ClinicalTrials.gov posted results on 2026-08-11 for NCT06391775, a terminated phase 1/2 study in malignant solid tumors that included pembrolizumab as a combination partner. The trial enrolled 21 participants and tested GEN1055 alone, with pembrolizumab, or with pembrolizumab plus standard chemotherapy.
Background
The study evaluated GEN1055 in participants with malignant solid tumor. According to the posted record, all participants received active drug and no one received placebo. Pembrolizumab, also known as Keytruda, was one of the combination therapies used in the trial.
Trial design
The record describes a two-part trial designed to assess safety and determine doses of GEN1055 when used alone and with pembrolizumab, with or without chemotherapy. The posted results include dose-escalation safety and pharmacokinetic data across 10 mg, 30 mg, 100 mg, and 200 mg cohorts.
Key results
In the dose-escalation cohorts, adverse events were reported in 3 participants at 10 mg, 5 participants at 30 mg, 6 participants at 100 mg, and 6 participants at 200 mg. Dose-limiting toxicities were reported in 0 participants at each dose level.
GEN1055 maximum plasma concentration rose with dose, with geometric mean Cmax values of 3.048 ug/mL at 10 mg, 9.726 ug/mL at 30 mg, 33.630 ug/mL at 100 mg, and 72.261 ug/mL at 200 mg. The corresponding geometric coefficients of variation were 23.681, 32.352, 18.501, and 9.985.
What this means
The posted results give a small early look at tolerability and exposure for GEN1055 in a mixed solid-tumor population that included pembrolizumab-containing regimens. With no dose-limiting toxicities reported in the posted dose-escalation cohorts, the data may help inform further development, but the study’s terminated status limits how far these findings can be generalized.
Source
This information is based on ClinicalTrials.gov results posted for NCT06391775 on 2026-08-11. The record is available at clinicaltrials.gov.