Advanced Magnetics Inc and Cytogen Corporation announced that Advanced Magnetics submitted a response to the approvable letter received from the US Food and Drug Administration (FDA) for Combidex, Advanced Magnetics' investigational molecular imaging agent to aid in the non-invasive diagnosis of metastatic lymph nodes.

In response to the submission, the US FDA requested that Advanced Magnetics provide certain additional details underlying the existing supporting data submitted. The US FDA subsequently communicated that the data Advanced Magnetics is in the process of gathering, once submitted, look encouraging to provide a complete response to the approvable letter.

"We are pleased by these positive steps forward in the approval process for Combidex," stated Jerome Goldstein, chairman, president and CEO of Advanced Magnetics.

Combidex (ferumoxtran-10) is an investigational molecular imaging agent consisting of iron oxide nanoparticles for use in conjunction with magnetic resonance imaging (MRI) to aid in the differentiation of cancerous from non-cancerous lymph nodes. Lymph nodes are frequently the site for metastases of many different types of cancer, particularly breast cancer and prostate cancer.

Computed tomography (CT) and MRI are the methods currently used for imaging lymph nodes. Current guidelines for imaging lymph nodes are that nodes greater than 10 mm in size are usually deemed cancerous while nodes less than 10 mm in size are generally presumed normal.

CT and MRI cannot distinguish between lymph nodes that are enlarged due to the infiltration of cancerous cells as opposed to inflammation nor can these methods reliably detect disease in nodes that are not enlarged. Clinical studies have shown that Combidex accumulates in non-cancerous lymph node tissue, which could enable doctors using MRI to have improved diagnostic confidence in differentiating between normal and diseased lymph nodes.

Combidex received an approvable letter from the FDA, subject to certain conditions, in June of 2000.