prostate cancer

Exelixis has begun the Phase 3 COMET-1 pivotal trial of cabozantinib in men with metastatic castration-resistant prostate cancer (mCRPC).

Cabozantinib is an investigational agent that provides coordinated inhibition of metastasis and angiogenesis to kill tumour cells, and is also being evaluated for its ability to reduce pain associated with bone metastases, in the COMET-2 Phase 3 trial in men with mCRPC.

COMET-1 is a double-blind, placebo-controlled Phase 3 study that will enrol 960 patients with mCRPC who have previously been treated with docetaxel, and abiraterone acetate and/or MDV3100.

"Cabozantinib could become an important new treatment option for men with mCRPC."

The study’s primary endpoint is overall survival (OS) in mCRPC patients who have had disease progression after treatment with docetaxel, and abiraterone acetate and/or MDV3100.

In the trial, patients will be randomised 2:1 to receive cabozantinib 60mg daily or prednisone 5mg twice daily. Each arm will also receive placebo in order to account for the once-daily versus twice-daily dosing regimens of cabozantinib and prednisone.

Massachusetts General Hospital Cancer Center, US, Genitourinary Malignancies Program director and lead investigator for COMET-1, Matthew Smith, said COMET-1 is a well-designed global study of a compound with the potential to address many of the unmet medical needs for men with mCRPC.

"The phase 2 studies of cabozantinib provide early evidence of impressive effects on measurable tumour, progression-free survival, bone scan response, pain alleviation and circulating tumour cell (CTC) counts," Smith added.

"If COMET-1 confirms these early findings and demonstrates a survival benefit, I believe cabozantinib could become an important new treatment option for men with mCRPC."

Exelixis president and CEO, Michael Morrissey, said that the initiation of the COMET-1 trial is an important milestone in the cabozantinib development programme in prostate cancer.

"A successful outcome for COMET-1 and for the ongoing COMET-2 pivotal trial would document the ability of cabozantinib to extend survival and to provide significant pain palliation in mCRPC, a distinct and differentiated profile that we believe provides the best opportunity to maximise cabozantinib’s clinical and commercial potential," Morrissey added.

The data from COMET-1 is likely to be announced in the first half of 2014.

Image: Micrograph of prostate adenocarcinoma, acinar type, the most common type of prostate cancer. Photo courtesy of: Nephron.