Data support potential of ADCT-402 to become an important treatment option for patients with relapsed or refractory diffuse large B-cell lymphoma

Lausanne, Switzerland, November 4, 2019 - ADC Therapeutics SA, a clinical-stage oncology-focused biotechnology company pioneering the development of highly potent and targeted antibody drug conjugates (ADCs) for patients suffering from hematological malignancies and solid tumors, today announced that ADCT-402 (loncastuximab tesirine) data have been published in Clinical Cancer Research, a journal of the American Association for Cancer Research (AACR), in a paper titled, "A Phase 1 study of ADCT-402 (Loncastuximab Tesirine), a Novel Pyrrolobenzodiazepine-Based Antibody Drug Conjugate, in Relapsed/Refractory B-Cell Non-Hodgkin Lymphoma."

The Phase 1 multi-center, open-label, single-arm, dose-escalation and dose-expansion clinical trial demonstrated the significant single-agent clinical activity and manageable tolerability profile of ADCT-402 in patients with CD19-positive relapsed or refractory B-cell non-Hodgkin lymphoma who had failed or were intolerant to established therapies. The published paper includes findings from the dose-escalation part of the trial. Notably, among the 61 patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) who were evaluable for efficacy, a 55 percent response rate was observed at doses >=120 µg/kg. Eighty-seven of the 88 patients enrolled in the trial experienced at least one treatment-emergent adverse event (TEAE). The most common TEAEs were low blood cell counts, fatigue, liver test abnormalities, nausea, rash, shortness of breath and tissue swelling.

Brad S. Kahl, MD, Professor of Medicine at Washington University School of Medicine and lead author of the paper, said, "The first-in-human study of ADCT-402 justified its continued evaluation and identified the initial 150 µg/kg dose for the Phase 2 clinical trial. The promising clinical activity and manageable toxicities observed thus far highlight the potential utility of ADCT-402 as an off-the-shelf therapy for heavily pre-treated patients with DLBCL, a population for which a significant unmet medical need remains."

Jay Feingold, MD, PhD, Senior Vice President, Chief Medical Officer and Head of Oncology Clinical Development at ADC Therapeutics, added, "The publication of early ADCT-402 data in a peer-reviewed journal further validates the potential of our lead product candidate to become an important part of the treatment paradigm for relapsed or refractory DLBCL. With enrollment in our pivotal 145-patient Phase 2 clinical trial of ADCT-402 complete, we plan to submit a Biologics License Application to the U.S. Food and Drug Administration for accelerated approval of ADCT-402 for the treatment of relapsed or refractory DLBCL in patients who have failed two or more treatment regimens in the second half of 2020."

ADCT-402 is also being evaluated in an ongoing Phase 1b clinical trial in combination with ibrutinib for the treatment of relapsed or refractory DLBCL or mantle cell lymphoma (MCL) and a Phase 1b clinical trial in combination with durvalumab for the treatment of relapsed or refractory DLBCL, MCL and follicular lymphoma.
About ADCT-402
ADCT-402 (loncastuximab tesirine) is an antibody drug conjugate (ADC) composed of a humanized monoclonal antibody directed against human CD19 and conjugated through a linker to a pyrrolobenzodiazepine (PBD) dimer cytotoxin. Once bound to a CD19-expressing cell, ADCT-402 is designed to be internalized by the cell, following which the warhead is released. The warhead is designed to bind irreversibly to DNA to create highly potent interstrand cross-links that block DNA strand separation, thus disrupting essential DNA metabolic processes such as replication and ultimately resulting in cell death. CD19 is a clinically validated target for the treatment of B-cell malignancies. ADCT-402 is being evaluated in a pivotal Phase 2 clinical trial in patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL) (NCT03589469), a Phase 1b trial in combination with ibrutinib in patients with R/R DLBCL or mantle cell lymphoma (MCL) (NCT03684694) and a Phase 1b trial in combination with durvalumab in patients with R/R DLBCL, MCL or follicular lymphoma (NCT03685344). The U.S. Food and Drug Administration granted orphan drug designation to ADCT-402 for the treatment of relapsed or refractory DLBCL and MCL.

About ADC Therapeutics
ADC Therapeutics SA is a clinical-stage oncology-focused biotechnology company pioneering the development of highly potent and targeted antibody drug conjugates (ADCs) for patients suffering from hematological malignancies and solid tumors. The Company develops ADCs by applying its decades of experience in this field and using next-generation pyrrolobenzodiazepine (PBD) technology to which ADC Therapeutics has proprietary rights for its targets. Strategic target selection for PBD-based ADCs and substantial investment in early clinical development have enabled ADC Therapeutics to build a deep clinical and research pipeline of therapies for the treatment of hematological and solid tumor cancers with significant unmet need. The Company has multiple PBD-based ADCs in ongoing clinical trials, ranging from first in human to pivotal Phase 2 clinical trials, in the USA and Europe, and numerous preclinical ADCs in development. ADCT-402, the Company's lead product candidate, has demonstrated significant single-agent clinical activity across a broad population of patients with relapsed or refractory diffuse large B-cell lymphoma, including difficult-to-treat patients. ADCT-301, the Company's second lead product candidate, has demonstrated clinical activity in heavily pretreated patients with Hodgkin lymphoma and, based on its mechanism of action, also has potential for the treatment of solid tumors. ADC Therapeutics is based in Lausanne (Biopôle), Switzerland and has operations in London, the San Francisco Bay Area and New Jersey. For more information, please visit https://adctherapeutics.com/.