Trial results for the Phase 1/Phase 2 study (NCT04837196) investigating ASP7517 alone and in combination with pembrolizumab in participants with advanced solid tumors were posted on ClinicalTrials.gov on 2025-08-08. The study reported varying numbers of participants experiencing treatment-emergent adverse events and serious adverse events, with up to 8 participants in the combination high-dose arm.
Background
The study investigated ASP7517 as a single agent and in combination with pembrolizumab, an established immunotherapy. Pembrolizumab (Keytruda) is a programmed death receptor-1 (PD-1) blocking antibody approved for various cancers. This trial focused on participants with advanced solid tumors and advanced cancer expressing the WT1 antigen.
Trial design
The study (NCT04837196) was a completed Phase 1/Phase 2 trial with an enrollment of 24 participants. It evaluated ASP7517 alone and in combination with pembrolizumab in participants with advanced solid tumors and advanced cancer. The primary objectives of the study were to assess the safety, tolerability, and clinical response of ASP7517, and to determine the Recommended Phase 2 Dose (RP2D) and/or the Maximum Tolerated Dose (MTD) of ASP7517 as a single agent and in combination with pembrolizumab.
Key results
The trial reported the number of participants experiencing treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs) across different treatment arms and doses:
- In the Phase 1: Monotherapy Dose Escalation arm with ASP7517 1x10^7 Cells/Dose, 3 participants experienced TEAEs and SAEs.
- For the Phase 1: Monotherapy Dose Escalation arm with ASP7517 1x10^8 Cells/Dose, 7 participants experienced TEAEs and SAEs.
- In the Phase 2: Monotherapy Dose Expansion arm with ASP7517 1x10^8 Cells/Dose, 2 participants experienced TEAEs and SAEs.
- For the Phase 1: Combination Therapy Dose Escalation arm with ASP7517 1x10^7 Cells/Dose and Pembrolizumab, 3 participants experienced TEAEs and SAEs.
- In the Phase 1: Combination Therapy Dose Escalation arm with ASP7517 1x10^8 Cells/Dose and Pembrolizumab, 8 participants experienced TEAEs and SAEs.
Additional data on baseline characteristics, specifically the ECOG Performance Status at Cycle 1 Day 1, was also reported:
- In the Phase 1: Monotherapy Dose Escalation arm with ASP7517 1x10^7 Cells/Dose, 1 participant had an ECOG Performance Status at Cycle 1 Day 1.
- In the Phase 1: Monotherapy Dose Escalation arm with ASP7517 1x10^8 Cells/Dose, 4 participants had an ECOG Performance Status at Cycle 1 Day 1.
What this means
The posted trial results provide initial safety and tolerability data for ASP7517 as a monotherapy and in combination with pembrolizumab in patients with advanced solid tumors. The varying numbers of participants experiencing adverse events across different dose levels and treatment arms offer early insights into the safety profile of these regimens. This data is crucial for determining appropriate dosing and for informing the design of future clinical trials for ASP7517, either alone or in combination with pembrolizumab.
Source
The information for these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04837196, titled "Study of ASP7517 Alone and With Pembrolizumab in Participants With Advanced Solid Tumors Expressing WT1 Antigen," were posted on 2025-08-08 on clinicaltrials.gov.