Molecular Insight Pharmaceuticals, Inc. Presents Clinical Data on Prostate Cancer Diagnostic

TrofexTM Demonstrates Potential to Rapidly Detect Prostate Cancer in Soft Tissues and Bone

CAMBRIDGE, - Molecular Insight Pharmaceuticals, Inc. (NASDAQ: MIPI) today presented clinical data on a radiolabeled, small-molecule molecular imaging pharmaceutical in development for diagnosis and staging of prostate cancer at the 2009 annual meeting of the Society of Nuclear Medicine (SNM) in Toronto. Trofex™, which targets prostate specific membrane antigen (PSMA), a protein highly expressed by prostate tumor cells, has the potential to both detect and, when labeled with a therapeutic isotope, to treat metastatic prostate cancer. This was one of four conference presentations on products and technologies under development at Molecular Insight.

In 2008, Molecular Insight initiated clinical studies of Trofex in patients with documented prostate cancer and confirmed hormone refractory metastatic disease. Two internally developed Trofex compounds, MIP-1072 and MIP-1095, were evaluated for their capacity to visualize the disease and to define their pharmacokinetic profiles. Both agents rapidly detected metastatic prostate cancer lesions in soft tissues and bone, confirming that targeting the extracellular domain of PSMA is a viable approach for the molecular targeting of this cancer. The compounds were uniquely able to detect metastases within one to two hours after injection.

"Based on the potential demonstrated here, to rapidly and clearly image prostate cancer, we have planned additional studies to investigate the performance of these radiolabeled small molecules in patients with metastatic prostate cancer," said John W. Babich, Ph.D., Executive Vice President, Chief Scientific Officer and President of Research and Development at Molecular Insight Pharmaceuticals. "Not only does this data demonstrate the capability to rapidly visualize bone metastasis and soft tissue lesions -- that may be missed by conventional imaging techniques -- imaging can be done in a single day, which is not possible with some of the products currently on the market for imaging recurrent metastatic disease.

"Currently more than 2.5 million American men suffer from prostate cancer," Dr. Babich said. "About 200,000 new cases are diagnosed yearly and there are 30,000 deaths from the disease annually. Conventional imaging technologies lack both sensitivity and specificity for detecting metastatic disease. The targeting compound that we developed for imaging is an Iodine-123 labeled small-molecule candidate. But when the compound is labeled with Iodine-131 we believe we also may have the potential to treat metastatic prostate cancer. We are conducting preclinical studies to assess the potential of Trofex as a therapeutic. Trofex could dramatically change the diagnosis of prostate cancer, as well as the treatment landscape. Our plan for 2009 is to first complete a proof of concept and dosimetry trial for the detection of prostate cancer. Appropriate results in the additional pilot studies could support a request for fast-track development designation for the detection of metastatic disease."

Molecular Insight Pharmaceuticals, Inc. to Present Clinical, Preclinical Data at the Society of Nuclear Medicine 2009 Annual Meeting

CAMBRIDGE, MA - Molecular Insight Pharmaceuticals, Inc. (NASDAQ: MIPI) researchers will present data on the Company's progress in developing novel radiopharmaceuticals that may provide a promising option for molecular imaging of solid tumors, at the Society of Nuclear Medicine (SNM) annual meeting in Toronto. The presentations include clinical data on Molecular Insight's Trofex(TM), a radiolabeled, small-molecule molecular imaging pharmaceutical in development for diagnosis and staging of prostate cancer. Trofex, an internally developed compound, targets prostate specific membrane antigen (PSMA), a protein highly expressed by prostate tumor cells, and has the potential to both detect and, when labeled with a therapeutic isotope, treat metastatic prostate cancer. Data also will be presented on Molecular Insight's recent discovery research oncology projects that have focused on the development of radiolabeled small-molecule inhibitors that target the cancer-related enzymes, carbonic anhydrase IX and seprase.

Molecular Insight Pharmaceuticals, Inc. Receives European Medicines Agency Approval to Proceed With Phase 3 Development of OnaltaTM

Molecular Insight Pharmaceuticals, Inc. Receives European Medicines Agency Approval to Proceed With Phase 3 Development of OnaltaTM

Orphan Drug in Development for Treatment of Neuroendocrine Tumors

CAMBRIDGE, MA- Molecular Insight Pharmaceuticals, Inc. (NASDAQ: MIPI) today announced that the European Medicines Agency (EMEA) has approved its Phase 3 protocol for Onalta (Yttrium-90 edotreotide). Onalta is the Company's lead radiotherapeutic product candidate under development for the treatment of metastatic carcinoid and pancreatic neuroendocrine tumors in patients whose symptoms are not controlled by conventional therapy. The compound has shown the potential to selectively deliver lethal radiation to cancer cells. The proposed Phase 3 trial will confirm that administration of Onalta results in stabilization, regression or complete remission of the carcinoid tumor, and improves carcinoid-related symptoms when compared to a high-dose regimen of the current standard therapy for this disease, Sandostatin®. With EMEA's approval of its proposed Phase 3 protocol in hand, Molecular Insight can proceed with the final clinical trial that will position Onalta for marketing authorization in the EU.

EMEA notified Molecular Insight that its Onalta Phase 3 protocol is acceptable, including the plan to assess and manage renal tolerance, that the endpoints and measures are appropriate, and that the number of patients proposed to be presented in support of safety for the future Marketing Authorization Application (MAA) is acceptable.

John W. Babich, Ph.D., Executive Vice President, Chief Scientific Officer and President of Research and Development of Molecular Insight, said that, "This is a significant Company milestone that allows us to proceed with a pivotal trial for Onalta in Europe. A successful trial would mean an innovative and well-understood therapy could be made available to thousands of patients whose lives are being cut short and who suffer from the debilitating symptoms that accompany this disease.

"The notification by EMEA comes on the heels of our Special Protocol Assessment (SPA) agreement with FDA allowing us to proceed to a pivotal phase 2 trial for Azedra™ Ultratrace™ (Iobenguane I-131) in another neuroendocrine cancer, pheochromocytoma. Azedra is also currently being evaluated for treatment of neuroblastoma. These drug candidates represent significant opportunities to provide neuroendocrine cancer patients with innovative therapies. Molecular Insight has selected Progression Free Survival (PFS) as the primary endpoint for the proposed Phase 3 study and overall survival will be assessed as a key secondary endpoint. The regulatory progress in Europe will hopefully be followed by regulatory progress in the USA."

According to Dr. Val Lewington, Consultant Physician, Royal Mardsen NHS Foundation Trust, "EMEA approval of this Phase 3 protocol represents a landmark in radionuclide therapy. The potential of this approach is well-recognized in Europe but this will be the first opportunity to evaluate this peptide-based radiotherapy in a major, multi-center, randomized clinical trial. It is difficult to overstate the importance of this step in the development of innovative therapies for inoperable neuroendocrine tumors which so often prove refractory to other treatment options. News of the EMEA decision will be welcomed enthusiastically both by clinicians and by patients with neuroendocrine disease."

The proposed Phase 3 protocol will evaluate 194 patients with metastatic, progressive, somatostatin receptor-positive, carcinoid cancer, receiving either Onalta or the standard of care. Carcinoid cancer is a rare, serious and life-threatening condition that affects a group of patients with few treatment options. Once the disease has metastasized, the patients' prognosis is poor: the best five-year survival rate is reported to be 20 - 30 percent.

Onalta is intended to complement Azedra™, Molecular Insight's other clinical stage radiotherapeutic candidate for the treatment of neuroendocrine tumors. In 2007, Molecular Insight acquired Onalta from Novartis Pharma AG, which had conducted three Phase 1 and three Phase 2 clinical trials involving more than 300 patients.

Molecular Insight Pharmaceuticals Inc. Reports Operating Results (10-Q)

Molecular Insight Pharmaceuticals Inc. (MIPI) filed Quarterly Report for the period ended 2009-03-31.

MOLECULAR INSIGHT PHARMACEUTICALS INC. is a biopharmaceutical company specializing in the emerging field of molecular medicine applying innovations in the identification & targeting of disease at the molecular level to improve healthcare for patients with life-threatening diseases. The company is focused on discovering developing & commercializing innovative molecular radiotherapeutics & molecular imaging pharmaceuticals with initial applications in the areas of oncology & cardiology. Its lead molecular radiotherapeutic product candidates Azedra & Onalta are being developed for detection & treatment of cancer. The company's lead molecular imaging pharmaceutical product candidate Zemiva is being developed for the diagnosis of cardiac ischemia or insufficient blood flow to the heart. In addition the company has a growing pipeline of product candidates resulting from application of its proprietary platform technologies to new and existing compounds. Molecular Insight Pharmaceuticals Inc. has a market cap of $103.5 million; its shares were traded at around $4.12 with and P/S ratio of 217.9.

Highlight of Business Operations:

Research and development expense decreased approximately $4.0 million or 40%, to $6.1 million for the three months ended March 31, 2009 from $10.0 million for the three months ended March 31, 2008. Key components of this spending decrease were attributed to the following: (1) completion of our Zemiva Phase 2 clinical trial which reduced overall program costs by about $3.1 million; (2) reduced clinical activity or costs of $0.6 million for Solazed to plan our Phase I clinical trial; and (3) reduction in costs of $0.8 million related to other non-key core programs to focus our resources on lead product candidates. These spending decreases were offset by an increase of $0.4 million for the development and validation of Onalta drug compound as we prepare for further clinical development.

General and administrative expense decreased $0.8 million or 15%, to $4.4 million for the three months ended March 31, 2009 from $5.2 million for the three months ended March 31, 2008. This decrease is due primarily to the $0.3 million savings in compensation and benefits realized from the workforce reduction implemented in late 2008 and reduction in costs of $0.4 million related to the use of consultants and outside services to support corporate management, marketing and communications. We anticipate a significant reduction in our general and administrative expenses for 2009 due to our cost-cutting initiatives implemented in the latter half of 2008.

Other expense, net increased $0.4 million to $5.0 million for the three months ended March 31, 2009 from other expense, net of $4.6 million for the three months ended March 31, 2008. During the first quarter of 2008 and 2009, interest expense was $5.8 million and $5.5 million, respectively, partially offset by interest income of $1.2 million and $0.5 million, respectively. The decrease in interest expense of $0.3 million in the first quarter of 2009 as compared to the first quarter of 2008 was due to lower LIBOR interest rates on our $150 million Senior Secured Floating Rate Bonds (“Bonds”), offset by an increase in the principal base on which interest is accrued. Interest accrued on the Bonds for the first three years from issuance date shall be payable through the issuance of paid-in-kind (“PIK”) and shall begin to accrue interest from the date of issuance of such PIK Bonds. The average interest rate was 11.79% and 9.84% for the three months ended March 31, 2008 and 2009, respectively. The decrease in interest income in the current quarter was the result of lower yields on our investments as well as a decrease in investment level. These investments and the associated income are utilized to fund current operations.

At March 31, 2009, we had $15.6 million in cash and cash equivalents, and $78.1 million of investments mainly in U.S. treasury bills with maturities over 90 days, for a total of $93.7 million available to finance future operations. Our cash and cash equivalents, and investments are held at two financial institutions, of which substantially all amounts were held in one institution.

Net cash used in operating activities decreased by $5.1 million to $11.9 million for the quarter ended March 31, 2009, compared to $17.0 million for the quarter ended March 31, 2008. The decrease in cash used in operations was primarily due to the decrease in net loss of $4.5 million and the decrease in payments for accounts payable and accrued expenses of $1.6 million in the first quarter 2009, compared to the first quarter 2008 and offset by an increase in prepayments to vendors of $0.6 million and reduction in non-cash interest expense of $0.3 million. The decreases in net loss and payments for accounts payable and accrued expenses were attributed to the reduction in research and development expenses of $4.0 million as compared to the same period in the prior year

with the completion of our clinical trial for Zemiva and implementation of non-development program-related cost-cutting measures in the second half of 2008 to optimize the use of our cash resources. Operational efficiencies implemented in general and administrative functions also contributed a $0.8 million decrease in net loss for the quarter ended March 31, 2009. Net cash provided by investing activities decreased by $5.5 million to $1.6 million for the quarter ended March 31, 2009 from a net cash provided of $7.1 million in the quarter ended March 31, 2008 primarily due to lower amounts of funds invested as such are utilized to fund operations. Net cash provided by financing activities related primarily to the exercise of common stock options. We anticipate that our annual cash burn will be reduced by 10 to 20 percent in 2009 as compared to the year ended 2008.

Molecular Insight Pharmaceuticals, Inc. to Announce First Quarter Financial Results on May 11, 2009

conference call on Monday, May 11, 2009 at 2 p.m., Eastern Time. During the call, senior management of Molecular Insight will review the Company's financial results and provide an update on its clinical development programs.

The Molecular Insight Pharmaceuticals' 2009 Annual Meeting of Stockholders will precede the conference call at 10:00 a.m., Eastern Time, the same day. The meeting will be held at the offices of Foley & Lardner LLP, 111 Huntington Avenue, Boston, MA 02199-7610.

Conference Call Details

To access the call on May 11, 2009 at 2 p.m., Eastern Time, dial 1-888-679-8038 (or 1-617-213-4850 for international participants) at least five minutes prior to the start of the call. The participant pass code is 18705639. For one week following the call, an audio replay can be accessed by dialing 1-888-286-8010 (or 1-617-801-6888 for international callers) and using the pass code 54219784.