Using a combination of the drugs temsirolimus (Torisel) and Bryostatin appears to be safe in patients with metastatic kidney cancer, according to early data from 25 patients in a phase 1 trial.

  The researchers said a pathway known as mTOR signaling promotes tumor cell proliferation and tumor blood vessel development. The temsirolimus-bryostatin combination blocks two portions of the mTOR signaling pathway, and the early data suggests the drugs may be active in patients with rare forms of renal cell cancer that are less likely to respond to other therapies.

  'We have certainly seen sustained responses with this combination, which are encouraging,' Dr. Elizabeth Plimack, a medical oncologist and attending physician at Fox Chase Cancer Center in Philadelphia, said in a news release from the center.

  'Patients with non-clear cell renal cell cancer, including papillary renal cancer, don't respond as well to tyrosine kinase inhibitors, such as sunitinib [Sutent] and sorafenib [Nexavar], as patients with clear cell renal cell. So there is an unmet need for therapy for these patients. We've seen that this combination may be active to some degree for them,' Plimack said.