Patients undergoing treatment for GC between 1997 and 2001 were tested for CD55PAT-SC1expression

Patients undergoing treatment for GC between 1997 and 2001 were tested for CD55PAT-SC1expression. patients showed signs of increased apoptosis Glutarylcarnitine within the primary tumour and 60% showed signs of tumour cell regression. Comparison of the 10-year survival rates of the R0-resected CD55PAT-SC1-positive patients treated with the PAT-SC1 antibody with a historical collective of R0-resected CD55PAT-SC1-positive patients not treated with PAT-SC1 indicated a survival benefit in the treated patients. Furthermore, comparison of the patient survival of CD55PAT-SC1-positive vs. CD55PAT-SC1-negative groups suggested that CD55PAT-SC1antigen expression is an independent predictor of poor survival in a Cox regression analysis. Antibody PAT-SC1 may be a useful additive therapeutic agent in the treatment of patients with CD55PAT-SC1-expressing GCs. In combination with radical standard surgery, PAT-SC1 given as an adjuvant or neoadjuvant immunotherapeutic agent induces apoptosis in tumour cells which may improve survival of these patients. Because of the human origin and its specific binding to the CD55PAT-SC1antigen, PAT-SC1 was well tolerated in this trial. Keywords:gastric cancer, antibody therapy, monoclonal antibody, PAT-SC1, prospective trial, gastrectomy, D2-lymphadenectomy, radical surgery == Introduction == Gastric cancer (GC) constitutes the second major cause of cancer-related mortality worldwide (1). The poor Rabbit Polyclonal to CLCN7 prognosis of this disease, including its high relapse rate even after curative resection and a high disease related mortality, has not been substantially improved in recent decades. Complete surgical resection is still the standard treatment for all patients with resectable GC; however, regional and less common systemic recurrence remain highly problematic. Although the role of extended lymphadenectomy Glutarylcarnitine remains controversial, it is still accepted that a modified D2-lymphadenectomy is reasonable, due to its beneficial role for a subgroup of patients (24). Yet, even among patients undergoing gastrectomy with curative intent, the 5-year survival rates are disappointingly low at 25 to 30% due to locoregional relapse and distant metastases (5). These circumstances have led to various adjuvant and neoadjuvant protocols. Although a beneficial role is attributed to adjuvant therapies, these are associated with severe side-effects often resulting in premature termination of a protocol (6,7). In contrast to these established procedures, the idea of tumour-specific therapy is captivating. Major advances have been achieved in the field of biological-based cancer therapies in the last decades. Some of the recently approved targeted therapeutics are currently being evaluated for the treatment of GC (8,9). The PAT-SC1 antibody described here was isolated with the aid of human hybridoma technology from a GC patient (10). This fully human IgM antibody reacts with a cancer-specific isoform of CD55 decay-accelerating factor (DAF), subsequently named CD55PAT-SC1(11). In previous studies the antigen was reported to be expressed in ~70% of diffuse-type gastric carcinoma and in 25% of intestinal-type according to the Lauren classification (12). More recent studies have demonstrated the expression of CD55PAT-SC1in ~80% Glutarylcarnitine of patients across different ethnic groups (unpublished data). Therefore, PAT-SC1 has a much broader potential than other targeted therapies which are currently under evaluation for the treatment of GC. One such therapy, trastuzumab, was found to react Glutarylcarnitine with only 22.9% of advanced GCs (13). PAT-SC1 shows no cross-reactivity with adult normal tissues, but some cross-reactivity with embryonal tissue, indicating that the antigen may be of oncofetal origin (10,14). Upon binding to CD55PAT-SC1, the antibody was found to induce apoptosis of stomach carcinoma cellsin vitro(14) andin vivoand showed tumour-suppressing activity in xenograft animal models (15). The apoptotic effect was not only noted in the primary tumour but in disseminated tumour cells as well (16). Disseminated tumour cells in the blood of patients with GC are Glutarylcarnitine an independent predictive marker of poor prognosis (17). Based on these promising results, an academic single-dose clinical study in patients with primary GC was initiated.