Dr. Grigg Discusses CABOSUN Trial in mRCC

Claud Grigg, MD, medical oncologist, Levine Cancer Institute, Atrium Health, discusses the design and results of the CABOSUN trial looking at the frontline treatment of patients with metastatic renal cell carcinoma (mRCC).

CABOSUN was a randomized phase II trial looking at the use of cabozantinib (Cabometyx), which is dosed daily, versus that of sunitinib (Sutent), which is dosed on a 4-week-on, 2-week-off schedule. This was a relatively small study, Grigg says, which enrolled only about 150 patients. CABOSUN was designed to detect an improvement of progression-free survival (PFS) with cabozantinib over the long-time standard of care sunitinib. This was a positive study, as data showed a median PFS of 8.6 months with the newer-generation TKI versus 5.3 months with sunitinib.

Despite meeting its primary endpoint, the study is criticized for its low PFS, Grigg notes. Overall response rate was also considerably modest at 20% and 9% with cabozantinib and sunitinib, respectively. However, Grigg concludes that it is still reassuring to have an additional frontline option for these patients. Recent data has suggested the efficacy of checkpoint inhibitors in the frontline setting, so ongoing research is being geared toward determining the feasibility of combining TKIs with anti-PD—1 and CTLA-4 agents.