Immunomedics Says Addition of Epratuzumab in Combination Chemotherapy Could Be Beneficial to Acute Lymphocytic Leukemia Patients

Immunomedics, Inc.

,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 announced that adult patients with relapsed or refractory acute lymphocytic leukemia (ALL) reported a complete response (CR and CRi) rate of 50% after receiving one cycle of treatment with epratuzumab in combination with the chemotherapy agents, clofarabine and cytarabine. Results from this Phase II S0910 study conducted by the Southwest Oncology Group (SWOG) of the National Cancer Institute (NCI) were presented at the 2012 Annual Meeting of the American Society of Hematology by Anjali S. Advani, MD, Principal Investigator and staff physician in the Department of the Hematologic Oncology and Blood Disorders at Cleveland Clinic's Taussig Cancer Institute, Cleveland, OH. In addition to Cleveland Clinic, other clinical research centers participating in this multicenter trial include City of Hope National Medical Center, Duarte, CA; Stanford University School of Medicine, Stanford, CA; University of Mississippi, Jackson, MS; University of Rochester Medical Center, Rochester, NY; Baylor College of Medicine, Houston, TX; Fred Hutchinson Cancer Research Center, and SWOG Statistical Center, Seattle, WA. SWOG had previously reported a CR rate of 17% in adult patients with ALL using only the combination of clofarabine and cytarabine. Because virtually all immature B cells express CD22, which is the target of the Company's proprietary humanized antibody, epratuzumab, the NCI-study group wanted to evaluate the CR rate of combining the anti-CD22 antibody with the two chemotherapeutic agents. Twenty patients were initially accrued into the study to test whether the CR rate is sufficiently high to warrant further investigation. After at least 2 complete responders were observed in the first 20 patients, an additional 12 patients were accrued. Among the 32 eligible patients evaluated, the overall CR rate was 50% (95% CI 32-68%), including 10 CRs and 6 CRis. The null response rate in this protocol was 10%, and the P-value comparing 50% to 10% is 1.2 x 10^-8 (P=0.000000012). The median overall survival for the 32 eligible patients with follow-up information was 4 months. Only 5 patients who achieved CR/CRi had their bone marrow tested for minimal residual disease (MRD). Of these, only 1 patient achieved a significant MRD response and this patient survived 11 months.