Immunomedics reports results of milatuzumab-based combination treatments for NHL patients

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 combination treatment with milatuzumab, the first humanized anti-CD74 antibody in clinical testing, and veltuzumab, a second-generation humanized anti-CD20 antibody, resulted in therapeutic responses in heavily pretreated and rituximab-refractory non-Hodgkin's lymphoma (NHL) patients.

The goal of this Phase I/II trial being conducted at the Ohio State University Comprehensive Cancer Center is to determine the safety, tolerability, and overall response rate of adding milatuzumab to veltuzumab in patients with relapsed or refractory B-cell NHL after at least 1 prior therapy. At the time of reporting, 11 patients have been enrolled and received veltuzumab at 200 mg/m² weekly combined with escalating doses of milatuzumab at 8, 16 and 20 mg/kg twice per week. Seven of the 11 patients were rituximab-refractory and 3 had prior autologous stem cell transplants. Four of 9 evaluable patients showed an objective response.

Dose escalation reached 16 mg/kg milatuzumab with no dose-limiting toxicities observed to date.  The primary observed toxicity of milatuzumab was infusion reactions, which were reversible. Accrual to the Phase I portion of the study is ongoing, and will be followed by a Phase II trial to further evaluate efficacy of the combination.

Results on other milatuzumab-based combination treatments were also presented at the meeting in two separate preclinical studies. Using a number of human lymphoma and leukemia cell lines, the first study, conducted by the Garden State Cancer Center in New Jersey, demonstrated that milatuzumab could significantly augment the efficacy of fludarabine and rituximab, two approved therapies for B-cell malignancies. 

In the second preclinical study, conducted by the Garden State Cancer Center and Coney Island Hospital, in New York, CD74, a receptor targeted by milatuzumab, was found to be present in acute myeloid leukemia (AML)patient specimens and in AML cell lines. Moreover, exposure of AML cell lines to interferon-gamma (IFN-y) increased the number of CD74 receptors, and resulted in improved activity of milatuzumab in 2 of 3 AML cell lines. These results suggest that combined IFN-y and milatuzumab may be useful for AML therapy.

Commenting on these results, Cynthia L. Sullivan, President and Chief Executive Officer of Immunomedics said, "Milatuzumab is the first anti-CD74 antibody in clinical studies, and we are pleased to see that it can complement and augment a number of existing cancer therapies, which may potentially broaden its use against a variety of cancers."