Mendus AB announced positive updated survival data from the Phase 2 ADVANCE II trial evaluating vididencel (DCP-001) in acute myeloid leukemia (AML) at the American Society of Hematology's 65th Annual Meeting (ASH 2023). The longer-term follow up data showed durable treatment responses with survival benefit exceeding historical results expected from the current standard of care in AML maintenance therapy. ADVANCE II is a Phase 2 monotherapy trial evaluating vididencel as a maintenance therapy in acute myeloid leukemia (AML) for patients brought into first complete remission (CR1) through chemotherapy, but with measurable residual disease (MRD).

Professor Dr. Arjan van de Loosdrecht, Principal Investigator, presented updated median relapse-free survival (RFS) and median overall survival (OS) data during an oral presentation on December 11 at the ASH 2023 meeting held in San Diego, California December 9-12. Additionally, Mendus and academic collaborators presented two posters at the meeting, featuring immunomonitoring data that supports vididencel's mechanism of action as an immunotherapy which stimulates anti-tumor activity and improves immune control over residual cancer cells. Phase 2 ADVANCE II trial ­ updated survival data: The ADVANCE II monotherapy trial (N=20) previously completed a 70-week follow-up period from the start of vididencel treatment and patients are now in long-term follow up.

As of November 24, 2023, the median follow-up for the entire study population was 31.6 months (range: 6.6-60 months). Median RFS stood at 30.4 months and median OS was not reached, with 14/20 patients still alive and 11 still in CR1 at the cut-off date. The RFS at 2 years was 56%, and the estimated 2-year and 3-year OS stood at 74.9% and 64.7%, respectively.

The only drug approved for AML maintenance therapy is oral azacitidine, which in MRD positive patients led to a median RFS of 7.1 months versus 2.7 months in the placebo arm and an OS of 14.6 months versus 10.4 months in the placebo arm of the registration trial. Immune responses were measured on blood samples before, during and after treatment with vididencel. Seventeen patients (85%) showed at least one vaccine-induced T-cell response (VIR) against tumor-associated antigens present in vididencel.

Patients remaining in CR during treatment had a significantly higher number of VIRs then patients who relapsed and a clear correlation is seen between the number of VIRs and survival. Patients with 3 or more VIRs were all still alive (100% OS) at the cut-off date. Blood samples were additionally analyzed to evaluate changes in immune cells induced by vididencel.

Increased frequencies of circulating B-cells and dendritic cells were observed, with the level of dendritic cells at the end of treatment correlating with longer RFS and OS. In depth analysis of skin biopsies of the area where vididencel was injected showed a strong influx of immune cells, indicative of an immune response being triggered. Close interaction was observed between host T-cells and host dendritic cells in the skin as part of the immune priming process following vididencel administration.

Patients with an MRD response demonstrated better RFS and OS, with all patients with an MRD response still alive.