Phase II trial of cystemustine, a new nitrosourea, as treatment of high-grade brain tumors in adults

Reagentless Chemistry "On-Water": An Atom-Efficient and "Green" Route to Cyclic and Acyclic β-Amino Sulfones via aza-Michael Addition Using Microwave Irradiation

A reagentless, catalyst-free, and sustainable methodology was developed for facile access to cyclic and acyclic β-amino sulfones "on-water" using a microwave. A variety of aromatic and aliphatic amines undergo double aza-Michael addition on the surface of the water with water-insoluble divinyl sulfones upon microwave irradiation at 150 °C for 10 min to mostly afford solid cyclic β-amino sulfones as easily separable products in excellent yields by simple filtration avoiding any workup steps. Thus, all atoms of the substrates are reflected in the product making it a 100% atom-efficient method. Both electron-rich and electron-deficient amines participated well in the reaction as well as good functional group tolerance was observed. The competitive experiments expectedly revealed faster reaction kinetics for electron-rich amines. The methodology was extended to acyclic β-amino sulfones by interacting phenyl/ethyl vinyl sulfones with various amines in a similar manner. Expectedly, the method afforded very low environmental factors (in a range of 0.05-0.5) and a high Ecoscale score (up to 94). In an attempt toward sustainable development, this reagent-free, metal-free, organic solvent-free, cost-effective protocol is certainly a viable alternative to the available methods for β-amino sulfones.

Cystemustine in recurrent high grade glioma

In this study, we have assessed the efficacy of a nitrosourea, cystemustine, in treating patients with recurrent high grade glioma with overall survival analysis as primary end-point. Forty-eight patients with recurrent high grade glioma (24 glioblastomas, 17 astrocytomas and 5 oligodendrogliomas) were treated every 2 weeks with 60 mg/m2 cystemustine by a 15 min-infusion. The median number of treatment cycles was 4 (range 1-17). The median overall survival was 8.3 months (range 1-97) and the 6- and 12-month overall survival rates were 55.3% (95% CI, 41.3-68.6%) and 29.8% (95% CI, 18.6-44.0%), respectively. The objective response rate was 18.8% (95% CI, 7.7-29.9%), and 54.2% of patients had stable disease (95% CI, 40.1-68.3%). Multivariate analysis showed that WHO performance status, histology and response to cystemustine were significant prognostic factors for survival of patients with recurrent glioma. In conclusion, cystemustine has encouraging activity for patients with recurrent high grade glioma.

Review of microdialysis in brain tumors, from concept to application: first annual Carolyn Frye-Halloran symposium

In individuals with brain tumors, pharmacodynamic and pharmacokinetic studies of therapeutic agents have historically used analyses of drug concentrations in serum or cerebrospinal fluid, which unfortunately do not necessarily reflect concentrations within the tumor and adjacent brain. This review article introduces to neurological and medical oncologists, as well as pharmacologists, the application of microdialysis in monitoring drug metabolism and delivery within the fluid of the interstitial space of brain tumor and its surroundings. Microdialysis samples soluble molecules from the extracellular fluid via a semipermeable membrane at the tip of a probe. In the past decade, it has been used predominantly in neurointensive care in the setting of brain trauma, vasospasm, epilepsy,and intracerebral hemorrhage. At the first Carolyn Frye-Halloran Symposium held at Massachusetts General Hospital in March 2002, the concept of microdialysis was extended to specifically address its possible use in treating brain tumor patients. In doing so we provide a rationale for the use of this technology by a National Cancer Institute consortium, New Approaches to Brain Tumor Therapy, to measure levels of drugs in brain tissue as part of phase 1 trials.

Methionine dependency and cancer treatment

Conventional chemotherapies have showed their limits, notably for patients with advanced cancer. New therapeutic strategies must be identified, and the metabolic abnormalities of cancer cells offer such opportunities. Many human cancer cell lines and primary tumors have absolute requirements for methionine, an essential amino acid. In contrast, normal cells are relatively resistant to exogenous methionine restriction. The biochemical mechanism for methionine dependency has been studied extensively, but the fundamental mechanism remains unclear. A number of investigators have attempted to exploit the methionine dependence of tumors for therapeutic effects in vivo. To reduce in vivo methionine in plasma and tumours, dietary and pharmacological treatments have been used. Methionine-free diet or methionine-deprived total parenteral nutrition causes regression of a variety of animal tumours. Alternatively, methionine depletion was achieved by the use of methioninase. This enzyme specifically degrades methionine and inhibits tumour growth in preclinical models. Because of potential toxicity and quality of life problems, prolonged methionine restriction with diet or with methioninase is not suitable for clinical use. Methionine restriction may find greater application in association with various chemotherapeutic agents. Several preclinical studies have demonstrated synergy between methionine restriction and various cytotoxic chemotherapy drugs. The experimental results accumulated during the last three decades suggest that methionine restriction can become an additional cancer therapeutic strategy, notably in association with chemotherapy.

Pharmacokinetic study of cystemustine, administered on a weekly schedule in cancer patients

BACKGROUND

Cystemustine is a chloroethylnitrosourea mostly active in humans against glioma and melanoma. The present report describes the results of a new phase I trial with cystemustine administered on a weekly schedule. The pharmacokinetic and pharmacodynamic properties of cystemustine were investigated.

PATIENTS AND METHODS

Forty-three patients entered this study. Cystemustine was administered at dose levels ranging from 30 to 60 mg/m2. The drug was given on days 1, 8, 15 and 22, followed by a 4-week rest period.

RESULTS

Thrombocytopenia was the dose-limiting toxicity and appeared to be reversible, but probably cumulative. This toxicity appeared dose-related, both in frequency and severity. The maximum tolerated dose was 60 mg/m2. Nonhematological toxicity was generally mild. Three partial responses were observed at dose levels of 50 and 60 mg/m2. Pharmacokinetics analysis showed mono- or biphasic cystemustine blood disposition with a mean a half-life of 4 min and mean terminal half-life of 49 min.

CONCLUSIONS

There was a clear linear relationship between the area under the blood drug concentration-time curve (AUC) and the dose of cystemustine (P < 0.001). There was also a significant relationship between the AUC and the toxic effects of cystemustine on platelets, granulocytes and leukocytes (P < 0.001). A reasonable starting dose for phase II studies is 40 mg/m2, with dose escalation based on blood cell counts.