Elios Therapeutics presented the primary analysis from a Phase IIb clinical trial evaluating its tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine in patients with Stage III and IV resected melanoma. The TLPLDC vaccine is a personalized treatment that is created using a patient’s own blood and tumor cells.
The Phase IIb trial is a prospective, randomized, double-blind, placebo-controlled design and has enrolled 144 patients who were randomized to receive either the vaccine or placebo to prevent recurrence. TLPLDC or placebo vaccines were initiated within three months of completion of standard of care (SoC) therapies and were given at 0, 1, 2, 6, 12, and 18 months. The protocol was amended to allow concurrent checkpoint inhibitor therapy once approved for the adjuvant setting. The patients were followed for recurrence per SoC. The primary efficacy analysis was performed on the intent-to-treat (ITT) and the per treatment (PT) populations as co-primary analyses given the high early recurrence rate often seen in patients with advanced melanoma. The primary endpoint was 24-month disease-free survival (DFS). The pre-specified per treatment (PT) analysis included all patients who completed the primary TLPLDC or placebo vaccine series (PVS) at six months.
In the PT analysis, 24-month DFS was significantly improved in the TLPLDC vaccine group compared to placebo (62.9% vs. 34.8%), representing a nearly 60% reduction in the relative risk of disease recurrence. There was a non-significant improvement in 24-month DFS between the TLPLDC and placebo arms in the ITT analysis (38.5% versus 27%), but a stronger trend in improved 24-month overall survival (OS) in this analysis (86.4% vs. 75.1%).
Therapy was well-tolerated with 31.7% of placebo patients and 35.9% of TLPLDC patients experiencing a related adverse event, the majority of which were grade 1 or 2. Additionally, an initial assessment of 36-month follow-up data on all patients indicated that the TLPLDC vaccine benefit is not only durable, but continues to increase beyond 24-months. As a result, the study will continue as designed to the 36-month landmark secondary endpoints of DFS and OS, anticipated in June 2020.
Elios Therapeutics is planning to meet with the FDA this month regarding Breakthrough Therapy and Regenerative Medicine Advanced Therapy (RMAT) designations. An End-of-Phase 2 meeting with the FDA is scheduled for January to seek guidance on the registrational Phase III trial design and optimal regulatory pathway for the TLPLDC vaccine.