Immunomedics, Inc. (Nasdaq:IMMU), a biopharmaceutical company primarily focused on the development of monoclonal antibody-based products for the targeted treatment of cancer, autoimmune and other serious diseases, today reported that consolidation treatment with fractionated yttrium-90 (Y-90) labeled epratuzumab, after induction therapy with rituximab and CHOP (R-CHOP) chemotherapy, improved remission status of adult patients with diffuse large B-cell lymphoma (DLBCL), a form of aggressive lymphoma. These results were presented by the French GOELAMS group at the 52nd annual meeting of the American Society of Hematology (ASH).
Sixty-four patients between the ages of 60 and 80 years who were not candidates for stem-cell transplant have been enrolled into this Phase II trial to receive 6 cycles of R-CHOP, followed 8 weeks later by two weekly infusions of Y-90-labeled epratuzumab. Most of the adverse events associated with the radiolabeled-antibody infusions were reversible hematologic toxicities.
Results reported at the ASH meeting included 33 patients; 30 underwent the entire course of R-CHOP and 27 also received the two Y-90 epratuzumab treatments. Overall, 20 of 28 evaluable patients (71.4%) achieved a complete response (CR) or unconfirmed CR (CRu) following R-CHOP therapies, with 7 patients (25.0%) reporting a partial response (PR) and 1 patient (3.6%) with stable disease.
Six weeks after Y-90 epratuzumab treatment, 4 of the 8 patients who achieved less than a CR or CRu with R-CHOP improved their remission status. As a result, 22 of 26 patients (84.6%) achieved a CR or CRu with the radiolabeled anti-CD22 antibody, while 3 patients (11.5%) had PRs and 1 patient (3.8%) had progressive disease. These early results indicate the feasibility of 90Y-epratuzumab as a consolidation therapy for elderly DLBCL patients who are not candidates for stem-cell transplants. The study group plans to enroll a total of 75 patients.
In a separate poster presentation, results with IMMU-114, the Company's proprietary humanized antibody directed against an immune response target, HLA-DR, were presented at the meeting. HLA-DR is a receptor located on the surface of antigen-presenting cells (APCs). The role of APCs is to present antigens that are foreign to the body to the immune system for the purpose of eliciting an immune response. The goal of this preclinical study is to evaluate the therapeutic potential of IMMU-114 against graft-versus-host disease (GVHD).
GVHD is a life-threatening complication of stem cell or bone marrow transplantation. It occurs when newly transplanted cells attack the recipient's body. Prevention and treatment of GVHD remains a major challenge because current therapeutic options, although effective for the control of GVHD, impair the overall immune functions and can lead to lethal infections and relapse of malignancies.
By assessing its effects on T cells and all subsets of APCs in human peripheral blood mononuclear cells, IMMU-114 was found to significantly deplete various APCs, including dendritic cells, B cells, and monocytes, without affecting the survival of T cells. Since APCs play a critical role in initiating GVHD, this selective depletion by IMMU-114 may offer an improved approach for the prevention and treatment of GVHD without alteration of preexisting anti-viral immunity, which could have a distinct advantage over currently available agents.