ASCO 2019, Chicago – New data of a first-in-human (FIH) phase I dose escalation study evaluating AMG 420, a B-cell maturation antigen (BCMA)-targeting BiTE molecule, were presented at the 55th Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago.
Data presented included updated investigational AMG 420 safety and efficacy results in patients with relapsed and/or refractory multiple myeloma (RRMM). BiTE technology is a targeted immuno-oncology platform that is designed to engage patients’ own T cells to a tumor-specific antigen, activating the cytotoxic potential of T cells.
“These updated results presented at the ASCO Annual Meeting showed that AMG 420 at the 400 µg/d dose was efficacious with no new safety concerns in heavily pre-treated patients with relapsed and/or refractory multiple myeloma,” said Max S. Topp, M.D., professor, University Hospital of Wuerzburg, Germany, and AMG 420 clinical study investigator. “Based on these results, we recommend AMG 420 at the 400 µg/d dose for further investigation.”
The objectives of the study included assessment of the safety, tolerability and anti-tumor activity of AMG 420 per International Myeloma Working Group 2006 Uniform Response Criteria for Multiple Myeloma. In the study, 42 patients relapsed or refractory myeloma who had progression after at least two prior lines of treatment (including a proteasome inhibitor and an immunomodulatory imide drug) received AMG 420 at varying doses [0.2 to 800 µg/day (d)]. Of the doses tested in this study, 400 µg/d was the maximum tolerated dose (MTD).
AMG 420 induced clinical responses in 13 of 42 patients across the dosing cohorts. Of the six patients that achieved a minimal residual disease (MRD)-negative complete response (CR), five were treated at the 400 µg/d dose. In addition, at the 400 µg/d dose, one patient achieved a very good partial response, and one achieved a partial response. The overall response rate at 400 µg/d was 70 percent (7/10). The median duration of response was nine months (range 5.8-13.6 months). Median time to response was one month, with 11 of 13 patients responding in the first cycle.
Serious adverse events (AEs) were reported in 19 patients (45 percent). Sixteen required hospitalization and four had prolonged hospitalization. No grade 3 or 4 central nervous system toxicities were observed. Serious AEs occurring in more than one patient included infections (n=13) and peripheral polyneuropathy (n=2). Treatment-related serious AEs included polyneuropathy (n=2, both grade 3) and edema (n=1, grade 3). Grade 3 cytokine release syndrome (CRS) was seen in one patient.