The phase 1b part is an open-label, multicenter, single-arm study where all participants will receive talimogene laherparepvec in combination with ipilimumab.~The phase 2 part of the study is an open-label, multicenter, randomized study to further assess the safety and to evaluate the efficacy of talimogene laherparepvec in combination with ipilimumab. Participants will be randomized 1:1 to receive talimogene laherparepvec plus ipilimumab or ipilimumab alone.~Participants randomized before amendment 2 will be stratified by stage of disease (stage IIIB/C, IVM1a, and stage IVM1b vs IVM1c) and v-raf murine sarcoma viral oncogene homolog B1 (BRAF) V600E (a mutation resulting in a substitution of glutamic acid for valine at codon 600) (mutation vs mutation not present). Participants randomized after amendment 2 will be stratified by stage of disease (stage IIIB/C and IVM1a vs stage IVM1b and IVM1c) and prior therapy (treatment naïve vs previously treated with systemic anticancer immunotherapy vs previously treated with systemic anticancer treatment other than immunotherapy).
Phase 1b of the study will evaluate the safety of talimogene laherparepvec in combination with ipilimumab. Phase 2 is a randomized study that will evaluate the safety and efficacy of talimogene laherparepvec in combination with ipilimumab versus ipilumumab alone.