Preliminary results from a Phase 1 trial testing ADC Therapeutics’ ADCT-301 to treat relapsed or refractory Hodgkin’s and non-Hodgkin’s lymphoma (NHL) demonstrated the medication’s therapeutic potential with good overall response rates and low degree toxicity effects.
ADCT featured the results of this trial in a poster presentation, “Interim Data from the First Clinical Study of Adct-301, a Novel Pyrrolobenzodiazapine-Based Antibody Drug Conjugate, in Relapsed/Refractory Hodgkin/Non-Hodgkin Lymphoma,” at the 14th International Conference on Malignant Lymphoma (ICML) in Lugano, Switzerland.
“The results seen in this early analysis are impressive for these patients with relapsed or refractory Hodgkin’s and non-Hodgkin’s lymphoma,” Dr. Jay Feingold, chief medical officer and senior vice president of Clinical Development at ADCT, said in a press release. “These data, combined with the positive results we have seen in preclinical studies, continue to highlight what we believe to be the significant potential of our ADC technology platform based on PBD-warheads.”
ADCT-301 is an antibody-drug conjugate, meaning that it consists of an antibody that specifically targets cancer cells, bound to an anti-cancer drug. It is made by an anti-CD25 molecule (licensed from Genmab), linked to a toxin based on the PBD (pyrrolobenzodiazepine) compound. When the ADCT-301 binds to a CD25-positive cell, the toxin enters the cell, killing it.
This new therapeutic strategy is very attractive for targeting some subtypes of lymphomas and leukemias, since these malignant cells often express the CD25 molecule at their surface, while healthy cells have very restricted expression of this molecule.
The Phase 1 trial (NCT02432235) will include 90 adults with refractory or relapsed lymphoma across several U.S. and British institutions. This dose-escalating study aims to evaluate the tolerability, safety, drug dynamics and efficacy of intravenous infusion of ADCT-301.
The results presented at the 14th ICML included data from 37 heavily pretreated adult patients who received ADCT-301 for a median of 43 days and two treatment cycles.
According to the interim results, the most common treatment-related adverse events reported were skin symptoms (44.4 percent), and decreased blood cell levels (22.2 percent).
Despite the toxicity effects, 38.5 percent of Hodgkin’s lymphoma patients treated with 30µg/kg ADCT-301 responded to treatment. The overall response rate across all dose cohorts was 32 percent.
“Patients with multiple relapsed or refractory Hodgkin’s or non-Hodgkin’s lymphoma have limited treatment options,” said principal investigator Steven M. Horwitz, medical oncologist at New York’s Memorial Sloan Kettering Cancer Center. “These early findings are very encouraging as they demonstrate a clear clinical benefit even at low doses for patients who failed, or are intolerant to any established therapy,”
Horwitz added: “We look forward to continuing this study to further identify the maximum tolerable dose of ADCT-301 and provide a preliminary assessment of its single-agent anti-tumor activity and toxicity profile.”
ADCT-301 is also being evaluated in an ongoing Phase 1 trial in acute myeloid leukemia and acute lymphoblastic leukemia (NCT02588092).