Exelixis on Monday announced results from a Phase II study at the European Society for Medical Oncology (ESMO) congress demonstrating that Cabometyx (cabozantinib) significantly cut the rate of disease progression or death versus Pfizer's Sutent (sunitinib) in patients with previously untreated advanced renal cell carcinoma (RCC). Exelixis said that based on the data it will seek to expand approval of Cabometyx in the US as a first-line treatment for advanced RCC.
The CABOSUN study randomised 157 patients with advanced RCC determined to be intermediate- or poor-risk by the IMDC criteria to receive Cabometyx or Sutent. Exeliis reported  in May that the trial met its primary endpoint of progression-free survival (PFS), while secondary goals included overall survival and objective response rate.
Exelixis said Monday that with a median follow-up of 20.8 months, Cabometyx showed a clinically meaningful and significant 31-percent reduction in the rate of disease progression or death compared to Sutent. The company noted that the median PFS for Cabometyx was 8.2 months versus 5.6 months for Sutent, corresponding to a 46-percent improvement. Further, the objective response rate was also significantly improved, at 46 percent for Cabometyx versus 18 percent for Pfizer's drug. Exelixis added that with a median follow up of 22.8 months, median overall survival was 30.3 months for Cabometyx and 21.8 months for Sutent.
Study leader Toni Choueiri remarked "not only has [Cabometyx] surpassed [Sutent], the current standard of care, in progression-free survival and objective response rate, [Cabometyx's] effects on progression-free survival were also consistently favourable across patient stratification subgroups."
Cabometyx, which targets MET, AXL and VEGFR-1, -2 and -3, gained FDA approval  earlier this year for the treatment of patients with advanced RCC who have received prior anti-angiogenic therapy. Meanwhile, last month, the European Commission authorised  the drug for the treatment of advanced RCC in adults who have received prior VEGF-targeted therapy. Ipsen signed an agreement  in February for the commercialisation and further development of Cabometyx outside of the US, Canada and Japan.