A new and convenient method for purification of 86Y using a Sr(II) selective resin and comparison of biodistribution of 86Y and 111In labeled Herceptin™

A simple and rapid procedure was developed for purification of cyclotron produced Y-86 via the Sr-86(p.n) Y-86 reaction. A commercially available Sr(II) selective resin was used to separate Y-86 from the cyclotron irradiated Sr(II) target with a recovery of the enriched Sr(II) target while yielding a 75-80% recovery of Y-86 suitable for radiolabeling either proteins or peptides. To demonstrate the utility of this methodology, the anti-HER2 monoclonal antibody Herceptin(TM) was radiolabeled with the purified Y-86 and compared to In-111 labeled Herceptin(TM). The biodistribution study demonstrated that In-111-Herceptin(TM) while a suitable surrogate for Y-90 in the major organs. did not parallel the uptake of Y-86-Herceptin(TM) in the bone, and thus may not accurately predict the level of Y-90 accumulation in the bone for clinical RIT applications. This result exemplifies the requirement of employing appropriate matched pair isotopes, for imaging and therapy to insure that dosimetry considerations may be addressed accurately. Published by Elsevier Science Inc. All rights reserved.