Medical Device Daily

GE Healthcare (Chalfont St. Giles, UK) reported earlier this week that it has initiated a “first-in-man” clinical study of a new molecular imaging agent to be used with positron emission tomography (PET), the study designed to validate the agent's ability to provide information on the extent and nature of cancer.

Specifically, GE said, the molecular imaging agent has a biological mechanism to track the process of angiogenesis, which the company said could help physicians identify the location and growth patterns of tumors earlier, thereby leading to earlier correction of drug therapy in either type or dosage.

“That's our hope: to reverse adverse effects, select the right therapies and doses of therapies, help longevity,” Don Black, MD, head of research and development at GE Healthcare's Medical Diagnostics division, told Medical Device Daily. Black noted that this involves a key balancing act “between the adverse effects of these drugs as well as the benefits of these drugs – we want to get the right amount of the right drugs, and you don't want the inadequate drugs or the inappropriate drugs.”

The current “gold standard” for tracking the progression of cancer is to administer several cycles of chemotherapy and repeat imaging of the patient to determine if the tumor has shrunk, Black said.

“The gold standard right now is usually some anatomical structural, usually either CT or MR, and look after a few rounds of chemotherapy if there's a shrinkage of the tumor, typically,” Black said. “And we're just trying to find if by using a more targeted product can we determine the best selection of therapy earlier?”

This new agent could specifically help clinicians to monitor the effectiveness of anti-angiogenic cancer drugs, which Black notes is “the basis for a lot of cancer therapy right now.” According to GE, more than $4 billion has been invested in the research and development of angiogenesis-based medicines.

“There was a recent announcement from GSK [GlaxoSmithKline], for example, that they have a small molecule that seems to be as good as other products, so there's a lot of interest in anti-angiogenic therapy,” Black said. “And we're sort of piggybacking on that same principle in a targeted diagnostic.”

He also thinks that GE is one or one of only a few companies working on molecular imaging agents, referencing the company's PET investigator's network, which brings together “the top 50 sites in the world,” he said. “From what we hear from them, we are the only ones looking to do multicenter studies with new PET agents.”

The current molecular imaging agent – one of several on which GE will begin work on later this year for PET imaging, Black said – is a radiolabeled small peptide in a configuration designed to allow high affinity binding of the peptide to specific integrin receptors.An integrin is a membrane protein that plays a role in the attachment of a cell to the extracelluar matrix.

GE says that integrins are associated with endothelial cell differentiation, proliferation, migration and attachment to the extra-cellular matrix, which are “critical” during angiogenesis.

Integrin receptors have limited tissue distribution with high levels of expression achieved during tumor growth, invasion and metastasis, GE said in reporting on this new clinical study at the annual conference of the Society of Nuclear Medicine Conference (Reston, Virginia) in San Diego earlier this week.

The trial, overseen by David Brooks, MD, chief medical officer at GE Imanet – GE Healthcare's international network of imaging research centers– is currently enrolling subjects at the Hammersmith Hospital in London. The imaging agent will be used to quantify response to therapy by imaging Stage IV metastatic tumors of the breast before and after cycles of chemotherapy.

“Angiogenesis is a characteristic process of many cancers, and we're excited to participate in the clinical trial, which may provide additional validation for the use of this novel molecular imaging agent in oncology applications,” said Brooks in a statement. “Data from this program could establish a new measurement used to assess the effectiveness of treatment approaches in cancer.”

Black said that because it is a Phase I study, the company does not yet know if there will be adverse effects of the molecular imaging agent. The company only has animal data at this point, but after the Phase I study, which should indicate tolerability and appropriate dose levels, GE hopes to progress from volunteers to patients actually requiring treatment.

“Of course, diagnostic products need to be very safe, because it is a diagnostic, after all, and when you look at the risk/benefit, they have to be quite safe,” Black said.

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