VIENNA—Pazopanib, an investigational drug, demonstrated similar efficacy to sunitinib as first-line treatment for metastatic renal cell carcinoma (mRCC), according to results from a phase 3 trial presented at the European Society for Medical Oncology 2012 Congress. Pazopanib showed superior results for some quality-of-life parameters.

Sunitinib and pazopanib are both targeted drugs available for first line treatment of metastatic RCC. Both agents are oral multi-kinase angiogenesis inhibitors that have demonstrated efficacy at improving progression-free survival (PFS) in patients with mRCC. The new findings are from the COMPARZ study, which directly compared efficacy, safety, and tolerability of pazopanib and sunitinib.

In this study, patients were randomized to receive to pazopanib 800 mg once daily continuous dosing or sunitinib 50 mg once daily in six-week cycles (four weeks on followed by two weeks off). The study had 557 patients in the pazopanib arm and 553 in the sunitinib arm. Based on a planned 631 PFS events by an independent review committee, the COMPARZ trial had 80% power to detect non-inferiority of pazopanib to sunitinib. The non-inferiority margin was chosen to exclude a difference of greater than 25% in the hazards, said lead investigator Robert Motzer, MD, a medical oncologist at Memorial Sloan Kettering Cancer Center in New York.

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For both drugs, the median PFS by the treating physician’s assessment was slightly more than 10 months (10.5 months for pazopanib vs. 10.2 months for sunitinib), Dr. Motzer reported. The median overall survival was 28.4 months for pazopanib versus 29.3 months for sunitinib.

Both drugs were associated with adverse events (AEs), but some of those recognized to be troublesome to patients occurred less frequently with pazopanib than sunitinib, the researchers found.

The investigators evaluated the most common AEs in 554 pazopanib-treated patients and 548 sunitinib-treated patients. Rates of diarrhea were slightly higher in the pazopanib arm (63 vs. 57 patients in the sunitinib arm) and the same was true for hypertension (46 vs. 41 patients in the sunitinib arm). Fatigue was less of a problem in the pazopanib arm (55 vs. 63) and the rate of hand-foot syndrome was significantly lower in the pazopanib arm (29 vs. 50).

Responses to quality-of-life questions favored pazopanib over sunitinib and suggested improved tolerability for pazopanib, Dr. Motzer said.