Interventions for cognitive deficits in adults with brain tumours

Increased life expectancy in patients with brain tumours has led to a greater risk of cognitive deficits, particularly during disease-free periods. Here, we review the empirical studies that have been done to treat or to prevent cognitive impairment in patients with brain tumours. Both pharmacological interventions and cognitive rehabilitation programmes have been used. Although both types of study have reported some successes, these are often difficult to interpret owing to limitations in the methods used. Most of the studies reviewed did not use a randomised group design to control for possible confounding factors such as placebo and practice effects. Investigations of newer, targeted therapies have reported delays in cognitive deterioration, but these need to be confirmed in future studies. Neuroprotection represents another potentially promising, novel approach to prevention of cognitive impairment in this vulnerable population of patients. Finally, we describe studies in patients with cancers outside the CNS, to highlight further possibilities for the prevention and treatment of cognitive deficits.

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.

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.

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.