Pazopanib has a disease control rate of 73%


CHICAGO —Pazopanib, a new oral angiogenesis inhibitor, may be effective in treating metastatic renal cell carcinoma (RCC), according to data from an ongoing phase II trial.

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“Based upon this preliminary analysis, our findings so far are very exciting,” said lead investigator Thomas Hutson, DO, PharmD, director of genitourinary oncology at Baylor-Sammons/Texas Oncology in Dallas.


The agent specifically targets vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and c-kit, important proteins in the angiogenic process. In contrast, sun-itinib and sorafenib, anti-angiogenesis drugs which recently became commercially available, target these receptors as well as others that are not believed to be involved in RCC.


“This drug [pazopanib] may turn out to be safer than other similarly targeted agents,” Dr. Hutson told Renal & Urology News.


The phase II study includes 225 patients with advanced RCC (mean age 59 years) who have not received prior systemic therapy or have failed one previous treatment (cytokine or bevacizumab-containing regimen). All subjects received 800 mg of pazopanib once daily during a 12-week lead-in period. Based on data available on 60 patients at a planned interim analysis, the Independent Data Monitoring Committee recommended that randomization to placebo for patients with stable disease should be discontinued. The study continued as an open-label, single arm study with all patients receiving pazopanib.


The preliminary response rate at week 12 for all 225 patients was 27%. Stable disease was achieved in 46% of patients, for a total disease control rate of 73%.


The most frequent adverse events were diarrhea, fatigue, hair color change, nausea, and hypertension. The study population had a low incidence of hand-foot syndrome (10%), rash (12%), hemorrhage (9%), and mucositis (5%).


“Compared to sunitinib and sorafenib, there seems to be less hand-foot syndrome,” said Dr. Hutson, who reported study findings here at the American Society of Clinical Oncology annual meeting.