The trial was terminated prematurely at the end of the dose-escalation based on Sponsor's strategic decision.

This is a Phase 1, multicentre, open-label, dose-escalation study to determine a recommended phase 2 dose (RP2D) of DT-9081, followed by an expansion study of DT-9081 in participants with advanced, recurrent or metastatic solid tumours

This first-in-human Phase 1, multicentre, open label study is evaluating the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of DT-9081 in adult patients with advanced, recurrent or metastatic solid tumours who failed standard of care therapies.

This Phase 1 study consists of 2 parts. The first part is a dose-escalation using a modified 3+3 design with up to 8 dose escalation cohorts at increasing levels. The dose-escalation part aims at determining the recommended phase 2 dose. The second part is an expansion to validate the dose/schedule of administration as well as to assess preliminary efficacy of DT-9081.

Patients will be dosed orally once daily. The schedule might be adjusted in case of toxicities.

Inclusion Criteria:

• Participants must have a histologically or cytologically confirmed advanced solid tumour that is locally advanced (i.e., not eligible for curative surgery or radiotherapy), recurrent or metastatic, and who have failed or are ineligible for standard of care therapies.
• Participants must be ≥18 years of age.
• Participants must have measurable disease per RECIST v1.1. Lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions.
• Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1.
• Participants must have adequate organ function.

Exclusion Criteria:

• Participants using drugs interfering with the COX-2 pathways or prohibited drugs.
• Participants with unresolved AEs from previous anti-cancer therapies of Grade ≥ 2 with exception of alopecia. Participants with Grade ≤ 2 neuropathy may be eligible.
• Participants who underwent major surgery or significant traumatic injury within 4 weeks prior to Cycle 1 Day 1 who have not recovered adequately from any AEs and/or complications from the intervention prior to starting study drug.
• Participants who have received prior radiotherapy within the last 4 weeks before start of study drug treatment (limited field palliative radiotherapy within 2 weeks).
• Participants who have already received EP4R antagonist in an investigational trial.

From the first dose of study drug up to 30 days after the last dose of study drug (with a total trial participation duration of up to 26 months).

The study was terminated prematurely as per Sponsor's strategic decision at the end of the dose-escalation. As a consequence, the Phase 1 expansion part of the study was not performed.