On June 16, 2025 ADC Therapeutics SA (NYSE: ADCT), a commercial-stage global leader and pioneer in the field of antibody drug conjugates (ADCs), reported updated data from a Phase 2 multicenter investigator-initiated trial (IIT) of ZYNLONTA to treat relapsed/refractory marginal zone lymphoma (r/r MZL) will be presented during a poster session at the 18th International Conference on Malignant Lymphoma (ICML) in Lugano, Switzerland on Friday, June 20 (Press release, ADC Therapeutics, JUN 16, 2025, View Source [SID1234653934]). These data will be made available online beginning on Wednesday, June 18, at 8:30 a.m. CEST. The single-arm, open-label, study is led by Izidore S. Lossos, MD, Chief, Division of Hematology Lymphoma Section, at Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine.
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"These updated results further support the potential of ZYNLONTA as an effective single-agent treatment for patients with r/r MZL, including high-risk POD24 patients," said Lossos, the study’s principal investigator. "Importantly, the treatment was generally well tolerated, with manageable safety consistent with the known profile."
As of February 10, 2025, a total of 27 adult patients with r/r MZL and previously treated with ≥1 line of systemic therapy were enrolled with 26 patients evaluable for response. Highlights of the data include:
Overall response rate (ORR) of 84.6% (22/26); complete response (CR) rate of 69.2% (18/26)
Among POD24 patients assessed for response, a CR rate of 61.5% (8/13) was observed
CR was maintained in 17 of 18 CR patients who achieved CR, with longest duration of CR of 27 months from start of treatment
Progression-free survival (PFS) was 92.9% at 12 months
27 enrolled patients experienced adverse events (AE), consistent with the known safety profile of ZYNLONTA and most commonly grade 1 or 2. Grade 3 and 4 AEs were observed in 16 and 2 patients, respectively and included neutropenia, RSV lung infection and hyponatremia (with 2 AEs occurring in the same patient). Three patients needed dose reduction and one patient discontinued treatment after cycle 4 due to cholestatic hepatitis that fully recovered.
The study is being conducted at Sylvester Comprehensive Cancer Center and at City of Hope, and recently expanded to Emory Winship Cancer Institute and Vanderbilt-Ingram Cancer Center to accelerate enrollment to 50 patients with r/r MZL. More details on this ongoing Phase 2 clinical trial can be found at View Source (identifier: NCT05296070).
"Based on the updated Phase 2 IIT data to be shared at ICML, we are encouraged by the potential opportunity in r/r MZL and look forward to seeing additional data, as the trial expands to other sites." said Mohamed Zaki, MD, PhD, Chief Medical Officer of ADC Therapeutics. "As this trial progresses, assuming the results continue to be positive, we plan to potentially pursue a regulatory pathway and compendia in parallel as soon as sufficient data are available."
In addition to the MZL poster presentation at ICML, an oral encore presentation of the LOTIS-7 Phase 1b open-label clinical trial evaluating the safety and efficacy of ZYNLONTA in combination with the bispecific antibody glofitamab (COLUMVI) in patients with relapsed or refractory diffuse large B-cell lymphoma (r/r DLBCL) will also be presented at ICML Friday, June 20 at 3:00 p.m. CEST.
About ZYNLONTA
ZYNLONTA is a CD19-directed antibody drug conjugate (ADC). Once bound to a CD19-expressing cell, ZYNLONTA is internalized by the cell, where enzymes release a pyrrolobenzodiazepine (PBD) payload. The potent payload binds to DNA minor groove with little distortion, remaining less visible to DNA repair mechanisms. This ultimately results in cell cycle arrest and tumor cell death.
The U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have approved ZYNLONTA (loncastuximab tesirine-lpyl) for the treatment of adult patients with relapsed or refractory (r/r) large B-cell lymphoma after two or more lines of systemic therapy, including diffuse large B-cell lymphoma (DLBCL) not otherwise specified (NOS), DLBCL arising from low-grade lymphoma and also high-grade B-cell lymphoma. The trial included a broad spectrum of heavily pre-treated patients (median three prior lines of therapy) with difficult-to-treat disease, including patients who did not respond to first-line therapy, patients refractory to all prior lines of therapy, patients with double/triple hit genetics and patients who had stem cell transplant and CAR-T therapy prior to their treatment with ZYNLONTA. This indication is approved by the FDA under accelerated approval and in the European Union under conditional approval based on overall response rate and continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial. Please see full prescribing information including important safety information about ZYNLONTA at www.ZYNLONTA.com.
ZYNLONTA is also being evaluated as a therapeutic option in combination studies in other B-cell malignancies and earlier lines of therapy.