Exelixis shares leap on promising XL184 cancer data

Shares of Exelixis ($EXEL) staged a comeback this morning after investigators reported promising data from two small Phase II studies of XL184, one of its lead cancer therapies. One drug for epithelial ovarian cancer demonstrated signs of tumor shrinkage in 81 percent of the patients who had measurable lesions while its castration-resistant prostate cancer therapy XL184 helped 95 percent of the patients--19 out of 20--taking the drug achieve complete or partial lesion resolution.

Exelixis shares jumped 25 percent on the news, regaining some of the value they've lost over a bumpy ride this year. Bristol-Myers Squibb ($BMS) wrote off $257 million last summer when it handed back its rights to the therapy. At the time, then CEO George Scangos, who soon after left to take the helm at Biogen Idec ($BIIB), said the two companies couldn't agree on the right clinical program for XL184. These new data sets should help spark some new excitement for the drug, which is slated for a Phase III glioblastoma trial.

"The initial activity of XL184 against metastatic soft-tissue and bone lesions in CRPC patients is very encouraging," said Michael Morrissey, president and chief executive officer of Exelixis. "These data suggest that XL184 has a novel and differentiated clinical profile in CRPC, and will provide critical guidance in defining our high priority development activities for XL184 in 2011."

"The activity of XL184 in women with both platinum-sensitive and platinum-resistant/refractory disease is unique and encouraging. The response rate and overall disease control rate of this oral agent are impressive especially in the group of patients with platinum refractory/resistant ovarian cancer, and compare favorably to other targeted and systemic agents in development," said, Ignace Vergote, head of the Department of Obstetrics and Gynaecology and Gynaecologic Oncology at the University Hospital Leuven, Leuven, Belgium. "I believe these encouraging data warrant further evaluation of XL184 in ovarian cancer."

- read the release on the ovarian cancer data
- and here's the release on the prostate cancer data
- see the Dow Jones story