Fast Track OK for g17dt anti-gastrin immunogen for gastric cancer therapy
MIAMI, FLA., Feb. 21, 2003 -- Aphton Corporation announced that the FDA has reviewed and granted Aphton's request for Fast Track designation for its G17DT (anti-gastrin) immunogen in combination with cisplatin and 5-FU, "for use in stage IV gastric cancer to improve overall survival."
Fast Track is a formal mechanism to interact with the FDA using approaches that are available to all applicants for marketing claims. The benefits of Fast Track include scheduled meetings to seek FDA input into development plans, the option of submitting a New Drug Application in sections rather than all components simultaneously, and the option of requesting evaluation of studies using surrogate endpoints. The Fast Track designation is intended for the combination of a product and a claim that addresses an unmet medical need, but is independent of the FDA's priority review and accelerated approval mechanisms.
It is estimated that there are approximately 570,000 patients with gastric cancer in the US, Europe and Japan, alone. The prognosis for the overwhelming majority of these patients is very poor.
Patients diagnosed with metastatic disease have five-year survival rates of only about three percent. Surgery and chemotherapy are the primary treatment options currently, but these regimens have shown only very limited benefit.
Aphton believes that its anti-gastrin targeted immunotherapy approach has the potential to extend patient survival without adding toxicity.
Aphton is conducting one Phase III and three Phase II clinical trials. Aphton's anti-gastrin targeted therapy induces antibodies in patients that bind to both gastrin 17 and gly-gastrin and remove them from circulation before they can bind to the cancer cell and initiate cell growth. Gastrin 17 and gly-gastrin are believed to be central growth factors, or the initiating signals, for cell growth, cell proliferation and metastasis (spread) in gastric, i.e. stomach, pancreatic, esophageal, colorectal and other gastrointestinal (GI) system cancers. This signaling program is accomplished by gastrin binding to the large numbers of gastrin receptors which appear, de novo, in the great majority of cases, on tumor cell surfaces throughout the gastrointestinal system.
Interrupting this process by immunizing the patient with Aphton's anti-gastrin immunogen is a precisely "targeted" immunotherapy. This specificity of targeting only cancer cells occurs because gastrin is not normally secreted and gastrin receptors are not normally found on cells in the GI system, unless they are malignant, or on the path to malignancy (except for those cells involved with normal acid secretion).
Recent findings have shown that inhibiting gastrin not only inhibits cell growth, proliferation and metastasis directly, but also "unblocks" a central pathway leading to cell-suicide (apoptosis). This tilts the balance, from cell growth, to cell suicide. This effect is amplified synergistically when Aphton's drug is given together with a chemotherapeutic drug.
Gastrin also stimulates the secretion and expression of other important growth factors and receptors within and on the surfaces of the cancer cells involved in tumor growth. Hence, inhibiting gastrin inhibits all of the foregoing factors contributing to tumor growth and spread, while simultaneously opening a central pathway to cell suicide. Aphton's anti-gastrin targeted therapy adds a biological dimension to the treatment of gastrointestinal cancers.
Source: Aphton Corporation
Posted: February 2003
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