Prognostic score for patients with advanced melanoma treated with ipilimumab

Immunotherapies like the cytotoxic T-lymphocyte antigen 4 inhibitor ipilimumab show durable clinical benefit in patients with advanced melanoma. Reliable prognostic markers and risk scores in the era of immunotherapy are still lacking.

We collected characteristics and outcomes on 134 patients with metastatic melanoma treated with ipilimumab between 2011 and 2014 at a single centre. Cox regression including multivariable fractional polynomials was used to identify independent markers for overall survival (OS). Internal model validation was done using bootstrap procedures.

After a median follow-up of 16.1 months the median OS was 7.1 months (95% confidence interval [CI], 6.5-9.8). Nineteen of 134 patients (14.2%) had tumour remissions, 16 partial and 3 complete; 75% had progressive disease. We identified three independent adverse factors for OS: elevated lactate dehydrogenase (LDH) (hazard ratio [HR] 1.03, 95% CI 1.02-1.04), Eastern Cooperative Oncology Group performance status >0 (HR 1.91, 95% CI 1.10-3.30), and number of organs involved (NOI) (HR 1.51, 95% CI 1.22-1.86). To build an easy-to-apply risk score, we dichotomized LDH (>upper limit of normal) and NOI (>2) to built 3 prognostic groups: favourable (no adverse factors, N = 17), intermediate (1 adverse factor, N = 38), and poor prognosis (≥2 adverse factors, N = 73). Respective 12 and 18-month OS for the risk groups were: 85% and 73% (favourable), 41% and 29% (intermediate), and 12% and 6% (poor) (p < 0.001).

We propose a simple prognostic score for survival in patients with advanced melanoma treated with ipilimumab using readily available clinical parameters.