Survival Curve May Begin at 3 Years With Ipilimumab in Advanced Melanoma Patients

In the largest analysis to date of overall survival (OS) in ipilimumab-treated patients with advanced melanoma, researchers have found there may be a plateau in the survival curve, beginning at approximately 3 years.  Dirk Schadendorf, who is with the University Hospital Essen, Essen, Germany, and colleagues report in the February 9, 2015 issue in the Journal of Clinical Oncology that the plateau appears to be independent of prior therapy or ipilimumab dose.

The investigators conducted a pooled analysis on OS for 1,861 patients from 10 prospective and two retrospective studies of ipilimumab.  Among the 12 studies, there were 1,257 previously treated patients and 604 treatment-naive patients.  All of the patients had advanced melanoma stage IIIC or IV.   Not all the patients received the same doses of ipilimumab (965 received ipilimumab 3 mg/kg and 706 patient received 10 mg/kg).

The pooled analysis demonstrated a median OS was 11.4 months.  The survival curve began to plateau around 36 months with follow-up of up to 10 years.  The 3-year survival rate was 22% for all patients.  The survival rate was 26% for treatment-naive patients and 20% for previously treated patients.  The findings suggest that previously treated advanced melanoma patients who survive 3 years are highly likely to have good long-term outcomes.

Antonio Ribas, who is with the Jonsson Comprehensive Cancer Center at the University of California, Los Angeles, published an accompanying editorial in which he writes that the great majority of patients had no serious adverse effects from ipilimumab therapy.  He noted that older patients and patients with more advanced disease appear to be candidates for ipilimumab as opposed to first-generation of cytokine-based therapy, such as high-dose interleukin-2 (IL-2).  Dr. Ribas writes that this pooled analysis does not provide information on the long-term outcomes of the patients in the control arms of the two pivotal phase III trials with ipilimumab.  So, indirect comparisons must be done with historical control series.

“The authors document a plateau in the survival curve at 21% starting at 3 years and maintained thereafter, suggesting that patients previously treated with ipilimumab who survive to 3 years are highly likely to have a good long-term outcome. It is this feature that motivates doctors and patients to consider treatment with ipilimumab,” wrote Dr. Ribas.