Chapters Transcript Video Shayna Sarosiek, MD discusses WM-NET 1 trial Deep responses following treatment with Ioncastuximab tesirine (WM-NET1 trial) in patients with Relapsed/Refractory including those with high risk, TP53-altered Waldenstrom macroglobulinemia. Loncetuximab tesserine is a CD-19 monoclonal antibody drug conjugate, and that medication has been FDA approved for use in large B cell lymphoma, but has not been previously used in Waldenstrom's. So in this initial trial, we are planning to enroll 20 patients. We have preliminary data that we are presenting. Um, that shows, um, an overall response rate that is, um, quite exciting. In terms of the patients that are valuable and presented, we have 14 patients. The 14 patients were treated with 6 cycles of Lantustuximab. The 1st 2 cycles were given at 150 mcg per kilogram, and the next 4 cycles at 75. This is standard dosing, but the dosing was done at 4-week intervals because this is a more indolent lymphoma. Than the large cell lymphoma. Um, most of these patients were heavily pre-treated. All patients had to have at least 2 prior lines of therapy, including a monoclonal anti-CD20 antibody and a BTK inhibitor, but the median number of therapies for these patients was 4, with some patients having received up to 10 prior lines of therapy. Additionally, what was unique about these patients is all of the patients had a mid 88 mutation, but 62% had a CXCR4 mutation and 57% had a TP53 alteration. So this is a very high risk group of patients. The patients seemed to tolerate the therapy, um, quite well overall and achieved a very excellent response rate. So with a median follow-up of just over 12 months, The overall response rate is 93%, with a major response rate of 86%. These data compare favorably to other available therapies for Waldenstrom's, and we even achieved very deep responses in patients, with 71% of patients having a very good partial response or a complete response. So that's the data in the overall population. But we actually saw similar information in those patients who had a TP 53 alteration. So that was 8 of the 14 patients, and of those 8 patients, 100% had a major response rate, and 88% had a VGPR or CR. So, even in high-risk, heavily pre-treated patients, Loustuximab is achieving deep responses. And the side effect profile includes um side effects that are typically seen with this medication, including some skin toxicity, grade 1 and 2, and some grade 3 and 4 events, um, including cytopenia. And, um, changes in liver function tests. Um, but these side effects were reversible, and, um, patients have done well. Um, again, we have a median follow-up of 12 months so far with a progression-free survival rate of 86%. We're very excited about this data and how it can change the, um, treatment, um, paradigm for patients with relapse disease and patients with high-risk mutations. Um, and we look forward to seeing the final results in the future as we enroll and treat the remaining patients on this trial. Published December 18, 2025 Created by Related Presenters Shayna Sarosiek, MD Medical Oncology View full profile