Drug & Device Development

Exelixis drug cabozantinib shown to control solid tumors

Last Updated: 2011-05-19 13:10:19 -0400 (Reuters Health)

By Deena Beasley

LOS ANGELES (Reuters) - Exelixis Inc's experimental cancer drug cabozantinib was shown in a phase II trial to help control advanced prostate, ovarian and liver cancers, according to data released May 18th.

The drug was also found to fully or partly eliminate cancer that had spread to the bone in patients with breast cancer, prostate cancer and melanoma, according to the American Society of Clinical Oncology, which featured the data ahead of its annual meeting in June.

"We saw unprecedented bone scan improvement," said the study's lead author Dr. Michael Gordon, from Pinnacle Oncology Hematology in Scottsdale, Arizona.

Cabozantinib is an oral drug designed to block the pathway that tumors need to form new blood vessels -- the same target as drugs like Roche's Avastin -- as well as MET, another driver of tumor formation.

The Phase II study included 483 patients with advanced, progressive solid tumors.

Patients received cabozantinib over 12 weeks. Those who responded stayed on the drug; patients with stable disease were randomized to cabozantinib or placebo; and patients whose cancer worsened were removed from the trial.

Dr. Gordon said further trial results will be presented at the ASCO meeting in June.

In the data released on Wednesday, for 398 evaluated patients with all types of cancer, 9% experienced partial tumor shrinkage.

But the rates of cancer stabilization were much higher - 76% of liver cancer patients, 71% of prostate cancer patients and 58% of ovarian cancer patients saw their tumors either shrink or remain unchanged.

Also, 59 of 68 patients with cancer that had spread to the bone (mostly from prostate cancer, but also from breast cancer and melanoma) had either partial or complete disappearance of the cancer on bone scans.

The effects were associated with improvement in pain, a reduction in narcotic requirements and improvement in anemia.

The most common serious side effects seen in the trial were fatigue and hand/foot tenderness. Drug dosage was reduced in 41% of patients because of side effects, and 12% of patients were removed from the trial for adverse events.

Exelixis is expected to report by midyear results from a phase III trial of cabozantinib in thyroid cancer patients.