Comparison of the docking model with the crystal structure recently obtained for a trimmed version of the complex reveals the high accuracy of the docking model, even down to an atomic level. This work shows that the architecture of large RNP complexes is within reach by NMR investigation in solution even for those cases where a traditional structural determination cannot be performed.

Dose-dependent effects of radiation therapy on cerebral blood flow, metabolism, and neurocognitive dysfunction

PURPOSE

A prospective study was performed to formally relate dose-dependent radiologically defined changes in normal brain induced by radiotherapy (RT) to neurocognitive dysfunction in subjects with primary brain tumors.

METHODS AND MATERIALS

Adult patients receiving three-dimensional RT for central nervous system (CNS) tumors were enrolled. Positron emission tomography (PET) scanning and neuropsychological testing were performed before RT and 3 weeks and 6 months after treatment. Analyses were performed for correlations between changes in 2-deoxy-2-[(18)F]-fluoro-d-glucose (FDG)-PET (metabolism), (15)O-PET (relative blood flow), regional radiation dose, follow-up time, and neuropsychological test scores.

RESULTS

Eleven subjects were enrolled and 6 completed follow-up studies. The PET data showed reduced FDG uptake, with average decreases of 2-6% in regions of the brain receiving greater than 40 Gy at 3 weeks' and 6 months' follow-up. The (15)O-H(2)O PET showed increases (<10%) at 3 weeks in relative regional blood flow in brain receiving greater than 30 Gy, but less at the 6-month follow-up studies. There were significant correlations between decreases in FDG uptake and increased scores from the Symptom Checklist-90-R, with an average increase in T score of 2 (p < 0.0001). The Wisconsin Card Sorting Test showed a significant correlation of decreased FDG uptake with increased errors and perseveration in test performance, with an average decrease in T score of 11 (p = 0.037).

CONCLUSIONS

A dose-dependent response of CNS tissue was detected using FDG PET in this small number of patients. Decreases in CNS metabolism correlated with decreased performance on neuropsychological tests for problem solving, cognitive flexibility, and global measures of psychopathology. Additional research is needed to verify and define these findings.

Integration of Cone-Beam CT in Stereotactic Body Radiation Therapy

This report describes the technique and initial experience using cone beam CT (CBCT) for localization of treatment targets in patients undergoing stereotactic body radiation therapy (SBRT). Patients selected for SBRT underwent 3-D or 4-D CT scans in a customized immobilization cradle. GTV, CTV, ITV, and PTV were defined. Intensity-modulated radiation beams, multiple 3-D conformal beams, or dynamic conformal arcs were delivered using a Varian 21EX with 120-leaf MLC. CBCT images were obtained prior to each fraction, and registered to the planning CT by using soft tissue and bony structures to assure accurate isocenter localization. Patients were repositioned for treatment based on the CBCT images. Radiographic images (kV, MV, or CBCT) were taken before and after beam delivery to further assess set-up accuracy. Ten patients with lung, liver, and spine lesions received 29 fractions of treatment using this technique. The prescription doses ranged 1250 ~ 6000 cGy in 1 ~ 5 fractions. Compared to traditional 2-D matching using bony structures, CBCT corrects target deviation from 1 mm to 15 mm, with an average of 5 mm. Comparison of pre-treatment to post-treatment radiographic images demonstrated an average 2 mm deviation (ranging from 0–4 mm). Improved immobilization may enhance positioning accuracy. Typical total “in-room” times for the patients are approximately 1 hour. CBCT-guided SBRT is feasible and enhances setup accuracy using 3-D anatomical information.

NMR assignment of human chemerin, a novel chemoattractant

Chemerin is a potent chemoattractant for cells expressing the GPCR CMKLR1, and is thought to play important roles in cell migration and recruitment to sites of tissue damage and inflammation. Here we report the NMR assignments of the 15.6 kDa active form of uniformly (15)N, (13)C labeled chemerin.

Histone deacetylase as therapeutic target in a rodent model of hemorrhagic shock: effect of different resuscitation strategies on lung and liver

BACKGROUND

DNA transcription is regulated in part by acetylation of nuclear histones, controlled by 2 groups of enzymes: histone deacetylases (HDAC) and histone acetyl transferases (HAT). We have shown previously that hemorrhage and resuscitation are associated with HDAC/HAT imbalance, which influences the acetylation status of cardiac histones. The goals of this study were to determine whether: (1) resuscitation after hemorrhage affects histone acetylation in a fluid- and organ-specific fashion; and (2) administration of HDAC inhibitors influences histone acetylation and subsequent gene expression.

METHODS

In the first experiment, rats (n = 6/group) were subjected to volume-controlled hemorrhage and resuscitated with: (1) racemic lactated Ringer's (DL-LR); (2) L-lactated Ringer's (L-LR); (3) 7.5% hypertonic saline (HTS); (4) ketone Ringer's (KR); or (5) pyruvate Ringer's (PR). Control groups included: (6) no hemorrhage (Sham); and (7) hemorrhage with no resuscitation (NR). In the second experiment (n = 5/group), 3 HDAC inhibitors, valproic acid (VPA), trichostatin A (TSA), and suberoylanilide hydroxamic acid (SAHA), were added to normal saline and used as fluid for resuscitation. At the end of resuscitation, lung and liver tissues were subjected to subcellular protein fractionation and Western blotting to analyze histone acetylation. In addition, cDNA microarrays and RT-PCR were used to measure expression of selected genes.

RESULTS

Hemorrhage did not change the level of histone acetylation in lungs, whereas resuscitation predominantly hyperacetylated histones. An analysis of histone acetylation on 10 lysine sites showed that L-LR, HTS, and KR resuscitation caused the largest number of changes (7, 6, and 6 respectively). SAHA hyperacetylated 7 sites in liver and affected expression of 57 genes (44 up, 13 down).

CONCLUSIONS

Resuscitation with various fluids, as well as infusion of pharmacologic HDAC inhibitors affects histone acetylation in a fluid- and organ-specific fashion, even when administered post-insult for a limited period of time. Uniquely affected genes are associated with metabolism, cellular growth, proliferation, differentiation, transformation, and cellular signaling.

Phase II open-label, safety, pharmacokinetic and efficacy study of 2-methoxyestradiol nanocrystal colloidal dispersion administered orally to patients with recurrent glioblastoma multiforme

2065

Background: 2-methoxyestradiol (2ME2) inhibits tumor cell proliferation and induces apoptosis by inhibiting microtubule polymerization and increasing reactive oxygen species-induced cell damage. In addition, 2ME2 downregulates HIF-1a at the posttranscriptional level and inhibits HIF-1a-mediated VEGF expression. Preclinical studies confirm significant in vitro and in vivo anti-glioma activity including tumor regression in combination with temozolomide. We therefore performed a single-center, phase 2 study to evaluate 2ME2 in recurrent glioblastoma multiforme (GBM) patients. Methods: Key eligibility include: adults with GBM at first or second recurrence; measurable disease; Karnofsky performance status = 70% and adequate organ function. 2ME2 was given orally 4 times/day at a dose of 1000mg for the first 11 patients and then escalated to 1500 mg for remaining patients. Patients are evaluated after every 28-day cycle. The primary efficacy endpoint is 6-month progression-free survival. Results: Sixteen patients (14 male) have been enrolled, including 7 at first recurrence and 9 at second recurrence. The median age is 52 years (range, 32–64 years). Thirty-five cycles have been administered to date. Grade II-IV, attributable toxicities include transaminase elevation (grade 3, n=3; grade 2, n=1); hypophosphatemia (grade 3, n=1); anorexia (grade 2, n=1) and rash (grade 2, n=1). Six patients (38%) have achieved stable disease including one minor response. PK studies revealed similar 2ME2 exposures to those achieved among solid tumor patients treated at the same dose level and no differences between GBM patients on or not on CYP3A-inducing anti-epileptic agents. Further accrual and follow-up is ongoing. Conclusions: Continuous daily 2ME2 dosing, administered as a monotherapeutic, is well tolerated and is associated with modest anti-tumor activity among recurrent GBM patients. Combination studies with temozolomide are underway.

No significant financial relationships to disclose.

Temporal onset of hypoxia and oxidative stress after pulmonary irradiation

PURPOSE

To investigate the temporal onset of hypoxia following irradiation, and to show how it relates to pulmonary vascular damage, macrophage accumulation, and the production of reactive oxygen species and cytokines. Our previous studies showed that tissue hypoxia in the lung after irradiation contributed to radiation-induced injury.

METHODS AND MATERIALS

Female Fisher 344 rats were irradiated to the right hemithorax with a single dose of 28 Gy. Serial studies were performed up to 20 weeks following irradiation. Radionuclide lung-perfusion studies were performed to detect changes in pulmonary vasculature. Immunohistochemical studies were conducted to study macrophages, tissue hypoxia (carbonic anhydrase-9 marker), oxidative stress (8-hydroxy-2'-deoxyguanosine), and the expression of profibrogenic (transforming growth factor-beta [TGF-beta]) and proangiogenic (vascular endothelial growth factor [VEGF]) cytokines.

RESULTS

Significant changes in lung perfusion along with tissue hypoxia were observed 3 days after irradiation. Significant oxidative stress was detected 1 week after radiation, whereas macrophages started to accumulate at 4 weeks. A significant increase in TGF-beta expression was seen within 1 day after radiation, and for VEGF at 2 weeks after radiation. Levels of hypoxia, oxidative stress, and both cytokines continued to rise with time after irradiation. The steepest increase correlated with vast macrophage accumulation.

CONCLUSIONS

Early changes in lung perfusion, among other factors initiate, the development of hypoxia and chronic oxidative stress after irradiation. Tissue hypoxia is associated with a significant increase in the activation of macrophages and their continuous production of reactive oxygen species, stimulating the production of fibrogenic and angiogenic cytokines, and maintaining the development of chronic radiation-induced lung injury.