This is a phase 1/2, dose-escalation, clinical study to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of DT-7012 (an anti-CCR8 monoclonal antibody) as a single agent and in combination with an immune checkpoint inhibitor in adult participants with selected advanced solid tumors.

This is a phase 1/2, first-in-human, multicenter, open-label clinical study to assess the safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of DT-7012, administered as monotherapy and in combination with an immune checkpoint inhibitor (ICI), in participants with selected recurrent advanced/metastatic solid tumors.

This study includes:

• a phase 1 Monotherapy Dose Escalation
• a phase 1b Combination Dose Escalation (this part will be initiated upon recommendation from the Safety Review Committee based on Monotherapy Dose Escalation data and corresponds to a dose escalation of a combination of DT-7012 with an ICI)
• a subsequent phase 2 Indication-Specific Efficacy part

The phase 1 aims at determining the maximum tolerated dose or maximum administered dose of DT-7012 as single agent and in combination with an ICI, and the safety and tolerability of DT-7012 as single agent and in combination with an ICI in participants with selected recurrent advanced/metastatic solid tumors.

The phase 2 will assess the efficacy of DT-7012 as monotherapy and/or in combination with an ICI in indication-specific cohorts.

Inclusion Criteria:

• Histologically or cytologically confirmed solid tumor, among selected cancer types, that is recurrent, locally advanced (i.e., not eligible for curative surgery or radiotherapy) or metastatic, has progressed after at least one line of systemic therapy and has no established curative option.
• Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 as assessed by the local site investigator/radiologist.
• At least 1 tumour lesion accessible to biopsy per treating physician judgement.
• Eastern Cooperative Oncology Group (ECOG) PS of 0 or 1.
• Adequate organ function.

Exclusion Criteria:

• Any unresolved AEs from previous anti-cancer therapies of grade ≥2, with the exception of alopecia.
• Prior severe immune-related AEs (irAEs) leading to immunotherapy treatment discontinuation.
• Major surgery or significant traumatic injury within 4 weeks prior to Cycle 1 Day 1 with unadequately recovered AEs and/or complications from the intervention prior to Cycle 1 Day 1.
• Prior radiotherapy within the 4 weeks prior to Cycle 1 Day 1 or limited field palliative radiotherapy within 2 weeks prior to Cycle 1 Day 1.
• Prior anti-CCR8 monoclonal antibody treatment received in an investigational trial