New Drug Delivery Technology Improves Response Rate to Cytarabine

Researchers at the University of California, San Diego, (UCSD) Cancer Center report success inusing a new technology to develop a sustained-release formulation of cytarabine (ara-C). The new formulation, called DepoCyt, produced a significantly better response rate than the standard ara-C formulation in patients with lymphomatous meningitis. Results of the open, multicenter, controlled study were reported at the 35th meeting of the American Society of Clinical Oncology (ASCO).

Of the 27 study participants, 14 were treated with DepoCyt, and 13 with standard ara-C. Both groups received the drug via direct injection into the cerebrospinal fluid surrounding the brain and spinal cord. In the DepoCyt group, injections were administered once every 2 weeks, and 71% of patients responded. The ara-C group received injections twice a week and had a 15% response rate. Patients were considered responders when, following 4 weeks of treatment with the drug, no cancer cells remained in the cerebrospinal fluid and there was no evidence of progression of neurologic symptoms.

The study also demonstrated that patients treated with DepoCyt had improved quality of life and tended to have a longer period during which they were free from worsening neurologic signs and symptoms.

Effective Drug Concentrations Maintained in the Cerebrospinal Fluid

DepoCyt recently received FDA approval for use in patients with lymphomatous meningitis. In its review, the FDA considered five additional patients who had been treated recently, and applied a different set of criteria for determining response. Nevertheless, the FDA’s analysis confirmed the large difference in response rates (41% with DepoCyt vs 6% with standard ara-C).

“We are pleased with the results of this trial,” said Stephen B. Howell, MD, professor of medicine at the UCSD School of Medicine. “We had expected the major benefit of the new formulation to be that it makes treatment easier for the patient because only one injection is required every 2 weeks. The results show, however, that DepoCyt is also much more effective.”

DepoCyt maintains effective concentrations of ara-C in the cerebrospinal fluid for more than 2 weeks in most patients, whereas injection of the standard formulation of ara-C provides effective cerebrospinal fluid drug levels for only a matter of hours.