Seattle Genetics, Inc. has initiated a phase I clinical trial of SGN-33, a humanized anti-CD33 monoclonal antibody, for patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS). The study is designed to evaluate the safety, pharmacokinetic profile and anti-tumour activity of escalating doses of SGN-33.
"SGN-33 is an important addition to our clinical portfolio and provides us with another significant product opportunity," Clay B. Siegall, President and CEO of Seattle Genetics said adding, "The initial objectives of the study include assessing the optimal dose, establishing the safety profile and identifying the target patient population. While this antibody has shown activity in previous clinical studies, we believe that by optimizing the dose and administration schedule we have an opportunity to exploit the therapeutic potential of SGN-33."
SGN-33 (HuM195, lintuzumab) is a humanized monoclonal antibody that targets the CD33 antigen, which is expressed on a number of haematologic malignancies, such as AML, MDS and several myeloproliferative disorders. Seattle Genetics exclusively licensed this program, including associated patents and clinical grade material, from Protein Design Labs in April 2005. This antibody was previously tested in more than 350 patients, primarily with relapsed and refractory AML. The safety profile and activity, especially in patients with low tumor burden, suggest that this may be an important therapeutic tool for AML and MDS patients, who currently have few treatment options.
The single-agent, open label, dose escalation phase I study of SGN-33 is expected to enrol up to 60 patients at multiple centres in the United States. The patient population will include those individuals with AML and MDS who are not eligible for intensive chemotherapy or stem cell transplantation as well as those who have failed previous therapy.
MDS is a collection of disorders in which blood cells remain at an immature stage within the bone marrow and never fully develop into cells capable of performing their normal functions. MDS patients do not meet criteria for leukaemia based on the percentage of blasts in the bone marrow.