New findings reinforce drug’s place as a reference standard as first-line therapy for metastatic RCC.

CHICAGO—Sunitinib (Sutent) remains a reference standard for the first-line treatment of metastatic renal cell carcinoma (RCC), with updated findings from a phase 3 trial confirming the superior efficacy of this agent over interferon-alfa, researchers reported here at the American Society of Clinical Oncology annual meeting.

Previously published data showed that sunitinib is associated with significantly improved progression-free survival (PFS) and objective response rate (ORR) compared with interferon-alfa as first-line therapy for metastatic RCC. That study established sunitinib as a new reference standard of care.

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At the time of the study’s publication in The New England Journal of Medicine (2007;356:115-124), the survival data were not mature and median overall survival (OS) had not been reached in both treatment arms of the trial.

In this study, 750 patients with previously untreated advanced RCC were randomized 1:1 to receive either sunitinib (50 mg orally daily for four weeks, then two weeks off treatment) or interferon-alfa (9 MU subcutaneously three times a week). The primary study outcome was PFS.

The initial protocol required subjects to stay on their assigned treatment until disease progression or unacceptable toxicity, after which participation in the study would end. Based on improved PFS observed with sunitinib at the second interim analysis, the Data Safety Monitoring Board recommended in February 2006 that the study protocol be amended to allow patients in the interferon-alfa arm to cross over to treatment with sunitinib when their disease progressed.

In the current analysis, researchers found sunitinib more than doubled PFS compared with interferon-alfa (11 vs. 5.1 months). In addition, sunitinib was associated with a significantly greater improvement in ORR (47% vs. 12%). The median OS was 26.4 months in the sunitinib arm compared with 21.8 months for those in the other arm, but the difference was not significant.

With continued and prolonged treatment, sunitinib offers improved quality and quantity of life for patients said lead investigator Robert Figlin, MD, professor of medical oncology at the City of Hope National Medical Center in Duarte, Calif. “This is the first such agent to do this for patients with metastatic renal cell carcinoma.”

The most common grade 3-4 treatment-related adverse events for the sunitinib group were hypertension (12%), fatigue (11%), diarrhea (8%), and hand-foot syndrome (8%). In the interferon-alfa arm, the most common adverse events were fatigue (13%) and anorexia (2%). There were no unexpected grade 3-4 treatment-related adverse events observed by Dr. Figlin’s group. It should still be considered a first-line treatment for patients.