Molecular Insight Pharmaceuticals, Inc. Presents Positive Phase 1 Prostate Cancer Data at the Annual Congress of the European Association of Nuclear Medicine

CAMBRIDGE, MA--(Marketwire - October 19, 2011) - Molecular Insight Pharmaceuticals, Inc. (MIP) presented positive new clinical data on breakthrough molecular imaging for the detection of metastatic prostate cancer in bone and soft tissue. The data were presented on October 18, 2011 at the Annual Congress of the European Association of Nuclear Medicine (EANM) in Birmingham, U.K. 99mTc-MIP-1404 and 99mTc-MIP-1405, internally developed at Molecular Insight, are technetium-99m-labeled small molecules that target prostate-specific membrane antigen (PSMA), a protein expressed at high levels in primary and metastatic prostate cancer. The Phase 1 data presented at EANM demonstrated that 99mTc-MIP-1404 and 99mTc-MIP-1405 rapidly detected both bone and lymph node lesions in 6 metastatic prostate cancer patients and in some cases demonstrated a greater number of lesions in bone than standard of care imaging such as bone scans. Neither compound localized in the normal prostate gland.

Study Background: 99mTc-MIP-1404 and 99mTc-MIP-1405 are small molecule inhibitors of PSMA that exhibit high affinity for the extracellular domain of this enzyme, an emerging and validated target for the detection of metastatic prostate adenocarcinoma. The aim of this study was to assess the pharmacokinetics and tumor localizing characteristics of 99mTc-MIP-1404 and 99mTc-MIP-1405 in six healthy men and in six men with metastatic prostate cancer.

Study Results: In healthy volunteers and prostate cancer patients, whole body imaging demonstrated rapid and persistent uptake of 99mTc-MIP-1404 and 99mTc-MIP-1405 in the salivary, lacrimal, and parotid glands. Liver and kidney uptake was also evident, with greater uptake and retention with 99mTc-MIP-1404. Both agents cleared the blood in a biphasic manner, with 99mTc-MIP-1404 demonstrating significantly lower urinary activity compared to 99mTc-MIP-1405. In men with metastatic prostate cancer, 99mTc-MIP-1404 and 99mTc-MIP-1405 rapidly localized to lesions in lymph nodes and bone as early as 1 hour post injection. SPECT/CT images at 4 and 24 hours demonstrated excellent lesion contrast with target-to-background ratios ranging from 3:1 to 28:1. Good correlation was seen with bone scans in most patients, though, in general, more lesions were visualized with 99mTc-MIP-1404 and 99mTc-MIP-1405 than bone scan.

Study Conclusions: 99mTc-MIP-1404 and 99mTc-MIP-1405 rapidly detect lesions in soft tissues and bone in patients with metastatic prostate cancer, and both imaging agents, in some patients, demonstrated a greater number of lesions in bone than bone scans. Enlarged and sub-centimeter lymph nodes were clearly visualized. Further work is planned with these novel Tc-99m-labeled PSMA-targeted agents to correlate imaging findings with histopathological findings.

Dr. John W. Babich, President and Chief Scientific Officer of Molecular Insight, noted, "Prostate cancer is the most commonly diagnosed malignancy and the second leading cause of cancer-related death among men in the U.S. affecting 1 in 6 men between the ages of 60 and 80. While prostate-specific-antigen (PSA) screening has become the primary tool for the detection of prostate cancer, this blood test provides no information about the location and extent of the disease. New imaging methods that will more accurately diagnose and stage metastatic prostate cancer, as well as monitor progression and response to therapy, should enable improved patient management including treatment selection and planning and should lead to better patient outcomes. PSMA is a protein highly expressed in prostate cancer and metastatic prostate cancer, with much lower levels expressed on normal prostate tissue. A correlation of PSMA expression with PSA level, tumor stage, disease recurrence, and time to progression has been demonstrated, making it an attractive molecular target for the detection of primary and metastatic prostate cancer."

Dr. Babich also explained that if it is possible to accurately visualize the burden of disease and see it shrink with the appropriate treatments or progress with ineffective therapies, we can offer a more sophisticated means of decision making for the oncologist which should translate to better patient outcomes. MIP is developing radiolabeled small molecular inhibitors of PSMA for medical imaging and for targeted radiotherapy of metastatic prostate cancer. The most recent clinical data have shown these compounds can readily image metastatic prostate cancer in bone and in soft tissues using a widely available and cost effective imaging modality known as SPECT or single photon emission computed tomography. Based on prior experience in animal tumor models and now in prostate cancer patients, MIP is developing a radiotherapeutic for prostate cancer.

"Molecular Insight (MIP) is continuing its effort to change the prostate cancer landscape by providing novel ways of imaging prostate cancer and potentially treating metastatic prostate cancer in man," said Dr. Babich.

Note: The abstract, Novel 99mTc-labeled Small Molecule Inhibitors of Prostate-Specific Membrane Antigen (PSMA): Initial experience in healthy volunteers and men with metastatic prostate adenocarcinoma (Pca), is currently available on the Company's website, www.molecularinsight.com, under the Molecular Medicine tab, Scientific Presentations.

About Molecular Insight Pharmaceuticals, Inc.
Molecular Insight Pharmaceuticals is a clinical-stage biopharmaceutical company and pioneer in molecular medicine. The Company is focused on the discovery, development, and commercialization of targeted therapeutic and imaging radiopharmaceuticals for use in oncology. For further information, please visit the Company's website: www.molecularinsight.com.