Temsirolimus improves overall survival of patients with advanced renal cell carcinoma with both clear-cell and other histologic types, according to results from a phase III trial presented at the annual meeting of the American Society of Clinical Oncology.

The data were derived from an open-label, randomized, trial comparing temsirolimus or a combination of temsirolimus plus interferon-alpha with interferon-alpha alone as first-line therapy in 626 patients with advanced disease and poor prognostic features.

"The results of these analyses expand our understanding of temsirolimus in patients with advanced kidney cancer," said Janice Dutcher, MD, Associate Director for Clinical Affairs, Our Lady of Mercy Medical Center, Bronx, N.Y., and Professor of Medicine, New York Medical College, Valhalla, N.Y.

Investigators conducted planned and post-hoc analyses to assess the influence of tumor cell type (clear-cell renal cell carcinoma versus other renal cell carcinomas), age (younger than 65 years versus 65 years and older) and prognostic-risk group (intermediate risk versus poor risk) on survival in patients treated with temsirolimus or interferon-alpha.

Treatment with temsirolimus increased overall survival and progression-free survival regardless of tumor cell type compared with interferon-alpha. Median overall survival in patients with clear-cell tumors, the most common form of the disease, was 10.6 months among patients treated with temsirolimus versus 8.2 months for interferon-alpha, and median progression-free survival was 5.5 months versus 3.8 months, respectively, as determined by independent assessment.

For patients with other tumor cell types, differences in median overall survival and progression-free survival were even greater. Median overall survival was more than twice as long in patients treated with temsirolimus compared with interferon-alpha (11.6 months versus 4.3 months), and median progression-free survival was nearly four times longer (7.0 months versus 1.8 months, respectively).

Among patients younger than 65 years, both overall survival and progression-free survival were longer in those treated with temsirolimus (12.0 months versus 6.9 months and 5.9 months versus 3.1 months, respectively) compared with interferon-alpha. There was no statistical difference between the two arms in overall survival or progression-free survival for patients aged 65 years and older.

Researchers also examined survival endpoints based on patients' prognostic risk. About three quarters of patients with advanced disease enrolled in the temsirolimus arm or interferon-alpha arm were classified as having poor prognostic features. Of these patients, those treated with temsirolimus had significantly longer overall survival (10.2 months versus 6.0 months) and progression-free survival (5.1 months versus 2.3 months). The study did not include enough patients with intermediate prognostic factors to allow for meaningful assessment of differences in survival.