Indium-111 pentetreotide therapy in somatostatin receptor expressing neoplasms: Results from clinical practice

Abstract

4269 Background: Therapeutic In-111 pentetreotide effectively controls symptoms in two-thirds of pts with hormonally active neuroendocrine neoplasms that overexpress the somatostatin receptor subtype 2. Auger electrons that are internalized into the nucleus provide cell-specific cytotoxicity. Renal excretion is the major route of elimination for In-111 pentetreotide. We hypothesized that In-111 pentetreotide therapy in community practice would not only offer an unmet medical need but provide an opportunity to further establish safety and efficacy of this particular form of radiolabeled somatostatin analog therapy. Methods: Between September 1999 and July 2003, pts undergoing therapeutic In-lll pentetreotide at Memorial Medical Center New Orleans, LA were included into this study. Clinical data including age, gender, diagnosis, date of diagnosis, prior treatment(s), hepatic and renal function were recorded. Serial data were collected for those pts receiving 2 or more In-111 pentetreotide therapies. Complete blood counts and differentials were reviewed. Creatinine clearance and survival were calculated as end measures of safety and efficacy, respectively. Results: 85 pts (46 females) were treated with an average dose of 487.9 mCi of In-111 pentetreotide during this 4-year period. The median age was 54.9 yrs. The majority of pts had a well-differentiated neuroendocrine tumor such as carcinoid or pancreatic islet cell carcinoma. 142 treatments were delivered with 41 pts receiving 2 or more treatments (28 pts were treated twice; 10 pts received 3 doses and 3 pts received 4 doses). The baseline creatinine clearance was 93 ml/min. For the 41 subjects treated on more than one occasion, subsequent creatinine clearances were 82.8, 95.2 and 81.9 ml/min following cumulative doses 493, 986 and 1,483 mCi, respectively. Treatment-related myelosuppression or myelodysplasia were not observed. The median survival was 22.1 mos from the time of the first In-111 pentetreotide treatment and 84.3 mos from the time of diagnosis. Conclusions: In-111 pentetreotide therapy can be safely administered in a community hospital setting. No significant financial relationships to disclose.