AsymmetRx, Inc. announces FDA approval of "Prostate-63 Cancer Diagnostic Test"

February 9, 2005

Washington, D.C. The Food and Drug Administration approved the Prostate-63 Cancer Diagnostic Test as a diagnostic test to detect prostate cancer. The test features a mouse monoclonal antibody, clone 4A4, that recognizes the human p63 protein in the nucleus of prostatic basal cells and urothelial tissues (Yang et al., 1998; Signoretti et al., 2000). The bright staining of p63 provides for an easy diagnosis of prostate cancer.

For In Vitro Diagnostic Use. The Prostate-63 Cancer Diagnostic Test features a mouse monoclonal antibody, clone 4A4, that recognizes the human p63 protein in the nucleus of prostatic basal cells and urothelial tissues (Yang et al., 1998; Signoretti et al., 2000). This test is intended for laboratory use to qualitatively identify by immunohistochemistry the p63 antigen in histological sections from formalin-fixed paraffin-embedded tissue of normal and/or pathological prostate tissue obtained by needle biopsy or surgical procedures. The presence or absence of p63 staining aids the pathologist in the differential diagnosis of prostate cancer in conjunction with morphological findings seen with hematoxylin and eosin staining complemented by proper controls (Signoretti et al., 2000; Weinstein et al., 2002; Shah et al., 2002; Davis et al., 2002; Shah et al., 2004). The clinical interpretation of any staining or its absence should be evaluated within the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.

p63 Background. p63 is a member of the p53 family, which also includes p73 (Yang et al., 1998; Yang and McKeon, 2000). p63 is strongly expressed in the basal or progenitor cells of a large number of epithelial tissues (Yang et al., 1998). These tissues include squamous, transitional, and glandular epithelia, such as prostate, breast, esophagus, bladder, airway, and epidermis, among others. In general, these p63 positive basal cells act as the progenitors or reserve cells in these regenerative epithelia (Parsa et al., 1999). p63-deficient mice lack all epithelial tissues in which p63 is highly expressed, such as prostate, breast and epidermis. p63 mutant mice also show severe defects in limb and craniofacial development (Yang et al., 1999). A similar pattern is observed in patients with EEC syndrome, an autosomal dominant disorder characterized by ectodactyly, ectodermal dysplasia, and facial clefts, where affected patients are found to have dominant heterozygous p63 mutations (Celli et al., 1999). Recent studies support the utility of the 4A4 anti-p63 monoclonal antibody in the differential diagnosis of prostate cancer. (Signoretti et al., 2000; Weinstein et al., 2002; Shah et al., 2002; Davis et al., 2002; Shah et al., 2004).