DURHAM, North Carolina"We have a positive randomized trial of
amifostine (Ethyol), and it represents the first time that a treatment has
been approved by the Food and Drug Administration (FDA) that interacts with
radiation therapy," David M. Brizel, MD, said.
An associate professor in the Department of Radiation Oncology at Duke
University Medical Center in Durham, North Carolina, Dr. Brizel reviewed
radioprotection concerns. "First, it is fairly obvious that we are
aiming to reduce the toxicity of our anticancer treatment. With amifostine
the endpoints relating to this consideration have been xerostomia and
mucositis," he said. "The second consideration is that when we
start to perturb the system, we must be certain that we not compromise the
effectiveness of anticancer treatment. Also, we have to be certain that we
are not simply trading one toxicity for another."
Proof of Principle
The positive trial Dr. Brizel referred to is the WR-38 study showing that
patients pretreated with amifostine had significantly better unstimulated
saliva production 1 year after radiotherapy. The WR-38 trial was the first
proof of principle that a chemical radioprotection strategy could be
incorporated into radiotherapy for head and neck cancer in a prospective,
"We still don’t know what is the optimal schedule or the optimal
dosage for amifostine," Dr. Brizel acknowledged.
Keratinocyte Growth Factor
Another new drug in development is keratinocyte growth factor (KGF), a
member of the fibroblast growth factor family. It is a glycoprotein, and a
very potent stimulant for the proliferation of normal epithelial cells. KGF
stimulates the proliferation of type-2 pneumocytes and also helps
differentiate them back toward type-1 pneumocytes, the cells in the alveoli
responsible for oxygen exchange.