External radiation therapy is used to treat most types of cancer, including cancer of the bladder, uterine, cervix, rectum, prostate and vagina. During delivery of treatment, some level of radiation will also be delivered to healthy tissue, including the bowel, leading to acute and chronic toxicities. The large and small bowel are very sensitive to radiation. The larger the dose of radiation, the greater the damage to normal bowel tissue. Radiation enteritis is a condition in which the lining of the bowel becomes swollen and inflamed during or after radiation therapy to the abdomen, pelvis or rectum. Most tumors in the abdomen and pelvis need large doses of radiation, and almost all patients receiving radiation to the abdomen, pelvis or rectum will show signs of acute enteritis.
Patients with acute enteritis may experience nausea, vomiting, abdominal pain, diarrhea and bleeding, among other symptoms. Some patients may develop severe dehydration and require hospitalization. With diarrhea, the gastrointestinal tract does not function normally, and nutrients such as fat, lactose, bile salts, and vitamin B12 are not well absorbed.
Symptoms will usually resolve within two to six weeks after therapy has ceased. Radiation enteritis is often not a self-limited illness, as over 80% of patients who receive abdominal radiation therapy complain of a persistent change in bowel habits. Moreover, acute radiation injury increases the risk of development of chronic radiation enteropathy, and overall 5% to 15% of the patients who receive abdominal or pelvic irradiation will develop chronic radiation enteritis.
Soligenix is currently developing a novel time-released form of oral beclomethasone dipropionate (oral BDP; research name - SGX201) for the prevention of acute radiation enteritis. SGX201 contains BDP, a highly potent, topically active corticosteroid that has a local effect on inflamed tissue. BDP has been marketed in the United States and worldwide since the early 1970s as the active pharmaceutical ingredient in inhalation products for the treatment of patients with allergic rhinitis and asthma. BDP is also the active ingredient in orBec®, currently in Phase 3 and Phase 2 development by Soligenix for the treatment and prevention of gastrointestinal Graft-versus-Host disease (GI GVHD), respectively. SGX201 is a time-release formulation of BDP specifically designed for oral use.
The US Food and Drug Administration (FDA) completed its review and cleared the Investigational New Drug (IND) application for SGX201 for the prevention of acute radiation enteritis. The FDA has also designated SGX201 a Fast Tracked Product.