Background: Uveal melanoma is the most common primary intraocular malignant tumor in adults. Overall Survival (OS) at 5 years(y) is 62% due high incidence of liver metastasis, fatal within 4-9 months(m) from diagnosis. No standard treatment exists for MUM. NIVO+IPI combination has shown efficacy in metastatic cutaneous melanoma. However, MUM pts were excluded in these trials. Methods: GEM1402 is a phase-2 trial evaluating NIVO+IPI in untreated adult pts with MUM; is being conducted in 10 centers in Spain, leading by the Spanish Melanoma Group. Eligible pts had histologically-confirmed MUM, ECOG-PS 0/1, and no prior systemic treatment for MUM. Treatment consisted in NIVO (1mg/kg, iv, q3 weeks [wk]) and 4 doses of IPI (3mg/kg iv q3wk) followed by NIVO (3mg/kg q2wk) until progressive disease (PD), toxicity or withdrawal. Primary endpoint is OS and secondary progression free survival (PFS), Overall Response Rate (ORR) (per RECIST 1.1) and safety. Radiologic evaluations q6wk. Interim analysis (n = 19) was planned per protocol to assess safety and ORR. Intention to treat analysis includes pts with PD at first radiological evaluation. Safety population includes all pts receiving at least one dose of study treatment. Results:19 pts enrolled from April to July 2016: Median age 62y (43y-82y), 63% male, liver M1 84% pts and extra-liver M1 42% pts, 31% elevated baseline LDH. 11 pts completed cycle 2 and 8 pts stopped after 1 dose (6 PD, 2 toxicity). Treatment-related adverse events were reported in 12 pts and lead to end of treatment in 2 pts. Grade ≥3 toxicities were seen in 7 pts (36.8%): diarrhea, transaminitis, dermatological events, anemia, acute thyroiditis. All G3/4 were resolved following the toxicity guideline. One G5 acute thyroiditis related to NIVO+IPI was reported. ORR was observed in 15.8% and disease stabilization in 47.4%. With a median follow-up of 4.6m, PFS was 4.99m. Median OS was not reached at time of this analysis. Conclusions: Combination of NIVO+IPI is feasible for MUM. In this INTERIM ANALYSIS, ORR did not reach yet 20%, but PFS seems promising. The clinical trial is ongoing. Final results will be updated. Clinical trial information: 2015-004429-15.