Survival and neurologic outcomes in a randomized trial of motexafin gadolinium and whole-brain radiation therapy in brain metastases

Prospective evaluation of quality of life and neurocognitive effects in patients with multiple brain metastases receiving whole-brain radiotherapy with or without thalidomide on Radiation Therapy Oncology Group (RTOG) trial 0118

PURPOSE

Radiation Therapy Oncology Group (RTOG) 0118 randomized patients with multiple brain metastases to whole-brain radiotherapy (WBRT) +/- thalidomide. This secondary analysis of 156 patients examined neurocognitive and quality of life (QOL) outcomes.

METHODS AND MATERIALS

Quality of life was determined with the Spitzer Quality of Life Index (SQLI). The Folstein Mini-Mental Status Exam (MMSE) assessed neurocognitive function. SQLI and MMSE were administered at baseline and at 2-month intervals. MMSE was scored with a threshold value associated with neurocognitive functioning (absolute cutoff level of 23) and with the use of corrections for age and educational level.

RESULTS

Baseline SQLI predicted survival. Patients with SQLI of 7-10 vs. <7 had median survival time (MST) of 4.8 vs. 3.1 months, p = 0.05. Both arms showed steady neurocognitive declines, but SQLI scores remained stable. Higher levels of neurocognitive decline were observed with age and education-level corrections. Of patients considered baseline age/educational level neurocognitive failures, 32% died of intracranial progression.

CONCLUSIONS

Quality of life and neuropsychological testing can be prospectively administered on a Phase III cooperative group trial. The MMSE should be evaluated with adjustments for age and educational level. Baseline SQLI is predictive of survival. Despite neurocognitive declines, QOL remained stable during treatment and follow-up. Poor neurocognitive function may predict clinical deterioration. Lack of an untreated control arm makes it difficult to determine the contribution of the respective interventions (i.e., WBRT, thalidomide) to neurocognitive decline. The RTOG has developed a trial to study the role of preventative strategies aimed at forestalling neurocognitive decline in this population.

Brain Metastases From Breast Carcinoma: Validation of the Radiation Therapy Oncology Group Recursive Partitioning Analysis Classification and Proposition of a New Prognostic Score

PURPOSE

To validate the Radiation Therapy Oncology Group Recursive Partitioning Analysis (RTOG RPA) classification and determine independent prognostic factors, to create a simple and specific prognostic score for patients with brain metastases (BM) from breast carcinoma treated with whole-brain radiotherapy (WBRT).

METHODS AND MATERIALS

From January 1998 through December 2003, 132 patients with BM from breast carcinoma were treated with WBRT. We analyzed several potential predictors of survival after WBRT: age, Karnofsky performance status, RTOG-RPA class, number of BM, presence and site of other systemic metastases, interval between primary tumor and BM, tumor hormone receptor (HR) status, lymphocyte count, and HER-2 overexpression.

RESULTS

A total of 117 patients received exclusive WBRT and were analyzed. Median survival with BM was 5 months. One-year and 2-year survival rates were 27.6% (95% confidence interval [CI] 19.9-36.8%) and 12% (95% CI 6.5-21.2%), respectively. In multivariate analysis, RTOG RPA Class III, lymphopenia (< or =0.7 x 10(9)/L) and HR negative status were independent prognostic factors for poor survival. We constructed a three-factor prognostic scoring system that predicts 6-month and 1-year rates of overall survival in the range of 76.1-29.5% (p = 0.00033) and 60.9-15.9% (p = 0.0011), respectively, with median survival of 15 months, 5 months, or 3 months for patients with none, one, or more than one adverse prognostic factor(s), respectively.

CONCLUSIONS

This study confirms the prognostic value of the RTOG RPA classification, lymphopenia, and tumor HR status, which can be used to form a prognostic score for patients with BM from breast carcinoma.

Phase I trial of motexafin gadolinium in combination with docetaxel and cisplatin for the treatment of non-small cell lung cancer

INTRODUCTION

Motexafin gadolinium is a novel antineoplastic drug that disrupts cancer cell antioxidant systems, thus contributing to cellular death. In patients with lung cancer, motexafin gadolinium has been shown to increase the time to neurologic progression when given in combination with whole-brain radiotherapy in randomized phase III studies. Preclinical data suggest that this drug might also enhance the antineoplastic effects of chemotherapy.

METHODS

In this one-arm, open label, phase I, dose-escalation study, we administered docetaxel (75 mg/m2), cisplatin (75 mg/m2), and motexafin gadolinium every 3 weeks to patients with metastatic non-small cell lung cancer. Twenty-one patients were treated at one of four motexafin dose levels.

RESULTS

The maximal tolerated motexafin dose was 10 mg/kg on day 1 of a 3-week cycle. Dose-limiting toxicities consisted of febrile neutropenia, hypertension, myocardial ischemia, and pneumonitis/pulmonary infiltrates. Other common grade 3-4 adverse events across all cohorts that did not appear to be exacerbated by motexafin gadolinium included granulocytopenia, fatigue, dehydration, nausea, and vomiting. Two episodes of myocardial ischemia and one sudden death of unknown cause were observed. Response rates were partial response (10%), stable disease (60%), and disease progression (30%).

CONCLUSIONS

The regimen studied was tolerable and showed activity in patients with metastatic non-small cell lung cancer. The recommended doses for future phase II trials are motexafin gadolinium 10 mg/kg, docetaxel 75 mg/m2, and cisplatin 75 mg/m2 intravenously on day 1 every 3 weeks. Caution is advised in patients with a history of cardiovascular disease.

Central nervous system tumors

Central nervous system tumors are relatively common in the United States, with more than 40,000 cases annually. Although more than half of these tumors are benign, they can cause substantial morbidity. Malignant primary brain tumors are the leading cause of death from solid tumors in children and the third leading cause of death from cancer in adolescents and adults aged 15 to 34 years. Common presenting symptoms include headache, seizures, and altered mental status. Whereas magnetic resonance imaging helps define the anatomic extent of tumor, biopsy is often required to confirm the diagnosis. Treatment depends on the histologic diagnosis. Benign tumors are usually curable with surgical resection or radiation therapy including stereotactic radiation; however, most patients with malignant brain tumors benefit from chemotherapy either at the time of initial diagnosis or at tumor recurrence. Metastases to the brain remain a frequent and morbid complication of solid tumors but are frequently controlled with surgery or radiation therapy. Unfortunately, the mortality rate from malignant brain tumors remains high, despite initial disease control. This article provides an overview of current diagnostic and treatment approaches for patients with primary and metastatic brain tumors.

Motexafin gadolinium injection for the treatment of brain metastases in patients with non-small cell lung cancer

Despite recent advances in technology, targeting, and chemotherapy, brain metastasis from non-small cell lung cancer (NSCLC) remains a significant problem. The vast majority of patients with this diagnosis undergo whole brain radiation therapy (WBRT). However, outcomes are still quite poor with median survivals measured in only months. In an effort to enhance outcomes from external beam radiation treatments, radiosensitizers have been investigated. Motexafin gadolinium (MGd) (Xcytrin^®, Sunnyvale, CA, USA) is a novel radiation sensitizer with a unique mechanism of action that may increase the therapeutic index of WBRT for patients with brain metastases, particularly in those with NSCLC histologies. Here we review the rationale for the use of this drug as well as its current and future role as a radiation enhancer in the management of NSCLC brain metastasis.

CNS complications of breast cancer: current and emerging treatment options

In general, the development of CNS metastases of breast cancer depends on several prognostic factors, including younger age and a negative hormone receptor status. Also, the presence of a breast cancer 1, early onset (BRCA1) germline mutation and expression of the human epidermal growth factor receptor 2 (Her2/neu) proto-oncogene seem to contribute to an increased rate of development of CNS metastases. The choice of appropriate therapy for brain metastases also depends on prognostic factors, including the age of the patient, the Karnofsky performance score, the number of brain metastases and the presence of systemic disease. Surgery followed by whole brain radiation therapy (WBRT) is generally restricted to ambulant patients with a single brain metastasis without active extracranial disease. In patients who have two to four metastases, stereotactic focal radiotherapy (i.e. radiosurgery) with or without WBRT is usually indicated. In the remainder of patients, WBRT alone provides adequate palliation. Although breast carcinoma is sensitive to chemotherapy, the role of chemotherapy in the treatment of brain metastases is still unclear. Objective responses after cyclophosphamide-based therapies were reported in studies performed in the 1980s. Subgroup analysis of data from a randomised study indicates that survival may improve if WBRT is combined with the radiosensitiser efaproxiral. Interestingly, the Her2/neu antibody trastuzumab, which does not cross the blood-brain barrier, produces systemic responses and enhanced survival, without a clear effect on brain metastases. Breast cancer constitutes the most common solid primary tumour leading to leptomeningeal disease. Clinical symptoms such as cranial nerve dysfunction or a cauda equina syndrome can be treated with local radiotherapy. A randomised study in patients with leptomeningeal disease secondary to breast cancer has revealed that intrathecal chemotherapy is associated with substantially more adverse effects than non-intrathecal treatment, without a clear benefit in terms of response or survival. Intramedullary metastasis is rare but often presents with a rapidly progressive myelopathy. Local radiotherapy may preserve neurological function. Epidural spinal cord metastasis occurs in approximately 4% of patients and can lead to paraplegia. A randomised study has shown that surgical intervention together with local radiotherapy is superior to local radiotherapy alone.

Neurocognitive Function of Patients with Brain Metastasis Who Received Either Whole Brain Radiotherapy Plus Stereotactic Radiosurgery or Radiosurgery Alone

PURPOSE

To determine how the omission of whole brain radiotherapy (WBRT) affects the neurocognitive function of patients with one to four brain metastases who have been treated with stereotactic radiosurgery (SRS).

METHODS AND MATERIALS

In a prospective randomized trial between WBRT+SRS and SRS alone for patients with one to four brain metastases, we assessed the neurocognitive function using the Mini-Mental State Examination (MMSE). Of the 132 enrolled patients, MMSE scores were available for 110.

RESULTS

In the baseline MMSE analyses, statistically significant differences were observed for total tumor volume, extent of tumor edema, age, and Karnofsky performance status. Of the 92 patients who underwent the follow-up MMSE, 39 had a baseline MMSE score of < or =27 (17 in the WBRT+SRS group and 22 in the SRS-alone group). Improvements of > or =3 points in the MMSEs of 9 WBRT+SRS patients and 11 SRS-alone patients (p = 0.85) were observed. Of the 82 patients with a baseline MMSE score of > or =27 or whose baseline MMSE score was < or =26 but had improved to > or =27 after the initial brain treatment, the 12-, 24-, and 36-month actuarial free rate of the 3-point drop in the MMSE was 76.1%, 68.5%, and 14.7% in the WBRT+SRS group and 59.3%, 51.9%, and 51.9% in the SRS-alone group, respectively. The average duration until deterioration was 16.5 months in the WBRT+SRS group and 7.6 months in the SRS-alone group (p = 0.05).

CONCLUSION

The results of the present study have revealed that, for most brain metastatic patients, control of the brain tumor is the most important factor for stabilizing neurocognitive function. However, the long-term adverse effects of WBRT on neurocognitive function might not be negligible.

Thioredoxin signaling as a target for cancer therapy

Thioredoxin (Trx) family members play critical roles in the regulation of cellular redox homeostasis. Cancer cells exist in a stressed environment and rely on the Trxs for protection against stress-disregulated redox signaling. The most extensively studied member of the family is Trx-1 whose levels are increased in many human cancers most likely in direct response to stress. Trx-1 contributes to many of the hallmarks of cancer including increased proliferation, resistance to cell death and increased angiogenesis. Trx-1 is a validated cancer drug target associated with aggressive tumor growth, resistance to standard therapy and decreased patient survival. A surrogate target for Trx-1 may be thioredoxin reductase (TR). Drugs that inhibit Trx-1 and TR are in clinical development with early promising results.

Toward improving the therapeutic ratio in stereotactic radiosurgery: selective modulation of the radiation responses of both normal tissues and tumor

✓A review of the radiobiological factors that influence the response of the brain to radiation is provided in relation to stereotactic radiosurgery (SRS). The prospects for intervention after radiation treatment to selectively modulate the expression of late central nervous system (CNS) injury is considered, as well as an account of recent interest in the use of radiation enhancers to selectively increase the response of tumors to radiation.

Brain necrosis in humans, after conventional irradiation, indicates that the risk of necrosis increases rapidly after an equivalent single dose of 12 or 13 Gy. When single-dose treatments are extended due to 60Co decay or planned extension of treatment times, account should be taken of the effects of the repair of sublethal radiation damage to DNA on the efficacy of treatment. Both repair capacity and repair kinetics will also influence tumor control, but parameters to quantify this effect have not yet been established.

The volume of CNS tissue that has been irradiated affects the tissue response, but this effect is only significant for volumes less than 0.05 cm3. The gain obtained from irradiation of small volumes is reduced, however, when focal irradiation is given within a wider field of irradiation.

Based on a vascular hypothesis explaining the pathogenesis of late CNS damage, approaches designed to selectively modulate the frequency of late CNS damage have been validated. Given the high intrinsic radioresistance of some tumors, as opposed to the presence of hypoxia, an interest has developed in the use of selective radiation enhancers in the treatment of tumors. The compound presently available has proved to be disappointing clinically due to toxicity at effective doses, when repeated administration is required. However, when given at high single doses it is less toxic and may be more effective. Less toxic radiation enhancers need to be developed.

Results of the phase I dose-escalating study of motexafin gadolinium with standard radiotherapy in patients with glioblastoma multiforme

PURPOSE

Motexafin gadolinium (MGd) is a putative radiation enhancer initially evaluated in patients with brain metastases. This Phase I trial studied the safety and tolerability of a 2-6-week course (10-22 doses) of MGd with radiotherapy for glioblastoma multiforme.

METHODS AND MATERIALS

A total of 33 glioblastoma multiforme patients received one of seven MGd regimens starting at 10 doses of 4 mg/kg/d MGd and escalating to 22 doses of 5.3 mg/kg/d MGd (5 or 10 daily doses then three times per week). The National Cancer Institute Cancer Therapy Evaluation Program toxicity and stopping rules were applied.

RESULTS

The maximal tolerated dose was 5.0 mg/kg/d MGd (5 d/wk for 2 weeks, then three times per week) for 22 doses. The dose-limiting toxicity was reversible transaminase elevation. Adverse reactions included rash/pruritus (45%), chills/fever (30%), and self-limiting vesiculobullous rash of the thumb and fingers (42%). The median survival of 17.6 months prompted a case-matched analysis. In the case-matched analysis, the MGd patients had a median survival of 16.1 months (n = 31) compared with the matched Radiation Therapy Oncology Group database patients with a median survival of 11.8 months (hazard ratio, 0.43; 95% confidence interval, 0.20-0.94).

CONCLUSION

The maximal tolerated dose of MGd with radiotherapy for glioblastoma multiforme in this study was 5 mg/kg/d for 22 doses (daily for 2 weeks, then three times weekly). The baseline survival calculations suggest progression to Phase II trials is appropriate, with the addition of MGd to radiotherapy with concurrent and adjuvant temozolomide.

Stereotactic Radiosurgery: Adjacent Tissue Injury and Response after High-Dose Single Fraction Radiation—Part II: Strategies for Therapeutic Enhancement, Brain Injury Mitigation, and Brain Injury Repair

IN THE FIRST part of this series, we reviewed the histological, radiographic, and molecular data gathered regarding the brain parenchymal response to radiosurgery and suggested future studies that could enhance our understanding of the topic. With this article, we begin by addressing methods of potentiating the effect of radiosurgery on target lesions of the central nervous system. Much of the work on potentiating the effects of cranial radiation has been performed in the field of whole-brain radiotherapy. Data from Phase III trials evaluating the efficacy of various agents as radiosensitizers or radioenhancers in whole-brain radiotherapy are reviewed, and trials for investigating certain agents as enhancers of radiosurgery are suggested. The roles of gene therapy and nanotechnology in enhancing the therapeutic efficacy of radiosurgery are then addressed. Focus is then shifted to a discussion of strategies of protecting healthy tissue from the potentially deleterious aspects of the brain's response to radiosurgery that were presented in the first article of this series. Finally, comments are made regarding the role of neural progenitor or stem cells in the repair of radiation-induced brain injury after radiosurgery. The importance of both the role of the extracellular matrix and properly directed axonal regrowth leading to appropriate target reinnervation is highlighted.

Regression After Whole-Brain Radiation Therapy for Brain Metastases Correlates With Survival and Improved Neurocognitive Function

Purpose

Brain metastasis (BM) is a major cause of suffering and health costs in cancer patients. Whole-brain radiation therapy (WBRT) offers tumor shrinking and palliation in many cases, but it has been speculated that these benefits may be outweighed by adverse effects on neurocognitive function (NCF).

Patients and Methods

Two hundred eight BM patients from the WBRT arm of phase III trial PCI-P120-9801 evaluating motexafin gadolinium were analyzed. NCF, assessed by tests of memory, executive function, and fine motor coordination, was correlated to magnetic resonance imaging–measured BM volume. NCF and survival were compared in 135 patients assessable at 2 months with tumor shrinkage below (poor responders) and above (good responders) the population median (45%). Mean NCF scores and BM volume at 4 and 15 months were compared.

Results

Good responders experienced a significantly improved survival (unidirectional P = .03). For all tests, the median time to NCF deterioration was longer in good compared with poor responders, with statistical significance seen for Trailmaking B (executive function), and two Pegboard tests (fine motor). In long-term survivors, tumor shrinkage significantly correlated with preservation of executive function and fine motor coordination (r = 0.68 to 0.88). During the early follow-up period, the population mean NCF scores were dominated by patients with progressive disease. A small subset of 15-month survivors had stable or improving scores, and greater mean BM reduction.

Conclusion

WBRT-induced tumor shrinkage correlates with better survival and NCF preservation. NCF is stable or improved in long-term survivors. Tumor progression adversely affects NCF more than WBRT does, thus making enhancement of radiation response a worthwhile aim in this patient population.

Targeted Therapy for Brain Metastases: Improving the Therapeutic Ratio

Brain metastasis is the most common intracranial malignancy in adults. Improvements in modern imaging techniques are detecting previously occult brain metastases, and more effective therapies are extending the survival of patients with invasive cancer who have historically died from extracranial disease before developing brain metastasis. This combination of factors along with increased life expectancy has led to the increased diagnosis of brain metastases. Conventional treatment has been whole brain radiotherapy, which can improve symptoms, but potentially results in neurocognitive deficits. Several strategies to improve the therapeutic ratio are currently under investigation to either enhance the radiation effect, thereby preventing tumor recurrence or progression as well as reducing collateral treatment-related brain injury. In this review article, we discuss new directions in the management of brain metastases, including the role of chemical modifiers, novel systemic agents, and the management and prevention of neurocognitive deficits.

Chemotherapy and cerebral metastases: misperception or reality?

Cerebral metastases remain a common complication among patients with cancer. Surgery and radiotherapy remain the principal therapeutic interventions. In contrast, the benefit of chemotherapy has long been viewed with skepticism. Nonetheless, as survival in cancer patients improves and the incidence of cerebral metastases increases, so does the demand for effective therapies. It is now recognized that the blood-brain barrier within metastases is permeable and thus allows entry of otherwise excluded drugs. Limited data have suggested that cerebral metastases have modest sensitivity to chemotherapy. Furthermore, novel agents and delivery strategies have been developed to facilitate central nervous system penetration. Nonetheless, data are limited by methodological flaws, including heterogeneous inclusion criteria, small sample sizes, lack of randomization, and inconsistencies in defined end points and response assessment criteria. Well-designed clinical trials are needed to address the effect of chemotherapy. Acceptable control arms must be established to measure the effect of chemotherapies. Standardized response criteria and disease-specific studies are essential.

Update in the treatment of brain metastases from lung cancer

Brain metastases from lung cancer represent a prevalent and challenging clinical dilemma. The brain is an extremely common site of failure for non-small-cell lung cancer and small-cell lung cancer, often as a solitary site of disease. Despite steady research developments during recent years, survival rates remain poor. Some research suggests that the outcomes and characteristics of brain metastases that result from lung cancer primary sites are perhaps different than those from other primary sites. Clinical treatment strategies should therefore be adjusted accordingly. This article reviews the clinical characteristics, prognostic factors, and treatment strategies of brain metastases from lung cancer with a particular emphasis on recent research developments in the field.

Motexafin gadolinium in the treatment of brain metastases

Motexafin gadolinium (MGd) is a novel, MRI-detectable, anticancer agent that enhances the cytotoxic potential of radiation therapy through several mechanisms, including depleting intracellular reducing metabolites that are necessary for repairing the oxidative damage induced by irradiation. It has tumor-specific uptake, normal tissue sparing, and tolerable and reversible toxicities in clinical trials. MGd's use in conjunction with whole-brain radiation therapy (WBRT) has demonstrated an improvement in neurocognitive decline, neurologic progression, and quality of life in patients with brain metastases from NSCLC. Its use in conjunction with radiosurgery and whole brain radiation therapy in the setting of brain metastases is currently being studied, as is MGd with radiation and temozolomide in patients with glioblastoma multiforme. MGd is also being actively investigated as a single agent or in combination with chemotherapy or radiation therapy in other tumors, including pediatric brain tumors, NSCLC, lymphoma, renal cell carcinoma, and pancreatic and biliary tumors.

Resection versus radiosurgery for patients with brain metastases

Brain metastases occur in 20–40% of adult cancer patients and the incidence is apparently increasing. Despite advances in treatment, the prognosis of these patients is poor, with a median survival of approximately 4 months. Whole brain radiation therapy is the standard of care for most patients with brain metastases. Randomized trials have demonstrated that focal treatments, such as resection and radiosurgery, yield significant improvement in the survival of patients with a single metastasis. The utility of these strategies, specifically in terms of increased survival, is unclear in patients with more than one metastasis. In addition to focal treatments, future directions in the treatment of brain metastases include the development of intraoperative imaging capabilities, improved methods of identifying patients who are likely to benefit from treatment, systemic agents, such as chemotherapy and radiosensitizers, and the incorporation of targeted and antiangiogenic therapies.

Chemotherapy and the treatment of brain metastases

Brain metastases have traditionally been treated with a surgical or radiotherapeutic approach. Chemotherapy is used occasionally as salvage therapy. The blood-brain barrier excludes most chemotherapeutic agents, rendering many systemic options ineffective within the CNS. Intrathecal chemotherapies do not penetrate into brain tissue or bulky parenchymal tumors, so are ineffective in treatment of brain metastases. However, some patients with brain metastases benefit from chemotherapy, and temozolomide or targeted therapies like gefitinib have demonstrated activity. A better understanding of the biological behavior of brain metastases may lead to development of effective treatments for this common complication of systemic cancer. The review discusses the biology of brain metastases and provides an update on current chemotherapeutic strategies.

Current therapeutic approaches in patients with brain metastases

The development of brain metastases is often viewed as the end stage of a disease course and engenders skepticism about the efficacy of treatment. Aggressive management of brain metastases is effective in both symptom palliation and the prolongation of life. The majority of patients with controlled intracranial metastases will expire from systemic disease rather than from recurrence of these metastases. Single brain metastases should be treated with surgical resection or stereotactic radiosurgery, though it is unclear at this time if one modality is more effective than the other. Surgical resection is preferred when a pathologic diagnosis is needed, for tumors larger than 3.5 cm, or when immediate tumor mass decompression is required. Stereotactic radiosurgery (SRS) should be applied for single tumors less than 3.5 cm in surgically inaccessible areas and for patients who are not surgical candidates. Small tumors (ie, < 3.5 cm) that cause minimal edema and are surgically accessible may be treated with either surgery or SRS. There is controversy over whether whole brain radiation therapy (WBRT) can be omitted following surgical resection or SRS. Omission of WBRT increases intracranial tumor recurrence; however, this has not been correlated with decreased survival. Clinicians who choose to omit upfront WBRT are obligated to monitor the patient closely for intracranial recurrence, at which time further salvage therapy in the form of surgery, SRS, or WBRT may be considered. Histology is of particular importance when considering WBRT for patients with radioresistant tumors such as melanoma, renal cell carcinoma, or sarcoma. WBRT may be of less clinical benefit in this setting. Chemotherapy has been demonstrated to improve response rates when used as an adjunct to radiation therapy. These improvements in response rates have not been correlated with an improvement in median survival. Noncytotoxic radiosensitizing agents such as motexafin and efaproxiral show promise. Phase III trials to assess the benefit of motexafin in patients with metastatic lung cancer and efaproxiral in patients with metastatic breast cancer are ongoing. Targeted therapies offer promise in achieving therapeutic efficacy while minimizing side effects. Surgical adjuncts such as BCNU (carmustine) wafers and the GliaSite Radiation System (Cytyc Corporation, Marlborough, MA) may be useful in the future in achieving optimal local tumor control.

Chemotherapy and targeted molecular therapies for brain metastases

As therapy for systemic cancers improves, an increasing number of patients are developing brain metastases. Although conventional therapy with surgery, radiation therapy and radiosurgery has improved the outcome of a significant number of patients, many develop multiple lesions that are not amenable to standard treatments. In this review, the current role of chemotherapy and targeted molecular agents for brain metastases is summarized and future directions are discussed.

Dose escalation beyond 30 grays in 10 fractions for patients with multiple brain metastases

BACKGROUND

Whole-brain radiotherapy (WBRT) to 30 grays (Gy) in 10 fractions is the standard treatment in patients with multiple brain metastases in the majority of treatment centers worldwide. The current study investigated the potential benefit of dose escalation beyond 30 Gy.

METHODS

Data regarding 416 patients who were treated with WBRT for multiple brain metastases were evaluated retrospectively. Survival and freedom from recurrent brain metastasis (local control) of 257 patients who were treated with 10 fractions of 3 Gy each for 2 weeks were compared with those of 159 patients treated with 45 Gy in 15 fractions for 3 weeks or 40 Gy in 20 fractions for 4 weeks. Eight additional potential prognostic factors were investigated including age, gender, Karnofsky performance score (KPS), tumor type, interval between tumor diagnosis and RT, number of metastases, extracranial metastases, and Recursive Partitioning Analysis (RPA) class.

RESULTS

On multivariate analysis, improved survival was found to be associated with lower RPA class (P < .001), age <60 years (P = .026), KPS >or=70 (P < .001), and absence of extracranial metastases (P = .003). A trend was observed for number of metastases (2-3 vs >or=4; P = .07). Improved local control was associated with a KPS >or=70 (P < .001) and breast cancer (P < .001). A trend was observed for number of metastases (P = .059). The RT schedule did not appear to have any significant impact on survival (P = .86) or local control (P = .61). The subgroup analyses, performed for each of the 3 RPA classes, did not demonstrate a significantly better outcome with dose escalation.

CONCLUSIONS

Dose escalation beyond 30 Gy in 10 fractions does not appear to improve survival or local control in patients with multiple brain metastases but does increase the treatment time and cost of therapy.

Motexafin gadolinium: A novel redox active drug for cancer therapy

Motexafin gadolinium (MGd, Xcytrin) is an aromatic macrocycle that has a strong affinity for electrons, i.e., it is easily reduced. In the presence of oxygen, MGd accepts electrons from various cellular reducing metabolites and forms superoxide and other reactive oxygen species (ROS) by redox cycling. The reaction with NADPH is dramatically accelerated by various oxido-reductases including thioredoxin reductase. In vitro studies with various cancer cell lines have shown an increase in ROS and intracellular free zinc in cells treated with MGd. MGd increases cytotoxicity of ionizing radiation and various chemotherapy agents and may be directly cytotoxic to tumor cells under certain conditions. MGd selectively localizes in tumors, perhaps due to their metabolic perturbations. MGd treatment in murine models enhances tumor response to radiation and chemotherapy agents. In controlled, randomized clinical trials, combining MGd treatment with ionizing radiation improves time to neurologic progression in lung cancer patients with brain metastases. The molecular target for MGd appears to be thioredoxin reductase which, when inhibited, results in cellular redox stress, cytotoxicity and an increase in tumor responsiveness to a variety of treatments.

La radiothérapie des métastases cérébrales

Brain metastases are an important cause of mortality and morbidity. The prognosis is poor with a median survival of less than one year in the majority of cases. From this review, whole-brain irradiation clearly appears as the standard treatment. However, its role could be discussed according to newer treatment modalities, radiosurgery or new chemotherapies. Post irradiation neurocognitive status remains insufficiently known.

Therapeutic management of metastatic brain tumors

Whole brain radiation therapy (WBRT) for patients with brain metastases provides increased local control, locoregional control, and median survival over supportive care or steroids alone. In addition, effective palliative relief is realized in the majority of patients. Despite this, median survival with WBRT alone remains fixed at a relatively unfortunate 4-6 months as demonstrated in prospective randomized controlled trials. Key issues in the therapeutic management of brain metastases include techniques to optimize the multimodal application of WBRT in conjunction with surgery, radiosurgery, chemotherapy, and radiosensitizers. Efforts to incorporate these approaches to improve survival are currently under active investigation.

Optimizing therapy for patients with brain metastases

Brain metastases from systemic cancers are the most common malignant brain tumors encountered. Although prognosis remains poor, it is possible to stratify patients according to risk. Furthermore, an aggressive therapeutic approach for good-risk patients that includes a combination of either surgery or stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) can improve survival and decrease the risk of central nervous system progression.

Cerebral metastases—a therapeutic update

Cerebral metastases remain a common complication among patients with cancer. Historically, whole-brain radiotherapy has remained the standard of care, with surgery being reserved for selected cases. Recent advances have changed our practice, however. In particular, stereotactic radiosurgery has emerged as a vital treatment modality for this disease. In addition, chemotherapy, including temozolomide, topoisomerase inhibitors and antimetabolites, and treatment sensitizers, such as efaproxiral and motexafin gadolinium, are actively being assessed in clinical trials, and are likely to play an increasing role in the management of cerebral metastases in the future. Nonetheless, many uncertainties remain, such as the optimal combination and timing of therapeutics. As the arsenal of therapeutics expands, it will be increasingly important to select appropriate patients for a particular treatment paradigm. Understanding the efficacy and toxicity of treatment is essential to this task.

Whole brain radiotherapy for the treatment of multiple brain metastases

BACKGROUND

Brain radiotherapy is used to treat cancer patients who have brain metastases resulting from various primary malignancies.

OBJECTIVES

To assess the effectiveness and adverse effects of whole brain radiotherapy (WBRT) in adult patients with multiple metastases to the brain.

SEARCH STRATEGY

CENTRAL (The Cochrane Library), MEDLINE, EMBASE, CANCERLIT, and CINAHL were searched.

SELECTION CRITERIA

Randomized controlled trials (RCTs) in which adult patients with multiple metastases to the brain from any primary cancer and treated with WBRT were included. Trials of prophylactic WBRT were excluded as well as trials that dealt with surgery or WBRT, or both, for the treatment of a single brain metastasis.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted information for each predetermined outcome: overall survival at six months, intracranial progression-free duration, local brain response, local brain control, quality of life, symptom control, neurological function, and the proportion of patients able to reduce the daily dexamethasone dose. Adverse effects were also collected.

MAIN RESULTS

Eight published reports (nine trials) showed no benefit of altered dose-fractionation schedules as compared to control fractionation (3000 cGy in 10 fractions) of WBRT on the probability of survival at six months. These studies also showed no difference in symptom control nor neurologic improvement among the different dose-fractionation schemes. The addition of radiosensitizers, in five RCTs, did not confer additional benefit to WBRT in either overall median survival times or brain tumor response rates. The addition of the radiosensitizer motexafin gadolinium did not improve quality of life nor time to neurologic progression overall. For the radiosensitizer misonidazole, there was no improvement in Karnofsky performance score outcomes. Three RCTs found no benefit in overall survival with the use of WBRT and a radiosurgery boost as compared to WBRT alone for selected patients with multiple brain metastases (up to four brain metastases). Overall, however, there was a statistically significant improvement in local brain control favoring the whole brain radiotherapy and radiosurgery boost arm. Only one trial of radiosurgery boost with WBRT reported an improved Karnofsky performance score outcome and improved ability to reduce dexamethasone dose. One RCT examined the use of WBRT and prednisone versus prednisone alone and produced inconclusive results.

AUTHORS' CONCLUSIONS

None of the RCTs with altered dose-fractionation schemes as compared to standard delivery (3000 cGy in ten fractions) found a benefit in terms of overall survival, neurologic function, or symptom control. The use of radiosensitizers or chemotherapy in conjunction with WBRT remains experimental. A radiosurgery boost with WBRT may improve local disease control in selected patients, although survival remains unchanged. The benefit of WBRT as compared to supportive care alone has not been studied in RCTs. It may be that supportive care alone, without WBRT, may be appropriate for some patients, particularly those with advanced disease and poor performance status.

EFNS Guidelines on diagnosis and treatment of brain metastases: report of an EFNS Task Force

The objectives have been to establish evidence-based guidelines and identify controversies regarding the management of patients with brain metastases. The collection of scientific data was obtained by consulting the Cochrane Library, bibliographic databases, overview papers and previous guidelines from scientific societies and organizations. A tissue diagnosis is necessary when the primary tumor is unknown or the aspect on computed tomography/magnetic resonance imaging is atypical. Dexamethasone is the corticosteroid of choice for cerebral edema. Anticonvulsants should not be prescribed prophylactically. Surgery should be considered in patients with up to three brain metastases, being effective in prolonging survival when the systemic disease is absent/controlled and the performance status is high. Stereotactic radiosurgery should be considered in patients with metastases of 3-3.5 cm of maximum diameter. Whole-brain radiotherapy (WBRT) after surgery or radiosurgery is debated: in case of absent/controlled systemic cancer and Karnofsky Performance score of 70 or more, one can either withhold initial WBRT or deliver early WBRT with conventional fractionation to avoid late neurotoxicity. WBRT alone is the treatment of choice for patients with single or multiple brain metastases not amenable to surgery or radiosurgery. Chemotherapy may be the initial treatment for patients with brain metastases from chemosensitive tumors.

Integration of chemotherapy into current treatment strategies for brain metastases from solid tumors

Patients with brain metastases represent a heterogeneous group where selection of the most appropriate treatment depends on many patient- and disease-related factors. Eventually, a considerable proportion of patients are treated with palliative approaches such as whole-brain radiotherapy. Whole-brain radiotherapy in combination with chemotherapy has recently gained increasing attention and is hoped to augment the palliative effect of whole-brain radiotherapy alone and to extend survival in certain subsets of patients with controlled extracranial disease and good performance status. The randomized trials of whole-brain radiotherapy vs. whole-brain radiotherapy plus chemotherapy suggest that this concept deserves further study, although they failed to improve survival. However, survival might not be the most relevant endpoint in a condition, where most patients die from extracranial progression. Sometimes, the question arises whether patients with newly detected brain metastases and the indication for systemic treatment of extracranial disease can undergo standard systemic chemotherapy with the option of deferred rather than immediate radiotherapy to the brain. The literature contains numerous small reports on this issue, mainly in malignant melanoma, breast cancer, lung cancer and ovarian cancer, but very few sufficiently powered randomized trials. With chemotherapy alone, response rates were mostly in the order of 20-40%. The choice of chemotherapy regimen is often complicated by previous systemic treatment and takes into account the activity of the drugs in extracranial metastatic disease. Because the blood-brain barrier is partially disrupted in most macroscopic metastases, systemically administered agents can gain access to such tumor sites. Our systematic literature review suggests that both chemotherapy and radiochemotherapy for newly diagnosed brain metastases need further critical evaluation before standard clinical implementation. A potential chemotherapy indication might exist as palliative option for patients who have progressive disease after radiotherapy.

Validation and use of three complementary analytical methods (LC–FLS, LC–MS/MS and ICP–MS) to evaluate the pharmacokinetics, biodistribution and stability of motexafin gadolinium in plasma and tissues

Liquid chromatography-fluorescence (LC-FLS), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and inductively coupled plasma-mass spectrometry (ICP-MS) methods were developed and validated for the evaluation of motexafin gadolinium (MGd, Xcytrin) pharmacokinetics and biodistribution in plasma and tissues. The LC-FLS method exhibited the greatest sensitivity (0.0057 microg mL(-1)), and was used for pharmacokinetic, biodistribution, and protein binding studies with small sample sizes or low MGd concentrations. The LC-MS/MS method, which exhibited a short run time and excellent selectivity, was used for routine clinical plasma sample analysis. The ICP-MS method, which measured total Gd, was used in conjunction with LC methods to assess MGd stability in plasma. All three methods were validated using human plasma. The LC-FLS method was also validated using plasma, liver and kidneys from mice and rats. All three methods were shown to be accurate, precise and robust for each matrix validated. For three mice, the mean (standard deviation) concentration of MGd in plasma/tissues taken 5 hr after dosing with 23 mg kg(-1) MGd was determined by LC-FLS as follows: plasma (0.025+/-0.002 microg mL(-1)), liver (2.89+/-0.45 microg g(-1)), and kidney (6.09+/-1.05 microg g(-1)). Plasma samples from a subset of patients with brain metastases from extracranial tumors were analyzed using both LC-MS/MS and ICP-MS methods. For a representative patient, > or = 90% of the total Gd in plasma was accounted for as MGd over the first hour post dosing. By 24 hr post dosing, 63% of total Gd was accounted for as MGd, indicating some metabolism of MGd.

MRI measurement of the uptake and retention of motexafin gadolinium in glioblastoma multiforme and uninvolved normal human brain

PURPOSE

Motexafin gadolinium (MGd) is an investigational pharmaceutical with radiation enhancing properties. Magnetic Resonance Imaging (MRI) was used to measure brain and tumor MGd levels to evaluate (1) the degree to which MGd passes through the intact blood brain barrier, and (2) the retention of MGd in tumor in patients with glioblastoma multiforme (GBM).

METHODS AND MATERIALS

MRI studies were performed on GBM patients who participated in a phase I clinical trial in which MGd was given during standard fractionated radiation therapy. MGd was administered daily (Monday to Friday) for five or 10 doses as a loading regimen, followed by three times per week dosing as a maintenance schedule. T1-weighted MRI was performed at intervals throughout the course of the MGd administration and radiation therapy in the 33 participating patients. Eleven patients had pre- and post-MGd scans, allowing for study of MGd's normal blood brain barrier penetration. Twenty-two patients had adequate residual tumor for measurements to evaluate MGd retention in tumor during the course of MGd and radiation administration.

RESULTS AND CONCLUSIONS

The studies of uninvolved brain tissue support the conclusion that MGd does not cross the intact blood brain barrier in detectable quantities. The tumor study showed MGd uptake during loading and maintenance without measurably significant fall off on non-dosage days during the maintenance dosing. Although the number of cases is small, the 10-day loading regimen showed greater drug loading and retention compared with the 5 days loading regimen.

Whole-brain radiotherapy in the management of brain metastasis

Brain metastases are an important cause of morbidity and mortality, afflicting nearly 170,000 Americans annually. The prognosis for these patients is poor, with median survival times measured in months. In this review article, we present the standard treatment approach of whole-brain radiotherapy and discuss new directions, including the role of chemical modifiers and the management and prevention of neurocognitive deficits.

Population pharmacokinetics and bioavailability of motexafin gadolinium (Xcytrin®) in CD1 mice following intravenous and intraperitoneal injection

Motexafin gadolinium (Xcytrin) is an expanded porphyrin macrocyclic compound under development for the treatment of several types of cancer. Currently clinical trials and non-clinical pharmacology and toxicology studies are ongoing. The goals of this open label, four arm, non-crossover bioavailability study were to explore motexafin gadolinium pharmacokinetics, determine the i.p. bioavailability, and define a pharmacokinetic model suitable for descriptive and predictive use. Mice received one or seven daily i.v. or i.p. injections (40 mg/kg) then blood samples were collected and analyzed. Plasma concentration data were modelled using population pharmacokinetic methods and a two compartment model was the most appropriate model. The stability and predictive performance of the model were evaluated using bootstrap procedures. The accuracy of the predicted concentrations was 8.3%. Motexafin gadolinium was rapidly cleared from the plasma and although T(1/2beta) was 12.9 h there was no accumulation following seven doses. The i.p. bioavailability was 87.4% and higher plasma concentrations were sustainable for a longer period with i.p. dosing. V(c) was larger than the blood volume and the tissue compartment volume was 38% of V(c), suggesting motexafin gadolinium was not widely distributed into less well perfused tissues. The pharmacokinetic profile in this study was similar to that in oncology patients administered multiple doses of motexafin gadolinium. The unbiased model yields reliable parameter estimates and insight into the pharmacokinetics of motexafin gadolinium in mice, is suitable for both descriptive and predictive purposes, and is a valuable tool in the planning, analysis, and interpretation of pharmacology and toxicology studies in mice.

Current strategies in whole-brain radiation therapy for brain metastases

Whole-brain radiation therapy (WBRT) has been the primary treatment for patients with brain metastases for more than 50 years and provides effective palliative relief in most patients. Although advancements in radiotherapeutic technique continue to improve local and locoregional control, median survival for patients treated with WBRT monotherapy remains fixed at approximately 4 to 6 months. Key issues in the use of WBRT include optimizing its efficacy when it is used in conjunction with surgery, radiosurgery, radiosensitizers, and new chemotherapeutic agents. These multimodal approaches to brain metastases have resulted in significant increases in the median survival time in many patients. Radiosurgery is part of a continuing effort to improve the effects of radiation therapy, especially in brain metastases. The optimal combination of WBRT and radiosurgery remains to be elucidated, including appropriate timing or sequence and use in conjunction with other modalities. Newer radiosensitizing agents (e.g., efaproxiral [RSR-13] and motexafin gadolinium) have shown promise in the treatment of brain tumors, especially in specific patient subsets. Recently developed systemic chemotherapy agents, such as temozolomide, which crosses the blood-brain barrier, have a synergistic effect on brain metastases when used in conjunction with radiation. In addition, the use of interstitial chemotherapy agents provides highly focused local chemotherapy in the brain without increasing systemic toxicity; carmustine polymer wafer, in combination with WBRT, has shown promising results in treating brain metastases.

Current treatment paradigms for the management of patients with brain metastases

Brain metastases continue to be a major and growing challenge in oncology, but recent advances in surgery, radiosurgery, and chemotherapy have broadened the number of treatment options. Current approaches to the management of brain metastases focus on individualizing patient care based on factors including the Karnofsky Performance Status, the tumor histology, the number of metastases, and the status of the systemic disease. A number of treatment approaches have been shown to be effective for brain metastases, including surgery; radiosurgery; whole-brain radiotherapy; and, more recently, chemotherapy. The use of adjuvant whole-brain radiotherapy with local therapies, such as surgery or radiosurgery, along with newer chemotherapy options, such as targeted biological agents, temozolomide, and implantable 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) Gliadel wafers, are at the forefront of recent advances in the treatment of patients with brain metastases that may provide longer survival and improved quality of life. Although there is no current standard treatment, some general guidelines are recommended for single metastases, oligometastases (two to three brain metastases), and multiple (four or more) brain metastases, and for new or recurrent disease. With advances in systemic therapy for cancer, the treatment of brain metastases is becoming an increasingly important determinant of the length of survival and quality of life for cancer patients.

Phase II trial of radiosurgery for one to three newly diagnosed brain metastases from renal cell carcinoma, melanoma, and sarcoma: an Eastern Cooperative Oncology Group study (E 6397)

PURPOSE

Long-term brain metastases survivors are at risk for neurologic morbidity after whole-brain radiotherapy (WBRT). Retrospective radiosurgery (RS) reports found no survival difference when compared with WBRT. Before RS alone was evaluated with delayed WBRT in a phase III trial, the feasibility of RS alone was tested prospectively.

PATIENTS AND METHODS

Patients with renal cell carcinoma, melanoma, or sarcoma; one to three brain metastases; and performance status of 0 to 2 were enrolled. Exclusion criteria were leptomeningeal disease; metastases in medulla, pons, or midbrain; or liver metastases. On the basis of tumor size, patients received 24, 18, or 15 Gy RS. At recurrence, management was discretionary. The primary end point was 3- and 6-month intracranial progression.

RESULTS

Between July 1998 and August 2003, 36 patients were accrued; 31 were eligible. Median follow-up was 32.7 months and the median survival was 8.3 months (95% CI, 7.4 to 12.2). Three- and 6-month intracranial failure with RS alone was 25.8% and 48.3%. Failure within and outside the RS volume, when in-field and distant intracranial failures were scored independently, was 19.3% and 16.2% (3 months) and 32.2% and 32.2% (6 months), respectively. Approximately 38% of patients experienced death attributable to neurologic cause. There were three grade 3 toxicities related to RS.

CONCLUSION

Intracranial failure rates without WBRT were 25.8% and 48.3% at 3 and 6 months, respectively. Delaying WBRT may be appropriate for some subgroups of patients with radioresistant tumors, but routine avoidance of WBRT should be approached judiciously.

Population pharmacokinetics of motexafin gadolinium in adults with brain metastases or glioblastoma multiforme

The purpose of this study was to determine clinical variables affecting motexafin gadolinium (MGd) pharmacokinetics. Motexafin gadolinium (4-5.3 mg/kg/d) was administered intravenously for 2 to 6.5 weeks. Plasma samples from 3 clinical trials were analyzed for MGd using liquid chromatography/mass spectroscopy. The pooled data were analyzed using population pharmacokinetic (POP-PK) methods. The POP-PK model included 243 patients (1575 samples). Clearance (CL) was 14% lower in women, but weight-normalized clearance was only 5% lower in women. Clearance decreased with increasing alkaline phosphatase, increasing age, and decreasing hemoglobin. Administration of phenytoin increased CL by approximately 30%. Central compartment volume (V1) was 21% lower in women and increased with increasing serum creatinine. For all covariates, except sex and phenytoin, the predicted change in CL or V1 (5th and 95th percentiles) varied < or =13% from the population mean CL or V1 estimate. It was concluded that a 3-compartment, open, POP-PK model predicts small but significant effects of age, sex, alkaline phosphatase, hemoglobin, serum creatinine, and phenytoin on MGd pharmacokinetics.

Radiation sensitization with redox modulators: A promising approach

PURPOSE

Radiation therapy plays a critical role in the local and regional control of malignant tumors. Its efficacy, however, is limited by a number of factors, including toxicity, tumor hypoxia, and tumor genetics. Recent attempts to enhance the efficacy of radiation therapy have focused on biologic agents that modulate reduction/oxidation reactions within tumor cells.

METHODS AND MATERIALS

We review five promising redox modulators that are in development. Tirapazamine and AQ4N are known as "hypoxic cell sensitizers" and are toxic in areas of low oxygen tension. RSR13 facilitates delivery of oxygen to tumor cells, thereby rendering them more sensitive to radiation. Motexafin gadolinium, with a porphyrin-like structure, selectively accumulates in tumor cells and thereby enhances radiation-induced DNA damage. HIF-1 inhibitors target a transcription factor that regulates hypoxia-related events and cell survival.

RESULTS

Our review of each agent included a thorough search of published preclinical and clinical data, including that presented in abstracts and posters at international meetings. Our objectives were not to identify a superior mechanism or drug, but rather to summarize the available safety and efficacy data.

CONCLUSION

Clearly, there is an unmet need for safer agents that augment the efficacy of radiation therapy. This review highlights five promising redox modulators that are in development. None has yet been approved by the Food and Drug Administration. These drugs were selected for discussion because they exemplify the current investigative landscape of radiosensitizers and are indicative of future directions in this area. These radiation sensitizers have the potential to succeed where others have failed, by locally increasing the radiosensitivity of tumor cells without enhancing that of surrounding normal tissues.

Whole-brain radiotherapy with or without efaproxiral for the treatment of brain metastases: Determinants of response and its prognostic value for subsequent survival

PURPOSE

To determine the prognostic factors for radiographic response and its prognostic value for subsequent survival in patients undergoing whole-brain radiotherapy (WBRT) for brain metastases.

METHODS AND MATERIALS

Five hundred fifteen eligible patients were randomized in a phase III trial evaluating WBRT and supplemental oxygen with or without efaproxiral, an allosteric modifier of hemoglobin that reduces hemoglobin oxygen-binding affinity and enhances tumor oxygenation, potentially increasing tumor radiosensitivity. Brain images were obtained at baseline and at scheduled follow-up visits after WBRT. Landmark analysis was used to assess the ability of response at selected time points to predict subsequent survival. Logistic regression was used to assess determinants of response at 3 months.

RESULTS

Treatment arm, Karnofsky Performance Status, presence or absence of liver metastases, and primary site were all determinants of response at the 3-month follow-up visit, with patients in the efaproxiral arm experiencing a 67% greater odds of response at this visit (p = 0.02). Response at 3 and 6 months was a significant prognostic factor for longer subsequent survival.

CONCLUSIONS

The 3-month scan is a valuable prognostic factor for subsequent survival in patients with brain metastases treated with WBRT. Patients in the efaproxiral arm had a higher response rate at 3 and 6 months than those in the control arm.

New polyethyleneglycol-functionalized texaphyrins: synthesis and in vitro biological studies

The synthesis of four new analogues of motexafin gadolinium (MGd), a gadolinium(III) texaphyrin complex in clinical trials for its anticancer properties, is described. These new derivatives contain either 1,2-diaminobenzene or 2,3-diaminonaphthalene subunits as the source of the imine nitrogens and bear multiple 2-[2-(2-methoxyethoxy)ethoxy]ethoxy (PEG) groups, on either meso aryl or beta-pyrrolic substituents, to increase their water solubility. All four analogues were found to be more active in vitro than the parent system MGd as judged from cell proliferation assays using the PC3 and A549 cell lines.

The therapeutic application of lanthanides

The biological properties of the lanthanides, based on their similarity to calcium, have stimulated research into their therapeutic application. Historical medical uses of the lanthanides and recent advances and successes will be described in the context of the biological chemistry of lanthanides, including a new metal-based drug, lanthanum carbonate, which has recently been approved as a phosphate binder for the treatment of hyperphosphatemia. This tutorial review will be of interest to those working on metal-based drugs, including inorganic chemists, and biological scientists.

Motexafin gadolinium and zinc induce oxidative stress responses and apoptosis in B-cell lymphoma lines

There is an emerging appreciation of the importance of zinc in regulating cancer cell growth and proliferation. Recently, we showed that the anticancer agent motexafin gadolinium (MGd) disrupted zinc metabolism in A549 lung cancer cells, leading, in the presence of exogenous zinc, to cell death. Here, we report the effect of MGd and exogenous zinc on intracellular levels of free zinc, oxidative stress, proliferation, and cell death in exponential phase human B-cell lymphoma and other hematologic cell lines. We find that increased levels of oxidative stress and intracellular free zinc precede and correlate with cell cycle arrest and apoptosis. To better understand the molecular basis of these cellular responses, gene expression profiling analyses were conducted on Ramos cell cultures treated with MGd and/or zinc acetate. Cultures treated with MGd or zinc acetate alone elicited transcriptional responses characterized by induction of metal response element-binding transcription factor-1 (MTF-1)-regulated and hypoxia-inducible transcription factor-1 (HIF-1)-regulated genes. Cultures cotreated with MGd and zinc acetate displayed further increases in the levels of MTF-1- and HIF-1-regulated transcripts as well as additional transcripts regulated by NF-E2-related transcription factor 2. These data provide insights into the molecular changes that accompany the disruption of intracellular zinc homeostasis and support a role for MGd in treatment of B-cell hematologic malignancies.

Phase III study of efaproxiral as an adjunct to whole-brain radiation therapy for brain metastases

PURPOSE

To determine whether efaproxiral, an allosteric modifier of hemoglobin, improves survival in patients with brain metastases when used as an adjunct to whole-brain radiation therapy (WBRT).

PATIENTS AND METHODS

Patients with brain metastases from solid tumors and a Karnofsky performance score of > or = 70 were randomly assigned to receive WBRT with supplemental oxygen and either efaproxiral at 75 or 100 mg/kg (efaproxiral arm) or no efaproxiral (control arm). The primary end point was survival.

RESULTS

The study consisted of 515 eligible patients (efaproxiral arm, n = 265; control arm, n = 250). The median survival time (MST) was 5.4 months for the efaproxiral arm versus 4.4 months for the control arm (hazard ratio [HR] = 0.87; P = .16). For the subgroup of patients with non-small-cell lung cancer (NSCLC) or breast cancer, the MST was 6.0 and 4.4 months, respectively (HR = 0.82; P = .07). Cox multiple regression analysis demonstrated a significant reduction in the risk of death for the efaproxiral arm in both primary populations. Further analysis indicated that the benefit may be restricted to the subgroup of patients with breast cancer. Response rates (radiographic complete response plus partial response) improved by 7% (P = .10) and 13% (P = .01) for all patients and for NSCLC and breast cancer patients in the efaproxiral arm, respectively. The most common severe adverse event in patients treated with efaproxiral was hypoxemia, which was reversible and effectively managed with supplemental oxygen in most patients.

CONCLUSION

The addition of efaproxiral, a noncytotoxic radiation sensitizer, to WBRT may improve response rates and survival in patients with brain metastases, particularly metastases from breast cancer. A confirmatory trial for breast cancer patients has been initiated.

Radiotherapy and chemotherapy of brain metastases

The authors have reviewed the results, the indications and the controversies regarding radiotherapy and chemotherapy of patients with newly diagnosed and recurrent brain metastases. Whole-brain radiotherapy, radiosurgery, hypofractionated stereotactic radiotherapy, brachytherapy and chemotherapy are the available options. New radiosensitizers and cytotoxic or cytostatic agents are being investigated. Adjuvant whole brain radiotherapy, either after surgery or radiosurgery, and prophylactic cranial irradiation in small-cell lung cancer are discussed, taking into account local control, survival, and risk of late neurotoxicity. Increasingly, the different treatments are tailored to the different prognostic subgroups, as defined by Radiation Therapy Oncology Group RPA Classes.

Symptomatic management and imaging of brain metastases

Brain metastasis is the most common malignancy of the nervous system. Survival is short and the majority of patients die within 5 months after diagnosis. In this review, clinical and pathophysiological aspects of brain metastases are described, including novel radiological methods as triple-dose gadolinium-enhanced MRI. Recursive partitioning analysis is a powerful tool to analyse prognosis, and recent studies contribute to subgroup division. Subsequently, treatment choices can be made, based on prognostic characteristics of the individual patient. Commonly, symptomatic therapy starts with the administration of corticosteroids, often resulting in improvement of neurological deficit. Anticonvulsants are administered in patients with symptomatic epilepsy. The risk on vascular complications in patients with brain metastases is increased and needs special attention. Treatment of psychiatric complications e.g. delirium or depression may also improve quality of life.

Current Management of Brain Metastases, With a Focus on Systemic Options

Brain metastases are an important sequelae of many types of cancer, most commonly lung cancer. Current treatment options include whole-brain radiation therapy (WBRT), surgical resection, stereotactic radiosurgery, and chemotherapy. Corticosteroids and antiepileptic medications are commonly used for palliation of mass effect and seizures, respectively. The overall median survival is only 4 months after WBRT. Combined-modality strategies of WBRT with either chemotherapy or novel anticancer agents are under clinical investigation. Promising results have been obtained with several experimental agents and confirmatory phase III trials are underway. Although improvement in overall survival has not been seen universally, reduction in death due to progression of brain metastases and prolongation of the time to neurologic and neurocognitive progression have been reported in selected series. On the basis of these findings, it might be possible to identify new agents that may enhance the efficacy of WBRT.

Phase I and pharmacokinetic study of the novel redox-active agent, motexafin gadolinium, with concurrent radiation therapy in patients with locally advanced pancreatic or biliary cancers

PURPOSE

To determine the maximum tolerated dose and dose-limiting toxicity (DLT) of the novel anticancer agent, motexafin gadolinium (MGd), administered concurrently with radiation therapy (RT) in patients with locally advanced pancreatic or biliary tumors. The pharmacokinetics of MGd were also evaluated.

METHODS

Cohorts of three to six patients were treated with escalating doses of MGd, administered three times per week for a total of 16 doses concurrent with RT. The dose of RT was fixed at 5,040 cGy, and given in 28 fractions, from Monday to Friday of every week. Plasma MGd concentrations were measured by high performance liquid chromatography.

RESULTS

Eight patients were treated at dose level 1 (2.9 mg/kg), with one DLT (grade 3 fever). Three patients were treated at dose level 2 (3.6 mg/kg), and two DLTs were noted. One DLT was grade 3 nausea and vomiting (N/V), and the other was grade 3 skin toxicity. The most common toxicity was N/V. There were no objective responses. The median survival was 6 months. The MGd plasma concentration versus time profile in each patient was best fit by a two-compartment, open, linear model. There was minimal accumulation of MGd in plasma with the three-times/week dosing schedule. Simulation of the time course of MGd in the peripheral compartment indicated that maximal MGd concentrations of 1-2 micromol/kg occurred between 4 and 6 h after MGd infusion.

CONCLUSION

Dose level 1 (2.9 mg/kg of MGd) is the recommended dose for combination with (RT) in phase II studies for locally advanced pancreatic and biliary cancers. Patient tolerance might be improved by modification of the RT schedule and antiemetic prophylaxis.