New Clinical Data for Cytogen's QUADRAMET and PROSTASCINT to be Reported at Upcoming Major Medical Meetings.

Data to include findings from Phase 1 QUADRAMET combination studies and outcomes data for PROSTASCINT

PRINCETON, N.J. -- Cytogen Corporation (NASDAQ: CYTO) today announced that five abstracts will be presented or published at upcoming major medical meetings. The data will include various Phase 1 clinical results for QUADRAMET[R] (samarium Sm-153 lexidronam injection) in combination settings for the treatment of metastatic bone disease arising from prostate cancer and multiple myeloma, as well as data from a study evaluating the outcomes of prostate cancer patients based on the findings of PROSTASCINT[R] (capromab pendetide) imaging. These presentations underscore Cytogen's strategy to maximize the market potential of its approved products through data-driven initiatives.

New data from three separate Phase 1 studies of QUADRAMET in combination with docetaxel (Taxotere[R], Sanofi-Aventis) in patients with hormone-refractory prostate cancer have been accepted for publication and/or presentation at the 43rd Annual Meeting of the American Society of Clinical Oncology (ASCO) taking place June 1-5, 2007, in Chicago, Illinois. The primary objective of each of these Phase 1 studies is to determine the safety and tolerability of the combination regimens utilizing a variety of doses and dosing regimens.

Additionally, new and complete data from a Phase 1 study evaluating QUADRAMET in combination with bortezomib (Velcade[R], Millennium Pharmaceuticals, Inc.) in patients with relapsed multiple myeloma will be presented in an oral presentation at the XIth International Myeloma Workshop taking place June 25-30, 2007 in Greece. The primary objective of the Phase 1 study was to determine the safety and tolerability of the combination regimen. As a secondary objective, the study also assessed response rates.

Today, Cytogen also reported that new data from an outcomes study in prostate cancer patients whose PROSTASCINT images showed uptake in the central abdomen as compared to those without such findings will be presented at a podium presentation at the American Urological Association (AUA) Annual Scientific Meeting taking place May 19-24, 2007 in Anaheim, California.

Consistent with the disclosure policies mandated by the meeting organizers, Cytogen will summarize the contents of these studies at the time the complete abstracts are presented or published.

About QUADRAMET

QUADRAMET is indicated for the relief of pain in patients with confirmed osteoblastic metastatic bone lesions that enhance on radionuclide bone scan. This press release describes clinical applications that differ from that reported in the QUADRAMET package insert.

QUADRAMET is an oncology product indicated for pain relief that pairs the targeting ability of a small molecule, bone-seeking phosphonate (EDTMP) with the therapeutic potential of radiation (samarium Sm-153). Skeletal invasion by prostate, breast, multiple myeloma, and other cancers often creates an imbalance between the normal process of bone destruction and formation. QUADRAMET selectively targets such sites of imbalance, thereby delivering radioactivity to areas of the skeleton that have been invaded by metastatic tumor.

QUADRAMET has demonstrated a range of characteristics that may be advantageous for the treatment of pain arising from metastatic bone disease, including early onset of pain relief (patients may experience pain relief within the first week with maximal relief generally occurring at three to four weeks after injection), length of pain relief, lasting a median of four months in responding patients, and predictable and reversible bone marrow toxicity or myelosuppression that tends to return to pretreatment levels after eight weeks. QUADRAMET is administered as a single intravenous injection, usually on an outpatient basis, and exhibits selective uptake in areas of bone formation with little or no detectable accumulation in soft tissue.

QUADRAMET Safety Profile

QUADRAMET causes bone marrow suppression. In clinical trials, white blood cell counts and platelet counts decreased to a nadir of approximately 40% to 50% of baseline in 123 (95%) of patients within 3 to 5 weeks after QUADRAMET, and tended to return to pretreatment levels by 8 weeks. Because of the unknown potential for additive effects on bone marrow, QUADRAMET should not be given concurrently with chemotherapy or external beam radiation therapy unless the clinical benefits outweigh the risks.

Blood counts should be monitored weekly for at least 8 weeks, or until recovery of adequate bone marrow function. Non-hematologic adverse events that occurred in 5% or more of patients and greater than placebo were pain flare (7%), diarrhea (6%), infection (7%), spinal cord compression (6.5%), arrhythmias (5%), and hematuria (5%). Patients who receive QUADRAMET should be advised that for several hours following administration, radioactivity will be present in excreted urine. To help protect themselves and others in their environment, precautions need to be taken for 12 hours following administration.

About PROSTASCINT

Cytogen's PROSTASCINT molecular imaging agent is the first and only commercial product targeting prostate-specific membrane antigen or PSMA. PROSTASCINT consists of Cytogen's proprietary PSMA-targeting monoclonal antibody, 7E11-C5, linked to the imaging radioisotope Indium-111. By targeting PSMA, the PROSTASCINT molecular imaging procedure can detect the extent and spread of prostate cancer using a standard gamma camera.

PROSTASCINT is indicated as a diagnostic imaging agent in newly diagnosed patients with biopsy-proven prostate cancer, thought to be clinically localized after standard diagnostic evaluation and who are thought to be at high risk for pelvic lymph node metastases. PROSTASCINT is also indicated as a diagnostic imaging agent in post-prostatectomy patients with a rising PSA and a negative or equivocal standard metastatic evaluation in whom there is a high clinical suspicion of occult metastatic disease.

About Cytogen

Founded in 1980, Cytogen is a biopharmaceutical company dedicated to advancing the treatment and care of cancer patients by building, developing, and commercializing a portfolio of specialty pharmaceutical products. The Company's specialized sales force currently markets CAPHOSOL([R]), QUADRAMET([R]), PROSTASCINT([R]), and SOLTAMOX([TM]) to the U.S. oncology market. CAPHOSOL is an advanced electrolyte solution for the treatment of oral mucositis and dry mouth that was approved as a prescription medical device. QUADRAMET is approved for the treatment of pain in patients whose cancer has spread to the bone, PROSTASCINTis a PSMA-targeting monoclonal antibody-based agent to image the extent and spread of prostate cancer, and SOLTAMOX is the first liquid hormonal therapy approved in the U.S. for the treatment of breast cancer in adjuvant and metastatic settings. The Company is also developing CYT-500, a third-generation radiolabeled antibody to treat prostate cancer. Cytogen's product-focused strategy focuses on attaining sustainable growth through clinical, commercial, and strategic initiatives.

A copy of the full prescribing information for CAPHOSOL, QUADRAMET, PROSTASCINT, and SOLTAMOX, including box warnings, may be obtained in the U.S. from Cytogen Corporation by calling toll free 800-833-3533 or by visiting Cytogen's web site at www.cytogen.com. The Company's website is not part of this press release.

This press release contains certain "forward-looking" statements within the meaning of the Private Securities Litigation Reform Act of 1995 and Section 21E of the Securities Exchange Act of 1934, as amended. All statements, other than statements of historical facts, included in this press release regarding our strategy, future operations, financial position, future revenues, projected costs, prospects, plans and objectives of management are forward-looking statements. Such forward-looking statements involve a number of risks and uncertainties and investors are cautioned not to put any undue reliance on any forward-looking statement. There are a number of important factors that could cause Cytogen's results to differ materially from those indicated by such forward-looking statements. In particular, Cytogen's business is subject to a number of significant risks, which include, but are not limited to the risk of obtaining the necessary regulatory approvals for new QUADRAMET or PROSTASCINT indications, as well as other factors expressed from time to time in Cytogen's periodic filings with the Securities and Exchange Commission (the "SEC"). As a result, this press release should be read in conjunction with Cytogen's periodic filings with the SEC. The statements contained herein are made only as of the date of this press release, and Cytogen undertakes no obligation to publicly update this information to reflect subsequent events or circumstances.