medwireNews: Previously untreated patients with advanced clear cell renal cell carcinoma (RCC) could benefit from treatment with cabozantinib plus atezolizumab, suggest COSMIC-21 data.
Similarly promising findings from the phase 1b multicohort trial have previously been reported for metastatic castration-resistant prostate cancer and urothelial cancer, with the current RCC data presented by Sumanta Pal (City of Hope Comprehensive Cancer Center, Duarte, California, USA) at the ESMO Virtual Congress 2020.
The cohort comprised 70 patients who had not received prior systemic therapy for locally advanced or metastatic clear cell RCC. Participants received the multikinase inhibitor cabozantinib at a dose of either 40 or 60 mg/day alongside the PD-L1 inhibitor atezolizumab 1200 mg every 3 weeks, with a median follow-up of 25.8 and 15.3 months for the 40 and 60 mg dose groups, respectively.
Just over half (53%) of the 34 patients who received cabozantinib 40 mg plus atezolizumab achieved a response, as did 58% of the 36 participants given cabozantinib 60 mg alongside atezolizumab. The median duration of response was unreached and 15.4 months, respectively, and the corresponding disease control rates were 94% and 92%.
Progression-free survival was a median of 19.5 months for the cabozantinib 40 mg group and 15.1 months for the cabozantinib 60 mg group.
The incidence of treatment-related adverse events (TRAEs) of grade 3 or 4 was a comparable 71% and 67% in the cabozantinib 40 mg and 60 mg dose groups, respectively. Pal highlighted that there were no grade 4 events in the cabozantinib 60 mg arm and no grade 5 events in either arm.
The proportion of patients who experienced grade 3 diarrhea and transaminase elevations was “modestly higher” in the cabozantinib 60 mg than 40 mg group, he reported. But Pal cautioned that “comparison of safety between the two doses is confounded by the shorter follow-up for the 60 mg group as well as, of course, the nonrandomized study design.”
A total of 56% of patients in the cabozantinib 40 mg arm required a dose reduction due to AEs, while the rate was higher, at 86%, in the cabozantinib 60 mg arm. The proportion of patients who discontinued either study drug to TRAEs was 24% and 19%, respectively.
Pal summarized that “the combination of cabozantinib and atezolizumab demonstrated encouraging clinical activity in previously untreated patients with advanced clear cell renal cell carcinoma.”
And he highlighted the ongoing phase 3 CONTACT-3 study of cabozantinib with or without atezolizumab in RCC patients who have received prior immune checkpoint inhibitor therapy.
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