Cytogen Corp. regained rights to Quadramet from Berlex Laboratories, a U.S. affiliate of Berlin-based Schering AG.

Princeton, N.J.-based Cytogen agreed to make an up-front payment and issue royalties on future sales in exchange for North and South American marketing rights to Quadramet (Samarium Sm 153 Lexidronam), a skeletal-targeting therapeutic radiopharmaceutical for the relief of bone pain in prostate and other types of cancer. Specific financial terms were not disclosed, though Wayne, N.J.-based Berlex said its Quadramet sales totaled about $8 million last year.

In a prepared statement, Cytogen President and CEO Michael Becker said the reacquisition of U.S. marketing rights "provides an excellent opportunity to accelerate Cytogen's product-driven, oncology-focused business model."

The transaction, which is expected to close within 90 days, remains subject to Cytogen obtaining any necessary financing for the reacquisition.

More than four years ago, Berlex obtained the product's North and South American marketing rights as Cytogen had not yet established an internal sales and marketing infrastructure. In the meantime, Cytogen received royalties on product sales through Berlex while building its own sales force. (See BioWorld Today, Oct. 30, 1998.)

Schering will continue to market the product in Europe through its unit, CIS Bio International, which it acquired in 2000.

Cytogen initially obtained a license to manufacture, use and sell Quadramet under a 1993 agreement with Dow Chemical Co. The product includes a short half-life therapeutic radionuclide (Samarium-153) bound to a small-molecule, bone-seeking phosphonate that targets and accumulates in osteoblastic sites - areas of new bone formation - delivering radioactivity in areas that have been invaded by metastatic tumor. The FDA approved Quadramet in 1997 for pain associated with confirmed osteoblastic metastatic bone lesions that enhance on radionuclide bone scan. (See BioWorld Today, April 1, 1997.)

Cytogen's stock (NASDAQ:CYTO) fell 19 cents Monday to close at $5.82.