The first half-yearly follow-up results from a phase I study of ilixadencel monotherapy in patients with advanced gastrointestinal stromal tumors will be presented by Alex Karlsson-Parra, MD, PhD on February 6, 2020, during poster session A, at the Clinical Immuno-Oncology Symposium, according to a press release from Immunicum AB, where Karlsson-Parra serves as the chief executive officer.<br />
The results will be reported in a press release coinciding with the conference presentation.
Top-line results reported in June 2019 showed that the study did meet its primary end point of safety. There were no life-threatening treatment-related adverse events, and no autoimmunity was observed. Additionally, these results signaled efficacy, showing that tumor shrinkage lasted 3 months in one patient, and partial regression in tumor growth occurred in another patient for 6 months. Based on these partial responses, ilixadencel was found to have a therapeutic impact on tyrosine kinase inhibitor (TKI) resistance in patients with unresectable or metastatic GIST who previously progressed on second- and third-line TKIs.2
“As a disease with limited therapeutic options, it is a considerable achievement to see partial response in two out of six advanced-stage GIST patients as the disease at that point has developed resistance to standard of care treatment with TKIs,” said principal investigator, Robert Bränström, MD, associate professor at Karolinska University Hospital, in a June statement.
The phase I open-label study (NCT02686944) evaluated the safety and efficacy of ilixadencel, which was administered intratumorally to patients with advanced GIST who were receiving third-, fourth-, or fifth-line TKI therapy. Ilixadencel was administered 2 or 3 times. The first injection was given to patients 1 through 12, and 14 days later, these same patients received a second injection. The third injection, which occurred 28 days after the second, was only administered to patients 7 through 12. The number of allogeneic dendritic cells in milliliters per injection was 10,000,000.
The co-primary end points of the study were changes in vital signs (ie, heart rate, blood pressure, body temperature), changes in laboratory parameters (ie, hematology and biochemistry), and adverse events according to the Common Terminology Criteria for Adverse Events. Secondarily, the study assessed outcomes like tumor response, progression-free survival, changes in the World Health Organization ECOG performance score, and levels of alloimmunization parameters.
The criterion for enrollment in the study included a diagnosis of GIST, radiologically measurable tumors, and clinically or CT scan verified disease progression despite second-, third-, and fourth-line TKI therapy. Female patients were required to be either post-menopausal for1 year or be negative for pregnancy and willing to use contraception throughout the study.
Persons were excluded from the study if they had an ECOG performance status of 2, and they had certain conditions or laboratory values that would interfere with treatment in the study. As far as prior treatment, individuals were excluded if they had corticosteroid treatment with doses exceeding 10 mg per day within 7 days prior to the first injection of ilixadencel, an organ transplantation, and investigational treatment within 28 days of beginning treatment in the study.
Ilixadencel is an off-the-shelf cell-based cancer immunotherapy with allogeneic dendritic cells as the active ingredient. The drug was developed for the treatment of solid tumors. In addition to GIST, Ilixadencel has also been tested in clinical trials for patients with metastatic renal cell carcinoma, hepatocellular carcinoma. Ilixadencel is also being evaluated in combination with other agents, such as, sunitinib (Sutent) and regorafenib (Stivarga), and the checkpoint inhibitor pembrolizumab (Keytruda).