The results of the phase 2/3 STAR trial were published in The Lancet Oncology recently. In this study, the researchers wanted to see if a temporary break in first-line tyrosine kinase inhibitor (TKI) treatment for advanced kidney cancer might help patients tolerate the treatment better without affecting survival outcomes. Although the researchers could not see if a break in treatment resulted in worse outcomes for patients compared to patients who continued on treatment with a first-line TKI, the treatment break did not significantly affect survival times in patients with advanced clear cell kidney cancer.
The average overall survival time was slightly higher in the group of patients who continued on TKI treatment compared to those who had a break in TKI treatment (average overall survival time was 28 months versus 27 months, respectively). There was also a small difference in quality of life between the two groups.
45% of patients in the conventional treatment group had a reduction in the dose of their medication compared to 46% in the drug-free interval group. 54% of patients in the drug-free interval group continued the trial past 24 weeks, of whom 85% started their first treatment break at week 24.
The average number of treatment breaks was one and the maximum number of breaks was 9. The average length of all treatment breaks was 87 days. 3% of patients in the drug-free interval group moved onto continuous treatment.
The most common serious or life-threatening side effects were high blood pressure, liver damage caused by the medicine, fatigue, problems with the gut, infection, and problems with breathing. Sadly, 74% of patients died during the study. Death was related to the study medication in 12 patients (3 from the conventional group and 9 from the drug-free interval group). Causes of death included problems with blood vessels and the heart, liver, gut, or nervous system disorders, and infection.
The response to treatment in the conventional treatment group (245 patients) was less than 1% with a complete response to treatment and all signs of their cancer disappeared, 26% with a partial response and their cancer got smaller, and 74% with stable disease. Among 250 patients in the drug-free interval group who responded to initial treatment, 1% had a complete response to treatment, 23% had a partial response, and 76% had stable disease.