Zynlonta Phase II Lymphoma Results Amid Revenue Decline

ADC Therapeutics recently revealed top-line data from its Phase II study of Zynlonta (loncastuximab tesirine-lpyl), an anti-CD19 antibody drug conjugate, demonstrating significant treatment responses in patients with relapsed or refractory marginal zone lymphoma.

The early findings are based on 15 evaluable patients from a total of 50 participants in the ongoing single-arm, open-label, mid-stage trial. Among these patients, 13 achieved a complete response (CR) to Zynlonta, with one showing partial response. All patient responses were sustained until the data cut-off point.

Regarding safety, Zynlonta presented a tolerable adverse event profile consistent with previous studies. Although one patient exited the study due to toxicity, the condition resolved after discontinuation of the drug, and the patient remains in CR.

The company plans to explore regulatory pathways and parallel compendia strategies if data continues to be positive, as stated by Chief Medical Officer Mohamed Zaki.

In conjunction with the data announcement, ADC Therapeutics reported a share sale to raise funds. The biotech is offering over 13.4 million common shares at $4.90 each and pre-funded warrants for the purchase of more than 8.1 million common shares at $4.812 per warrant, aiming for approximately $105 million in gross proceeds.

Zynlonta is designed to target the CD19 protein on B cells, a validated target in related cancers. The drug is internalized by cancer cells, where it releases a toxic agent, pyrrolobenzodiazepine, which binds to DNA and induces cell death.

The FDA granted accelerated approval to Zynlonta 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 certain types of diffuse large B-cell lymphoma.

However, in July 2023, ADC Therapeutics halted the Phase II LOTIS-9 trial for Zynlonta in previously untreated, difficult-to-treat diffuse large B-cell lymphoma following seven patient deaths.

Zynlonta's sales have been underwhelming. In 2023, the drug generated $69.1 million, a decline from $75 million in 2022. First-quarter earnings showed a further dip, with sales falling to $17.85 million from nearly $19 million in the same period in 2023.