Abstract CT119: Zilovertamab vedotin in pediatric and young adult hematologic malignancies or solid tumors: Phase 1/2 LIGHTBEAM-U01A study
Authors: Hyoung Jin Kang, Pablo Berlanga, Quentin Campbell-Hewson, Steven G. DuBois, Kyung-Nam Koh, Christine Mauz-Koerholz, Michael Sullivan, David Mangum, Rachael Windsor, David S. Dickens, Alexandre Duarte, Farzana Pashankar, Shifra Ash, Andrew Bellantoni, Scott J. Diede, Rohini Singh, Yulia Sidi, Michal Yalon
Journal: Cancer Research (2025)

Abstract Background: Zilovertamab vedotin (ZV) is an antibody-drug conjugate comprising an anti-ROR1 antibody, a proteolytically cleavable linker, and monomethyl auristatin E. Substudy 01A of LIGHTBEAM-U01 (NCT06395103) is a single-arm, open-label, phase 1/2 basket study designed to determine the preliminary recommended phase 2 dose (RP2D), safety, and antitumor activity of ZV in 4 disease cohorts: pediatric patients (pts) with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL), diffuse large B-cell lymphoma (DLBCL)/Burkitt lymphoma, or neuroblastoma, and pediatric or young adult pts with Ewing sarcoma. Study Design and Methods: Eligible pts are aged 0 months to ≤25 years. Pts with B-ALL or DLBCL/Burkitt lymphoma must have relapsed after ≥2 prior lines of therapy and exhausted all therapies of known clinical benefit. Pts with B-ALL must have ≥5% (M2 or M3) bone marrow blasts. Pts with DLBCL/Burkitt lymphoma must have radiographically measurable disease per International Pediatric Non-Hodgkin Lymphoma staging system response criteria. Pts with neuroblastoma or Ewing sarcoma must have measurable disease per RECIST v1.1 (or MIBG-avid evaluable neuroblastoma) and be refractory to front-line therapy and for whom further standard therapy is not available/appropriate. All pts must also have a Lansky play-performance scale ≥50 if aged ≤16 years, a Karnofsky performance status ≥50 if aged &amp;gt;16 to &amp;lt;18 years, or an ECOG PS of 0 or 1 if aged ≥18 years. Approximately 50 to 90 pts will be enrolled across the study, which will consist of 2 parts: dose escalation and confirmation (part 1) and efficacy expansion (part 2). In part 1, ≥3 pts will be enrolled for 2 age groups: 1 to &amp;lt;6 years and 6 to &amp;lt;18 years. Pts will receive ZV at a starting dose of 2 mg/kg IV Q3W, with escalation to 2.25 and 2.5 mg/kg or de-escalation to 1.75 mg/kg per a modified toxicity probability interval design-2. In part 2, the age of pts will be expanded to ≥6 months for all indications and ≤25 years for R/R Ewing sarcoma. Approximately 10 pts will be enrolled in each cohort and will receive ZV at the preliminary RP2D determined in part 1. For all pts except those with B-ALL, imaging/disease assessments will be performed Q8W for 6 months, then Q12W through 24 months, Q24W through 5 years, and annually thereafter. Disease assessments for B-ALL will be performed at the end of each cycle, at 6 months and 1 year, and then annually. Adverse events (AEs) will be monitored throughout the study and for 30 days after the last dose of study treatment (90 days for serious AEs or 30 days if new anticancer therapy is initiated). AEs will be graded per NCI CTCAE v5.0. Primary end points are safety and tolerability and objective response rate. Secondary end points include pharmacokinetics, immunogenicity, duration of response, and eligibility for transplant/CAR-T therapy in pts with B-ALL or DLBCL/Burkitt lymphoma. Recruitment is ongoing. Citation Format: Hyoung Jin Kang, Pablo Berlanga, Quentin Campbell-Hewson, Steven G. DuBois, Kyung-Nam Koh, Christine Mauz-Koerholz, Michael Sullivan, David Mangum, Rachael Windsor, David S. Dickens, Alexandre Duarte, Farzana Pashankar, Shifra Ash, Andrew Bellantoni, Scott J. Diede, Rohini Singh, Yulia Sidi, Michal Yalon. Zilovertamab vedotin in pediatric and young adult hematologic malignancies or solid tumors: Phase 1/2 LIGHTBEAM-U01A study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT119.