Pemetrexed in Recurrent or Progressive Central Nervous System Lymphoma: A Phase I Multicenter Clinical Trial

LESSONS LEARNED

The findings from this study using monotherapy with pemetrexed in a pretreated patient population are, overall, encouraging. Unlike high-dose methotrexate, which requires several days of inpatient hospitalization, pemetrexed is relatively easy to administer in the outpatient setting and remains a viable treatment option in this patient population. The maximum tolerated dose of pemetrexed administered (900 mg/m² every 2 weeks) was generally well tolerated and showed activity in patients with relapsed or refractory CNSL.

BACKGROUND

There is currently no standard salvage treatment for patients with relapsed/refractory central nervous system (CNS) lymphoma (CNSL). We report the results of a phase I study of pemetrexed, an antifolate drug with broader activity than methotrexate (MTX). We provide the safety, tolerability, and maximum tolerated dose (MTD) of pemetrexed in patients with recurrent CNSL.

METHODS

Through October 2015, 17 patients with relapsed/refractory CNSL received pemetrexed every 2 weeks with the first cohort receiving 600 mg/m² and dose escalation in increments of 300 mg/m² to a maximum of 1,200 mg/m² . Three patients were to enroll at each dose level with expansion to six patients in the event of dose-limiting toxicity. Patients with both primary CNS lymphoma (PCNSL) and secondary CNS lymphoma (SCNSL) could be enrolled.

RESULTS

Seventeen patients were evaluable with a median age of 63.7 years. Main adverse events included fatigue (82.4%), anemia (82.4%), and neutropenia (70.6%). The MTD was established at 900 mg/m² . Dose-limiting toxicities were recorded in one patient in the 600 mg/m² cohort and in two patients in the 1,200 mg/m² cohort. Fourteen patients were evaluable for response assessment; 21.4% achieved a complete response, 35.7% had a partial response, 14.3% had stable disease, and 28.6% had progressive disease. The median progression-free survival was 4.2 months. The median overall survival was 44.5 months. In the original study protocol, the plan was to add an expansion cohort of six patients at MTD level. However, the first phase of the study was characterized by slow recruitment. Therefore, after achieving the primary objective of the study and establishing the MTD, the investigators decided to amend the protocol and to close the study.

CONCLUSION

Pemetrexed administered at 900 mg/m² every 2 weeks exhibits single-agent activity in patients with recurrent CNSL; it is well tolerated, and side effects are manageable.

Detection of wild-type EGFR amplification and EGFRvIII mutation in CSF-derived extracellular vesicles of glioblastoma patients

Background

RNAs within extracellular vesicles (EVs) have potential as diagnostic biomarkers for patients with cancer and are identified in a variety of biofluids. Glioblastomas (GBMs) release EVs containing RNA into cerebrospinal fluid (CSF). Here we describe a multi-institutional study of RNA extracted from CSF-derived EVs of GBM patients to detect the presence of tumor-associated amplifications and mutations in epidermal growth factor receptor (EGFR).

Methods

CSF and matching tumor tissue were obtained from patients undergoing resection of GBMs. We determined wild-type (wt)EGFR DNA copy number amplification, as well as wtEGFR and EGFR variant (v)III RNA expression in tumor samples. We also characterized wtEGFR and EGFRvIII RNA expression in CSF-derived EVs.

Results

EGFRvIII-positive tumors had significantly greater wtEGFR DNA amplification (P = 0.02) and RNA expression (P = 0.03), and EGFRvIII-positive CSF-derived EVs had significantly more wtEGFR RNA expression (P = 0.004). EGFRvIII was detected in CSF-derived EVs for 14 of the 23 EGFRvIII tissue-positive GBM patients. Conversely, only one of the 48 EGFRvIII tissue-negative patients had the EGFRvIII mutation detected in their CSF-derived EVs. These results yield a sensitivity of 61% and a specificity of 98% for the utility of CSF-derived EVs to detect an EGFRvIII-positive GBM.

Conclusion

Our results demonstrate CSF-derived EVs contain RNA signatures reflective of the underlying molecular genetic status of GBMs in terms of wtEGFR expression and EGFRvIII status. The high specificity of the CSF-derived EV diagnostic test gives us an accurate determination of positive EGFRvIII tumor status and is essentially a less invasive "liquid biopsy" that might direct mutation-specific therapies for GBMs.

Coding and noncoding landscape of extracellular RNA released by human glioma stem cells

Tumor-released RNA may mediate intercellular communication and serve as biomarkers. Here we develop a protocol enabling quantitative, minimally biased analysis of extracellular RNAs (exRNAs) associated with microvesicles, exosomes (collectively called EVs), and ribonucleoproteins (RNPs). The exRNA complexes isolated from patient-derived glioma stem-like cultures exhibit distinct compositions, with microvesicles most closely reflecting cellular transcriptome. exRNA is enriched in small ncRNAs, such as miRNAs in exosomes, and precisely processed tRNA and Y RNA fragments in EVs and exRNPs. EV-enclosed mRNAs are mostly fragmented, and UTRs enriched; nevertheless, some full-length mRNAs are present. Overall, there is less than one copy of non-rRNA per EV. Our results suggest that massive EV/exRNA uptake would be required to ensure functional impact of transferred RNA on brain recipient cells and predict the most impactful miRNAs in such conditions. This study also provides a catalog of diverse exRNAs useful for biomarker discovery and validates its feasibility on cerebrospinal fluid.

While circulating DNA has been extensively explored as a potential cancer biomarker, RNA potential has been overlooked so far. Here the authors present a comprehensive analysis of extracellular RNA secreted by glioblastoma cells that could prove a valuable resource for biomarker discovery and a means of intercellular communication.

A cerebrospinal fluid microRNA signature as biomarker for glioblastoma

Purpose

To develop a cerebrospinal fluid (CSF) miRNA diagnostic biomarker for glioblastoma.

Experimental Design

Glioblastoma tissue and matched CSF from the same patient (obtained prior to tumor manipulation) were profiled by TaqMan OpenArray^® Human MicroRNA Panel. CSF miRNA profiles from glioblastoma patients and controls were created from three discovery cohorts and confirmed in two validation cohorts.

Results

miRNA profiles from clinical CSF correlated with those found in glioblastoma tissues. Comparison of CSF miRNA profiles between glioblastoma patients and non-brain tumor patients yielded a tumor “signature” consisting of nine miRNAs. The “signature” correlated with glioblastoma tumor volume (p=0.008). When prospectively applied to cisternal CSF, the sensitivity and specificity of the ‘signature’ for glioblastoma detection were 67% and 80%, respectively. For lumbar CSF, the sensitivity and specificity of the signature were 28% and 95%, respectively. Comparable results were obtained from analyses of CSF extracellular vesicles (EVs) and crude CSF.

Conclusion

We report a CSF miRNA signature as a “liquid biopsy” diagnostic platform for glioblastoma.

Pain as an Indicator of Bone Metastasis

Patients with breast or prostate cancer routinely referred for bone scintigraphy were evaluated for the presence of skeletal pain, as determined by a self administered questionnaire. Pain was a common finding, whether or not metastatic disease was present, and occurred in over half of patients. Although most patients with bone metastases did report bone pain, a significant fraction (21% of breast and 22% of prostate patients) were asymptomatic. A distinct minority of individual anatomic regions of metastasis were painful: pain was reported in 23 % of sites of breast metastases and 15% of metastatic prostate cancer sites. Of all sites at which pain was present, metastases were demonstrated in only about one half. These results indicate that pain is not a reliable indicator of the presence of location of metastatic bone disease.

Applying extracellular vesicles based therapeutics in clinical trials - an ISEV position paper

Extracellular vesicles (EVs), such as exosomes and microvesicles, are released by different cell types and participate in physiological and pathophysiological processes. EVs mediate intercellular communication as cell-derived extracellular signalling organelles that transmit specific information from their cell of origin to their target cells. As a result of these properties, EVs of defined cell types may serve as novel tools for various therapeutic approaches, including (a) anti-tumour therapy, (b) pathogen vaccination, (c) immune-modulatory and regenerative therapies and (d) drug delivery. The translation of EVs into clinical therapies requires the categorization of EV-based therapeutics in compliance with existing regulatory frameworks. As the classification defines subsequent requirements for manufacturing, quality control and clinical investigation, it is of major importance to define whether EVs are considered the active drug components or primarily serve as drug delivery vehicles. For an effective and particularly safe translation of EV-based therapies into clinical practice, a high level of cooperation between researchers, clinicians and competent authorities is essential. In this position statement, basic and clinical scientists, as members of the International Society for Extracellular Vesicles (ISEV) and of the European Cooperation in Science and Technology (COST) program of the European Union, namely European Network on Microvesicles and Exosomes in Health and Disease (ME-HaD), summarize recent developments and the current knowledge of EV-based therapies. Aspects of safety and regulatory requirements that must be considered for pharmaceutical manufacturing and clinical application are highlighted. Production and quality control processes are discussed. Strategies to promote the therapeutic application of EVs in future clinical studies are addressed.

Extracellular RNAs: development as biomarkers of human disease

Ten ongoing studies designed to test the possibility that extracellular RNAs may serve as biomarkers in human disease are described. These studies, funded by the NIH Common Fund Extracellular RNA Communication Program, examine diverse extracellular body fluids, including plasma, serum, urine and cerebrospinal fluid. The disorders studied include hepatic and gastric cancer, cardiovascular disease, chronic kidney disease, neurodegenerative disease, brain tumours, intracranial haemorrhage, multiple sclerosis and placental disorders. Progress to date and the plans for future studies are outlined.

Minimal experimental requirements for definition of extracellular vesicles and their functions: a position statement from the International Society for Extracellular Vesicles

Secreted membrane-enclosed vesicles, collectively called extracellular vesicles (EVs), which include exosomes, ectosomes, microvesicles, microparticles, apoptotic bodies and other EV subsets, encompass a very rapidly growing scientific field in biology and medicine. Importantly, it is currently technically challenging to obtain a totally pure EV fraction free from non-vesicular components for functional studies, and therefore there is a need to establish guidelines for analyses of these vesicles and reporting of scientific studies on EV biology. Here, the International Society for Extracellular Vesicles (ISEV) provides researchers with a minimal set of biochemical, biophysical and functional standards that should be used to attribute any specific biological cargo or functions to EVs.

Informatic system for a global tissue-fluid biorepository with a graph theory-oriented graphical user interface

The Richard Floor Biorepository supports collaborative studies of extracellular vesicles (EVs) found in human fluids and tissue specimens. The current emphasis is on biomarkers for central nervous system neoplasms but its structure may serve as a template for collaborative EV translational studies in other fields. The informatic system provides specimen inventory tracking with bar codes assigned to specimens and containers and projects, is hosted on globalized cloud computing resources, and embeds a suite of shared documents, calendars, and video-conferencing features. Clinical data are recorded in relation to molecular EV attributes and may be tagged with terms drawn from a network of externally maintained ontologies thus offering expansion of the system as the field matures. We fashioned the graphical user interface (GUI) around a web-based data visualization package. This system is now in an early stage of deployment, mainly focused on specimen tracking and clinical, laboratory, and imaging data capture in support of studies to optimize detection and analysis of brain tumour-specific mutations. It currently includes 4,392 specimens drawn from 611 subjects, the majority with brain tumours. As EV science evolves, we plan biorepository changes which may reflect multi-institutional collaborations, proteomic interfaces, additional biofluids, changes in operating procedures and kits for specimen handling, novel procedures for detection of tumour-specific EVs, and for RNA extraction and changes in the taxonomy of EVs. We have used an ontology-driven data model and web-based architecture with a graph theory-driven GUI to accommodate and stimulate the semantic web of EV science.

Phase 2 trial of high-dose rituximab with high-dose cytarabine mobilization therapy and high-dose thiotepa, busulfan, and cyclophosphamide autologous stem cell transplantation in patients with central nervous system involvement by non-Hodgkin lymphoma

BACKGROUND

High-dose thiotepa, busulfan, and cyclophosphamide (TBC) with autologous stem cell transplantation (ASCT) has been used in patients with central nervous system (CNS) involvement by non-Hodgkin lymphoma (NHL). Despite limited penetration into the CNS, rituximab is active in primary CNS NHL. Therefore, high-dose rituximab was combined with TBC for ASCT in patients with CNS NHL.

METHODS

A single-arm phase 2 trial using high-dose rituximab with cytarabine for stem cell mobilization followed by high-dose rituximab combined with thiotepa, busulfan, and cyclophosphamide (R-TBC) for ASCT was conducted. Doses of rituximab at 1000 mg/m(2) were given on days 1 and 8 of mobilization and on days -9 and -2 of TBC. The primary endpoint was efficacy.

RESULTS

Thirty patients were enrolled. Eighteen patients had primary CNS NHL (12 with complete remission (CR)/first partial remission (PR1) and 6 with CR/PR2), and 12 patients had secondary CNS lymphoma (5 with CR/PR1 and 7 with CR/PR2 or beyond). All patients were in partial or complete remission. Twenty-nine patients proceeded to R-TBC ASCT. Two patients developed significant neurotoxicity. The 100-day nonrelapse mortality rate was 0%, and 1 patient died because of nonrelapse causes 5 months after ASCT. For all patients, at a median follow-up of 24 months (range, 12-40 months), the estimated 2-year progression-free survival rate was 81% (95% confidence interval, 59%-92%), and the 2-year overall survival rate was 93% (95% confidence interval, 76%-98%). There were no relapses or deaths among the 18 patients with primary CNS lymphoma.

CONCLUSIONS

For patients with CNS involvement by B-cell NHL and especially for patients with primary CNS NHL, R-TBC ASCT shows encouraging activity and merits further study.

Extracellular vesicles modulate the glioblastoma microenvironment via a tumor suppression signaling network directed by miR-1

Extracellular vesicles have emerged as important mediators of intercellular communication in cancer, including by conveying tumor-promoting microRNAs between cells, but their regulation is poorly understood. In this study, we report the findings of a comparative microRNA profiling and functional analysis in human glioblastoma that identifies miR-1 as an orchestrator of extracellular vesicle function and glioblastoma growth and invasion. Ectopic expression of miR-1 in glioblastoma cells blocked in vivo growth, neovascularization, and invasiveness. These effects were associated with a role for miR-1 in intercellular communication in the microenvironment mediated by extracellular vesicles released by cancer stem-like glioblastoma cells. An extracellular vesicle-dependent phenotype defined by glioblastoma invasion, neurosphere growth, and endothelial tube formation was mitigated by loading miR-1 into glioblastoma-derived extracellular vesicles. Protein cargo in extracellular vesicles was characterized to learn how miR-1 directed extracellular vesicle function. The mRNA encoding Annexin A2 (ANXA2), one of the most abundant proteins in glioblastoma-derived extracellular vesicles, was found to be a direct target of miR-1 control. In addition, extracellular vesicle-derived miR-1 along with other ANXA2 extracellular vesicle networking partners targeted multiple pro-oncogenic signals in cells within the glioblastoma microenvironment. Together, our results showed how extracellular vesicle signaling promotes the malignant character of glioblastoma and how ectopic expression of miR-1 can mitigate this character, with possible implications for how to develop a unique miRNA-based therapy for glioblastoma management.

Standardization of sample collection, isolation and analysis methods in extracellular vesicle research

The emergence of publications on extracellular RNA (exRNA) and extracellular vesicles (EV) has highlighted the potential of these molecules and vehicles as biomarkers of disease and therapeutic targets. These findings have created a paradigm shift, most prominently in the field of oncology, prompting expanded interest in the field and dedication of funds for EV research. At the same time, understanding of EV subtypes, biogenesis, cargo and mechanisms of shuttling remains incomplete. The techniques that can be harnessed to address the many gaps in our current knowledge were the subject of a special workshop of the International Society for Extracellular Vesicles (ISEV) in New York City in October 2012. As part of the “ISEV Research Seminar: Analysis and Function of RNA in Extracellular Vesicles (evRNA)”, 6 round-table discussions were held to provide an evidence-based framework for isolation and analysis of EV, purification and analysis of associated RNA molecules, and molecular engineering of EV for therapeutic intervention. This article arises from the discussion of EV isolation and analysis at that meeting. The conclusions of the round table are supplemented with a review of published materials and our experience. Controversies and outstanding questions are identified that may inform future research and funding priorities. While we emphasize the need for standardization of specimen handling, appropriate normative controls, and isolation and analysis techniques to facilitate comparison of results, we also recognize that continual development and evaluation of techniques will be necessary as new knowledge is amassed. On many points, consensus has not yet been achieved and must be built through the reporting of well-controlled experiments.

Effects of cediranib, a VEGF signaling inhibitor, in combination with chemoradiation on tumor blood flow and survival in newly diagnosed glioblastoma

2009

Background: Anti-angiogenic therapy is hypothesized to synergize with radiation and chemotherapy by improving tumor blood flow. We evaluated the tolerability, efficacy and potential mechanism of action of radiation, temozolomide, and cediranib in newly diagnosed glioblastoma patients. Methods: Newly diagnosed glioblastoma patients were treated with radiation, temozolomide, and cediranib followed by monthly temozolomide for 6 cycles and daily cediranib until tumor progression or toxicity as part of an IRB-approved, Phase Ib/II clinical trial. MRI scans including measurement of cerebral blood flow were performed at baseline, weekly during the 6 weeks of chemoradiation and then monthly. Radiographic response was determined by RANO criteria. Results: Six patients were enrolled in the phase Ib part of the study with cediranib 30 mg daily in combination with temozolomide and radiation. No dose-limiting toxicities were identified. Forty patients were enrolled in the phase II part of the study. Among the entire cohort of 46 patients, median age was 57 (range 35-74), median KPS was 90% (60-100), 36 patients underwent a subtotal resection and 10 underwent biopsy. 26/30 patients taking corticosteroids were able to taper corticosteroids during chemoradiation. Off study reasons included toxicity (14), disease progression (18), and patient preference (2). Five patients remain on study without disease progression and 20 patients have died. Median duration on study was 158 days. Median progression free survival was 288 days (95%CI 240,∞) and median overall survival was 786 days (95%CI 411 ,∞). Best radiographic response in patients who completed chemoradiation was CR in 2 patients, PR in 20 patients, and SD in 15 patients. Patients with increased tumor perfusion during chemoradiation survived nearly 1 year longer (mean OS=611 days) than patients with decreased perfusion (mean OS=269 days). Conclusions: Cediranib was well tolerated and led to improved PFS and OS compared to historical controls, particularly in those with improved perfusion. This combination is being evaluated in an ongoing randomized trial (RTOG 0837).

Abstract C140: RNA expression patterns in serum microvesicles from patients with glioblastoma multiforme and ovarian cancer

Background: Recent studies have shown that RNA isolated from exosomes and other microvesicles (exoRNA) contain diagnostically relevant transcripts of tumor origin. In this study we sought to identify specific biomarkers of glioblastoma multiforme (GBM) and malignant ovarian cancer in the ribonucleic acid fraction extracted from microvesicles (exoRNA) isolated from the serum of affected patients.

Methods: All samples were collected following informed consent in accordance with the appropriate protocols approved by the MGH Institutional Review Board (GBM) and the Umeå University ethics committee (ovarian tumors). Patients with primary GBM (N=9), normal controls (N=7); and pathologically proven benign (N=16), borderline (N=19), and malignant (N=29, stage I-IV, grade 1–3) neoplastic transformation of the ovaries were included. ExoRNA isolated from patient serum was amplified and analyzed by microarray analysis on Agilent 4×44K arrays (GBM) and Agilent 8×60K arrays (ovarian tumors). Differential expressions between control and GBM samples were validated by qRT-PCR in a separate set of samples (N=10 in both groups).

Results: Array analysis of the amplified exoRNA yielded significant signals from at least 10,000 genes on the array for all samples. The expression profiles of the exoRNA from GBM patients were shown to be different from those of normal healthy volunteers. The most significant expression differences observed in the array analysis pertained to down-regulated genes (121 genes >2-fold down) in the GBM patient exoRNA, which was validated by qRT-PCR on several genes. Gene ontology analysis of the down-regulated genes indicated these are primarily mRNAs coding for ribosomal proteins and other genes related to ribosome production. Supervised analysis showed no significant differential gene expression between the benign, borderline, and malignant ovarian tumors. However, unsupervised Consensus Clustering yielded a clear segregation of the patients into two new groups (100% resampling consensus for 61 samples). Gene Set Enrichment Analysis (GSEA) showed a strong association of one of the two groups with genes linked to translation initiation (FDR q-value 0.04), and mRNA processing (FDR q-value 0.032). GSEA also confirmed a strong overlap of the genes separating the ovarian cancer samples into two groups with those discriminating GBM from healthy control individuals.

Conclusions: Microvesicle isolated RNA from patients with GBM is significantly different from that of normal control individuals. The same genes support a binary classification of ovarian tumors suggesting that common biological processes may be in effect for these different tumor types. The common signature is hallmarked by messenger RNAs coding for ribosome production, which are significantly downregulated in GBM exoRNA and in one of two novel subgroups of ovarian tumors. While the biological role of this signature remains to be elucidated, we conclude that exosomal RNA expression profiling has the potential to serve as a clinically relevant diagnostic source of information about the biology, malignancy, and state of tumors. This underlines the diagnostic potential of exosomes not only in early diagnosis, but also in directing therapies, evaluating response and in situations where biopsy samples are difficult to access.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C140.

Abstract C139: Detection of BRAF mutations in serum/plasma microvesicles (exosomes) of malignant melanoma patients

Background: BRAF is one of the most frequently activated oncogenes in melanoma comprising 40–60% of all mutations. About ninety percent of activating BRAF mutations occur at the V600E position enabling specific therapeutic targeting with inhibitors such as vemurafenib. Detection of the BRAF V600E mutation is therefore important for guiding treatment; however, access to tissue for testing is limited. We have recently shown that microvesicles (exosomes) isolated from serum/plasma contain RNA (exoRNA) and that tumor-derived exoRNA can be extracted from microvesicles circulating in peripheral blood. Thus the detection of the BRAF V600E mutation in blood represents a potentially useful biomarker for non-invasive diagnosis and monitoring therapeutic response.

Methods: ExoRNA was extracted from the serum and plasma of 18 patients with biopsy confirmed grade IV melanoma and 12 healthy controls. Patients were consented and samples were collected in accordance with protocols approved by the IRB at MGH and LMU. Some patients included in the study were undergoing chemotherapy or drug treatment during blood draw (13/18), while others did not receive any treatment (5/18). BRAF V600E mutation in the isolated exoRNA from serum/plasma was measured by two methods.

qPCR based assay: This assay used Taqman MGB™ probes and ARMS primers. The assay was able to detect mutations as low as <0.5% and could detect to as little as 10 mutant copies in a wild-type background.

Ultra-deep Sequencing assay using Illumina HiSeq technology: Eight melanoma patient samples were used for this assay (3 from group I and 5 from group II). Using PCR, a 100 bp region of BRAF encompassing the V600E mutation locus was amplified. Illumina library preparation protocol and bioinformatics methodology was then optimized to identify BRAF V600E mutations from ultra-high coverage amplicon sequencing data. To establish the sensitivity of the sequencing platform, we also made admixtures of synthetic DNA oligos with known sequences diluting the V600E variant in up to 10,000 copies of the wild type. We found that the lower detection limit for the rare mutant variant is about 1 in 5000 wild type molecules.

Results: qPCR results indicate that 66% patients had concordance with biopsy. The healthy controls tested were all negative for V600E (0/12), giving the assay a specificity of 100% Ultra deep sequencing of exoRNA indicated that 62% patients had concordance with biopsy. By this method 2 million sequencing reads were generated per sample. The fraction of V600E to wild type variant was estimated to range from 0.05% to 10% in the samples.

Conclusions: Both qPCR and ultra-deep sequencing have identified the BRAF V600E mutation from microvesicles circulating in peripheral blood in patients with malignant melanoma. Ultra-deep sequencing further allows accurate estimation of the fraction of tumor-derived microvesicles which may be used as a surrogate marker for the actual tumor burden. ExoRNA from peripheral blood has the potential to act as a novel class of diagnostic tests for both mutation detection and therapy response monitoring without the need for invasive biopsy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C139.

Phase II trial of oral gimatecan in adults with recurrent glioblastoma

2009

Background: Gimatecan is a highly lipophilic oral camptothecin analogue with impressive preclinical activity in glioma models. Methods: We conducted a multicenter two-stage phase II trial to evaluate the efficacy of gimatecan in adults with recurrent glioblastoma. Eligibility criteria included ≤1 prior treatment for recurrent disease, age ≥18, ECOG performance status 0 or 1, and normal organ function. Patients taking enzyme-inducing anti-seizure medications were excluded. Gimatecan 1.22 mg/m2 was given orally once daily for 5 consecutive days during each 28-day cycle. Radiographic response was evaluated by MRI after every second cycle. The primary endpoint of the study was 6 months PFS. A Simon's 2-stage design was used in which 19 patients were evaluated in the first stage, with an additional 36 patients accrued if > 4 patients in stage 1 achieved 6 month PFS. Results: A total of 29 patients were enrolled in the study, with median age of 58 years (range, 25–77 years); 58.6% female; all of whom had received prior surgery, radiation therapy, and at least one regimen of chemotherapy. The daily dose was reduced to 1.0 mg/m2 after four of the first 10 patients experienced grade 4 hematologic toxicity. One patient was removed from trial due to toxicity (grade 3 leukopenia and thrombocytopenia). Treatment delay occurred in 11 patients (38%) and dose reduction was necessary in eight patients (28%). Treatment-related grade 3/4 toxicities included thrombocytopenia (17.2%), leukopenia (17.2%), and neutropenia (10.3%). Only 1/19 patients treated with 1.0 mg/m2/day experienced grade 3/4 hematologic toxicity. The 18% reduction in the daily dose resulted in a 19% decrease in the concentration of total gimatecan in plasma prior to administration of the fifth daily dose (56 ± 23 vs. 45 ± 20 ng/mL) and a 33% decrease in the AUC for dose 5 (8.0±4.8 vs. 5.3±4.2 ng*h/mL). Only one patient had a partial radiographic response by the modified Macdonald criteria and stable disease was the best response in 13 patients. All other patients had progressive disease after two cycles of therapy. Only three patients (12%) were progression-free at 6 months. Median time to progression was 12.0 weeks (95% CI: 7.0, 17.0). Conclusions: Treatment with single-agent gimatecan 1.0 mg/m2/day for 5 days, repeated every 28-days showed minimal efficacy.

[Table: see text]

Phase II trial of lapatinib for brain metastases in patients with human epidermal growth factor receptor 2-positive breast cancer

PURPOSE

One third of women with advanced human epidermal growth factor receptor 2 (HER-2)-positive breast cancer develop brain metastases; a subset progress in the CNS despite standard approaches. Medical therapies for refractory brain metastases are neither well-studied nor established. We evaluated the safety and efficacy of lapatinib, an oral inhibitor of epidermal growth factor receptor (EGFR) and HER-2, in patients with HER-2-positive brain metastases.

PATIENTS AND METHODS

Patients had HER-2-positive breast cancer, progressive brain metastases, prior trastuzumab treatment, and at least one measurable metastatic brain lesion. Patients received lapatinib 750 mg orally twice a day. Tumor response was assessed by magnetic resonance imaging every 8 weeks. The primary end point was objective response (complete response [CR] plus partial response [PR]) in the CNS by Response Evaluation Criteria in Solid Tumors (RECIST). Secondary end points included objective response in non-CNS sites, time to progression, overall survival, and toxicity.

RESULTS

Thirty-nine patients were enrolled. All patients had developed brain metastases while receiving trastuzumab; 37 had progressed after prior radiation. One patient achieved a PR in the brain by RECIST (objective response rate 2.6%, 95% conditional CI, 0.21% to 26%). Seven patients (18%) were progression free in both CNS and non-CNS sites at 16 weeks. Exploratory analyses identified additional patients with some degree of volumetric reduction in brain tumor burden. The most common adverse events (AEs) were diarrhea (grade 3, 21%) and fatigue (grade 3, 15%).

CONCLUSION

The study did not meet the predefined criteria for antitumor activity in highly refractory patients with HER-2-positive brain metastases. Because of the volumetric changes observed in our exploratory analysis, further studies are underway utilizing volumetric changes as a primary end point.

Topotecan as salvage therapy for relapsed or refractory primary central nervous system lymphoma

Treatment for patients with refractory or relapsed primary CNS lymphoma (PCNSL) remains unsatisfactory. Topotecan is an intravenous topoisomerase I inhibitor with good CSF penetration and documented efficacy in patients with relapsed systemic non-Hodgkin's lymphoma. In this study 15 patients with refractory or relapsed PCNSL were treated with intravenous topotecan (1.5 mg/m(2)) for five consecutive days during each 21-day cycle. All 15 patients had measurable, contrast-enhancing tumor on cranial MRI at the time of relapse. Three (20%) patients achieved a complete response after one, three and four cycles, respectively, while three (20%) patients achieved a partial response after two cycles each, for a total response proportion of 40%. Three patients had stable disease at the end of topotecan treatment. Six patients (40%) had progressive disease during treatment. Median overall survival was 981 days (95% CI: 275, NA) and median progression free survival was 60 days (95% CI: 46, 945). Three out of 15 patients had grade 3 thrombocytopenia. Six out of 15 patients had grade 3 neutropenia, while 5/15 patients had grade 4 neutropenia, and 13/15 patients received g-CSF at some point during treatment. There were no deaths directly related to treatment toxicity. Our study shows that topotecan, as a salvage therapy in patients with relapsed or refractory PCNSL, is associated with an overall response proportion of 40% and should be considered in patients who have failed prior methotrexate-based chemotherapy and/or whole brain irradiation. However, progression is frequent and early and most patients required growth factor support due to myelotoxicity.

Phase I and correlative biology study of cilengitide in patients with recurrent malignant glioma

PURPOSE

This multi-institutional phase I trial was designed to determine the maximum-tolerated dose (MTD) of cilengitide (EMD 121974) and to evaluate the use of perfusion magnetic resonance imaging (MRI) in patients with recurrent malignant glioma.

PATIENTS AND METHODS

Patients received cilengitide twice weekly on a continuous basis. A treatment cycle was defined as 4 weeks. Treatment-related dose-limiting toxicity (DLT) was defined as any grade 3 or 4 nonhematologic toxicity or grade 4 hematologic toxicity of any duration.

RESULTS

A total of 51 patients were enrolled in cohorts of six patients to doses of 120, 240, 360, 480, 600, 1,200, 1,800, and 2,400 mg/m2 administered as a twice weekly intravenous infusion. Three patients progressed early and were inevaluable for toxicity assessment. The DLTs observed were one thrombosis (120 mg/m2), one grade 4 joint and bone pain (480 mg/m2), one thrombocytopenia (600 mg/m2) and one anorexia, hypoglycemia, and hyponatremia (800 mg/m2). The MTD was not reached. Two patients demonstrated complete response, three patients had partial response, and four patients had stable disease. Perfusion MRI revealed a significant relationship between the change in tumor relative cerebral blood flow (rCBF) from baseline and area under the plasma concentration versus time curve after 16 weeks of therapy.

CONCLUSION

Cilengitide is well tolerated to doses of 2,400 mg/m2, durable complete and partial responses were seen in this phase I study, and clinical response appears related to rCBF changes.

Isolated optic nerve lymphoma diagnosed by optic nerve biopsy

PURPOSE

To report a case of isolated optic nerve lymphoma diagnosed by optic nerve biopsy.

DESIGN

Case report.

METHODS

A 66-year-old woman was referred to the Neuro-Ophthalmology Service because of a decrease in visual acuity and right optic disk edema.

RESULTS

A magnetic resonance image of the brain showed only enhancement of the optic nerve. An examination that included ANA, c-ANCA, p-ANCA, Lyme titers, FTA-ABS, ACE level, chest x-ray, and lumbar puncture was negative. Because of rapid progression on clinical examination and serial imaging, an optic nerve biopsy was performed, which showed B-cell lymphoma.

CONCLUSION

Optic nerve lymphoma can be confused with a variety of inflammatory and neoplastic infiltrations of the optic nerve on clinical and radiographic examinations. Optic nerve biopsy can be valuable in diagnosing isolated optic nerve lymphoma if other diagnostic tests are unrevealing, but the procedure carries considerable risk of loss of visual acuity and should be recommended judiciously.

A randomized, double-blind, placebo-controlled, phase 2 study of RMP-7 in combination with carboplatin administered intravenously for the treatment of recurrent malignant glioma

RMP-7, a bradykinin analog, temporarily increases the permeability of the blood-brain tumor barrier to chemotherapy drugs like carboplatin. We conducted a randomized, controlled trial of carboplatin and RMP-7 versus carboplatin and placebo in patients with recurrent malignant glioma. The primary outcome measure was time to tumor progression (TTP). Adults with recurrent glioblastoma multiforme or anaplastic glioma were randomized in a 1:1 ratio to receive carboplatin and either RMP-7 or placebo. Radiation therapy had failed in all patients, and they may have received prior chemotherapy. Carboplatin (dosed to achieve an area under the curve of 5 mg/ml x time for patients who had received prior chemotherapy, or 7 mg/ml x time for those who had not) was given intravenously every 4 weeks, followed by intravenous infusion of either RMP-7 or placebo (300 ng/kg). TTP, tumor response, neuropsychological assessments, functional independence, and quality of life assessments were analyzed every 4 weeks. There were 122 patients enrolled, 62 in the RMP-7 and carboplatin group and 60 in the placebo and carboplatin group. Median TTP was 9.7 weeks (95% CI, 8.3-12.6 weeks) for the RMP-7 and carboplatin group and 8.0 weeks (95% CI, 7.4-12.6 weeks) for the placebo and carboplatin group. Median survival times were 26.9 weeks (95% CI, 21.3-37.6 weeks) for the RMP-7 group and 19.9 weeks (95% CI, 15.0-31.3 weeks) for the placebo group. No differences were noted for time to worsening of neuropsychological assessments, functional independence, or quality of life assessments. The use of RMP-7 had no effect on the pharmacokinetics or toxicity of carboplatin. At the dose and schedule used in this trial, RMP-7 did not improve the efficacy of carboplatin. Recent preclinical pharmacokinetic modeling of RMP-7 suggests that higher doses of RMP-7 may be required to increase carboplatin delivery to tumor.

Treatment of primary CNS lymphoma with methotrexate and deferred radiotherapy: a report of NABTT 96-07

PURPOSE

A multicenter, phase II study of single-agent, intravenous methotrexate in newly diagnosed non-AIDS-related primary CNS lymphoma was conducted in the New Approaches to Brain Tumor Therapy (NABTT) CNS Consortium.

METHODS

Methotrexate (8 g/m(2)) was initially administered every 2 weeks. The primary end point was radiographic CR or PR, as defined by standard radiographic criteria, and secondary end points were survival and drug-related toxicity.

RESULTS

Twenty-five patients were enrolled with a mean age of 60 years and median Karnofsky Performance Score of 80. Three of 14 patients who underwent lumbar puncture had malignant cells on CSF cytopathology, and five of 25 patients had ocular involvement. Two patients could not be evaluated for the primary end point because of the absence of measurable disease in one and death before radiologic imaging in another. All patients have completed the treatment program or progressed. Among 23 patients, there were 12 CR (52%), five PR (22%), one (4%) with stable disease, and five progressions (22%) while on therapy. Seven patients died of tumor progression, and two died of other causes. Median progression-free survival was 12.8 months. Median overall survival for the entire group had not been reached at 22.8+ months. The toxicity of this regimen was modest, with no grade 3 or 4 toxicity in 13 of 25 patients, grade 3 toxicity in eight of 25 patients, and grade 4 toxicity in four of 25 patients after 287 cycles of chemotherapy.

CONCLUSION

These results indicate that high-dose methotrexate is associated with modest toxicity and a radiographic response proportion (74%) comparable to more toxic regimens.

L-dopa-resistant parkinsonism syndrome following cerebral radiation therapy for neoplasm

A bradykinetic form of parkinsonism, unresponsive to levo-dopa therapy developed in four patients two to eight weeks after completion of external beam irradiation (39.2 Gy to 59.4 Gy) of their intracranial neoplasm. In the absence of other causative factors, we relate the movement disorder to radiation-induced changes within the basal ganglia. At post-mortem examination one patient had putamenal gliosis and thickened vessels with loss of nigral neurons.

Prodrug activation enzymes in cancer gene therapy

Among the broad array of genes that have been evaluated for tumor therapy, those encoding prodrug activation enzymes are especially appealing as they directly complement ongoing clinical chemotherapeutic regimes. These enzymes can activate prodrugs that have low inherent toxicity using both bacterial and yeast enzymes, or enhance prodrug activation by mammalian enzymes. The general advantage of the former is the large therapeutic index that can be achieved, and of the latter, the non-immunogenicity (supporting longer periods of prodrug activation) and the fact that the prodrugs will continue to have some efficacy after transgene expression is extinguished. This review article describes 13 different prodrug activation schemes developed over the last 15 years, two of which - activation of ganciclovir by viral thymidine kinase and activation of 5-fluorocytosine to 5-fluorouracil - are currently being evaluated in clinical trials. Essentially all of these prodrug activation enzymes mediate toxicity through disruption of DNA replication, which occurs at differentially high rates in tumor cells compared with most normal cells. In cancer gene therapy, vectors target delivery of therapeutic genes to tumor cells, in contrast to the use of antibodies in antibody-directed prodrug therapy. Vector targeting is usually effected by direct injection into the tumor mass or surrounding tissues, but the efficiency of gene delivery is usually low. Thus it is important that the activated drug is able to act on non-transduced tumor cells. This bystander effect may require cell-to-cell contact or be mediated by facilitated diffusion or extracellular activation to target neighboring tumor cells. Effects at distant sites are believed to be mediated by the immune system, which can be mobilized to recognize tumor antigens by prodrug-activated gene therapy. Prodrug activation schemes can be combined with each other and with other treatments, such as radiation, in a synergistic manner. Use of prodrug wafers for intratumoral drug activation and selective permeabilization of the tumor vasculature to prodrugs and vectors should further increase the value of this new therapeutic modality.

Prodrug activation enzymes in cancer gene therapy

Among the broad array of genes that have been evaluated for tumor therapy, those encoding prodrug activation enzymes are especially appealing as they directly complement ongoing clinical chemotherapeutic regimes. These enzymes can activate prodrugs that have low inherent toxicity using both bacterial and yeast enzymes, or enhance prodrug activation by mammalian enzymes. The general advantage of the former is the large therapeutic index that can be achieved, and of the latter, the non-immunogenicity (supporting longer periods of prodrug activation) and the fact that the prodrugs will continue to have some efficacy after transgene expression is extinguished. This review article describes 13 different prodrug activation schemes developed over the last 15 years, two of which - activation of ganciclovir by viral thymidine kinase and activation of 5-fluorocytosine to 5-fluorouracil - are currently being evaluated in clinical trials. Essentially all of these prodrug activation enzymes mediate toxicity through disruption of DNA replication, which occurs at differentially high rates in tumor cells compared with most normal cells. In cancer gene therapy, vectors target delivery of therapeutic genes to tumor cells, in contrast to the use of antibodies in antibody-directed prodrug therapy. Vector targeting is usually effected by direct injection into the tumor mass or surrounding tissues, but the efficiency of gene delivery is usually low. Thus it is important that the activated drug is able to act on non-transduced tumor cells. This bystander effect may require cell-to-cell contact or be mediated by facilitated diffusion or extracellular activation to target neighboring tumor cells. Effects at distant sites are believed to be mediated by the immune system, which can be mobilized to recognize tumor antigens by prodrug-activated gene therapy. Prodrug activation schemes can be combined with each other and with other treatments, such as radiation, in a synergistic manner. Use of prodrug wafers for intratumoral drug activation and selective permeabilization of the tumor vasculature to prodrugs and vectors should further increase the value of this new therapeutic modality.

Happy families: a twin study of humour

The objective of this study was to estimate how much of an individual's appreciation of humour is influenced by genetic factors, the shared environment or the individual's unique environment. A population-based classical twin study of 127 pairs of female twins (71 monozygous (MZ) and 56 dizygous (DZ) pairs) aged 20-75 from the St Thomas' UK Adult Twin Registry elicited responses to five 'Far Side' Larson cartoons on a scale of 0-10. Within both MZ and DZ twin pairs, the tetrachoric correlations of responses to all five cartoons were significantly greater than zero. Furthermore, the correlations for MZ and DZ twins were of similar magnitude and in some cases the DZ correlation was greater than that of the MZ twins. This pattern of correlations suggests that shared environment rather then genetic effects contributes to cartoon appreciation. Multivariate model-fitting confirmed that these data were best explained by a model that allowed for the contribution of the shared environment and random environmental factors, but not genetic effects. However, there did not appear to be a general humour factor underlying responses to all five cartoons and no effect of age was seen. The shared environment, rather than genetic factors, explains the familial aggregation of humour appreciation as assessed by the specific 'off the wall' cognitive type of cartoons used in this study.

Lack of efficacy of 9-aminocamptothecin in adults with newly diagnosed glioblastoma multiforme and recurrent high-grade astrocytoma. NABTT CNS Consortium

9-Aminocamptothecin (9-AC) was administered as a 72-h i.v. infusion every 2 weeks to a total of 99 adults with high-grade astrocytomas. Fifty-one patients with newly diagnosed glioblastoma multiforme received 9-AC treatment prior to radiation therapy and 48 patients with high-grade astrocytomas were treated at the time of tumor recurrence. Upon entrance into these research protocols, all patients had measurable disease that was evaluated on a monthly basis with volumetric CT or MRI scans. A partial response was defined by > or =50% reduction in the contrast enhancing volume on stable or decreasing doses of glucocorticoids. The study specified that all apparent responders would have central review of their radiologic studies and histopathology. The initial patients treated with 9-AC were also receiving anticonvulsants and were noted to have minimal myelosuppression with this chemotherapy. Thus, 9-AC doses were escalated from the previously reported maximum tolerated dose (MTD) of 850 microg/m2/24 h. We then established new MTDs for patients receiving enzyme-inducing anticonvulsants. We defined these MTDs to be 1,776 microg/m2/24 h for newly diagnosed, previously untreated patients and 1,611 microg/m2/24 h for patients with recurrent disease. Twenty-two patients with newly diagnosed glioblastoma multiforme received 9-AC at doses > or =1,776 microg/m2/24 h. Of these, 18 had evaluable disease on central review, and 0 of 18 (0%) demonstrated a partial or complete response. Twenty-one patients with recurrent high-grade astrocytomas were treated at 1,611 microg/m2/24 h; 20 had evaluable disease and 0 of 20 (0%) had a partial or complete response. Thus, the overall response rate in the 38 evaluable patients treated at the MTD was 0 of 38 (0%). Furthermore, of the 51 evaluable patients who were treated at doses less than the MTD, only one partial response was observed, yielding an overall response rate of 2%. Evidence of drug failure was rapid with tumor progression in one-half of patients after 2 drug cycles. 9-AC lacks evidence of substantial activity in patients with newly diagnosed or recurrent high-grade astrocytomas.

Improved delineation of human brain tumors on MR images using a long-circulating, superparamagnetic iron oxide agent

The purpose of this study was to corroborate experimental findings that long-circulating, superparamagnetic iron oxide contrast agents accumulate at the margins of human brain tumors, thereby improving their delineation on magnetic resonance (MR) images. This limited clinical study examined a total of four patients with brain tumors (three with primary gliomas and one with metastatic melanoma; n = 8 lesions) who were given a pharmaceutical formulation of a superparamagnetic, ultra-small-particulate iron oxide (USPIO, intravenous dose of 1.1 mg Fe/kg). The agent has a characteristically long plasma half-life and is currently undergoing Phase III clinical trials for liver disease (AMI-227, Advanced Magnetics, Cambridge, MA). MR (conventional spin-echo and gradient-echo) images of the brain were obtained before and 12, 24, and/or 36 hours after administration of the agent, with follow-up several weeks later. Twelve to 36 hours after IV administration of the USPIO, both primary and metastatic brain tumors showed readily detectable increases in signal intensity on T1-weighted spin-echo images. Unlike the pattern of enhancement with a gadolinium (Gd) chelate, which occurred immediately and decreased within hours, that with the USPIO occurred gradually, with a peak at 24 hours, and decreased over several days. Whereas the enhancing tumor margin with the Gd chelate blurred with time due to diffusion of the agent, the margin with the USPIO remained sharp, presumably due to the much lower diffusion coefficient (large size) of the particles and partly because of local endocytosis by tumor cells. Compared with Gd chelates, long-circulating, superparamagnetic iron oxide contrast agents can provide prolonged delineation of the margins of human brain tumors on MR images, which has implications for the targeting of diagnostic biopsies and the planning of surgical resections.

Increased 9-aminocamptothecin dose requirements in patients on anticonvulsants. NABTT CNS Consortium. The New Approaches to Brain Tumor Therapy

BACKGROUND

High grade astrocytomas remain uniformly fatal despite aggressive surgery and radiotherapy. As existing chemotherapeutic agents are of limited benefit, clinical trials are underway to screen new drugs, such as 9-aminocamptothecin (9-AC), for activity in high grade astrocytomas.

PURPOSE

This study was designed to estimate the efficacy of 9-AC in patients with newly diagnosed glioblastoma multiforme and recurrent high grade astrocytomas. The planned dose of 9-AC for this trial was 850 microg/m2 per 24 h as a 72-h continuous intravenous infusion every 2 weeks. This was the maximum tolerated dose (MTD) on this schedule in multiple phase I studies in patients with systemic malignancies. However, we found this dose subtherapeutic in our patient population. As a result, the purpose of the study was altered to determine the MTD.

METHODS

A group of 32 patients were studied using 850 microg/m2 per 24 h with a provision to escalate to 1000 microg/m2 per 24 h if the first three cycles of 9-AC were without significant hematologic toxicity. Once it was determined that myelosuppression did not occur in patients on anticonvulsants, dose escalations were initiated using the continual reassessment method. Dose escalations were conducted independently in newly diagnosed and recurrent patients and in those taking and not taking hepatic enzyme-inducing anticonvulsants. Pharmacologic studies were conducted during the first cycle of 9-AC. Toxicity was determined using the NCI common toxicity criteria and efficacy was assessed using serial volumetric brain scans.

RESULTS

9-AC was administered to 59 patients, 31 with newly diagnosed glioblastoma multiforme and 28 with recurrent high grade astrocytomas. No grade III-IV myelosuppression was noted in the 29 patients (128 cycles) on phenytoin, carbamazepine, phenobarbital, and/ or valproic acid who received 850 microg/m2 per 24 h. In contrast, two of three patients (five cycles) who were not taking anticonvulsants developed grade IV myelosuppression. Steady-state total 9-AC plasma levels were lower in patients on anticonvulsants (median 25.3 nM) than in patients who were not taking anticonvulsants (median 76.5 nM). Dose escalations performed in 27 additional patients determined the MTD in patients taking anticonvulsants to be 1776 microg/m2 per 24 h for patients with newly diagnosed tumors and 1611 microg/m2 per 24 h for patients with recurrent disease.

CONCLUSIONS

We describe a new and unexpected drug interaction between 9-AC and anticonvulsants. This is similar to recent findings with paclitaxel, and suggests that higher than "usual" doses of some chemotherapeutic agents are required in patients on anticonvulsants. Prospectively defined dose escalations and pharmacologic studies are essential for the careful evaluation of new chemotherapeutic agents in patients with brain tumors.

High-dose intravenous methotrexate for patients with nonleukemic leptomeningeal cancer: is intrathecal chemotherapy necessary?

PURPOSE

Standard treatments for neoplastic meningitis are only modestly effective and are associated with significant morbidity. Isolated reports suggest that concurrent systemic and intrathecal (i.t.) therapy may be more effective than i.t. therapy alone. We present our experience, which includes CSF and serum pharmacokinetic data, on the use of high-dose (HD) intravenous (i.v.) methotrexate (MTX) as the sole treatment for neoplastic meningitis.

PATIENTS AND METHODS

Sixteen patients with solid-tumor neoplastic meningitis received one to four courses (mean, 2.3 courses) of HD (8 g/m2 over 4 hours) i.v. MTX and leucovorin rescue. Serum and CSF MTX concentrations were measured daily. Toxicity, response, and survival were retrospectively compared with a reference group of 15 patients treated with standard i.t. MTX during the same time interval.

RESULTS

Peak methotrexate concentrations ranged from 3.7 to 55 micromol/L (mean, 17.1 micromol/L) in CSF and 178 to 1,700 micromol/L (mean, 779 micromol/L) in serum. Cytotoxic CSF and serum MTX concentrations were maintained much longer than with i.t. dosing. Toxicity was minimal. Cytologic clearing was seen in 81% of patients compared with 60% of patients treated intrathecally (P = .3). Median survival in the HD i.v. MTX group was 13.8 months versus 2.3 months in the i.t. MTX group (P = .003).

CONCLUSION

HD i.v. MTX is easily administered and well tolerated. This regimen achieves prolonged cytotoxic serum MTX concentrations and CSF concentrations at least comparable to those achieved with standard i.t. therapy. Cytologic clearing and survival may be superior in patients treated with HD i.v. MTX. Prospective studies and a reconsideration of the use of i.t. chemotherapy for patients with neoplastic meningitis are warranted.

Perfusion Magnetic Resonance Imaging to Assess Brain Tumor Responses to New Therapies

BACKGROUND: Although magnetic resonance imaging (MRI) is effective in detecting the location of intracranial tumors, new imaging techniques have been studied that may enhance the specificity for the prediction of histologic grade of tumor and for the distinction between recurrence and tumor necrosis associated with cancer therapy. METHODS: The authors review their experience and that of others on the use of perfusion magnetic resonance imaging to evaluate responses of brain tumors to new therapies. RESULTS: Functional imaging techniques that can distinguish tumor from normal brain tissue using physiological parameters. These new approaches provide maps of tumor perfusion to monitor the effects of novel compounds that restrict tumor angiogenesis. CONCLUSIONS: Perfusion MRI not only may be as effective as radionuclide-based techniques in sensitivity and specificity in assessing brain tumor responses to new therapies, but also may offer higher resolution and convenient co-registration with conventional MRI, as well as time- and cost-effectiveness. Further study is needed to determine the role of perfusion MRI in assessing brain tumor responses to new therapies.

Treatment of recurrent malignant glioma with BCNU-fluosol and oxygen inhalation. A phase I-II study

OBJECTIVES

To evaluate the toxicity and response rate following BCNU with oxygen inhalation and escalating dosages of fluosol administered to patients with radiographic progression of malignant glioma after definitive surgery and radiotherapy.

METHOD

This single arm, phase I-II multicenter trial, enrolled 99 patients with malignant gliomas recurrent after definitive surgery and radiotherapy. All patients received a fixed dose (200 mg/m2) of BCNU along with 100% oxygen and fluosol, a perfluorochemical. Fluosol doses were escalated between patients (150, 275, 400 and 600 ml/m2). Treatment was repeated every 6 weeks for a maximum of 6 cycles. Patients were assessed for toxicity at the time of infusion and sequentially thereafter. Response was evaluated clinically and radiologically at least every 6 weeks.

RESULTS

Treatment was well tolerated. Dose reductions were required at least once in 18 patients, treatment delays were necessary at least once in 33 patients. Grade 3-4 leukopenia occurred in 6 patients (12 events), grade 3-4 thrombocytopenia in 10 patients (25 events) and grade 3-4 liver enzymes elevations in 18 patients (31 events). Higher fluosol dosages did not produce increases in toxicity or responses. Response or stabilization was seen in 57% (38% were stabilizations) of the patients who entered the trial with progressive disease. The median time to progression was 45 weeks, and median survival was 66 weeks for patients who had response or stabilization. For patients with glioblastoma response/stabilization was seen in 45% with a mean duration of 24 weeks, for patients with anaplastic astrocytoma response/stabilization was seen in 68% with a mean duration of 50 weeks.

CONCLUSION

This treatment regimen is well tolerated. Our results suggest fluosol may enhance the effectiveness of BCNU for the treatment of recurrent malignant gliomas. Future studies will be performed using fluosol at the dose of 400 ml/m2.

Late motor deficits of Chilean manganese miners: a blinded control study

High-level chronic manganese (Mn) exposure produces dystonic rigidity and proximal tremor. The late effects of asymptomatic exposure are uncertain. To evaluate hand movements of asymptomatic Chilean miners, we utilized a manual tremormeter (EAP) and a digitizing tablet (MOVEMAP). In Andacollo, Chile, we examined 59 individuals aged > 50 years (mean age, 64.4 years). Twenty-seven exposed miners had heavy Mn dust exposure in Mn mines for more than 5 years (mean duration, 20.25 years), ending at least 5 years previously. Thirty-two control miners had never worked in Mn mines or had short-term Mn employment. Tests of resting tremor (EAP Tremormeter, MOVEMAP Steady paradigm), action tremor (MOVEMAP Square paradigm), and repetitive hand movements (EAP Tapping Test and Orthokinesimeter) differentiated performance of exposed miners from that of controls. Chronic asymptomatic Mn exposure results in detectable late-life abnormalities of movement.

Sentinel lesions of primary CNS lymphoma

Some patients ultimately diagnosed with primary CNS lymphoma (PCNSL) have transient symptomatic contrast enhancing lesions. These "sentinel lesions" of PCNSL recede spontaneously or with corticosteroid treatment and present an important diagnostic dilemma because they show variable, but non-diagnostic histopathological features. Four previously healthy, immunocompetent patients aged 49 to 58 years had contrast enhancing intraparenchymal brain lesions. Before biopsy, three of the four were treated with corticosteroids. Initial biopsies showed demyelination with axonal sparing in two, non-specific inflammation in one, and normal brain in one. Infiltrating lymphocytes predominantly expressed T cell markers with rare B cells. All four patients recovered within two to four weeks after the initial biopsy and imaging studies showed resolution of the lesions. The CSF was normal in three of the four patients tested; oligoclonal bands were absent in both of the two tested. After seven to 11 months, each patient developed new symptomatic lesions in a different region of the brain, biopsy of which showed a B cell PCNSL. The mechanism of spontaneous involution of sentinel lesions is not understood, but may represent host immunity against the tumour. Sentinel lesions of PCNSL should be considered in patients with contrast enhancing focal parenchymal lesions that show non-specific or demyelinative histopathological changes. Close clinical and radiographic follow up is essential if PCNSL is to be diagnosed early in such patients.