New FDA Orphan Drugs: Leukocyte Interleukin, Pafuramidine Maleate, Plevitrexed

Jill Taylor

June 15, 2007

June 15, 2007 — The US Food and Drug Administration (FDA) has granted orphan drug designation for leukocyte interleukin as neoadjuvant therapy for patients with squamous cell carcinoma of the head and neck, pafuramidine maleate for the prevention of malaria, and plevitrexed for the treatment of gastric cancer.

Orphan Drug Leukocyte Interleukin for Cancer of the Head and Neck

On May 21, the FDA granted orphan drug designation to leukocyte interleukin (Multikine, CEL-SCI Corporation) as neoadjuvant therapy for patients with squamous cell carcinoma of the head and neck, an aggressive cancer that is estimated to account for up to 600,000 new cases of cancer occurring annually around the world. Patients with advanced disease typically have a 50% chance of survival in the 3 years after their first treatment.

Developed on the premise that cancer occurs when the immune system is imbalanced or weakened, Multikine is a mixture of naturally occurring cytokines representative of the cytokine mixture produced by a healthy immune system. According to CEL-SCI, it is the first immunotherapy developed as a first-line treatment for cancer.

Orphan Drug Pafuramidine Maleate for Malaria

On May 14, the FDA granted orphan drug designation to pafuramidine maleate (DB289, Immtech Pharmaceuticals, Inc) for the prevention of malaria, which has been estimated to kill more than 1 million people each year.

Global efforts to control malaria have been hampered by malarial resistance and dangerous adverse effects in currently available therapies. The World Health Organization reports that the majority of deaths from malaria occur in Africa, where the disease accounts for 1 in 5 childhood fatalities. Other at-risk populations in endemic areas are pregnant women and people infected with HIV.

In a phase 2a malaria-treatment trial, oral administration of pafuramidine maleate 200 mg per day for 5 days resulted in a 96% cure rate. Immtech Pharmaceuticals announced in April the initiation of a phase 2b clinical trial, in which uncomplicated malaria will be treated with pafuramidine maleate 400 or 600 mg per day for 3 days for the purpose of establishing a dose that can be studied as monotherapy in a subsequent phase 3 trial.

Orphan Drug Plevitrexed for Gastric Cancer

On May 29, the FDA granted orphan drug designation to plevitrexed (BGC 9331, BTG International, Ltd) for the treatment of gastric cancer, which forms in the tissue lining the stomach.

Because early stomach cancer is not detectable by physical examination and often does not cause symptoms, the majority of patients are diagnosed in advanced stages. In the United States, according to the National Cancer Institute, 21,260 new cases of gastric cancer and 11,210 gastric cancer deaths are projected in 2007.

Plevitrexed is a selective small-molecule thymidylate synthase inhibitor that has been shown in phase 1 and 2 trials to be effective as a single agent in the treatment of gastric, pancreatic, and ovarian cancers. BTG International reports that it is currently sponsoring an international multicenter phase 1/2 trial to evaluate an improved clinical protocol with plevitrexed in patients with advanced gastric cancer.



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