Exelixis to expand mid-stage brain cancer trial
* Independent review shows 15 pct response rate
* Trial will enroll 100 more patients
* Lower dose to be studied
By Deena Beasley
ORLANDO, Fla., May 31 (Reuters) - Exelixis Inc (EXEL.O) and Bristol-Myers Squibb Co (BMY.N) plan to enroll 100 additional patients in an mid-stage trial of their experimental brain cancer drug, known as XL184, and will also test a lower dose of the drug,
An independent radiology review of trial results shows that 15 percent of 46 evaluated patients with advanced glioblastoma multiforme, the most common and deadly form of brain cancer, had tumor shrinkage, the companies said on Sunday.
Looking only at patients not previously treated with anti-angiogenic drugs, 20 percent responded to the drug.
Those numbers are lower than interim rates reported earlier by trial investigators.
The median duration of response was 2.9 months, according to the latest data, reported at a meeting of the American Society of Clinical Oncology.
The independent review "is a very conservative picture," said Renzo Canetta, head of global oncology development at Bristol-Myers.
XL184 is an oral drug designed to block the vascular endothelial growth factor, the same target as drugs like Roche Holding AG's (ROG.VX) Avastin, as well as MET and RET, two other drivers of tumor formation,
Avastin was approved recently by U.S. regulators to treat glioblastoma multiforme once the disease has recurred.
"We can only hope that broadening the targets can broaden the clinical benefits," Canetta said.
The companies are also planning a Phase III trial program, but said the current trial of patients with previously treated glioblastoma multiforme, may be sufficient for a regulatory filing.
Exelixis said 87 percent of patients in the study stopped treatment at some point and it will evaluate a lower daily dose in order to provide sustained exposure to the drug.
The companies are also testing the drug in thyroid cancer and lung cancer.
"We have a broad Phase II program to identify the next tumor type," said Michael Morrissey, president of research and development at Exelixis. (Editing by Peter Cooney)
