Exelixis, Inc. today announced results from two analyses evaluating the effect of PD-L1 expression or prior treatment with immune checkpoint inhibitors on the efficacy of cabozantinib in patients with advanced renal cell carcinoma (RCC). The findings are being presented this week at the European Society for Medical Oncology (ESMO) 2018 Congress being held October 19-23 in Munich, Germany.
An analysis of data from the CABOSUN and METEOR trials demonstrated that cabozantinib improved clinical outcomes regardless of PD-L1 status in patients with advanced RCC, relative to sunitinib or everolimus, the respective comparator arms for each trial. The late-breaking abstract [LBA 34] is being presented today in the Genitourinary Tumors, Non Prostate poster discussion session starting at 2:45 p.m. CEST (local Munich time).
Tumor tissue from 110 patients in the CABOSUN trial and 306 patients in the METEOR trial were evaluated to determine whether PD-L1 expression (≥1% of tumor cells) predicted outcomes or response to treatment. The findings showed that PD-L1 expression was associated with shorter median progression-free survival (PFS) and overall survival (OS) in both METEOR and CABOSUN. Treatment with cabozantinib, however, improved PFS and OS compared with everolimus (METEOR) and sunitinib (CABOSUN) in both PD-L1 positive and PD-L1 negative patients.
"As cabozantinib has become a new standard of care for the treatment of advanced kidney cancer, there is great interest in identifying biomarkers to help select for patients who would potentially derive the most clinical benefit," said Toni Choueiri, M.D., Director, Lank Center for Genitourinary Oncology, Dana-Farber Cancer Institute, and lead investigator. "While evidence suggests that patients who are negative for PD-L1 have less benefit with immune checkpoint inhibitors, this analysis demonstrated that cabozantinib may be an effective treatment option regardless of PD-L1 status for patients with advanced kidney cancer."
An additional analysis evaluating the activity of cabozantinib in 69 patients with advanced RCC who progressed on immune checkpoint inhibitors [abstract 879P] will be presented by lead investigator Bradley McGregor, M.D., Dana-Farber Cancer Institute, at ESMO on Monday, October 22 in a poster display session at 12:45 p.m. CEST. This retrospective analysis found that cabozantinib was active in patients previously treated with immune checkpoint inhibitors, either alone or in combination with anti-VEGF or other therapies. At a median follow-up of 12 months, objective response rate was 33 percent, disease control rate was 79 percent and the one-year overall survival rate was 53 percent.
"With a growing number of options available for advanced kidney cancer, physicians need to consider multiple factors when selecting and sequencing treatments for patients," said Michael M. Morrissey, Ph.D., President and Chief Executive Officer of Exelixis. "The findings from these additional analyses demonstrate the potential benefit with cabozantinib for patients regardless of PD-L1 expression as well as after treatment with immune checkpoint inhibitors, reinforcing its role as the TKI of choice for advanced kidney cancer."