Low-dose bevacizumab is effective in radiation-induced necrosis

Can low-dose intravenous bevacizumab be as effective as high-dose bevacizumab for cerebral radiation necrosis?

Although intravenous bevacizumab (IVBEV) is the most promising treatment for cerebral radiation necrosis (CRN), there is no conclusion on the optimal dosage. Our retrospective study aimed to compare the efficacy and safety of high-dose with low-dose IVBEV in treating CRN associated with radiotherapy for brain metastases (BMs). This paper describes 75 patients who were diagnosed with CRN secondary to radiotherapy for BMs, treated with low-dose or high-dose IVBEV and followed up for a minimum of 6 months. The clinical data collected for this study include changes in brain MRI, clinical symptoms, and corticosteroid usage before, during, and after IVBEV treatment. At the 3-month mark following administration of IVBEV, a comparison of two groups revealed that the median percentage decreases in CRN volume on T2-weighted fluid-attenuated inversion recovery and T1-weighted gadolinium contrast-enhanced image (T1CE), as well as the signal ratio reduction on T1CE, were 65.8% versus 64.8% (p = 0.860), 41.2% versus 51.9% (p = 0.396), and 37.4% versus 35.1% (p = 0.271), respectively. Similarly, at 6 months post-IVBEV, the median percentage reductions of the aforementioned parameters were 59.5% versus 62.0% (p = 0.757), 39.1% versus 31.3% (p = 0.851), and 35.4% versus 28.2% (p = 0.083), respectively. Notably, the incidence of grade ≥3 adverse events was higher in the high-dose group (n = 4, 9.8%) than in the low-dose group (n = 0). Among patients with CRN secondary to radiotherapy for BMs, the administration of high-dose IVBEV did not demonstrate superiority over low-dose IVBEV. Moreover, the use of high-dose IVBEV was associated with a higher incidence of grade ≥3 adverse events compared with low-dose IVBEV.

Low-Dose Bevacizumab for the Treatment of Focal Radiation Necrosis of the Brain (fRNB): A Single-Center Case Series

Focal radiation necrosis of the brain (fRNB) is a late adverse event that can occur following the treatment of benign or malignant brain lesions with stereotactic radiation therapy (SRT) or stereotactic radiosurgery (SRS). Recent studies have shown that the incidence of fRNB is higher in cancer patients who received immune checkpoint inhibitors. The use of bevacizumab (BEV), a monoclonal antibody that targets the vascular endothelial growth factor (VEGF), is an effective treatment for fRNB when given at a dose of 5-7.5 mg/kg every two weeks. In this single-center retrospective case series, we investigated the effectiveness of a low-dose regimen of BEV (400 mg loading dose followed by 100 mg every 4 weeks) in patients diagnosed with fRNB. A total of 13 patients were included in the study; twelve of them experienced improvement in their existing clinical symptoms, and all patients had a decrease in the volume of edema on MRI scans. No clinically significant treatment-related adverse effects were observed. Our preliminary findings suggest that this fixed low-dose regimen of BEV can be a well-tolerated and cost-effective alternative treatment option for patients diagnosed with fRNB, and it is deserving of further investigation.

[Expert Consensus on the Treatment of Antiangiogenic Agents for Radiation Brain Necrosis]

Vascular damage is followed by vascular endothelial growth factor (VEGF) expression at high levels, which is an important mechanism for cerebral radiation necrosis (CRN) development. Antiangiogenic agents (Bevacizumab) alleviates brain edema symptoms caused by CRN through inhibiting VEGF and acting on vascular tissue around the brain necrosis area. Many studies have confirmed that Bevacizumab effectively relieves symptoms caused by brain necrosis, improves patients' performance status and brain necrosis imaging. Considering that the efficacy of antiangiogenic therapy is mainly related to the duration of drug action, low-dose antiangiogenic agents can achieve favorable efficacy. Prevention is the best treatment. The occurrence of CRN is associated with tumor-related factors and treatment-related factors. By controlling these factors, CRN can be effectively prevented.
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Single low-dose targeted bevacizumab infusion in adult patients with steroid-refractory radiation necrosis of the brain: a phase II open-label prospective clinical trial

OBJECTIVE

There is an unmet need for safe and rapidly effective therapies for refractory brain radiation necrosis (RN). The aim of this prospective single-arm phase II trial was to evaluate the safety and efficacy of a single low-dose targeted bevacizumab infusion after blood-brain barrier disruption (BBBD) in adult patients with steroid-refractory brain RN.

METHODS

Ten adults with steroid-refractory, imaging-confirmed brain RN were enrolled between November 2016 and January 2018 and followed for 12 months after treatment. Bevacizumab 2.5 mg/kg was administered as a one-time targeted intra-arterial infusion immediately after BBBD. Primary outcomes included safety and > 25% decrease in lesion volume. Images were analyzed by a board-certified neuroradiologist blinded to pretrial diagnosis and treatment status. Secondary outcomes included changes in headache, steroid use, and functional status and absence of neurocognitive sequelae. Comparisons were analyzed using the Fisher exact test, Mann-Whitney U-test, linear mixed models, Wilcoxon signed-rank test, and repeated-measures 1-way ANOVA.

RESULTS

Ten adults (mean ± SD [range] age 35 ± 15 [22–62] years) participated in this study. No patients died or exhibited serious adverse effects of systemic bevacizumab. At 3 months, 80% (95% CI 44%–98%) and 90% (95% CI 56%–100%) of patients demonstrated > 25% decrease in RN and vasogenic edema volume, respectively. At 12 months, RN volume decreased by 74% (median [range] 76% [53%–96%], p = 0.012), edema volume decreased by 50% (median [range] 70% [−11% to 83%], p = 0.086), and headache decreased by 84% (median [range] 92% [58%–100%], p = 0.022) among the 8 patients without RN recurrence. Only 1 (10%) patient was steroid dependent at the end of the trial. Scores on 12 of 16 (75%) neurocognitive indices increased, thereby supporting a pattern of cerebral white matter recovery. Two (20%) patients exhibited RN recurrence that required further treatment at 10 and 11 months, respectively, after bevacizumab infusion.

CONCLUSIONS

For the first time, to the authors’ knowledge, the authors demonstrated that a single low-dose targeted bevacizumab infusion resulted in durable clinical and imaging improvements in 80% of patients at 12 months after treatment without adverse events attributed to bevacizumab alone. These findings highlight that targeted bevacizumab may be an efficient one-time treatment for adults with brain RN. Further confirmation with a randomized controlled trial is needed to compare the intra-arterial approach with the conventional multicycle intravenous regimen.

Clinical trial registration no.: NCT02819479 (ClinicalTrials.gov)

Bevacizumab Treatment of Radiation-Induced Brain Necrosis: A Systematic Review

Background

Radiation brain necrosis (RBN) is a serious complication in patients receiving radiotherapy for intracranial disease. Many studies have investigated the efficacy and safety of bevacizumab in patients with RBN. In the present study, we systematically reviewed the medical literature for studies reporting the efficacy and safety of bevacizumab, as well as for studies comparing bevacizumab with corticosteroids.

Materials and Methods

We searched PubMed, Cochrane library, EMBASE, and ClinicalTrials.gov from their inception through 1 March, 2020 for studies that evaluated the efficacy and safety of bevacizumab in patients with RBN. Two investigators independently performed the study selection, data extraction, and data synthesis.

Results

Overall, the present systematic review included 12 studies (eight retrospective, two prospective, and two randomized control trials [RCTs]) involving 236 patients with RBN treated who were treated with bevacizumab. The two RCTs also had control arms comprising patients with RBN who were treated with corticosteroids/placebo (n=57). Radiographic responses were recorded in 84.7% (200/236) of patients, and radiographic progression was observed in 15.3% (36/236). Clinical improvement was observed in 91% (n=127) of responding patients among seven studies (n=113). All 12 studies reported volume reduction on T1 gadolinium enhancement MRI (median: 50%, range: 26%–80%) and/or T2 FLAIR MRI images (median: 59%, range: 48%–74%). In total, 46 responding patients (34%) had recurrence. The two RCTs revealed significantly improved radiographic response in patients treated with bevacizumab (Levin et al.: p = 0.0013; Xu et al.: p < 0.001). Both also showed clinical improvement (Levin et al.: NA; Xu et al.: p = 0.039) and significant reduction in edema volume on both T1 gadolinium enhancement MRI (Levin et al.: p=0.0058; Xu et al.: p=0.027) and T2 FLAIR MRI (Levin et al.: p=0.0149; Xu et al.: p < 0.001). Neurocognitive improvement was significantly better after 2 months of treatment in patients receiving bevacizumab than in those given corticosteroids, as assessed by the MoCA scale (p = 0.028). The recurrence rate and side effects of the treatments showed no significant differences.

Conclusions

Patients with RBN respond to bevacizumab, which can improve clinical outcomes and cognitive function. Bevacizumab appears to be more efficacious than corticosteroid-based treatment. The safety profile was comparable to that of the corticosteroids.

Bevacizumab for radiation necrosis following radiotherapy of brain metastatic disease: a systematic review & meta-analysis

Background

Radiotherapy is the mainstay of brain metastasis (BM) management. Radiation necrosis (RN) is a serious complication of radiotherapy. Bevacizumab (BV), an anti-vascular endothelial growth factor monoclonal antibody, has been increasingly used for RN treatment. We systematically reviewed the medical literature for studies reporting the efficacy and safety of bevacizumab for treatment of RN in BM patients.

Materials and methods

PubMed, Medline, EMBASE, and Cochrane library were searched with various search keywords such as “bevacizumab” OR “anti-VEGF monoclonal antibody” AND “radiation necrosis” OR “radiation-induced brain necrosis” OR “RN” OR “RBN” AND “Brain metastases” OR “BM” until 1st Aug 2020. Studies reporting the efficacy and safety of BV treatment for BM patients with RN were retrieved. Study selection and data extraction were carried out by independent investigators. Open Meta Analyst software was used as a random effects model for meta-analysis to obtain mean reduction rates.

Results

Two prospective, seven retrospective, and three case report studies involving 89 patients with RN treated with BV were included in this systematic review and meta-analysis. In total, 83 (93%) patients had a recorded radiographic response to BV therapy, and six (6.7%) had experienced progressive disease. Seven studies (n = 73) reported mean volume reductions on gadolinium-enhanced T1 (mean: 47.03%, +/− 24.4) and T2-weighted fluid-attenuated inversion recovery (FLAIR) MRI images (mean: 61.9%, +/− 23.3). Pooling together the T1 and T2 MRI reduction rates by random effects model revealed a mean of 48.58 (95% CI: 38.32–58.85) for T1 reduction rate and 62.017 (95% CI: 52.235–71.799) for T2W imaging studies. Eighty-five patients presented with neurological symptoms. After BV treatment, nine (10%) had stable symptoms, 39 (48%) had improved, and 34 (40%) patients had complete resolution of their symptoms. Individual patient data was available for 54 patients. Dexamethasone discontinuation or reduction in dosage was observed in 30 (97%) of 31 patients who had recorded dosage before and after BV treatment. Side effects were mild.

Conclusions

Bevacizumab presents a promising treatment strategy for patients with RN and brain metastatic disease. Radiographic response and clinical improvement was observed without any serious adverse events. Further class I evidence would be required to establish a bevacizumab recommendation in this group of patients.

Radioprotection and Radiomitigation: From the Bench to Clinical Practice

The development of protective agents against harmful radiations has been a subject of investigation for decades. However, effective (ideal) radioprotectors and radiomitigators remain an unsolved problem. Because ionizing radiation-induced cellular damage is primarily attributed to free radicals, radical scavengers are promising as potential radioprotectors. Early development of such agents focused on thiol synthetic compounds, e.g., amifostine (2-(3-aminopropylamino) ethylsulfanylphosphonic acid), approved as a radioprotector by the Food and Drug Administration (FDA, USA) but for limited clinical indications and not for nonclinical uses. To date, no new chemical entity has been approved by the FDA as a radiation countermeasure for acute radiation syndrome (ARS). All FDA-approved radiation countermeasures (filgrastim, a recombinant DNA form of the naturally occurring granulocyte colony-stimulating factor, G-CSF; pegfilgrastim, a PEGylated form of the recombinant human G-CSF; sargramostim, a recombinant granulocyte macrophage colony-stimulating factor, GM-CSF) are classified as radiomitigators. No radioprotector that can be administered prior to exposure has been approved for ARS. This differentiates radioprotectors (reduce direct damage caused by radiation) and radiomitigators (minimize toxicity even after radiation has been delivered). Molecules under development with the aim of reaching clinical practice and other nonclinical applications are discussed. Assays to evaluate the biological effects of ionizing radiations are also analyzed.

Bevacizumab for pediatric radiation necrosis

Background

Radiation necrosis is a frequent complication occurring after the treatment of pediatric brain tumors; however, treatment options remain a challenge. Bevacizumab is an anti-VEGF monoclonal antibody that has been shown in small adult cohorts to confer a benefit, specifically a reduction in steroid usage, but its use in children has not been well described.

Methods

We describe our experience with bevacizumab use for symptomatic radiation necrosis at 5 institutions including patients treated after both initial irradiation and reirradiation.

Results

We identified 26 patients treated with bevacizumab for symptomatic radiation necrosis, with a wide range of underlying diagnoses. The average age at diagnosis of radiation necrosis was 10.7 years, with a median time between the last dose of radiation and the presentation of radiation necrosis of 3.8 months (range, 0.6-110 months). Overall, we observed that 13 of 26 patients (50%) had an objective clinical improvement, with only 1 patient suffering from significant hypertension. Radiological improvement, defined as reduced T2/fluid-attenuated inversion recovery signal and mass effect, was observed in 50% of patients; however, this did not completely overlap with clinical response. Both early and late radiation necrosis responded equally well to bevacizumab therapy. Overall, bevacizumab was very well tolerated, permitting a reduction of corticosteroid dose and/or duration in the majority of patients.

Conclusions

Bevacizumab appears to be effective and well-tolerated in children as treatment for symptomatic radiation necrosis and warrants more robust study in the context of controlled clinical trials.

Ultra-Low-Dose Bevacizumab For Cerebral Radiation Necrosis: A Prospective Phase II Clinical Study

Objective

To investigate the treatment efficacy of ultra-low-dose bevacizumab for cerebral radiation necrosis.

Methods

Patients with cerebral radiation necrosis after stereotactic radiotherapy (SRT) confirmed by imaging were included. Bevacizumab (1 mg/kg, once every three weeks, for at least three continuous treatments) was administered. The primary endpoints included change in cerebral necrosis symptoms, volume of intracranial edema, and changes in MRI signals. The secondary endpoints were adverse reactions of bevacizumab treatment.

Results

In total, 21 patients were included in this study, all of whom received SRT between December 2016 and February 2019, developed cerebral radiation necrosis, and were treated with bevacizumab. Twenty patients were symptomatic from radiation necrosis, and the symptoms were alleviated in 18 patients (90%). Twenty patients had intracranial edema, and the grade of edema index (EI) was improved in 19 patients (95%). The intensity of the intracranial-enhanced MRI signals was significantly reduced in 20 patients (95.24%). The adverse reactions of bevacizumab treatment were mild, and no adverse reactions more severe than grade 2 were found.

Conclusion

The preliminary results showed that ultra-low-dose bevacizumab had high efficacy for treating cerebral radiation necrosis, and could be a valid alternative to the standard-dose bevacizumab.

Clinical registry

Chinese clinical trial registry (ChiCTR-IOD-16009803).

Bevacizumab treatment for radiation brain necrosis: mechanism, efficacy and issues

Vascular damage is followed by vascular endothelial growth factor (VEGF) expression at high levels, which is an important mechanism forradiation brain necrosis development. Bevacizumab alleviates brain edema symptoms caused by radiation brain necrosis through inhibiting VEGF and acting on vascular tissue around the brain necrosis area. Many studies have confirmed that bevacizumab effectively relieves symptoms caused by brain necrosis, improves patients' Karnofsky performance status (KPS) scores and brain necrosis imaging. However, necrosis is irreversible, and hypoxia and ischemia localized in the brain necrosis area may easily lead to radiation brain necrosis recurrence after bevacizumab is discontinued. Further studies are necessary to investigate brain necrosis diagnoses, bevacizumab indications, and the optimal mode of administration, bevacizumab resistance and necrosis with a residual or recurrent tumor.

Bevacizumab as an effective treatment for radiation necrosis after radiotherapy for melanoma brain metastases

Radiation necrosis (RN) is a potential late complication of radiotherapy for intracranial malignancy, which is often associated with significant neurological morbidity. Prolonged treatment with high-dose corticosteroids or surgical resection has been the standard care for RN, but protracted steroid use can lead to significant side effects and surgical resection is not always feasible. The antivascular endothelial growth factor monoclonal antibody bevacizumab induces clinical and radiographic improvements in RN, with overall good tolerance. However, evidence supporting its use for RN in melanoma brain metastases is minimal, likely secondary to concern for intracranial bleeding. Immunotherapy is now one of the most commonly used and effective therapies for metastatic melanoma. A higher risk of RN has been reported with immunotherapy, making alternative treatment for RN in this population a priority, especially as prolonged use of steroids may counteract the treatment efficacy of immunotherapy. We report on seven melanoma patients who developed RN after stereotactic radiosurgery with or without whole-brain radiation therapy who were treated with 2-6 doses of bevacizumab. All patients experienced improvements in symptoms and quality of life, with a concurrent improvement in imaging in six patients. Furthermore, bevacizumab was well tolerated and none of the seven patients experienced intracranial or extracranial bleeding. Our series suggests that in selected melanoma brain metastases patients, bevacizumab may be a safe and effective treatment for RN, especially for those who are undergoing immunotherapy, and should be further evaluated in a prospective setting.

Bevacizumab for the Treatment of Radiation-Induced Cerebral Necrosis: A Systematic Review of the Literature

Radiation necrosis (RN) of brain tissue is a serious late complication of brain irradiation and recently bevacizumab has been suggested as treatment option of RN. There is a lack of data in the literature regarding the effectiveness of bevacizumab for the treatment of RN. The purpose of this review was to perform a comprehensive analysis of all reported cases using bevacizumab for the treatment of brain RN. In September 2016, we performed a comprehensive literature search of the following electronic databases: PubMed, Web of Science, Scopus and Cochrane Library. The research for the review was conducted using a combination of the keywords "radiation necrosis", "radiotherapy" and "bevacizumab" alongside the fields comprising article title, abstract and keywords. Randomized trials, non-randomized trials, prospective studies, retrospective studies and single case reports were included in the review. Our research generated 21 studies and 125 cases where bevacizumab had been used for the treatment of RN. The median follow-up was 8 months and the most frequent bevacizumab dose used was 7.5 mg/kg for 2 weeks with a median of four cycles. Low-dose bevacizumab resulted in effectiveness with improvement in both clinical and radiographic response. The median decrease in T1 contrast enhancement and in T2/FLAIR signal abnormality was 64% and 60%, respectively. A reduction in steroidal therapy was observed in majority of patients treated. Based on the data of our review, bevacizumab appears to be a promising agent for the treatment of brain RN. Future prospective studies are required to evaluate the role of bevacizumab in RN and to define the optimal scheduling, dosage and duration of therapy.

Treatment of Melanoma CNS Metastases

The discovery of the BRAFV600 mutation and the development of targeted therapies directed against this mutation as well as effective immunotherapies with durable benefits have revolutionized the treatment of patients with melanoma. Nonetheless, the frequent occurrence of brain metastases in patients with advanced melanoma represents a significant obstacle to long-term, high quality survival. The application of stereotactic radiation therapy has provided an opportunity to control brain metastases in the majority of patients with metastatic melanoma reducing the impact of these lesions on morbidity and mortality and enabling patients to receive and potentially benefit from these novel systemic treatments. Encouragingly, several of these novel new therapies have shown antitumor activity against CNS metastases that approach that seen against extracranial disease. As a consequence, several effective treatment options are now available for patients with melanoma brain metastases. With these tools in hand, it is anticipated that further investigation into the optimal sequence and/or combination of systemic therapies and local therapies along with multidisciplinary team practice will continue to improve the outcome of patients with this previously life-limiting disease complication.