Correlation between efficacy and toxicity in pts with pretreated advanced melanoma treated within the Italian cohort of the ipilimumab expanded access programme (EAP).

Abstract

9065 Background: Ipilimumab was the first agent approved for the treatment of unresectable or metastatic melanoma that showed an overall survival benefit in randomised phase III trials. Early clinical studies explored the potential relationship between immune-related adverse events (irAEs) associated with ipilimumab and antitumor activity but no definitive conclusion has been reached. Here, we evaluated the possible correlation between efficacy of ipilimumab treatment and irAEs in patients (pts) enrolled in the EAP in Italy. Methods: Ipilimumab was available upon physician request for pts aged ≥16 years with unresectable stage III/stage IV melanoma who had either failed systemic therapy or were intolerant to ≥1 systemic treatment and for whom no other therapeutic option was available. Ipilimumab 3 mg/kg was administered intravenously every 3 weeks for 4 doses. Tumour assessments were conducted at baseline and after completion of induction therapy using immune-related response criteria. Pts were monitored for adverse events (AEs), including immune-related AEs (irAEs), using Common Terminology Criteria for Adverse Events v.3.0. Results: In total, 855 Italian pts participated in the EAP from June 2010 to April 2012 across 55 centres. Among 833 evaluable pts, 278 pts (33.4%) reported an irAE and 555 (66.6%) did not. As of December 2012, the disease control rates among pts with or without irAEs were 35.3% and 33.9% respectively. We noted that there was a difference in the distribution of pts with or without irAEs among pts who experienced a fast progression, thus not being able to receive at least 3 cycles, and pts with slow progression. In fact, due to the mechanism of action of the drug and consequent delayed onset of irAEs, pts with irAEs among fast and slow progressors were 22% and 37% respectively. Therefore, median overall survival was evaluated by adjusting the 2 groups for this factor and results showed a comparable survival between pts who reported an irAE and pts who did not (10.0 vs 9.7 months respectively). Conclusions: This exploratory analysis of EAP data suggest that activity and efficacy of ipilimumab is not related with the occurrence of irAEs.