Clinical outcome of first-line melanoma patients who continue tremelimumab in spite of early disease progression.

2574 Background: Tremelimumab (CP-675,206) is an immune activating agent that stimulates the immune system rather than having a direct effect on tumors. Due to the potential for a delayed tumor effect, treatment guidelines in tremelimumab protocols allow patients to continue dosing in spite of progressive disease (PD) at the first assessment as long as the patient is not deteriorating clinically. The clinical outcome of melanoma patients (pts) who continued tremelimumab after early progression in the phase III study (A3671009) is described. Methods: Pts with unresectable stage IIIc-IV melanoma without brain metastasis, LDH below 2x ULN, and no prior systemic treatment for advanced melanoma were randomized 1:1 to either tremelimumab 15 mg/kg IV q90d, or physician's choice of TMZ 200 mg/m2 p.o. d1-5 q28d or DTIC 1,000 mg/m2 IV q21d (chemotherapy arm). Results: 328 pts were randomized to the tremelimumab arm, with 324 treated. 225 pts had PD at the first assessment (≤ 100 days) according to the investigator....