1184 - iSCORE: Immunotherapy Sequencing in COlon and REctal Cancer

Background

95% of metastatic colorectal cancers (mCRCs) have normal mismatch repair proficient (pMMR) expression and a stable microsatellite phenotype (MSS). As a consequence, checkpoint inhibiting immunotherapy currently plays no role in these tumours. We recently found that RAS/RAF wild type (WT) mCRCs (50% of all CRCs) that first responded to cetuximab and then acquired resistance had converted from an immune-excluded or immune-desert phenotype before treatment to an inflamed phenotype at progression. This progression was characterized by increased CD8⁺ T cell infiltrates and upregulation of PDL1 and LAG3 immune checkpoints. To assess if the cetuximab induced immune infiltrates can be exploited for therapeutic benefit, the iSCORE trial will treat 25 patients with combined anti-PD1 (nivolumab) and anti-LAG3 (relatlimab) immunotherapy starting ideally within 4 weeks after progression on immunogenic FOLFIRI chemotherapy and cetuximab.

Trial design

iSCORE is designed to evaluate the efficacy of nivolumab and relatlimab in patients with RAS/RAF WT mCRC who have had radiological response to first line FOLFIRI and cetuximab, but then progressed. Eligible patients will receive nivolumab 480mg and relatlimab 160mg every 4 weeks. The primary endpoint is disease control rate (DCR) at 6 months from treatment initiation. With an A’Hern single stage design for efficacy, 5% significance and a power of 80%, 25 patients would need to be treated and a minimum of 6 would need to be progression free at 6 months in order to support an increase of the DCR at 6 months from <10% to 30% or more. Secondary endpoints include DCR at 12 and 24 months, duration of disease control, best objective response rate at 6, 12 and 24 months, progression free survival and overall survival. Exploratory objectives include investigating dynamic changes in the gut microbiota/metabonome, immune infiltrates, immune checkpoints and molecular tumour characteristics induced by LAG3 and PDL1 blockade. This will be achieved through sequential collection of stool and tumour biopsies and baseline tumour characteristics will be correlated with tumour response and survival. iSCORE is a single-centre phase II trial. Recruitment opened in March 2019 and 25 patients will be recruited in 36 months.

Clinical trial identification

NCT03867799.

Editorial acknowledgement

Legal entity responsible for the study

The Royal Marsden NHS Foundation Trust.

Funding

The Royal Marsden NHS Foundation Trust, Bristol-Myers Squibb.

Disclosure

D. Cunningham: Research grant / Funding (institution): AstraZeneca; Research grant / Funding (institution): Celgene; Research grant / Funding (institution): MedImmune; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): 4SC; Research grant / Funding (institution): Clovis; Research grant / Funding (institution): Eli Lilly; Research grant / Funding (institution): Janssen; Research grant / Funding (institution): Merck. I. Chau: Advisory / Consultancy: Eli Lilly; Advisory / Consultancy: BMS; Advisory / Consultancy: MSD; Advisory / Consultancy: Bayer; Advisory / Consultancy: Roche; Advisory / Consultancy: Merck-Serono; Advisory / Consultancy: Five Prime Therapeutics; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Oncologie International; Advisory / Consultancy: Pierre Fabre; Research grant / Funding (institution): Eli Lilly; Research grant / Funding (institution): Janssen-Cilag; Research grant / Funding (institution): Sanofi Oncology; Research grant / Funding (institution): Merck-Serono; Honoraria (self): Eli-Lilly. M. Gerlinger: Research grant / Funding (institution): BMS; Research grant / Funding (institution): Merck KG. N. Starling: Research grant / Funding (institution): AstraZeneca; Research grant / Funding (institution): BMS; Research grant / Funding (institution): Pfizer; Travel / Accommodation / Expenses: AstraZeneca; Travel / Accommodation / Expenses: BMS; Travel / Accommodation / Expenses: Eli Lilly; Travel / Accommodation / Expenses: Merck; Travel / Accommodation / Expenses: Roche; Honoraria (self): AstraZeneca; Honoraria (self): Eli Lilly; Honoraria (self): Merck; Honoraria (self): Servier; Advisory / Consultancy: Pfizer; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Servier. All other authors have declared no conflicts of interest.