Production of Commerical High Specific Activity Sn-117M Radiochemical and Chelates

Period of Performance: 01/01/2012 - 12/31/2012


Phase 1 SBIR

Recipient Firm

Clear Vascular, Inc.
21 Waterway Ave., Suite 225
The Woodlands, TX 77380
Principal Investigator
Firm POC


As outlined in the document Technical Topics Descriptions, FY 2012, Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) Programs, July 2011, page 137: Sn-117m has gotten a lot of interest in the last few years. It has favorable nuclear properties for both imaging and therapy. However commercial quantities of the isotope at high specific activity are not available. Supply of commercial quantities of high specific activity Sn-117m would be of high interest. Sn-117m has traditionally been made in significant quantities in reactors. However, the low specific activity ( & lt;10 Ci/g) produced by this method inherently restricts its applications. As a result, the difficulty of producing high specific activity Sn-117m has been a barrier to entry for this isotope in the field of nuclear medicine. In recent years, accelerator produced material has been demonstrated with high specific activities ( & gt;1000 Ci/g) but producing and purifying commercial quantities at a reasonable cost remains a challenge. Our initial small scale experiments have demonstrated the possibility of preparing high specific activity Sn-117m. However, further development of existing small-scale production methods and extending these methods to large-scale commercial manufacturing is needed. We plan to provide a reliable source of Sn-117m radiochemical and chelates for new medical products anticipated to enter the medical markets over the next few years. The availability of high specific activity Sn-117m will make it possible to prepare a variety of Sn-117m labeled compounds ranging from small chelates to large proteins such as monoclonal antibodies that target cancer. The aim of this work is to develop and demonstrate the viability of the making these products on a commercial scale for future medical uses. In order to provide a future commercial supply of high specific activity Sn-117m, we propose a Phase 1SBIR that expands on our prior experiences to include the following specific aims: 1. Reproducibly prepare high specific activity Sn-117m in high enough quantities to perform chelation and conjugation experiments that could be used in human clinical studies. 2. Prepare at least two different chelates of high enough purity to evaluate in-vivo or in-vitro for biological activity. 3. Show that it is possible to scale up the production of Sn-117m to commercially relevant and economically viable quantities. Commercial Applications and Other Benefits: Clear Vascular, Inc. and other companies are presently developing Sn-117m based radiopharmaceuticals for imaging and therapy of a number of medical conditions. The Clear Vascular product is an injectable radioactive imaging agent that targets vulnerable plaque (VP) and can be imaged non-invasively using any standard gamma camera found in any cardiology practice. Because there are no other non-invasive ways to detect VP, it will provide an important and needed diagnostic that can enable the cardiologist to aggressively treat patients with VP to reduce the number of sudden deaths, the cost of treating heart disease morbidity and the loss of productivity associated with cardiac artery disease (CAD) due to VP. VP is now recognized to be as large (or larger) a problem than arterial calcified plaque so a method to directly image, quantify and potentially treat VP should have similar or possibly larger market potential. Although Clear Vasculars focus is on cardiovascular products, we envision the utility of Sn-117m to be much broader. In our evaluation of the field we believe that Sn-117m would be an ideal isotope in bone pain palliation and in combination with proteins and peptides for the diagnosis and treatment of autoimmune diseases and cancer. In all these applications, high specific activity Sn-117m is the essential ingredient either because receptor sites are limited or because of the potential for overloading the body with toxic levels of certain chelates.