Personalized Vaccine Shows Protective Benefit Against Disease Recurrence in High-Risk Melanoma

A personalized therapeutic cancer vaccine being developed by Elios Therapeutics for patients with high-risk melanoma demonstrated positive results in a phase 2b clinical trial, according to a press release.

The tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine was evaluated for efficacy and safety in patients with stage 3 and 4 resected melanoma. Because of the high early recurrence rate seen in patients with high-risk melanoma and the time needed for vaccines to activate the immune system, the pre-specified primary efficacy analysis was performed in the intent-to-treat (ITT) and the per treatment (PPT) population as co-primary analyses.

The TLPLDC vaccine is developed from a patient’s tumor and blood to deliver personalized protection once administered. The vaccine is designed to administer the patient’s complete repertoire of tumor antigens to the immune system to activate fighter T cells and trigger the immune system to destroy cells containing specific antigen and mutations from the patient’s tumor, according to Elios.

A total of 144 patients were enrolled in the study. Patients received either the vaccine or placebo to prevent disease recurrence, with both arms initiated within 3 months of completion of standard of care therapies. The vaccine or placebo was given at 0, 1, 2, 6, 12, and 18 months.

Among all patients in the ITT analysis—including those who were never or were incompletely vaccinated—the recurrence rate was 66% in the placebo arm compared with 54% in the vaccine arm. This resulted in an 18% clinically meaningful—though statistically non-significant—reduction in the relative risk of disease recurrence, according to the data. In the PPT analysis of all patients who completed the primary vaccine series of 6 months, the results showed that patients in the placebo arm had a 56% recurrence rate compared with 29% in the vaccine arm. These data represent a highly statistically significant 50% reduction in the relative risk of disease recurrence, according to the press release.

Only one-third of patients experienced a related adverse event (AE), the majority of which were grade 1 or 2, according to the Independent Data Safety Monitoring Board (DSMB). These findings suggest that the TLPLDC vaccine benefit is not only durable, but continues to show benefit beyond 24 months. As such, the DSMB recommended that the study continue as designated to the 36-month landmark endpoints of disease-free survival and overall survival. Results are expected in June 2020.

According to Buddy Long, chief executive officer of Elios Therapeutics, this is the first positive phase 2b study of a personalized cancer vaccine in patients with high-risk melanoma.

“Despite advances in the treatment of metastatic melanoma, there remains a need for therapeutic innovations that further reduce the risk of the disease returning,” Kyleigh LiPira, MBA, chief executive officer of the Melanoma Research Foundation, said in a statement. “From the moment a person is diagnosed to long after their final treatment, the fear of disease recurrence remains constant for many patients. The possibility of having a personalized immunotherapy that can prevent melanoma from coming back after surgery makes this a welcome advance for patients and families.”

Reference

Elios Therapeutics Announces Positive Top-Line Data from Phase 2b Study Evaluating TLPLDC, a Personalized Therapeutic Cancer Vaccine, in Patients with High-Risk Melanoma [news release]. Elios Therapeutics. http://www.eliostherapeutics.com/press/. Accessed July 18, 2019.