Phase 1 dose-escalation study of the antiplacental growth factor monoclonal antibody RO5323441 combined with bevacizumab in patients with recurrent glioblastoma

BACKGROUND

We conducted a phase 1 dose-escalation study of RO5323441, a novel antiplacental growth factor (PlGF) monoclonal antibody, to establish the recommended dose for use with bevacizumab and to investigate the pharmacokinetics, pharmacodynamics, safety/tolerability, and preliminary clinical efficacy of the combination.

METHODS

Twenty-two participants with histologically confirmed glioblastoma in first relapse were treated every 2 weeks with RO5323441 (625 mg, 1250 mg, or 2500 mg) plus bevacizumab (10 mg/kg). A standard 3 + 3 dose-escalation trial design was used.

RESULTS

RO5323441 combined with bevacizumab was generally well tolerated, and the maximum tolerated dose was not reached. Two participants experienced dose-limiting toxicities (grade 3 meningitis associated with spinal fluid leak [1250 mg] and grade 3 cerebral infarction [2500 mg]). Common adverse events included hypertension (14 participants, 64%), headache (12 participants, 55%), dysphonia (11 participants, 50%) and fatigue (6 participants, 27%).The pharmacokinetics of RO5323441 were linear, over-the-dose range, and bevacizumab exposure was unaffected by RO5323441 coadministration. Modulation of plasmatic angiogenic proteins, with increases in VEGFA and decreases in FLT4, was observed. Dynamic contrast-enhanced/diffusion-weighted MRI revealed large decreases in vascular parameters that were maintained through the dosing period. Combination therapy achieved an overall response rate of 22.7%, including one complete response, and median progression-free and overall survival of 3.5 and 8.5 months, respectively.

CONCLUSION

The toxicity profile of RO5323441 plus bevacizumab was acceptable and manageable. The observed clinical activity of the combination does not appear to improve on that obtained with single-agent bevacizumab in patients with recurrent glioblastoma.

Cilengitide combined with standard treatment for patients with newly diagnosed glioblastoma with methylated MGMT promoter (CENTRIC EORTC 26071-22072 study): a multicentre, randomised, open-label, phase 3 trial

BACKGROUND

Cilengitide is a selective αvβ3 and αvβ5 integrin inhibitor. Data from phase 2 trials suggest that it has antitumour activity as a single agent in recurrent glioblastoma and in combination with standard temozolomide chemoradiotherapy in newly diagnosed glioblastoma (particularly in tumours with methylated MGMT promoter). We aimed to assess cilengitide combined with temozolomide chemoradiotherapy in patients with newly diagnosed glioblastoma with methylated MGMT promoter.

METHODS

In this multicentre, open-label, phase 3 study, we investigated the efficacy of cilengitide in patients from 146 study sites in 25 countries. Eligible patients (newly diagnosed, histologically proven supratentorial glioblastoma, methylated MGMT promoter, and age ≥18 years) were stratified for prognostic Radiation Therapy Oncology Group recursive partitioning analysis class and geographic region and centrally randomised in a 1:1 ratio with interactive voice response system to receive temozolomide chemoradiotherapy with cilengitide 2000 mg intravenously twice weekly (cilengitide group) or temozolomide chemoradiotherapy alone (control group). Patients and investigators were unmasked to treatment allocation. Maintenance temozolomide was given for up to six cycles, and cilengitide was given for up to 18 months or until disease progression or unacceptable toxic effects. The primary endpoint was overall survival. We analysed survival outcomes by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00689221.

FINDINGS

Overall, 3471 patients were screened. Of these patients, 3060 had tumour MGMT status tested; 926 patients had a methylated MGMT promoter, and 545 were randomly assigned to the cilengitide (n=272) or control groups (n=273) between Oct 31, 2008, and May 12, 2011. Median overall survival was 26·3 months (95% CI 23·8-28·8) in the cilengitide group and 26·3 months (23·9-34·7) in the control group (hazard ratio 1·02, 95% CI 0·81-1·29, p=0·86). None of the predefined clinical subgroups showed a benefit from cilengitide. We noted no overall additional toxic effects with cilengitide treatment. The most commonly reported adverse events of grade 3 or worse in the safety population were lymphopenia (31 [12%] in the cilengitide group vs 26 [10%] in the control group), thrombocytopenia (28 [11%] vs 46 [18%]), neutropenia (19 [7%] vs 24 [9%]), leucopenia (18 [7%] vs 20 [8%]), and convulsion (14 [5%] vs 15 [6%]).

INTERPRETATION

The addition of cilengitide to temozolomide chemoradiotherapy did not improve outcomes; cilengitide will not be further developed as an anticancer drug. Nevertheless, integrins remain a potential treatment target for glioblastoma.

FUNDING

Merck KGaA, Darmstadt, Germany.

Phase I study of anti-PlGF monoclonal antibody (mAb) RO5323441 (RO) and anti-VEGF mab bevacizumab (BV) in patients with recurrent glioblastoma (GBM)

2092

Background: BV inhibits VEGF and is approved for progressive GBM following prior therapy. The placental growth factor (PlGF) is a member of the VEGF family and PlGF expression has been shown to correlate with tumor stage and survival in several human malignancies. In cancer patients (pts) PlGF is up-regulated upon treatment with VEGF inhibitors. RO is a humanized IgG1 mAb directed against PlGF that has demonstrated antitumor activity in an orthotopic GBM model. Single agent RO was previously tested in advanced solid tumors. Methods: Eligibility criteria included histologically confirmed GBM with documented radiographic progression upon front line therapy, ≥18 years of age, KPS ≥70, adequate bone marrow reserve and organ function. Prior treatment with VEGF/PLGF targeted therapies was not permitted. Three to six pts were enrolled per dose level (DL), the MTD defined as the dose with DLTs ≤ 1/6 pts during 28-days of cycle 1, using CTCAE v4. Results: A total of 22 pts (16m/6f) have been enrolled in 3 DLs: RO 625mg (4 pts), 1250mg (6), and 2500mg (12) IV every 2 weeks (q2w), each in combination with BV 10mg/kg IV q2w. Median age: 58 years (range 37-72). RO serum concentrations increased proportionally, while serum exposures of BV were similar between all DLs. Two pts experienced a DLT: Meningitis G3 (1250 mg) and cerebral infarction G3 (2500 mg). Most commonly reported adverse events included hypertension (14 pts), headache (11), dysphonia (10), fatigue (6), nasopharyngitis (5), epistaxis (4), constipation (4), nausea (3), and arthralgia (3). Across all DLs tested, the overall response rate by RANO criteria was 22.7%. Conclusions: The tolerability of RO in combination with BV is acceptable; a MTD was not determined. Anti-PlGF treatment does not appear to add on clinical activity observed for single agent BV in recurrent GBM. Clinical trial information: NCT01308684.

The concepts, diagnosis and management of early imaging changes after therapy for glioblastomas

Since postoperative radiotherapy plus concomitant temozolomide followed by adjuvant temozolomide has become standard treatment for glioblastoma, the phenomenon of early post-treatment enlargement of the imaged tumour volume, usually without clinical deterioration, has become widely recognised. The term pseudoprogression has been used to describe a poorly understood pathophysiological process. In this review, the pathophysiological concepts, relevance, diagnosis and management of patients with 'pseudoprogression' and 'pseudoresponse' are discussed. Guidelines are given with respect to radiological imaging modality, mode and frequency. Further biological and clinical insights into these phenomena require carefully designed prospective studies.

Symptom experience in patients with primary brain tumours: a longitudinal exploratory study

PURPOSE

This study was undertaken to further understand the symptom experience and the impact of symptoms in daily life in people treated for brain tumours.

METHODS

A qualitative prospective longitudinal design was used with 9 people who were interviewed over 4 time points (soon after diagnosis, 3 months, 6 months and 12-months post-diagnosis), providing 21 interviews in total.

RESULTS

Key issues for these participants were ongoing fatigue, memory loss and inability to drive. Fatalistic views about the outcomes of their disease were the norm. Participants made adjustments to their lives to accommodate their functional limitations. These included making home alterations, introducing regular exercise to their lives and using complementary therapies. Their expectations did not always match with the reality of the situation, which made several participants angry and dissatisfied with health care professionals.

CONCLUSIONS

Issues of quality of life are paramount in this group of poor prognosis patients, therefore, health professionals should provide preparatory information to patients on what to expect from the illness and its treatments. Health professionals should also assist patients to manage debilitating symptoms such as fatigue and cognitive impairment.

Online adaptive radiotherapy of the bladder: Small bowel irradiated-volume reduction

PURPOSE

To assess the potential reduction of small bowel volume receiving high-dose radiation by using kilovoltage X-ray cone beam computed tomography (CBCT) and quantized margin selection for adaptive bladder cancer treatment.

METHODS AND MATERIALS

Twenty bladder patients were planned conformally using a four-field, 15-mm uniform margin technique. Two additional planning target volumes (PTVs) were created using margins quantized to 5 and 10 mm in the superior direction only. CBCTs (approximately 8 scans/patient) were acquired during treatment. CBCT volumes were registered with CT planning scans to determine setup errors and to select the appropriate PTV of the day. Margin reduction in other directions was considered. Outlining of small bowel in every fraction is required to properly quantify the volume of small bowel spared from high doses. In the case of CBCT this is not always possible owing to artifacts created by small bowel movement and the presence of gas. A simpler method was adopted by considering the volume difference between PTVs created using uniform and adapted margins, which corresponds to the potential volume of small bowel sparing.

RESULTS

The average small bowel volume that can be spared by this form of adaptive radiotherapy is 31 +/- 23 cm3 (+/-1 SD). The bladder for 1 patient was systematically smaller than the planning scan and hence demonstrated the largest average reduction of 76 cm3. The clinical target volume to PTV margins in other directions can be safely reduced to 10 mm except in the anterior direction where, like the superior direction, the bladder showed significant variation.

CONCLUSIONS

Online CBCT-assisted plan selection based on quantized margins can significantly reduce the volume of small bowel receiving high doses for some bladder patients. CBCT allows the 15-mm margins used in some directions to be safely reduced to 10 mm.

Dual-component miniature excitatory synaptic currents in rat hippocampal CA3 pyramidal neurons

1. Spontaneous miniature synaptic events were studied with tight-seal whole-cell recordings from CA3 neurons maintained in the hippocampal slice from immature rats (3-15 days). CA3 neurons suffer a constant, high-frequency barrage of inhibitory synaptic input. When inhibitory postsynaptic currents were suppressed by bicuculline, a smaller contribution from excitatory synapses was revealed. 2. Addition of tetrodotoxin (TTX) removed a persistent inward current and substantially reduced the baseline noise facilitating the detection of ,miniature- excitatory currents. Addition of hyperosmotic media increased the frequency of spontaneous excitatory postsynaptic currents (EPSCs). 3. Under both physiological and elevated potassium conditions, individual spontaneous miniature EPSCs (10-30 pA amplitude) were composed of components mediated by N-methyl-D-aspartate (NMDA) and non-NMDA receptors as determined by their voltage dependence, time course, and sensitivity to selective antagonists. 6-Cyano-7-nitro-quinoxaline-2,3-dione (CNQX) or D-2-amino-5-phosphonovaleric acid (D-APV) shifted the amplitude distribution of miniature EPSCs to a smaller mode at both +40 mV and -40 mV. Similar to EPSCs recorded in CA1 neurons, the rise and decay times of the NMDA receptor component were slower than those of the non-NMDA component. The time course of the non-NMDA component was voltage independent. 4. In 13 of 21 neurons, no correlation existed between individual EPSC rise times and their corresponding halfwidth, peak amplitude, or decay time constant. This suggests that the large range of EPSC kinetics observed in each individual neuron was not due solely to cable attenuation of EPSCs widely distributed over the dendritic tree. Plots of the mean EPSC rise time against mean halfwidth for each cell, however, revealed a striking correlation, suggesting that in neonates, active synapses may be grouped in a restricted region of the dendritic tree and as such are subject to similar amounts of dendritic filtering. 5. The electrotonic length of CA3 neurons (L = 0.52) predicted that at this maturity the electrotonic compactness of the neuron facilitated voltage control over all but the most distal synapses. The reversal potential of the fast component of spontaneous events was close to 0 mV, whereas the reversal potential of exogenously applied kainate and NMDA was more positive. This discrepancy likely reflects a compromise of the voltage clamp by the activation of conductances distributed over the entire cell.(ABSTRACT TRUNCATED AT 400 WORDS)