Distinguishing Extravascular from Intravascular Ferumoxytol Pools within the Brain: Proof of Concept in Patients with Treated Glioblastoma.

BACKGROUND AND PURPOSE: Glioblastoma-associated macrophages are a major constituent of the immune response to therapy and are known to engulf the iron-based MR imaging contrast agent, ferumoxytol. Current ferumoxytol MR imaging techniques for localizing macrophages are confounded by contaminating intravascular signal. The aim of this study was to assess the utility of a newly developed MR imaging technique, segregation and extravascular localization of ferumoxytol imaging, for differentiating extravascular-from-intravascular ferumoxytol contrast signal at a delayed 24-hour imaging time point. MATERIALS AND METHODS: Twenty-three patients with suspected post-chemoradiotherapy glioblastoma progression underwent ferumoxytol-enhanced SWI. Segregation and extravascular localization of ferumoxytol imaging maps were generated as the voxelwise difference of the delayed (24 hours) from the early (immediately after administration) time point SWI maps. Continuous segregation and extravascular localization of ferumoxytol imaging map values were separated into positive and negative components. Image-guided biologic correlation was performed. RESULTS: Negative segregation and extravascular localization of ferumoxytol imaging values correlated with early and delayed time point SWI values, demonstrating that intravascular signal detected in the early time point persists into the delayed time point. Positive segregation and extravascular localization of ferumoxytol imaging values correlated only with delayed time point SWI values, suggesting successful detection of the newly developed extravascular signal. CONCLUSIONS: Segregation and extravascular localization of ferumoxytol MR imaging improves on current techniques by eliminating intrinsic tissue and intravascular ferumoxytol signal and may inform glioblastoma outcomes by serving as a more specific metric of macrophage content compared with uncorrected T1 and SWI techniques.

Diagnostic impact of preoperative corticosteroids in primary central nervous system lymphoma.

PURPOSE: High dose corticosteroids are an effective tool for rapidly alleviating neurologic symptoms caused by intracranial mass lesions. However, there is concern that preoperative corticosteroids limit the ability to obtain a definitive pathologic diagnosis, particularly if imaging features suggest primary central nervous system lymphoma (PCNSL). METHODS: To explore the impact of preoperative corticosteroids in newly diagnosed PCNSL patients, from 2009 to 2018 treated at our institution. RESULTS: We identified 54 patients; 18 had received corticosteroids prior to biopsy or resection. Only in one case did the patient have a prior non-diagnostic biopsy, requiring a second procedure. The cumulative doses of preoperative dexamethasone ranged from 4 mg to 120 mg (mean 32 mg, median 24 mg), given over 1-14 days (mean 2 days, median 1 day), and the majority had received corticosteroids for only 1-2 days. There was a trend for a larger diameter of lesional T1 contrast enhancement for patients who received steroids (39 mm vs. 34 mm, p = 0.11). In this series of cases with pathologically and clinically proven PCNSL, preoperative corticosteroids had been given in a third of cases, suggesting that they may be given for symptomatic relief without compromising pathologic diagnosis. CONCLUSIONS: Despite the commonly held tenet that preoperative corticosteroids can obscure the pathologic diagnosis in PCNSL, this is likely not the case in the majority of patients who receive a short course preoperatively. Obtaining a second stereotactic scan to confirm continued presence of the lesion prior to tissue sampling may also mitigate these concerns.

Enhancing the cytotoxicity of chemoradiation with radiation-guided delivery of anti-MGMT morpholino oligonucleotides in non-methylated solid tumors.

The DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT) is epigenetically silenced in some tumors by MGMT gene promoter methylation. MGMT-hypermethylated solid tumors have enhanced susceptibility to the cytotoxic effects of alkylating chemotherapy such as temozolomide, compared with non-methylated tumors. In glioblastoma, subjects with MGMT hypermethylation have significantly longer survival rates after chemoradiotherapy. We report the first successful use of a non-ablative dose of ionizing radiation to prime human cancer cells to enhance the uptake of unmodified anti-MGMT morpholino oligonucleotide (AMON) sequences. We demonstrate >40% reduction in the in vitro proliferation index and cell viability in radiation-primed MGMT-expressing human solid tumor cells treated with a single dose of AMONs and temozolomide. We further demonstrate the feasibility of using a non-ablative dose of radiation in vivo to guide and enhance the delivery of intravenously administered AMONs to achieve 50% MGMT knockdown only at radiation-primed tumor sites in a subcutaneous tumor model. Local upregulation of physiological endocytosis after radiation may have a role in radiation-guided uptake of AMONs. This approach holds direct translational significance in glioblastoma and brain metastases where radiation is part of the standard of care; our approach to silence MGMT could overcome the significant problem of MGMT-mediated chemoresistance.

What Does the Boxed Warning Tell Us? Safe Practice of Using Ferumoxytol as an MRI Contrast Agent.

BACKGROUND AND PURPOSE: Despite the label change and the FDA's boxed warning added to the Feraheme (ferumoxytol) label in March 2015, radiologists have shown increasing interest in using ferumoxytol as an MR imaging contrast agent as a supplement or alternative to gadolinium. The goals of this study were to provide information regarding ferumoxytol safety as an imaging agent in a single center and to assess how the Feraheme label change may affect this potential, currently off-label indication. MATERIALS AND METHODS: This retrospective study evaluated the overall frequency of ferumoxytol-related adverse events when used for CNS MR imaging. Patients with various CNS pathologies were enrolled in institutional review board-approved imaging studies. Ferumoxytol was administered as multiple rapid bolus injections. The risk of adverse events was correlated with demographic data/medical history. RESULTS: The safety of 671 ferumoxytol-enhanced MR studies in 331 patients was analyzed. No anaphylactic, life-threatening, or fatal (grade 4 or 5) adverse events were recorded. The overall proportion of ferumoxytol-related grade 1-3 adverse events was 10.6% (8.6% occurring within 48 hours), including hypertension (2.38%), nausea (1.64%), diarrhea (1.04%), and headache (1.04%). History of 1 or 2 allergies was associated with an increased risk of adverse events (14.61% versus 7.51% [no history]; P = .007). CONCLUSIONS: The frequency of mild ferumoxytol-related adverse events was comparable with literature results, and no serious adverse event was recorded. Although the recommendations in the boxed warning should be followed, serious adverse events appear to be rare, and with proper precautions, ferumoxytol may be a valuable MR imaging agent.

Primary CNS lymphoma with intraocular involvement: International PCNSL Collaborative Group Report.

OBJECTIVE: To describe the demographics, diagnostic details, therapeutic management, and outcome in patients with primary CNS lymphoma (PCNSL) with ocular involvement. METHODS: A retrospective study of 221 patients was assembled from 16 centers in seven countries. Only HIV-negative, immunocompetent patients with brain and ocular lymphoma were included; none had systemic lymphoma. RESULTS: Median age at diagnosis was 60. Fifty-seven percent were women. Median Eastern Cooperative Oncology Group performance status was 2. Ocular disturbance and behavioral/cognitive changes were the most common presenting symptoms. Diagnosis of lymphoma was made by brain biopsy (147), vitrectomy (65), or CSF cytology (11). Diagnosis of intraocular lymphoma was made by vitrectomy/choroidal/retinal biopsy (90) or clinical ophthalmic examination (141). CSF cytology was positive in 23%. Treatment information was available for 176 patients. A total of 102 received dedicated ocular therapy (ocular radiotherapy 79, intravitreal methotrexate 22, and both 1) in addition to treatment for their brain lymphoma. Sixty-nine percent progressed at a median of 13 months; sites of progression included brain 52%, eyes 19%, brain and eyes 12%, and systemic 2%. Patients treated with local ocular therapy did not have a statistically significant decreased risk of failing in the eyes (p = 0.7). Median progression free survival and overall survival for the entire cohort were 18 and 31 months. CONCLUSION: This is the largest reported series of primary CNS lymphoma (PCNSL) with intraocular involvement. Progression free and overall survival was similar to that reported with PCNSL. Dedicated ocular therapy improved disease control but did not affect overall survival.

Primary intraocular lymphoma: an International Primary Central Nervous System Lymphoma Collaborative Group Report.

BACKGROUND: Primary intraocular lymphoma (PIOL) is an uncommon subset of primary central nervous system lymphoma. Because it is rare and difficult to diagnose, the natural history and optimal management are unknown. PATIENTS AND METHODS: A retrospective study of 83 HIV negative, immunocompetent PIOL patients was assembled from 16 centers in seven countries. RESULTS: Median age at diagnosis was 65. Median ECOG performance status was 0. Presenting symptoms included blurred vision, decreased visual acuity, and floaters. Median time to diagnosis was 6 months. Diagnosis was made by vitrectomy (74), choroidal/retinal biopsy (6) and ophthalmic exam (3). Eleven percent had positive CSF cytology. Initial treatment was categorized as focal in 23 (intra-ocular methotrexate, ocular radiotherapy) or extensive in 53 (systemic chemotherapy, whole brain radiotherapy). Six received none; details are unknown in one. Forty-seven relapsed: brain 47%, eyes 30%, brain and eyes 15%, and systemic 8%. Median time to relapse was 19 months. Focal therapy alone did not increase risk of brain relapse. Median progression free (PFS) and overall survival (OS) were 29.6 and 58 months, respectively, and unaffected by treatment type. CONCLUSION: Treatment type did not affect relapse pattern, median PFS or OS. Focal therapy may minimize treatment toxicity without compromising disease control.

Imaging and nanomedicine for diagnosis and therapy in the central nervous system: report of the eleventh annual Blood-Brain Barrier Disruption Consortium meeting.

The blood-brain barrier (BBB) presents a major obstacle to the treatment of malignant brain tumors and other central nervous system (CNS) diseases. The Eleventh Annual Blood-Brain Barrier Disruption Consortium Meeting was convened to discuss recent advances and future directions in imaging and nanomedicine. Two sessions, one on Cell and Molecular Imaging in the CNS and another on Nanotechnology, Nanobiology, and Nanomedicine, were held March 17-18, 2005, in Portland, Ore. CNS imaging presentations targeted differentiating tumor, neural lesions, and necrosis from healthy brain tissue; methods of delivery of imaging agents across the BBB; and new iron oxide-based nanoparticle contrast agents for MR imaging. Nanobiology presentations covered the development of new nanotechnology and its use in imaging, diagnosis, and therapy in the CNS. Discussions at this meeting stressed the role of biotechnology in the convergence of CNS imaging and nanomedicine and are summarized in this article.

Imaging of iron oxide nanoparticles by MR and light microscopy in patients with malignant brain tumours.

OBJECTIVE: Ferumoxtran-10 (Combidex), a dextran-coated iron oxide nanoparticle, provides enhancement of intracranial tumours by magnetic resonance (MR) for more than 24 h and can be imaged histologically by iron staining. Our goal was to compare ferumoxtran imaging and histochemistry vs. gadolinium enhancement in malignant brain tumours on preoperative and postoperative MR. METHODS: Seven patients with primary and metastatic malignant tumours underwent MR imaging with gadolinium and ferumoxtran both pre- and postoperatively. Normalized signal intensities on the ferumoxtran-enhanced scans were determined in representative regions of interest. Resected tissue from six ferumoxtran patients and from three patients who did not receive ferumoxtran was assessed for localization of iron in tumour and reactive brain. RESULTS: All malignant tumours (all of which enhanced by gadolinium MR) showed ferumoxtran accumulation with T1 and T2 signal changes, even using a 0.15 T intraoperative MR unit in one patient. Iron staining was predominantly in reactive cells (reactive astrocytes and macrophages) and not tumour cells. In five of the seven patients, including two patients who showed additional lesions, areas enhancing with ferumoxtran but not with gadolinium were observed. Comparison of the pre- and postoperative MR revealed residual ferumoxtran-enhancing areas in four of seven cases. CONCLUSION: In malignant tumours, ferumoxtran may show areas of enhancement, even with a 0.15 T intraoperative MR, that do not enhance with gadolinium. Ferumoxtran-enhancing lesions have persistent increased T1 signal intensity for 2-5 days, which may provide advantages over gadolinium for postoperative imaging. Histochemistry for iron shows uptake of ferumoxtran in reactive cells (astrocytes and macrophages) rather than tumour cells.

Trafficking of superparamagnetic iron oxide particles (Combidex) from brain to lymph nodes in the rat.

Central nervous system (CNS) drainage may occur via connections to the vasculature, but in animal models up to 50% occurs via perivascular, perineural and primitive lymphatic drainage to cervical lymph nodes. We evaluated efflux of particles from the brain to cervical lymph nodes in normal rats, using Combidex iron oxide-based magnetic resonance imaging (MRI) agent. After intracerebral, intraventricular, intracarotid or intravenous injection of Combidex in normal Long Evans rats, particle localization was assessed by MRI and histochemistry for iron and the dextran coat (n = 27). Intraventricular or intracerebral injection, but not intracarotid administration of Combidex (100 micro g), resulted in MRI signal changes in the deep cervical lymph nodes around the carotid artery, and, less strongly, in the superficial cervical nodes. Within 2 h of Combidex administration, iron was histologically localized in cervical lymph nodes, with patched staining of capsule and peripheral sinus consistent with delivery via multiple afferent lymphatic vessels. Lymph node staining in groups receiving CNS Combidex was significantly different from controls (P < 0.0001) and was significantly localized in the deep vs. superficial cervical lymph nodes (P = 0.0003). The trafficking of the superparamagnetic iron particles from the CNS in the rat could be visualized by MRI and histology. Combidex provides a powerful tool to rapidly assess drainage of virus-sized particles from the CNS.

Efficacy after sequencing of brain radiotherapy and enhanced antibody targeted chemotherapy delivery in a rodent human lung cancer brain xenograft model.

PURPOSE: The objective of this study was to evaluate the efficacy of sequencing radiation therapy (RT) and antibody targeted chemotherapy (BR96-DOX) in nude rats bearing human lung cancer (B.5 LX-1) intracerebral (i.c.) xenografts. METHODS AND MATERIALS: Our approach was to administer RT using 20 Gy single-fraction cranial irradiation either before, concurrent with, or after BR96-DOX treatment via osmotic blood-brain barrier disruption to enhance immunoconjugate delivery. All rats were inoculated with i.c. B.5 LX-1 tumors and were randomly assigned to treatment groups. RESULTS: BR96-DOX alone on Day 6 or Day 12 significantly increased survival compared to negative control rats receiving no treatment (25.9 +/- 2.1 and 23.3 +/- 2.5 days vs. 14.8 +/- 1.9 days, p < 0.05). Rats that received chemotherapy before radiation (34.0 +/- 2.0 days) lived the longest compared to the other sequences (RT prior, 29.5 +/- 1.9; RT concurrent, 27.1 +/- 2.1). Histopathology of 39 rat brains did not reveal any neuropathology. CONCLUSIONS: Enhanced delivery of immunoconjugates is more effective in combination with RT for the treatment of experimental metastatic brain tumors. Moreover, BR96-DOX administration prior to RT significantly increased survival compared to those receiving RT and chemotherapy concurrently (p < 0.05).

Therapeutic efficacy of aortic administration of N-acetylcysteine as a chemoprotectant against bone marrow toxicity after intracarotid administration of alkylators, with or without glutathione depletion in a rat model.

Modulation of thiol levels may alter both the efficacy and toxicity of chemotherapeutic agents. We investigated cytoenhancement, using L-buthionine-[S,R]-sulfoximine (BSO) to reduce cellular glutathione levels prior to intracarotid alkylator administration. We also evaluated chemoprotection against chemotherapy-induced systemic toxicity when the thiol agents N-acetylcysteine (NAC) and sodium thiosulfate were administered into the descending aorta to limit brain delivery. BSO treatment reduced rat brain and intracerebral tumor glutathione levels by 50-65%, equivalent to the reduction in liver and s.c. tumor. BSO treatment significantly enhanced the toxicity of chemotherapy with carboplatin, melphalan, and etoposide phosphate against granulocytes, total white cells, and platelets. Intracarotid administration of NAC resulted in high delivery to the brain, whereas infusion via the descending aorta minimized brain delivery. When NAC, with or without sodium thiosulfate, was administered via aortic infusion prior to chemotherapy, the magnitude of the bone marrow toxicity nadir was minimized, even with BSO-enhanced myelosuppression. Thus, BSO depleted brain and brain tumor glutathione but thereby increased chemotherapy-induced myelosuppression. Surprisingly, although NAC was found to readily cross the blood-brain barrier when given into the carotid artery, aortic infusion of NAC resulted in minimal exposure to the central nervous system (CNS) vasculature because of rapid clearance. As a result, aortic infusion of NAC to perfuse bone marrow and minimize myelosuppression and toxicity to visceral organs could be performed without interfering with the CNS cytotoxicity of intracarotid alkylators, even after BSO depletion of CNS glutathione.

Combined intraarterial carboplatin, intraarterial etoposide phosphate, and IV Cytoxan chemotherapy for progressive optic-hypothalamic gliomas in young children.

BACKGROUND AND PURPOSE: Optic pathway and/or hypothalamic astrocytomas in children are often quiescent, but in some cases, more aggressive tumors may cause progressive visual, endocrine, and neurologic deterioration. The initial treatment of these gliomas includes surgery and IV chemotherapy. Radiotherapy is not recommended in young children because of its severe adverse effects on cognitive and neuroendocrine function. This report suggests a new approach using combined intraarterial and IV carboplatin-based chemotherapy for patients for whom first line treatment has already failed. METHODS: Six children (mean age, 57 months) with the diagnosis of optic pathway hypothalamic gliomas, who had tumor progression after surgery and underwent IV chemotherapy, were treated monthly with intraarterially administered carboplatin, intraarterially administered etoposide phosphate, and IV administered Cytoxan. Four of the children had histologically verified pilocytic astrocytomas, and in two cases, diagnosis was made on the basis of clinical findings. Administration of the intraarterial chemotherapy required catheter placement in both internal carotid arteries at the level of C2-C3 and into one of the vertebral arteries at the level of C6-C7, with the patient under general anesthesia. RESULTS: Four of six patients had partial radiographic response, one had stable disease, and one had progressive disease after one cycle. Three patients showed clinical improvement. There were no serious complications associated with the angiographic procedures. Toxicities included bronchospasm that resolved after 3 to 4 minutes in one patient. One patient showed mild ototoxicity, and four patients needed platelet transfusion because of hematologic toxicity of drugs. CONCLUSION: These results suggest that this modality of chemotherapy (administered after failure of systemic [ie, IV] chemotherapy), of progressive optic-hypothalamic astrocytomas in young children may be an effective treatment prior to radiotherapy.

Association of total dose intensity of chemotherapy in primary central nervous system lymphoma (human non-acquired immunodeficiency syndrome) and survival.

OBJECTIVE: The importance of enhanced drug delivery in patients with central nervous system (CNS) malignancies has not yet been demonstrated conclusively. Intra-arterial chemotherapy in combination with osmotic bloodbrain barrier disruption (BBBD) increases drug delivery to tumor by 2- to 5-fold and to surrounding brain tissue by 10- to 100-fold as compared with intravenous administration of chemotherapy. Primary CNS lymphoma (PCNSL) is an excellent model for studying dose intensity because PCNSL is a highly infiltrative, chemosensitive, primary CNS malignancy in which the integrity of the blood-brain barrier is highly variable. METHODS: Survival time was assessed in 74 non-acquired immunodeficiency syndrome patients with PCNSL who underwent a total of 1047 BBBD procedures. Total dose intensity is estimated by using the number of intraarterial infusions or a cumulative degree of BBBD score. RESULTS: Using proportional hazards multivariable analyses to adjust for baseline characteristics, survival was significantly associated with the total intensity of BBBD (P < 0.05). Additional statistical analyses demonstrate that survival bias does not fully explain these associations. Even when only patients who attained a complete response are considered, increased dose intensity resulted in increased survival. CONCLUSION: In patients with PCNSL, a chemotherapy-responsive tumor type, survival time is highly associated with total drug dose delivered, even in analyses designed to control for potential survival biases. These results probably constitute the strongest evidence to date of the importance of total dose intensity in treating CNS malignancies.

Delayed sodium thiosulfate as an otoprotectant against carboplatin-induced hearing loss in patients with malignant brain tumors.

Carboplatin is effective in the treatment of malignant brain tumors. However, when administered in conjunction with osmotic opening of the blood-brain barrier (BBB), carboplatin is ototoxic. The purpose of this study was to determine whether delayed administration of sodium thiosulfate (STS), given after BBB closure, provided protection against carboplatin ototoxicity. Patients underwent monthly treatment with intra-arterial carboplatin (200 mg/m2/day x 2) in conjunction with osmotic opening of the BBB, for up to 1 year. Audiological assessment was conducted at baseline and within 24 h before each monthly treatment. STS was administered i.v. as one (20 g/m2) or two (20 g/m2 and 16 g/m2) 15-min doses, depending on baseline hearing status. The initial group received the first STS dose 2 h (or 2 and 6 h) after carboplatin (STS2) and a subsequent group received STS 4 h (or 4 and 8 h) after carboplatin (STS4). Audiological data were compared with a historical comparison group (HCG) treated with carboplatin without STS. Spearman correlation coefficients comparing STS 2 (n = 24), STS4 (n = 17), and HCG (n = 19) indicated significantly lower rates of ototoxicity with increased delay in STS (P = 0.0006). On the basis of the analysis of hearing levels, there were significant differences among the two STS groups and HCG at 8000 Hz (P = 0.0010) and at 4000 Hz (P = 0.0075). The log-rank test for time to ototoxicity indicated a significant difference between STS4 and HCG (P = 0.0018). Delayed STS was effective in protecting against carboplatin-induced hearing loss. STS delayed to 4 h after carboplatin significantly decreased time to development of ototoxicity and rate of ototoxicity when compared with HCG.

Importance of dose intensity in neuro-oncology clinical trials: summary report of the Sixth Annual Meeting of the Blood-Brain Barrier Disruption Consortium.

Therapeutic options for the treatment of malignant brain tumors have been limited, in part, because of the presence of the blood-brain barrier. For this reason, the Sixth Annual Meeting of the Blood-Brain Barrier Disruption Consortium, the focus of which was the "Importance of Dose Intensity in Neuro-Oncology Clinical Trials," was convened in April 2000, at Government Camp, Mount Hood, Oregon. This meeting, which was supported by the National Cancer Institute, the National Institute of Neurological Disorders and Stroke, and the National Institute of Deafness and Other Communication Disorders, brought together clinicians and basic scientists from across the U.S. to discuss the role of dose intensity and enhanced chemotherapy delivery in the treatment of malignant brain tumors and to design multicenter clinical trials. Optimizing chemotherapy delivery to the CNS is crucial, particularly in view of recent progress identifying certain brain tumors as chemosensitive. The discovery that specific constellations of genetic alterations can predict which tumors are chemoresponsive, and can therefore more accurately predict prognosis, has important implications for delivery of intensive, effective chemotherapy regimens with acceptable toxicities. This report summarizes the discussions, future directions, and key questions regarding dose-intensive treatment of primary CNS lymphoma, CNS relapse of systemic non-Hodgkin's lymphoma, anaplastic oligodendroglioma, high-grade glioma, and metastatic cancer of the brain. The promising role of cytoenhancers and chemoprotectants as part of dose-intensive regimens for chemosensitive brain tumors and development of improved gene therapies for malignant gliomas are discussed.

Rescue from enhanced alkylator-induced cell death with low molecular weight sulfur-containing chemoprotectants.

Modulation of glutathione has been proposed as a mechanism to alter the efficacy and toxicity of chemotherapeutic agents. We investigated in vitro cytoenhancement of chemotherapy toxicity by reducing cellular glutathione levels with L-buthionine-[S,R]-sulfoximine (BSO), and chemoprotection with small molecular weight sulfur-containing agents that mimic or replace glutathione. Cytotoxicity, caspase-2 enzymatic activity, and in situ DNA staining for apoptosis were assessed in cultured human small cell lung carcinoma cells and fibroblasts. BSO treatment reduced the half-maximal cytotoxic dose of the alkylating chemotherapeutics melphalan, carboplatin, and cisplatin, and increased the total magnitude of cell death. Melphalan was more sensitive than carboplatin or cisplatin to BSO. The chemoprotective agents sodium thiosulfate, N-acetylcysteine, and glutathione ethyl ester reduced the cytotoxicity of all three alkylating chemotherapeutics regardless of BSO treatment, but D-methionine was effective only against the platinum agents. N-Acetylcysteine was the most effective protectant tested. Chemoprotection against melphalan toxicity was maximally effective only if administered concurrent with chemotherapy, whereas chemoprotection for the platinum agents remained effective if delayed 4 h after chemotherapy. BSO enhancement and N-acetylcysteine chemoprotection for melphalan toxicity occurred at least partially through an apoptotic mechanism. Modulation of glutathione levels will be valuable in the clinical setting if chemotherapy and chemoprotectant can be physically and/or temporally separated. Cytoenhancement and chemoprotection may be particularly useful in the central nervous system where the blood-brain barrier of the cerebral vasculature creates two compartments, for cytoenhancement in brain tumors and systemic chemoprotection.

Unexpected neurotoxicity of etoposide phosphate administered in combination with other chemotherapeutic agents after blood-brain barrier modification to enhance delivery, using propofol for general anesthesia, in a rat model.

OBJECTIVE: Osmotic blood-brain barrier disruption (BBBD) increases brain and brain tumor delivery of chemotherapeutic agents, which results in increased efficacy against brain tumors. We previously noted that the use of propofol anesthesia for BBBD increased the percentage of successful disruptions, resulting in delivery of increased amounts of chemotherapeutic drugs. This study evaluated the neurotoxicity of combination chemotherapeutic administration with this enhanced delivery system. METHODS: Osmotic BBBD was performed in Long-Evans rats with isoflurane (n = 11) or propofol (n = 90) anesthesia. Carboplatin and/or melphalan, methotrexate, or etoposide phosphate was administered intra-arterially (IA) after BBBD using propofol anesthesia. Animals were assessed for systemic and neurological toxicity. Animals were killed for neuropathological evaluation 30 days after treatment. RESULTS: With propofol or isoflurane anesthesia, BBBD alone produced no systemic or neurological toxicity. Single agents were relatively non-neurotoxic when administered IA with BBBD, as were the combinations of carboplatin or melphalan with methotrexate. Etoposide phosphate in combination with any other agent was observed to be highly neurotoxic if both agents were administered after BBBD. Administration of etoposide phosphate before BBBD completely eliminated neurotoxicity, although acute pulmonary toxicity occurred with any combination of etoposide phosphate and methotrexate, regardless of the timing of administration. CONCLUSION: Neurotoxicity was significantly increased for etoposide phosphate combination groups, particularly when both drugs were administered IA after BBBD. This increase in neurotoxicity may reflect on increase in drug delivery observed with propofol anesthesia. The neurotoxicity of IA administered etoposide phosphate with BBBD and propofol anesthesia could be minimized by administering etoposide phosphate IA before BBBD and administering carboplatin or melphalan IA after BBBD.

Iatrogenic arterial spasm relieved by intraarterial mannitol infusion.

Catheter placement for blood brain-barrier disruption and enhanced chemotherapy delivery can sometimes trigger arterial spasm of moderate-to-severe degree. A slow infusion of a small quantity of intraarterially administered mannitol (10 mL of 25% mannitol) was evaluated as a means to obtain a rapid resolution of catheter placement-induced spasm. We prospectively report 12 consecutive cases of blood brain-barrier disruption among patients who developed catheter placement-induced spasm that was treated by this means without side effects, resulting in rapid resolution of spasm.

Enhanced delivery improves the efficacy of a tumor-specific doxorubicin immunoconjugate in a human brain tumor xenograft model.

OBJECTIVE: To evaluate dose intensification with osmotic blood-brain barrier disruption (BBBD) and the potential use of drug targeting with monoclonal antibody (MAb) BR96 conjugated to doxorubicin (BR96-DOX, now called SGN15) for treatment of intracerebral and subcutaneous human LX-1 small cell lung carcinoma xenografts in rats. METHODS: LX-1 tumors with high, low, or heterogeneous levels of the Lewis(y) antigen for BR96 were evaluated. Rats were treated with intracarotid or intravenous BR96-DOX, with or without osmotic BBBD. RESULTS: Both BR96-DOX and MAb BR96 treatment resulted in significant regression of subcutaneous tumors, in contrast to control groups including doxorubicin alone, saline, or nonbinding doxorubicin immunoconjugate. BR96-DOX delivered with BBBD to brain tumors with low antigen expression resulted in significantly (P < 0.001) increased rat survival time compared with animals that received intravenous or intra-arterial BR96-DOX. CONCLUSION: The combination of an effective drug such as doxorubicin with a MAb to facilitate tumor-selective localization and osmotic BBBD to increase tumor delivery may have practical application in the clinic, because an increased delivery of drug to tumor can be obtained without increasing the dose of systemic drug.