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Elios Therapeutics Advancing Personalized Cancer Vaccine in Melanoma After Positive Phase II Data

NEW YORK – Elios Therapeutics today announced that based on positive Phase II results it has pinpointed the version its personalized vaccine that it will continue developing in late-stage melanoma patients at high risk of recurrence.

The personalized tumor lysate, particle-loaded, dendritic-cell (TLPLDC) vaccine is created from patients' own blood and tumor cells collected when they undergo tumor resection. Patients' frozen samples are sent to the lab where an autologous tumor lysate is integrated into yeast cell wall particles, which is injected into patients' dendritic cells. The whole process from tumor resection to vaccine injection takes three weeks.

On Wednesday, the company reported the results from a randomized Phase IIb trial, in which researchers evaluated 36-month disease-free survival and overall survival rates in melanoma patients who received one of two TLPLDC vaccine formulations. Researchers also considered these outcomes according to patients' disease stage and whether they received standard checkpoint inhibitors. In the study, 144 stage III and stage IV melanoma patients were randomized to receive vaccine A, made from isolated dendritic cells from 120 mL of blood, or vaccine B, made from dendritic cells isolated after a single injection of filgrastim followed by 50 mL to 70 mL of blood, or placebo.

Vaccine B was determined to be ineffective and resulted in clinical outcomes similar to the placebo arm. However, there was a statistically significant difference in the 36-month disease-free survival rate between patients treated with vaccine A, vaccine B, and placebo: 52 percent versus 23 percent versus 27 percent, respectively.  Similarly, the 36-month overall survival rate was 93 percent versus 63 percent versus 70 percent, for those receiving vaccine A, vaccine B, and placebo, respectively.

"We now have long-term data demonstrating that use of the TLPLDC vaccine for the adjuvant treatment of high-risk melanoma correlates with a 93 percent increase in patients alive at three years without their disease returning," Elios CEO Buddy Long said in a statement. "This trial also significantly improves our understanding of the optimal method of vaccine production."

Patients with stage III and stage IV melanoma experienced improved outcomes with vaccine A, which also was well tolerated, resulting in mostly grade 1 and grade 2 adverse events. Furthermore, when vaccine A was given with current standard-of-care checkpoint inhibitors, there was a statistically significant improvement in the 36-month disease-free survival rate compared to when patients received just checkpoint inhibitors, 49 percent versus 24 percent, according to Elios.

Based on this data, Elios will advance a registrational Phase III trial evaluating the TLPLDC vaccine.