A phase 2 trial evaluating the combination of IO102-IO103, a cancer vaccine, with pembrolizumab has shown promising early results in patients with advanced squamous cell carcinoma of the head and neck (SCCHN). The study, presented at the European Society for Medical Oncology (ESMO) Congress 2024, indicates a potential new approach to enhance immune response and improve outcomes in this challenging cancer type.
Activating the Immune System
The rationale behind combining IO102-IO103 with pembrolizumab lies in the vaccine's ability to activate T cells against IDO-positive and PD-L1–positive cells. According to Dr. Jonathan Riess, director of thoracic medicine at UC Davis Health, the subcutaneous injection of IO102-IO103 triggers an immune response that attacks immunosuppressive cells within the tumor microenvironment. This, in turn, creates a more immunopermissive environment, facilitating further tumor cell killing by recruited tumor-specific T cells.
"The inflamed tumor microenvironment becomes more immunopermissive, which enables further tumor cell killing by the recruited tumor-specific T cells," Dr. Riess explained.
Efficacy and Safety Data
The phase 2 trial included 21 patients with advanced SCCHN, with 18 being evaluable for efficacy. The primary endpoint, partial response rate, was met with 44.4% of evaluable patients experiencing a partial response after at least two cycles of treatment. This translates to 8 out of 18 patients showing tumor shrinkage, indicating a signal of potential activity.
"We had 18 efficacy evaluable patients where we looked at how well the tumor shrunk after receiving at least 2 cycles of treatment or more, and what we saw was a partial response rate of 44.4%," Dr. Riess noted. "So, we met our primary endpoint."
In terms of safety, the observed immune-related adverse events were consistent with those typically seen with single-agent pembrolizumab, along with some injection site reactions related to the vaccine administration. The safety profile suggests that the combination is generally well-tolerated.
Unmet Needs and Future Directions
Cancer vaccines like IO102-IO103 have the potential to address unmet therapeutic needs by further enhancing the immune response against head and neck squamous cell cancers, as well as other cancers. The early data from this phase 2 trial provide a foundation for larger studies to confirm these findings and explore the full potential of this combination therapy.
"Based upon this data, it provides a foundation to support a larger study to confirm these findings," Dr. Riess concluded.
