Broad-Based QUADRAMET Marketing Campaign Announced; Large Specialized Berlex Sales Force Will Reach More Prescribing Physicians in Cancer Pain Management.

PRINCETON and MONTVILLE, N.J.--(BUSINESS WIRE)--Feb. 16, 1999-- CYTOGEN Corporation (NASDAQ: CYTO) and Berlex Laboratories, Inc. today announced that on March 9, 1999, Berlex will formally launch a new marketing campaign for QUADRAMET(R) (Samarium 153 Lexidronam Injection). The product is approved in both the U.S. and Canada to treat bone pain caused by metastatic cancer. Through the combined efforts of its 130 specialized oncology and hospital-focused sales representatives, Berlex expects to significantly expand QUADRAMET(R)'s U.S. market presence to a broader base of physicians.

"The Berlex QUADRAMET(R) campaign will provide the tools and resources necessary to reach the doctors whose choices in cancer pain management can make a difference in patients' lives," said CYTOGEN President and Chief Executive Officer H. Joseph Reiser, Ph.D. "Berlex has demonstrated a significant commitment to QUADRAMET(R) and to the oncology community in planning this effort, and CYTOGEN is pleased to have a partner of Berlex's caliber. We believe Berlex's marketing and sales campaign will position QUADRAMET(R) as the unsurpassed treatment for relief of this type of bone pain."

Since signing an exclusive QUADRAMET(R) marketing agreement with CYTOGEN late in 1998, Berlex has been developing integrated marketing and medical initiatives to support the marketing campaign. Said Howard Robin, Berlex VP and General Manager for Therapeutics, "Many people with metastatic bone lesions experience severe pain, and QUADRAMET(R) can make a big difference in the quality of their lives. QUADRAMET(R) is an important alternative to existing treatments, and educating physicians about QUADRAMET(R) is a very high priority for Berlex."

Committed to developing novel therapeutics that address unmet medical needs, Berlex Laboratories, Inc. researches, manufactures, and markets ethical pharmaceuticals in three strategic areas: Diagnostic Imaging, Female Healthcare, and Therapeutics for life-threatening and disabling diseases. In the Therapeutics category, Berlex also markets FLUDARA(R) (fludarabine phosphate) to treat chronic lymphocetic leukemia, BETASERON(R) (Interferon beta-1b) to treat relapsing-remitting multiple sclerosis, and BETAPACE(R) (sotolol HCI) to treat life-threatening ventricular arrhythmias. Berlex business divisions are located in Montville and Wayne, New Jersey, and in Richmond, California. For more information, visit the Berlex website at www.berlex.com.

CYTOGEN is a biopharmaceutical company engaged in the development, manufacture, and commercialization of products for the targeted delivery of diagnostic and therapeutic substances directly to disease sites. CYTOGEN has demonstrated its ability to develop new technology from early discovery through clinical development, regulatory approval, and commercial scale biologic manufacturing. In addition to QUADRAMET(R) CYTOGEN has two FDA-approved products on the market: PROSTASCINT(R) (kit for the preparation of Indium In111 Capromab Pendetide), a prostate cancer imaging agent, and ONCOSCINT(R) (CR/OV imaging agent), an imaging agent for colorectal and ovarian cancers. Visit CYTOGEN's website at www.cytogen.com

Information in this press release, which is not historical, is forward looking and involves risks and uncertainties. Actual results may differ materially for various reasons, including CYTOGEN's ability to carry out its

business plan and successful development and commercial acceptance of CYTOGEN's products, and other factors discussed in CYTOGEN's filings with the Securities and Exchange Commission.