New agent for metastatic RCC: One-third of patients show response

Sunitinib malate (Sutent) appears to be a promising treatment for metastatic renal cell carcinoma, according to a preliminary study published last week in JAMA (2006; 295:2516-24). Sunitib, which received FDA approval earlier this year for the treatment of advanced RCC, is one of two drugs for the condition to be granted FDA approval in 2006. The other is sorafenib (Nexavar).

The multicenter, phase II trial included 106 patients whose disease was refractory to prior cytokine therapy. Patients were enrolled between February and November 2004, with follow-up continuing until disease progression, unacceptable toxicity, or withdrawal of consent. Patients received repeated 6-week cycles of sunitinib, 50 mg per day, orally for 4 consecutive weeks followed by 2 weeks off per treatment cycle.

Of the 105 evaluable patients, 36 (34%) achieved partial response and a median progression-free survival of 8.3 months, as evaluated by an independent third-party imaging laboratory, according to lead author Robert J. Motzer, MD, of Memorial Sloan-Kettering Cancer Center in New York.

The most common adverse effects were fatigue and diarrhea.

“The results of this trial demonstrate the efficacy of sunitinib as a single agent in second-line therapy for patients with cytokine-refractory metastatic clear-cell RCC,” the authors wrote. “The initial observation of antitumor activity for sunitinib has been confirmed in a larger trial. Sunitinib as a first-line therapy for metastatic clear-cell RCC is currently being investigated versus interferon-alfa in a randomized phase III study.”