By Kim Coghill

Washington Editor

Curis Inc. and Stryker Corp., after years of trying, received U.S. regulatory approval for a new therapy that activates the body¿s ability to repair and regenerate tissue.

The FDA granted OP-1, an osteogenic protein, humanitarian device exemption (HDE) status for limited use as an alternative to autograft in bone nonunions when autograft is not feasible or when patients fail other treatments. The approval status allows OP-1 to be used in up to 4,000 patients annually.

¿What¿s really important about this is that it¿s the first approval of a new generation of therapies which utilizes the body¿s own reparative mechanisms,¿ Daniel Passeri, president and CEO of Cambridge, Mass.-based Curis, told BioWorld Today. ¿For instance, when a person breaks a bone, the damaged tissue has to be repaired and certain pathways are turned on. A coordinated gene expression occurs in a sequenced manner that is utilized by the body to form the needed tissue. Morphogenic proteins, such as OP-1, are gatekeepers for regulating pathways; they turn on other genes allowing cells to communicate with surrounding cells.¿

Stryker, of Kalamazoo, Mich., intends to launch Curis¿ OP-1 later this quarter. Stryker already is marketing OP-1 in Australia and the European Union for specific trauma indications.

The relationship between Curis and Stryker is an outgrowth of the merger of Creative BioMolecules Inc., of Hopkinton, Mass.; Ontogeny Inc., of Cambridge, Mass.; and Reprogenesis Inc., also of Cambridge, that formed Curis. At the time of the merger, Creative Biomolecules was in a partnership with Stryker to develop OP-1. (See BioWorld Today, Feb. 16, 2000.)

Doros Platika, chairman of Curis, gave Stryker the credit for maneuvering OP-1 through the FDA process. Earlier this year, the companies received notification that OP-1 was unapprovable due to a lack of statistical data. (See BioWorld Today, Jan. 31, 2001.)

¿That was a request for additional data to make sure the bone produced by this process of reactivating the body¿s ability to repair is equally strong to the bone produced by the bone graft,¿ Platika said. ¿Part of the reason why the FDA wants to be careful and why we and Stryker are so excited about this is that OP-1 represents a whole new category of product involving regenerative medicine, which is Curis¿ primary focus.¿

Platika added that the HDE status gives the FDA the chance to look at the performance of OP-1 in a more limited population before it is put on a broad label. ¿This first indication is probably the toughest patient population because these people have not healed,¿ he said. For example, some patients who may need this type of therapy would include diabetics or women with osteoporosis.

Stryker, though, is testing OP-1 in the larger spinal fusion population, and also has rights for all bone repair, periodontal diseases, and fresh fractures. Curis has the rights in other fields and, Platika said, OP-1 appears to be involved in renal repair and is showing strong evidence in stroke repair.

Curis will receive a royalty stream from the sales of OP-1, Passeri said.

Stryker and Creative BioMolecules had been working together since 1985 on OP-1, which belongs to the transforming growth factor-beta family. The device is a paste-like combination of OP-1 and a resorbable collagen scaffold that is surgically implanted in unhealed bone fractures.

This first FDA approval for Curis means a number of things, Passeri said. ¿First and foremost it gives us a revenue stream, which is obviously important for the ongoing operation of the company. But just as important, it gives validation to the underlying premise for our business of regenerative medicine. This is validation of our business model.¿