ADC Therapeutics Reports Promising Phase 2 Results for Lymphoma Treatment, Zynlonta Shows 84.6% Overall Response Rate and 69.2% Complete Response Rate

ADC Therapeutics has reported promising Phase 2 trial results for Zynlonta, a treatment for relapsed or refractory marginal zone lymphoma. The therapy showed an overall response rate of 84.6% and a complete response rate of 69.2%. Adverse effects were primarily grade 1 or 2, but some severe cases were noted. The company's average target price is $9.00 with an upside of 151.40% from the current price of $3.58.

ADC Therapeutics (NYSE: ADCT) has announced updated data from a Phase 2 investigator-initiated trial (IIT) of ZYNLONTA®, an antibody drug conjugate (ADC) therapy, for the treatment of relapsed or refractory marginal zone lymphoma (r/r MZL). The data, to be presented at the 18th International Conference on Malignant Lymphoma (ICML) in Lugano, Switzerland, on June 20, 2025, demonstrated an overall response rate (ORR) of 84.6% and a complete response (CR) rate of 69.2%.

The single-arm, open-label study, led by Izidore S. Lossos, MD, included 27 adult patients with r/r MZL who had previously received at least one line of systemic therapy. Among the 26 evaluable patients, 22 achieved an overall response, with 18 achieving complete response. Notably, 17 of the 18 CR patients maintained their response for at least 27 months from the start of treatment.

The study also reported a progression-free survival (PFS) rate of 92.9% at 12 months. Adverse events (AEs) were consistent with the known safety profile of ZYNLONTA, with most events being grade 1 or 2. Severe AEs, including neutropenia, RSV lung infection, and hyponatremia, were observed in a small subset of patients. Three patients required dose reduction, and one patient discontinued treatment after cycle 4 due to cholestatic hepatitis, which fully recovered.

The study is being conducted at Sylvester Comprehensive Cancer Center and has recently expanded to Emory Winship Cancer Institute and Vanderbilt-Ingram Cancer Center to accelerate enrollment to 50 patients with r/r MZL. The trial is ongoing and further data will be crucial for assessing the long-term efficacy and safety of ZYNLONTA in this patient population.

ADC Therapeutics is optimistic about the potential of ZYNLONTA as a single-agent treatment for r/r MZL, including high-risk POD24 patients. The company plans to pursue regulatory pathways and compendia submissions as the trial progresses and sufficient data become available.

The stock price of ADC Therapeutics, currently at $3.58, has an average target price of $9.00 with an upside of 151.40%. This reflects the market's optimism about the potential of ZYNLONTA and the company's broader ADC portfolio.

References
[1] https://www.biospace.com/press-releases/adc-therapeutics-announces-updated-zynlonta-investigator-initiated-trial-data-in-r-r-marginal-zone-lymphoma-presented-at-18th-international-conference-on-malignant-lymphoma-icml