Pharmacyclics drug helps find brain cancer-study

By Bill Berkrot

NEW YORK, June 3 (Reuters) - Pharmacyclics Inc.'s (PCYC.O) experimental drug Xcytrin showed promise in helping improve the effectiveness of radiosurgery treatment and in detecting hard to find cancerous brain lesions in a mid-stage clinical trial, researchers said on Sunday.

Final data from the study of the drug, known chemically as motexafin gadolinium, were presented at the American Society of Clinical Oncology annual meeting in Chicago.

In the mid-stage clinical trial, Xcytrin allowed physicians to identify occult brain metastases -- previously undetected cancer that has spread to the brain -- in 24 percent of patients whose lesions were missed using standard MRI contrast agents and were candidates for stereotactic radiosurgery, researchers said.

"This study demonstrates that Xcytrin may be used both to enhance the effectiveness of radiation and to improve detection of occult lesions in patients with brain metastases," said Dr Minesh Mehta, professor of Human Oncology and Neurological Surgery at the University of Wisconsin Medical School who presented the study at the year's most important cancer meeting.

"It appears that a significant number of patients are being under-treated since current imaging and stereotactic radiosurgery techniques fail to identify and treat all the tumors," Mehta said.

The gadolinium part of the molecule is a metal with paramagnetic properties that enable it to show up on MRI scans with more sensitivity than standard imaging agents, Mehta explained.

He said patients eligible for radiosurgery usually have just a few lesions.

"We give them radiosurgery in order to try to control the disease for a longer period of time in the brain and hopefully have them live longer and have better neurologic quality of life," Mehta said.

"If you find missed lesions two or three months later we have to put the patient through the procedure all over again and it's an expensive procedure," he said.

"If you find it with motexafin gadolinium you make it more cost effective, and the other advantage is we pick up the tumor when it's smaller, which gives us a better chance of controlling it with radiosurgery and that could translate into better survival and better quality of life for a patient."

Xcytrin in conjunction with radiation therapy demonstrated a median time to neurologic progression -- deterioration of brain function -- exceeding 18 months in the study.

Researchers also said they have demonstrated the safety of Xcytrin when used with whole brain radiation and radiosurgery.

"We did not see any untoward significant toxicity in this study," Mehta said.

Brain metastases occur in 20 percent to 25 percent of patients with solid cancer tumors, affecting up to 200,000 patients per year in the United States, Pharmacyclics said.

The company is awaiting a U.S. approval decision for Xcytrin for use in combination with whole brain radiation therapy in lung cancer that has spread to the brain.