A personalized vaccine has demonstrated long-term disease-free and overall survival benefits in patients with stage 3 or stage 4 melanoma at a high risk of recurrence following complete surgical resection, according to the vaccine’s manufacturer, Elios Therapeutics.

Elios recently reported final data from a prospective, randomized, double-blind, placebo-controlled phase 2b trial that evaluated the adjuvant use of the company’s personalized tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine.

Researchers developed and assessed two versions of the vaccine – one which was produced by isolating dendritic cells from 120 milliliters (ml) of a patient’s blood (vaccine-A) and one with dendritic cells isolated after a single injection of filgrastim followed by 50-70 ml of blood (vaccine-B) – in 144 patients who were then randomized to receive either version of the vaccine or placebo to prevent recurrence.

“These new data, combined with the doubled rate of disease-free survival among patients treated with the vaccine and standard-of-care checkpoint inhibitors, further strengthen our confidence that the personalized TLPLDC vaccine provides a clinically meaningful benefit for people with high-risk melanoma,” said Elios Therapeutics’ CEO Buddy Long in a company-issued press release.

When compared with vaccine-B (23.4%) and placebo (27.1%), vaccine-A (51.8%) significantly improved 36-month disease-free survival (DFS). Vaccine-A (92.9%) also significantly improved overall survival compared to vaccine-B (62.8%) and placebo (70.3%).

Additionally, improvement in disease-free survival (DFS) was seen with vaccine-A across both stage 3 (49.7% vs. 29.4%) and stage 4 (68.6% vs. 9.4%) melanoma. Adding vaccine-A to current standard-of-care checkpoint inhibitors (48.5%) also led to a significant improvement in 36-month DFS compared with checkpoint inhibitors alone (24.1%).

More than 90% of the treatment-related side effects that occurred in 34.7% of patients within the trial were minor in nature.

“To demonstrate a long-term survival benefit with low toxicity in a therapeutic is what we hope for in every clinical trial. Achieving this with an aggressive disease like melanoma offers great promise for patients,” said Dr. Mark B. Faries, co-director of the Melanoma Program at Cedars-Sinai at The Angeles Clinic and Research Institute, in the release. “With data showing a two-fold increase in disease-free survival with the vaccine alone and in combination with checkpoint inhibitors, we hope to one day change the narrative for people with melanoma — turning this disease into a chronic condition that can be treated and managed over time.”

The plan, according to the release, is to continue with a registrational phase 3 trial.