Phase I trial evaluating safety and efficacy of intratumorally administered allogeneic monocyte-derived cells (ilixadencel) in advanced gastrointestinal stromal tumors.

Abstract

15 Background: Ilixadencel is a cell-based, off-the-shelf product based on allogeneic monocyte-derived inflammatory cells aimed to prime an anti-cancer immune response when injected intratumorally. The present single arm Phase I trial (ClinicalTrials.gov Identifier: NCT02686944) assessed the safety and efficacy of ilixadencel in subjects with progressing advanced/metastatic GIST despite ongoing treatment with second or later lines of tyrosine kinase inhibitors (TKI). Methods: Three GIST patients were progressing while on sunitinib (second-line), one on regorafenib (third-line), and two on pazopanib (fifth-line). Treatment consisted of two intratumoral injections of ilixadencel two weeks apart. If further tumor progression was observed at the 3-month follow up, the TKI was withdrawn and the subject performed an end of study visit. If stable disease or objective response was observed, the subject continued with the TKI until progression of disease. Results: No severe adverse events were found to be related to ilixadencel administration. Four patients showed continued tumor progression at 3 months per RECIST 1.1 and Choi criteria. Two patients had stable disease as best response; one of these patients (on third-line regorafenib) progressed at 12 months and the other (a patient on second-line sunitinib) showed continued stable disease at end of study (12 months) as per RECIST 1.1. These two patients also developed a partial response as per Choi criteria with a duration of 3 and 6 months, respectively. No serious adverse events were found to be possibly or probably related to ilixadencel administrtion. Conclusions: Ilixadencel treatment presented an acceptable safety profile among advanced GIST patients who developed resistance to TKI. Encouraging radiological tumor responses were detected in 33% of treated patients, supporting further investigation. Clinical trial information: 02686944.