Glossary:
Objective response rate: patients who responded partially or completely to treatment.
Complete response: the disappearance of cancer.
Progression-free survival: the time a patient lives without their disease spreading or worsening.
Overall survival: the time a patient lives, regardless of disease status.
At a median follow-up of 24.3 months, 35 patients, or 70%, had demonstrated a confirmed objective response, with four (8%) who experienced a complete response and 31 (62%) who had a partial response.
Additionally, a post-hoc analysis found that 49, or 98% of patients, had disease control, meaning a confirmed best overall response of stable disease or better.
The median time to response was 1.9 months, and as of the data cutoff 24, or 48% of patients, were still under ongoing treatment. The median duration of response was 28.6 months, and the median progression-free survival was 30.3 months. The median overall survival was not reached, but the estimated 12- and 24-month overall survival rates were 96% and 86%. By the time of data cutoff, five, or 10% of patients, had died, researchers reported.
Researchers reported that the most common grade 3 (severe) to 4 (life-threatening) treatment-related side effects were hypertension (12%), anemia (10%) and fatigue (8%). While seven, or 14%, of patients had serious treatment-related side effects, no treatment-related deaths occurred, researchers reported.
Researchers noted that all patients experienced at least one all-cause side effect, with grade 3 to 5 (fatal) events occurring in 30, or 60%, of patients. One patient died from a died from hepatic failure and spontaneous bacterial peritonitis as of the data cutoff, with neither event considered related to study treatment by the investigator, according to the study.
Treatment-related side effects occurred in all patients, with grade 3 treatment-related side effects occurring in 22, or 44% of patients and a grade 4 case of hypertension determined to be related to Cabometyx occurring in one patient.
Side effects led to Welireg dose reductions in 14, or 28% of patients, and interruptions in 24, or 48%, of patients, while they led to Cabometyx dose reductions and interruptions in 37, or 74%, of patients. Side effects led to the discontinuation of Welireg and Cabometyx in five, or 10%, and six or 12%, of patients, respectively.
Reference:
“Belzutifan plus cabozantinib as first-line treatment for patients with advanced clear-cell renal cell carcinoma (LITESPARK-003): an open-label, single-arm, phase 2 study” by Dr. Toni K. Choueiri, et al., The Lancet Oncology.
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