Shares of Exelixis Inc. soared Thursday after the company reported positive data from studies that are testing its drug candidate XL 184 as a treatment for ovarian cancer and prostate cancer.
Its shares rose $1.29, or 27.3 percent, to $6.01 in midday trading.
The South San Francisco, Calif., company presented interim results from the mid-stage clinical trials at a conference in Berlin. Exelixis said the drug appears effective in shrinking tumors in ovarian cancer patients, and in clearing up bone lesions from prostate cancer. Those bone lesions can lead to bone breaks and severe pain.
The trial is not complete and Exelixis has not evaluated all the patients in either study. It said that out of 31 evaluated patients in the ovarian cancer study, 10 had a partial response, meaning their tumors shrank, while 30 out of the 37 patients who had metastatic lesions experienced tumor shrinkage. Exelixis said 20 patients in the prostate cancer trial had cancer that metastasized to the bone, and 19 of those men had their lesions shrink or disappear. The company was able to evaluate the tumor response of 55 patients, and it said 38 of them had some tumor shrinkage.
The side effects of treatment with XL 184 were similar in the two studies, including fatigue, diarrhea, nausea, high blood pressure, rash, and a condition called hand foot syndrome. Hand foot syndrome is a side effect of chemotherapy in which small amounts of the drug leak out of the blood vessels in the palms and the soles of the feet, causing reddened skin, tenderness, and peeling. Patients in the prostate cancer study also experienced coughing, and some patients in the ovarian cancer study reported vomiting and low magnesium levels.
Exelixis said it is testing XL 184 against nine other tumor types, including cancers of the skin, breast, prostate, brain, liver, and lungs.