An update to the phase II study of loncastuximab tesirine in patients with relapsed or refractory diffuse large B-cell lymphoma showed promising overall response rate, according to a press release from ADC Therapeutics SA.
Jay Feingold, MD
An update to the phase II study of loncastuximab tesirine (ADCT-402) in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) showed promising overall response rate (ORR), according to a press release from ADC Therapeutics SA.1
The ORR with loncastuximab tesirine was 45.5%, with responses observed in 66 out of 145 patients. Twenty percent of the responses were complete responses (CRs), and 25.5% were partial responses (PRs).1These data follow another promising study update presented at the 2019 American Society for Hematology (ASH) Annual Meeting.2
The ORR observed in 24 of the 52 study participants as of October 4, 2019, was 46.2%, which included CRs in 19.2% of patients and PRs in 26.9% of patients. At the time, the median duration of response (DOR) in complete responders was not reached. However, the median DOR among partial responders was 5.7 months. Additionally, 19.2% of the patients had stable disease.2
The toxicity profile of loncastuximab tesirine reported at ASH was manageable in the relapsed/refractory DLBCL patient population. Most of the adverse events (AEs) were grade 3 or lower and occurred in only 5% of the study participants. The most common AEs were neutrophil count decreased (32.7%), gamma-glutamyl transferase increased (25%), platelet count decreased (21.2%), and anemia (11.5%), and hypokalemia (5.8%).2
The latest phase II data also showed a significant improvement in ORR compared with results seen in the phase I study of loncastuximab tesirine in patients with relapsed/refractory DLBCL. The phase I ORR was 41.4% in 29 out of 70 patients, which included CRs in 21.4% of patients and PRs in 20% of patients.1
“These data exceeded our primary end point target and reinforce the significant single-agent antitumor activity and manageable toxicity profile of loncastuximab tesirine in patients with relapsed or refractory DLBCL who have failed established therapies. Loncastuximab tesirine has demonstrated its potential to fill a critical unmet need for a new therapy and become a key part of the treatment paradigm for all heavily pretreated patients with DLBCL. We plan to present final data from the pivotal phase II clinical trial at a future scientific meeting,” Jay Feingold, MD, PhD, senior vice president and chief medical officer of ADC Therapeutics, said in a press release.
The single-arm, multi-center, open-label phase II clinical trial is ongoing, evaluating the safety, efficacy, and pharmacokinetics of loncastuximab tesirine, an antibody-drug conjugate, in patients with relapsed/refractory DLBCL. Patients in the trial are given intravenous infusions of loncastuximab tesirine for 30 minutes once every 3 weeks. For the first 2 cycles, the dosage is 150 μg/kg followed by 75 μg/kg for subsequent cycles. Treatment with loncastuximab tesirine is continued for up to 1 year or until the time of disease progression, unacceptable toxicity, or other discontinuation criteria.1
Based on these data, ADC Therapeutics plans to submit a Biologic License Application to the FDA for accelerated approval of loncastuximab tesirine as a single-agent treatment for relapsed/refractory DLBCL in the United States. The company is also preparing to launch the drug in the second quarter of 2021.1