Recent reports on drug development for patients with castration-resistant prostate cancer (CRPC) have appropriately focused on new androgen receptor–targeted agents, such as abiraterone and enzalutamide , as well on as other agents with diverse targets and mechanisms of action, such as sipuleucel-T , cabazitaxel , and radium 223. Recently, another multitargeted agent, the oral tyrosine kinase inhibitor cabozantinib, demonstrated activity against vascular endothelial growth factor receptor 2 and mesenchymal-epithelial transition factor (MET), both of which are overexpressed in CRPC. In an early report of an international, phase II, randomized, discontinuation trial of cabozantinib, use of the drug was associated with a clinical benefit in patients with metastatic CRPC.
Now, researchers report updated results of that trial, which enrolled 171 CRPC patients with measureable disease, good performance and organ function, and progressive disease; 87% had bone metastasis, and 46% had received the one allowed prior regimen of chemotherapy. All patients received open-label treatment with cabozantinib (100 mg daily) during a 12-week lead-in stage. Those with stable disease were then randomly assigned to cabozantinib or placebo and were observed until disease progression, at which time patients on placebo could receive cabozantinib. Randomization was suspended after 122 patients were enrolled in the open-label portion of the study because cabozantinib recipients had improvements in bone scan results and reduced pain. Before suspension of randomization, 14 patients had been assigned to receive cabozantinib and 17 had been assigned to receive placebo. Median duration of cabozantinib therapy was 3.2 months.
Patients randomly assigned to cabozantinib achieved significantly longer median progression-free survival (the primary endpoint) than those assigned to placebo (23.9 vs. 5.9 weeks; hazard ratio, 0.12; P
This is simply more peripheral reporting of the RDT P2 CRPC results first reported at ASCO 2011, and most recently published in the peer-reviewed JCO last November.
These sort of news releases should distinguish themselves by advising the reader that the real news lies in the fact that these 2011 clinical results have successfully attained peer-review and publication in a prestigious medical journal.
We probably haven't seen the last of these...