crolibulin (EPC2407)

In this single-arm, multi-center, phase 2 study, eligible patients had metastatic untreated HER2-negative gastric adenocarcinoma with centrally confirmed expression of PD-L1 (CPS≥5; DAKO 28-8) and FGFR2 (moderate (2+) and strong (3+) membranous staining in more than 1% of tumor cells; Abсam EPR24075-418). Patients received nivolumab 360 mg with CapeOX (capecitabine and oxaliplatin) every 3 weeks... An interim analysis demonstrates modest efficacy and an acceptable safety profile of nivolumab in combination with chemotherapy in patients with FGFR2-positive, PD-L1-positive metastatic GC. Further follow-up is ongoing. 1.

Clone EPR24075-418 showed the best result in assessing the expression of FGFR2: the correlation with FISH results in reaction 3+ was 100%. Due to the high heterogeneity of FGFR2 expression, it is recommended to either examine the material of the primary tumor and metastasis, or evaluate a large volume of the primary tumor.

Pairwise comparison of 4 tests based on the same patient population was performed: 3 IHC assays [Abcam clone EPR24075-418, R&D clone 98706, Santa Cruz clone C-8] and one FISH test... Among patients who were negative by FISH, 86%-93% of the patients were negative by IHC assay (Abcam). Among patients who were positive by FISH, 75-80% of them were positive by IHC. FISH should not be recommended as a substitute for a FGFR2 IHC assay due to high probability of false negative prediction as a result of intratumoral heterogeneity and low PCC.