Cytogen Corp. filed a lawsuit against DuPont Merck Pharmaceutical Co., charging DuPont with failure to meet its obligations under a marketing agreement for Quadramet, a radiopharmaceutical drug for pain related to cancer that has spread to the bone.

Fred Kanner, an attorney with Dewey Ballantine LLP, of New York, representing Princeton, N.J.-based Cytogen, said the company "has a no-comment position at this point."

The deal with DuPont Merck, of Wilmington, Del., calls for percentage-based royalties, or a guaranteed contractual amount (whichever is greater) and milestone payments. As of March 31, Cytogen had recorded $1.6 million in Quadramet revenues, and about 74 percent of the company's accounts receivable balance was due from DuPont.

Cytogen had $2.4 million at the end of this year's first quarter, with a net loss of $4.3 million for the period.

DuPont Merck is a joint venture between E.I. DuPont & Co., of Wilmington, Del., and Whitehouse Station, N.J.-based Merck & Co. Inc. Last week DuPont agreed to pay $2.6 billion to buy out Merck's half. (See BioWorld Today, May 21, 1998, p. 1.)

Cytogen has three products on the market: Quadramet; ProstaScint, a diagnostic imaging agent for prostate cancer; and OncoScint CR/OV, a monoclonal antibody for detecting colorectal and ovarian cancers.

The company's stock (NASDAQ:CYTO) closed Friday at $0.75, down $0.281. — Randall Osborne