CAPROMAB PENDETIDE - A REVIEW OF ITS USE AS AN IMAGING AGENT IN PROSTATE-CANCER

Capromab pendetide, radiolabelled with indium-lll, is a radioimmunosci ntigraphic imaging agent used in patients with prostate cancer. It con sists of a murine monoclonal antibody (7E11-C5.3) covalently joined to a linker-chelator molecule. 7E11-C5.3 is thought to be directed again st the intracellular domain of human prostate-specific membrane antige n (PSMA), a transmembrane glycoprotein expressed by prostate epithelia l cells. The diagnostic utility of capromab pendetide has been investi gated in 2 distinct patient groups. In patients with untreated prostat e cancer at high risk for pelvic lymph node metastases, capromab pende tide imaging had respective sensitivities and specificities of 52 and 96% in 1 study and 62 and 72% in another, as confirmed by pelvic lymph node dissection biopsy results. In patients with suspected occult rec urrent or residual disease after prostatectomy, capromab pendetide had respective sensitivities and specificities of 49 and 7 % in 1 study a nd 77 and 35 % in another for detection of cancer in the prostate bed. Almost half of these patients also had evidence of lesions outside th e prostate fossa (usually in the pelvic and abdominal lymph nodes) acc ording to immunoscintigraphic scans, but too few cases were confirmed to allow an evaluation of capromab pendetide. Four per cent of patient s who received single doses of capromab pendetide experienced adverse events. Elevated bilirubin levels, hypertension and hypotension each a ffected 1% of patients and elevated liver enzymes and injection site r eactions <1% of patients. Detectable human anti-mouse antibodies were reported in 8% of patients after a single dose of capromab pendetide a nd in 19% of patients after repeat infusions. Conclusions. Capromab pe ndetide offers improved sensitivity in the detection of prostate cance r over other noninvasive techniques. When used in conjunction with oth er techniques, it offers the possibility of defining the extent of loc alised and metastatic disease, thereby refining patient management.