A Phase I/II, open-label, adaptive two-part trial to evaluate the safety, efficacy, optimal dose and pharmacokinetics of BNT326 as monotherapy and in combination with cancer immunotherapies in participants with advanced solid tumors.

This is a phase I/II open-label, two part trial to look how safe and well tolerated the study drug (called BNT326) is, when given alone (Part 1) or in combination with an immunotherapy (Part 2), and whether it helps to prevent certain types of cancer from getting worse in participants with advanced solid tumours. This study is divided into two separate parts:• Part 1: Part 1 has six cohorts:o Five cohorts (called 1A to 1E) will evaluate the safety, how well BNT326 is tolerated, and its anti-cancer activity when given alone (BNT326 monotherapy).o One cohort (called 1F) will evaluate the effects of other drugs on the levels of BNT326 in participants blood, as well as the safety, tolerability, and anti-cancer activity of BNT326. This cohort will use BNT326 given with drugs that could change the levels of BNT326 in participants blood.• Part 2: Part 2 has two cohorts (called 2A and 2B). All cohorts will evaluate the safety, how well BNT326 is tolerated, and the anti-cancer activity of BNT326 when given in combination with an immunotherapy (combination therapy). Cohorts differ with regard to the immunotherapy given in combination with BNT326 and the type of tumour studied. In Cohort 2A and 2B BNT326 will be combined with BNT327.In total, up to 370 participants are planned to be enrolled (up to 270 participants in Part 1 and up to 100 participants in Part 2). For each trial participant, the treatment and follow-up periods are projected to be completed within~38 months (Part 1) and ~48 months (Part 2).