“The grant of this US patent is an important hallmark in the development of vididencel as an active immunotherapy in ovarian cancer. In the patent application we describe how vididencel, which is derived from cells with a leukemic origin, can be used to induce tumor-directed immune responses in preclinical ovarian cancer models. With the patent approval, USPTO validates the innovative nature of applying vididencel in ovarian cancer and this significantly broadens the patent portfolio around the vididencel program,” said Mendus CEO Erik Manting. “The potential relevance of vididencel in the treatment of ovarian cancer is supported by the clinical data presented at ASCO last June, which demonstrated that the successful induction of tumor-directed immune responses following vididencel treatment was associated with stable disease in this hard-to-treat life-threatening malignancy.”

Vididencel is currently being studied in the ongoing Phase 1 trial ALISON as a maintenance therapy for ovarian cancer in combination with standard of care, in collaboration with the University Medical Center Groningen (UMCG). ALISON trial data presented at the 61st Annual American Society of Clinical Oncology conference (ASCO 2025) demonstrated that stable disease was associated with the successful induction of tumor-directed immune responses following vididencel treatment in patients with high-grade serous ovarian cancer (HGSOC), which is associated with a high recurrence rate and poor overall prognosis. In the majority of patients, vididencel treatment resulted in immune responses against one or more tumor antigens frequently upregulated in HGSOC and these responses were associated with higher stable disease rates. A next read-out of the trial based on 2-year follow-up is anticipated in the fourth quarter of 2025.

The newly approved patent (US 12,364,758) covers the use of vididencel in ovarian cancer and expires in November 2042. Corresponding patent applications are pending in other regions including Europe. This new patent adds to an extensive patent portfolio which Mendus has obtained for vididencel and which includes granted patent coverage in all major markets globally.