NEW YORK – Cel-Sci on Thursday said the US Food and Drug Administration agreed with its plan to select head and neck cancer patients with low PD-L1 tumor expression in a confirmatory registrational clinical trial of its cell-based immunotherapy Multikine (leukocyte interleukin injection).
The trial will begin in the first quarter of 2025 and enroll about 200 patients with newly diagnosed, advanced squamous cell carcinoma of the head and neck, no lymph node involvement, and low PD-L1 expression, defined as a tumor proportion score of less than 10. The goal of the trial is to confirm Multikine's safety and efficacy in the PD-L1-low population, which the company observed in an earlier Phase III randomized trial.
In that study, researchers compared treatment with Multikine alone or combined with a chemotherapy regimen against chemotherapy alone in more than 900 patients with untreated squamous cell carcinoma of the oral cavity or soft palate. Median overall survival in the Multikine-only arm was 58.1 months and 46.3 months in the Multikine-chemo arm. However, the median overall survival was 52.9 months in the control arm, not a statistically significant difference compared to the Multikine treatment arms.
After seeing these results, the FDA requested a confirmatory study focusing on patients who appeared to have the best survival outcomes on Multikine. Cel-Sci determined that patients with newly diagnosed, locally advanced primary head and neck cancer with no lymph node involvement and low PD-L1 expression fit those criteria. Among those patients in the earlier Phase III trial, 73 percent on Multikine were still alive after five years compared to 45 percent of patients in the control group.
The Vienna, Virginia-based company is focusing on patients with low PD-L1 expression based on a scientific rationale that PD-L1 acts as a brake on the immune system and Multikine activates the immune system to fight cancer more effectively without that brake. This positions Multikine as a promising therapy for head and neck cancer patients, around 70 percent of whom have low PD-L1 expression.
"To our knowledge, Multikine is the only neoadjuvant immunotherapy that has shown overall survival benefit in the low and negative PD-L1 head and neck cancer population," Cel-Sci CEO Geert Kersten said in a statement. "This underscores the critical importance of having reached an agreement with the FDA on the method for identifying and selecting patients with low PD-L1 tumor expression for our upcoming confirmatory registration study."