Phase III Results Reported for Pazopanib and Temsirolimus in Renal Cell Carcinoma
Results have important implications, researchers say (Oct. 1)
New results from phase III trials exploring treatment options for patients with advanced renal cell carcinoma (RCC) were announced on October 1 by the Congress of the European Society for Medical Oncology (ESMO) and were presented at the society’s 2012 Congress in Vienna.
The results of the phase III randomized, open-label COMPARZ trial showed that pazopanib and sunitinib were similarly effective in controlling metastatic RCC. Both drugs are available for first-line treatment in this setting. Sunitinib is considered the reference standard of treatment, although nonrandomized trials have suggested similar efficacy and a lower incidence of side effects with pazopanib.
The investigators compared the efficacy, safety, and quality of life (QOL) of pazopanib and sunitinib in 1,100-patients with metastatic RCC. The primary objective of the study was to establish the noninferiority of progression-free survival (PFS) with pazopanib versus sunitinib. Safety and QOL were evaluated as secondary endpoints.
The median PFS was slightly more than 10 months for each drug.
Both pazopanib and sunitinib caused side effects, but some of these effects, such as fatigue and skin sores, occurred less often with pazopanib, the researchers found.
In the phase III INTORSECT trial, temsirolimus did not improve survival over sorafenib in the second-line treatment of RCC.
The two drugs inhibit different cancer-associated molecules: temsirolimus inhibits mammalian target of rapamycin (mTOR), which regulates cell growth and proliferation, whereas sorafenib targets several tyrosine kinases, including vascular endothelial growth factor (VEGF) receptors.
The study included 511 patients with RCC whose disease had progressed after first-line treatment with sunitinib. Median PFS with temsirolimus was 4.28 months compared with 3.91 months with sorafenib. Median overall survival for the temsirolimus group was 12.27 months compared with 16.64 months for the sorafenib group. Thus, temsirolimus did not show superiority over sorafenib in either the primary endpoint of PFS or the secondary endpoint of overall survival.
“This trial shows that drugs that inhibit the VEGF pathway may be a better option than mTOR inhibitors for patients progressing on sunitinib,” chief investigator Dr. Thomas Hutson said. “In addition, mTOR inhibitors may be appropriate for first line use for a select group of non–clear-cell renal cell carcinoma patients and/or those patients with poor performance status.”
Another phase III study — the INTORACT trial — failed to confirm early clinical results with the combination of bevacizumab and temsirolimus in RCC. The randomized, open-label study compared temsirolimus plus bevacizumab with interferon plus bevacizumab as first-line treatment in 791 patients with predominantly clear-cell metastatic RCC.
At the data cutoff for final analysis, 489 patients had independently assessed PFS events. Median PFS with the temsirolimus combination was 9.1 months compared with 9.3 months for the interferon group. Median overall survival was 25.8 months in the temsirolimus group and 25.5 months in the interferon group.
For more information, visit the ESMO Web site.