Immunomedics announced that epratuzumab labeled with the potent radioisotope, yttrium-90 (Y-90), when given in small fractionated doses to patients with non-Hodgkin’s lymphoma (NHL), achieved high rates of durable responses at total Y-90 doses exceeding the 32-mCi limit approved for a single dose of ibritumomab tiuxetan. Results from this multicenter, open label study were presented at the Society of Nuclear Medicine 56th Annual Meeting
TORONTO, CANADA | June 15, 2009 | Immunomedics, Inc. (Nasdaq:IMMU), a biopharmaceutical company focused on developing monoclonal antibodies to treat cancer and other serious diseases, today announced that epratuzumab labeled with the potent radioisotope, yttrium-90 (Y-90), when given in small fractionated doses to patients with non-Hodgkin’s lymphoma (NHL), achieved high rates of durable responses at total Y-90 doses exceeding the 32-mCi limit approved for a single dose of ibritumomab tiuxetan. Results from this multicenter, open label study were presented at the Society of Nuclear Medicine 56th Annual Meeting.
"We believe this study demonstrated that by splitting the radioactive dose over two or three fractions, higher total radiation can be delivered to the tumor without increasing the harmful effects of radiation to the bone marrow, thereby making the therapy more tolerable and potentially more effective," commented Cynthia L. Sullivan, President and CEO.
The goal of the study is to determine the safety, optimal dosing and preliminary efficacy of Y-90-labeled epratuzumab (yttrium-90 epratuzumab tetraxetan) for NHL. Sixty-four adult patients who had failed one or more therapies, including rituximab, had been enrolled to receive 2 or 3 weekly infusions of Y-90 labeled epratuzumab. The starting Y-90 dose was 5.0 mCi/m(2), 2.5 mCi/m(2) for patients with prior bone marrow involvement, with increments of 2.5 mCi/m(2) or 5.0 mCi/m(2). For 17 patients with prior bone marrow transplant, grade 3 to 4 hematologic toxicity limited dose escalation to a total dose of 10 mCi/m(2). For other patients, the treatment was manageable up to 45 mCi/m(2) (15 mCi/m(2) for 3 weeks) total dose.
The overall objective response rate (partial and complete responses) in 62 evaluable patients was 64%, with 49% of patients having a complete response. Both the objective and complete response rates appear to correlate with cumulative doses. In 16 patients unresponsive to last therapy, 75% responded to Y-90 epratuzumab tetraxetan with 56% complete responses. More importantly, responses were seen across all different types of NHL. For follicular lymphoma patients, treatment at 20 mCi/m(2) for 2 weeks was particularly effective, with all 10 patients responding to the treatment, 9 of which were complete responders. In addition, for all 21 follicular lymphoma patients with complete responses, the estimated median progression-free survival is 17.9 months, including responses continuing up to 5 years.
Y-90 dose-response results are listed below:
Total dose Number of Objective Complete
(in mCi/m(2)) Patients Response Response
5 - 10 17 41% 29%
15 - 20 12 58% 50%
> 20 33 79% 61%
NHL subtype responses are listed below:
NHL Subtypes Number of Objective Complete
Patients Response Response
Follicular 34 74% 62%
Mantle cell 14 50% 21%
Diffuse large
B-cell 10 40% 30%
Marginal zone 4 100% 100%
About Immunomedics
Immunomedics is a New Jersey-based biopharmaceutical company primarily focused on the development of monoclonal, antibody-based products for the targeted treatment of cancer, autoimmune and other serious diseases. We have developed a number of advanced proprietary technologies that allow us to create humanized antibodies that can be used either alone in unlabeled or "naked" form, or conjugated with radioactive isotopes, chemotherapeutics or toxins, in each case to create highly targeted agents. Using these technologies, we have built a pipeline of therapeutic product candidates that utilize several different mechanisms of action. We also have a majority ownership in IBC Pharmaceuticals, Inc., which is developing a novel Dock-and-Lock (DNL) methodology with us for making fusion proteins and multifunctional antibodies, and a new method of delivering imaging and therapeutic agents selectively to disease, especially different solid cancers (colorectal, lung, pancreas, etc.), by proprietary, antibody-based, pretargeting methods. We believe that our portfolio of intellectual property, which includes approximately 134 patents issued in the United States and more than 300 other patents issued worldwide, protects our product candidates and technologies. For additional information on us, please visit our website at www.immunomedics.com. The information on our website does not, however, form a part of this press release.
SOURCE: Immunomedics, Inc.
