Abstract 1059P
Background
Combination therapy with anti-PD1 and low-dose ipilimumab has shown reduced rate of immune-related adverse effects compared with standard dose used in the Checkmates studies 067 and 204. However, the discussion whether low-dose ipilimumab may hamper the response rate in advanced melanoma is still open.
Methods
We conducted a retrospective analysis of response evaluation based on 18F-FDG PET/CT for patients with advanced melanoma treated with combination of nivolumab 3mg/kg plus ipilimumab 1mg/kg for 4 cycles (N3+I1) followed by anti-PD1 maintenance therapy and compared the results to RECIST 1.1 response criteria in the same population.
Results
Between December 2017 and August 2020, 45 patients with advanced melanoma treated with N3+I1 in first-line setting were identified.
Unresectable stage III/stage IV were 2/43 patients, respectively. Among stage IV patients, 60.5% were M1c, 23.3% had elevated LDH and 28% had brain metastasis (3 or more brain lesions: 58%). At a median follow-up of 16.7 months, 11 patients (24.4%) had G3/G4 toxicity. During induction phase, three patients (6.6%) discontinued all drugs and 2 other patients (4.4%) interrupted only ipilimumab. Review of response evaluation by RECIST was possible in 36 patients and showed an objective response of 50%. Complete response (CR): 11% and partial response (PR): 39%. Eight percent presented progressive disease (PD). In 37 patients, review of response evaluation using 18F-FDG PET/CT was possible. Twenty-four patients (65%) achieved metabolic CR, 5 (13.5%) PD and 8 (21.5%) were classified as non-CR non-PD. Median progression-free survival (PFS) and overall survival (OS) were not reached. 12-month PFS and OS were: 72.5 and 89%, respectively. During the study follow-up, only 1 patient with metabolic complete response relapsed and 3 out of 8 with non-CR non-PD progressed.
Conclusions
Using low-dose ipilimumab combination does not hamper the response rates and, possibly due to fewer protocol interruptions, these patients may achieve more complete responses as showed by 18F-FDG PET/CT evaluation.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
A.C. Camargo Cancer Center.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.