A phase I dose escalation (DE) and cohort expansion (CE) study of ERY974, an anti-glypican 3 (GPC3)/CD3 bispecific antibody, in patients with advanced solid tumors.

Abstract

TPS3112 Background: Bispecific antibodies to facilitate T-cell directed cytotoxicity (TDCC) is a proven therapy strategy in cancer. ERY974 is a humanized IgG4 bispecific antibody designed to simultaneously bind to cytotoxic T-cell CD3 receptors and GPC3 (a glycoprotein expressed on cell surface of several tumors) to elicit T-cell activation and TDCC. The objectives of this multi-country, phase 1 study of ERY974 is to determine the maximum tolerated dose (MTD) and to perform a preliminary assessment of anti-tumor activity in patients with solid tumors expressing GPC3. Methods: ERY974 is dosed IV weekly. All patients receive premedication with dexamethasone (DEX) prior to 1st and 2nd ERY974 dose. DE uses an accelerated titration design (ATD), then a modified continual reassessment method (mCRM) described by one-parameter logistic model, to determine MTD, where DLT occurrence rate is 0.25. Combining ATD and mCRM is to permit rapid dose escalation whilst minimizing patient numbers exposed to sub-therapeutic doses, and to accurately determine MTD. Once grade 2 (G2) cytokine release syndrome (CRS) is observed, DEX is increased. If ≥G2 CRS is again observed, then at all subsequent doses the 1st dose of ERY974 is fixed at the last dose level when < G2 CRS was not seen, DE proceeds with the 2nd dose. ATD commences with n = 1, increasing to n = 3 once drug-related ≥G2 toxicity is seen. mCRM starts after 1st dose limiting toxicity (DLT), with the modifications of at least 3 patients required to dose escalate and up to 1.5x increment to minimize risk of toxicity. CE has 3 arms: GPC3+ gastric/gastroesophageal junction adenocarcinoma; GPC3+ squamous esophageal cancer; and other GPC3+ tumors. A 2-stage design is used to allow CE to stop early for futility. Subjects are adults with histologically confirmed, measurable malignant solid tumors and/or metastatic disease not amenable to standard therapy, and life expectancy ≥3 months. Patients with > 1cm or > 1 brain metastasis, current/previous interstitial lung disease, and acute/chronic infection are excluded. 3 cohorts have been completed without DLT. Cohort 4 began in January 2017. Clinical trial information: NCT02748837.