ADC Therapeutics Reports Early Phase II Zynlonta Lymphoma Data Amid 5.8% Revenue Decline

ADC Therapeutics recently unveiled preliminary Phase II results for its anti-CD19 antibody-drug conjugate, Zynlonta (loncastuximab tesirine-lpyl), showing promising efficacy in patients with relapsed or refractory marginal zone lymphoma. The data, released on Monday, highlighted significant treatment responses among the participants.

The early findings stem from a group of 15 assessable patients out of 50 total participants in the company's single-arm, open-label mid-stage trial. Among these patients, thirteen exhibited a complete response (CR), while one patient showed a partial response to the treatment. All these responses were sustained up to the data cut-off point.

Regarding safety, Zynlonta was generally well-tolerated, with its adverse event profile aligning with previous studies. Two patients exited the trial due to toxicities, but these issues were fully resolved once the treatment was halted. Both patients continued to maintain their complete response status after discontinuing Zynlonta.

With these promising results, ADC Therapeutics aims to potentially advance through a regulatory pathway and establish compendia, as suggested by Chief Medical Officer Mohamed Zaki. This strategic plan depends on the continued positive outcomes from ongoing studies.

Alongside the Phase II data release, ADC Therapeutics announced a significant financial move. The company is offering over 13.4 million common shares at $4.90 each, along with pre-funded warrants for the purchase of more than 8.1 million common shares at $4.812 per warrant. Through this initiative, ADC Therapeutics aims to raise approximately $105 million in gross proceeds.

Zynlonta is engineered as an antibody-drug conjugate (ADC) targeting the CD19 surface protein, prevalent on B cells and a validated target in related cancers. Upon binding to its target, the ADC is internalized by the cancer cell, releasing a toxic pyrrolobenzodiazepine payload that attacks the DNA, leading to cell death.

The FDA granted Zynlonta accelerated approval in April 2021 for treating patients with relapsed or refractory large B-cell lymphoma who have undergone at least two prior systemic therapies. The approval also covers specific types of diffuse large B-cell lymphoma.

However, the journey has not been without setbacks. In July 2023, ADC Therapeutics terminated the Phase II LOTIS-9 trial of Zynlonta in previously untreated, hard-to-treat diffuse large B-cell lymphoma due to seven patient fatalities.

Despite the setbacks, the company continues to push forward, although sales figures for Zynlonta have been underwhelming. In 2023, Zynlonta generated $69.1 million, a decline from $75 million in 2022. In its recent first-quarter earnings report, ADC Therapeutics revealed that sales dropped to $17.85 million from nearly $19 million during the same period in 2022.