Safety and Preliminary Efficacy of MBS8(1V270) in Cancer Patients With Advanced Solid Tumours

Must have received: pembrolizumab (pembrolizumab)

Prior exposure to pembrolizumab for ≥6 months, with radiologic evidence of an initial decrease in measurable tumour burden, and subsequent disease progression following that period of initial tumour control (Cohort A)

Must have received: tebentafusp (tebentafusp)

Prior tebentafusp exposure with subsequent progression. ≥16 weeks of exposure to tebentafusp with documented radiological tumour reduction in at least 1 lesion. RECIST v1.1 progression on tebentafusp. (Cohort B)

Cannot have received: systemic immunotherapy (except pembrolizumab)

Any prior exposure to systemic or IT immunotherapy, except pembrolizumab, including Montanide, TLR7, TLR8, and TLR9 agonists, polyinosinic:polycytidylic acid, cationic adjuvant formulation, and messenger ribonucleic acid -based vaccines.

Cannot have received: experimental anti-cancer vaccines

Participants who have been previously treated with experimental anti-cancer vaccines.

Cannot have received: pembrolizumab and T cell combination therapy

Prior exposure to pembrolizumab and T cell combination therapy (Cohort A)

Cannot have received: biologic, hormonal, anti-neoplastic chemotherapy, or radiation therapy

Exception: except for medications with half-lives <5.5 days

Have had biologic, hormonal, anti-neoplastic chemotherapy, or radiation therapy within 4 weeks prior to Screening (6 weeks required for nitrosourea or mitomycin) except for medications with half-lives <5.5 days.

Cannot have received: investigational agent

Use of investigational agent in the 4 weeks or 5 half-lives prior to the first dose of MBS8(1V270), whichever was shortest.