Immunomedics, Inc. (Nasdaq:IMMU), a biopharmaceutical company focused on developing monoclonal antibodies to treat cancer and other serious diseases, today announced the dosing of the first patient in a Phase I/II clinical trial of the doxorubicin conjugate of milatuzumab for the treatment of patients with relapsed multiple myeloma.
Milatuzumab is a new humanized antibody developed by the Company for the treatment of cancer. It is the first antibody to have entered human testing that binds to a marker called CD74. CD74 is an attractive target for antibody therapy because it is present in limited amounts in normal tissues but widely found in leukemias, lymphomas and the vast majority of multiple myeloma cases. It is involved in a cell-to-cell communication pathway that is critical for survival. When CD74 is blocked by milatuzumab, it can lead to cell death. More importantly, CD74 internalizes rapidly once it is bound by milatuzumab, making it an ideal target for the delivery of chemotherapeutic agent against CD74-expressed tumors. Indeed, milatuzumab conjugated with doxorubicin has demonstrated very potent anti-tumor activities in preclinical studies with human lymphomas and myelomas. This product candidate is the Company's first antibody-drug conjugate (ADC) to be tested clinically.
The open-label, multi-center Phase I/II study aims to evaluate the safety and tolerability of milatuzumab-doxorubicin conjugate in patients with recurrent or refractory multiple myeloma, and to obtain preliminary information on efficacy, pharmacokinetics, and immunogenicity. The ADC will be administered intravenously on days 1, 4, 8, & 11 every 21 days for up to 8 treatment cycles. Four different dose levels of the doxorubicin conjugate of milatuzumab will be studied in groups of 3-6 patients. Once an optimal dose has been found, up to an additional 30 patients will be studied at that dose level.
"We are pleased to have initiated the patient dosing of our first ADC," commented Cynthia L. Sullivan, President and CEO. "Our next ADC candidates will be based on SN-38, the active metabolite of irinotecan (CPT-11) that has been approved for the treatment of metastatic colorectal cancer. We plan to link it with our proprietary humanized antibodies that target solid cancers such as breast, colorectal, lung and ovarian," she added.