CHICAGO ( TheStreet) -- Exelixis ( EXEL) and investors have been focused on the development of cabozantinib in prostate cancer, but Saturday, research was presented showing the experimental drug's activity in ovarian cancer. Treatment with cabozantinib led to objective response, or significant tumor shrinkage, in 24% of patients with metastatic ovarian cancer, according to results from a phase II study reported at the American Society of Clinical Oncology (ASCO) annual meeting. Another 29% of cabozantinib-treated patients had tumors that stopped growing or had minimal shrinkage, leading to an overall disease control rate of 53%. The median duration of response in the study has not yet been reached. Seventy ovarian cancer patients were enrolled in the phase II study of cabozantinib, which also included patients with other forms of cancer. About half of ovarian cancer patients were previously treated with platinum-based chemotherapy and included patients with advanced disease that was no longer responding to platinums. Two of 11 patients, or 18%, of patients with platinum-refractory disease achieved a confirmed tumor response. Ten of 36 patients, or 28%, with platinum sensitive disease achieved a partial tumor response. Two ovarian cancer patients died during the study for reasons that investigators deemed related to treatment with cabozantinib. Another 37% of patients had to have their doses of cabozantinib reduced because the drug was causing too many side effects, which included diarrhea and fatigue. Exelixis plans further studies of cabozantinib in ovarian cancer but details have not yet been disclosed. The company is focusing most of its near-term efforts on developing the drug in prostate cancer. Prostate cancer data from this same phase II study will be reported at the ASCO meeting on Monday afternoon. Cabozantinib is garnering a lot of attention from Wall Street investors because of previously released data from this mid-stage study demonstrating the drug's ability to both shrink and stabilize tumors but also fully or partly eliminate cancer that had spread to bone in patients. Cabozantinib is a targeted cancer drug that works by blocking two different molecular pathways that tumors use to grow.
Earlier today, Roche ( RHHBY) presented new data on the use of Avastin in ovarian cancer. Other companies developing ovarian cancer drugs include Nektar Therapeutics ( NKTR) and Endocyte ( ECYT). --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein. >To submit a news tip, send an email to: email@example.com.