Filip de Vos

Single-agent bevacizumab or lomustine versus a combination of bevacizumab plus lomustine in patients with recurrent glioblastoma (BELOB trial): a randomised controlled phase 2 trial

BACKGROUND Treatment options for recurrent glioblastoma are scarce, with second-line chemotherapy showing only modest activity against the tumour. Despite the absence of well controlled trials, bevacizumab is widely used in the treatment of recurrent glioblastoma. Nonetheless, whether the high response rates reported after treatment with this drug translate into an overall survival benefit remains unclear. We report the results of the first randomised controlled phase 2 trial of bevacizumab in recurrent glioblastoma. METHODS The BELOB trial was an open-label, three-group, multicentre phase 2 study undertaken in 14 hospitals in the Netherlands. Adult patients (≥18 years of age) with a first recurrence of a glioblastoma after temozolomide chemoradiotherapy were randomly allocated by a web-based program to treatment with oral lomustine 110 mg/m(2) once every 6 weeks, intravenous bevacizumab 10 mg/kg once every 2 weeks, or combination treatment with lomustine 110 mg/m(2) every 6 weeks and bevacizumab 10 mg/kg every 2 weeks. Randomisation of patients was stratified with a minimisation procedure, in which the stratification factors were centre, Eastern Cooperative Oncology Group performance status, and age. The primary outcome was overall survival at 9 months, analysed by intention to treat. A safety analysis was planned after the first ten patients completed two cycles of 6 weeks in the combination treatment group. This trial is registered with the Nederlands Trial Register (www.trialregister.nl, number NTR1929). FINDINGS Between Dec 11, 2009, and Nov 10, 2011, 153 patients were enrolled. The preplanned safety analysis was done after eight patients had been treated, because of haematological adverse events (three patients had grade 3 thrombocytopenia and two had grade 4 thrombocytopenia) which reduced bevacizumab dose intensity; the lomustine dose in the combination treatment group was thereafter reduced to 90 mg/m(2). Thus, in addition to the eight patients who were randomly assigned to receive bevacizumab plus lomustine 110 mg/m(2), 51 patients were assigned to receive bevacizumab alone, 47 to receive lomustine alone, and 47 to receive bevacizumab plus lomustine 90 mg/m(2). Of these patients, 50 in the bevacizumab alone group, 46 in the lomustine alone group, and 44 in the bevacizumab and lomustine 90 mg/m(2) group were eligible for analyses. 9-month overall survival was 43% (95% CI 29-57) in the lomustine group, 38% (25-51) in the bevacizumab group, 59% (43-72) in the bevacizumab and lomustine 90 mg/m(2) group, 87% (39-98) in the bevacizumab and lomustine 110 mg/m(2) group, and 63% (49-75) for the combined bevacizumab and lomustine groups. After the reduction in lomustine dose in the combination group, the combined treatment was well tolerated. The most frequent grade 3 or worse toxicities were hypertension (13 [26%] of 50 patients in the bevacizumab group, three [7%] of 46 in the lomustine group, and 11 [25%] of 44 in the bevacizumab and lomustine 90 mg/m(2) group), fatigue (two [4%], four [9%], and eight [18%]), and infections (three [6%], two [4%], and five [11%]). At the time of this analysis, 144/148 (97%) of patients had died and three (2%) were still on treatment. INTERPRETATION The combination of bevacizumab and lomustine met prespecified criteria for assessment of this treatment in further phase 3 studies. However, the results in the bevacizumab alone group do not justify further studies of this treatment. FUNDING Roche Nederland and KWF Kankerbestrijding.

Phase I Safety, Pharmacokinetic, and Pharmacodynamic Study of the Thrombospondin-1–Mimetic Angiogenesis Inhibitor ABT-510 in Patients With Advanced Cancer

PURPOSE ABT-510 is an angiogenesis inhibitor derived from thrombospondin-1, a naturally occurring inhibitor of angiogenesis. We investigated ABT-510, which was administered subcutaneously in patients with advanced solid malignancies, to assess safety, pharmacokinetics, and serum markers of angiogenesis. PATIENTS AND METHODS ABT-510 was administered subcutaneously as a continuous infusion (100 mg/24 h) and bolus injections (100, 200, and 260 mg once daily; 50 and 100 mg twice daily) in 28-day cycles. RESULTS Thirty-nine patients received a total of 144 treatment cycles. Administration by continuous infusion was hampered by the onset of painful skin infiltrates at the injection site. In the bolus injection regimens, the most common toxicities observed were mild injection-site reactions and fatigue. Maximum-tolerated dose was not defined, but 260 mg was defined as the maximum clinically practical dose. ABT-510 pharmacokinetics were linear across the dosage ranges tested, and the potential therapeutic threshold (plasma concentrations > 100 ng/mL > 3 h/d) was achieved with all dose regimens. Median serum basic fibroblast growth factor (bFGF) levels decreased from 14.1 pg/mL (range, 0.5 to 77.7 pg/mL) at baseline to 3.2 pg/mL (range, 0.2 to 29.4 pg/mL) after 56 days of treatment (P = .003). No correlations with time on study or ABT-510 dose or exposure were observed for individual changes in bFGF. Stable disease lasting for six cycles or more was seen in six patients. CONCLUSION ABT-510 demonstrated a favorable toxicity profile and linear and time-independent pharmacokinetics with biologically relevant plasma concentrations. The significant number of patients with prolonged stable disease and the convenient method of dosing merit further studies with this angiogenesis inhibitor.

Dextromethorphan As a Phenotyping Test to Predict Endoxifen Exposure in Patients on Tamoxifen Treatment

PURPOSE Tamoxifen, a widely used agent for the prevention and treatment of breast cancer, is mainly metabolized by CYP2D6 and CYP3A to form its most abundant active metabolite, endoxifen. Interpatient variability in toxicity and efficacy of tamoxifen is substantial. Contradictory results on the value of CYP2D6 genotyping to reduce the variable efficacy have been reported. In this pharmacokinetic study, we investigated the value of dextromethorphan, a known probe drug for both CYP2D6 and CYP3A enzymatic activity, as a potential phenotyping probe for tamoxifen pharmacokinetics. METHODS In this prospective study, 40 women using tamoxifen for invasive breast cancer received a single dose of dextromethorphan 2 hours after tamoxifen intake. Dextromethorphan, tamoxifen, and their respective metabolites were quantified. Exposure parameters of all compounds were estimated, log transformed, and subsequently correlated. RESULTS A strong and highly significant correlation (r = -0.72; P < .001) was found between the exposures of dextromethorphan (0 to 6 hours) and endoxifen (0 to 24 hours). Also, the area under the plasma concentration-time curve of dextromethorphan (0 to 6 hours) and daily trough endoxifen concentration was strongly correlated (r = -0.70; P < .001). In a single patient using the potent CYP2D6 inhibitor paroxetine, the low endoxifen concentration was accurately predicted by dextromethorphan exposure. CONCLUSION Dextromethorphan exposure after a single administration adequately predicted endoxifen exposure in individual patients with breast cancer taking tamoxifen. This test could contribute to the personalization and optimization of tamoxifen treatment, but it needs additional validation and simplification before being applicable in future dosing strategies.

Valproic acid for the treatment of malignant gliomas: review of the preclinical rationale and published clinical results.

Introduction: Glioblastoma multiforme is the most common and aggressive primary brain tumor. Valproate has been used as an anti-epileptic drug and mood stabilizer for decades. Recently, it was found to inhibit the proliferation of various cancers including glioblastoma multiforme. Areas covered: We provide a comprehensive review of the mechanisms of action of valproate in gliomas, of its potential side effects and of the published clinical results obtained with this drug in glioblastomas. Valproate inhibits a subset of histone deacetylases and cellular kinases, and affects gene transcription through histone hyperacetylation, DNA hypomethylation and the modulation of several transcription factors. As a result, VPA induces differentiation of glioma cells, can prevent their invasion in surrounding tissues and may inhibit tumor angiogenesis. VPA can also inhibit DNA repair, thereby potentiating cytotoxic treatments such as chemotherapies or radiation therapy. Based on these mechanisms and case reports of glioblastoma remissions following VPA treatment, several clinical studies currently assess the therapeutic potential of VPA in glioma therapy. Expert opinion: The combination of VPA treatment with chemotherapy and radiotherapy in glioblastoma appears a rational option that deserves well-designed prospective clinical trials that assess the efficacy and the molecular characteristics of the responding tumors in these patients.

The impact of bevacizumab on health-related quality of life in patients treated for recurrent glioblastoma: Results of the randomised controlled phase 2 BELOB trial

BACKGROUND The BELOB study, a randomised controlled phase 2 trial comparing lomustine, bevacizumab and combined lomustine and bevacizumab in patients with recurrent glioblastoma, showed that the 9-month overall survival rate was most promising in the combination arm. Here we report the health-related quality of life (HRQoL) results, a secondary trial end-point. METHODS HRQoL was measured at baseline and every 6weeks until progression using the European Organisation for Research and Treatment of Cancer (EORTC) core questionnaire (QLQ-C30) and brain module (QLQ-BN20). HRQoL was assessed over time for five preselected scales (global health (GH), physical (PF) and social functioning (SF), motor dysfunction (MD) and communication deficit (CD)). Moreover, mean changes in HRQoL from baseline until progression were determined. RESULTS 138/148 patients with at least a baseline HRQoL assessment were analysed. Over time, HRQoL remained relatively stable in all treatment arms for all five scales, at least during the first three treatment cycles. More than half (54-61%) of the patients showed stable (<10 point change) or improved (⩾10 point change) HRQoL during their progression-free time, except for SF (43%), irrespective of treatment arm. Deterioration of mean HRQoL was most profound at disease progression for all scales except SF, which deteriorated earlier in disease course. Compared to baseline, 40% of patients had clinically relevant (⩾10 points) worse GH, PF and SF, while 44% and 31% had increased MD and CD at disease progression, irrespective of treatment arm. CONCLUSIONS Bevacizumab, whether or not in combination with lomustine, did not negatively affect HRQoL in patients treated for recurrent glioblastoma in this randomised study.

Combined BRAF, EGFR, and MEK Inhibition in Patients with BRAFV600E-Mutant Colorectal Cancer

Although BRAF inhibitor monotherapy yields response rates >50% in BRAFV600-mutant melanoma, only approximately 5% of patients with BRAFV600E colorectal cancer respond. Preclinical studies suggest that the lack of efficacy in BRAFV600E colorectal cancer is due to adaptive feedback reactivation of MAPK signaling, often mediated by EGFR. This clinical trial evaluated BRAF and EGFR inhibition with dabrafenib (D) + panitumumab (P) ± MEK inhibition with trametinib (T) to achieve greater MAPK suppression and improved efficacy in 142 patients with BRAFV600E colorectal cancer. Confirmed response rates for D+P, D+T+P, and T+P were 10%, 21%, and 0%, respectively. Pharmacodynamic analysis of paired pretreatment and on-treatment biopsies found that efficacy of D+T+P correlated with increased MAPK suppression. Serial cell-free DNA analysis revealed additional correlates of response and emergence of KRAS and NRAS mutations on disease progression. Thus, targeting adaptive feedback pathways in BRAFV600E colorectal cancer can improve efficacy, but MAPK reactivation remains an important primary and acquired resistance mechanism.Significance: This trial demonstrates that combined BRAF + EGFR + MEK inhibition is tolerable, with promising activity in patients with BRAFV600E colorectal cancer. Our findings highlight the MAPK pathway as a critical target in BRAFV600E colorectal cancer and the need to optimize strategies inhibiting this pathway to overcome both primary and acquired resistance. Cancer Discov; 8(4); 428-43. ©2018 AACR.See related commentary by Janku, p. 389See related article by Hazar-Rethinam et al., p. 417This article is highlighted in the In This Issue feature, p. 371.

Pneumocystis jirovecii pneumonia prophylaxis during temozolomide treatment for high-grade gliomas

High-grade glioma patients receiving concomitant chemoradiotherapy with temozolomide 75mg/m(2) during six to seven weeks or dose-dense temozolomide regimens especially in combination with chronic use of corticosteroids have a high risk for developing Pneumocystis jirovecii pneumonia. In this review, we define risk groups and propose a guideline for prophylaxis using risk stratification.

Primary intracranial germ-cell tumors in adults: a practical review

Primary intracranial germ-cell tumors are rare tumors primarily of adolescence, and literature on this disease in adults is scarce. The available evidence on intracranial germ-cell tumors is reviewed with a focus on adult patients whenever possible, and used to make suggestions for diagnosis and treatment. Diagnostic and treatment algorithms were developed to provide an evidence-based backbone to base treatment on in adult patients with a (suspected) primary intracranial germ-cell tumor.

Venous thromboembolism and intracranial hemorrhage after craniotomy for primary malignant brain tumors: a National Surgical Quality Improvement Program analysis

Venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), frequently complicates the postoperative course of primary malignant brain tumor patients. Thromboprophylactic anticoagulation is commonly used to prevent VTE at the risk of intracranial hemorrhage (ICH). We extracted all patients who underwent craniotomy for a primary malignant brain tumor from the National Surgical Quality Improvement Program (NSQIP) registry (2005–2015) to perform a time-to-event analysis and identify relevant predictors of DVT, PE, and ICH within 30 days after surgery. Among the 7376 identified patients, the complication rates were 2.6, 1.5, and 1.3% for DVT, PE, and ICH, respectively. VTE was the second-most common major complication and third-most common reason for readmission. ICH was the most common reason for reoperation. The increased risk of VTE extends beyond the period of hospitalization, especially for PE, whereas ICH occurred predominantly within the first days after surgery. Older age and higher BMI were overall predictors of VTE. Dependent functional status and longer operative times were predictive for VTE during hospitalization, but not for post-discharge events. Admission two or more days before surgery was predictive for DVT, but not for PE. Preoperative steroid usage and male gender were predictive for post-discharge DVT and PE, respectively. ICH was associated with various comorbidities and longer operative times. This multicenter study demonstrates distinct critical time periods for the development of thrombotic and hemorrhagic events after craniotomy. Furthermore, the VTE risk profile depends on the type of VTE (DVT vs. PE) and clinical setting (hospitalized vs. post-discharge patients).

Diagnostic challenges of respiratory adverse events during everolimus treatment

Everolimus has important clinical activity in various malignancies, but its use can be complicated by respiratory adverse events. Important everolimus-induced respiratory adverse events are interstitial lung disease (ILD) and infections, either typical or opportunistic. Furthermore, non-everolimus-related respiratory events can occur. Due to the non-specific presentation of most of these respiratory disorders, it is often not possible to differentiate between these causes on clinical and radiological grounds only. Considering the potential fatal nature of opportunistic infections, these are especially important to recognize. To be able to distinguish between ILD and (opportunistic) infections as the underlying cause, an aggressive diagnostic workup, including bronchoalveolar lavage, should be performed in patients treated with everolimus who develop respiratory disease. We report three cases of severe opportunistic pulmonary infections during everolimus treatment, concerning two Pneumocystis jirovecii pneumonia infections. These cases illustrate the diagnostic challenges of respiratory adverse events and the importance of a thorough diagnostic workup for correct diagnosis and treatment.