FDA approves bone graft

by Cathy Mike

The U.S. Food and Drug Administration has approved the use of INFUSE Bone Graft, a revolutionary treatment that promises to reduce pain and recovery time for the more than 190,000 Americans who undergo lumbar spinal fusion surgery each year.

In this new procedure, protein-saturated sponges are placed in a patient’s spine to replace the disc removed during fusion surgery. The sponges contain bone growth factor, a substance that produces bone to complete the fusion.

“The availability of INFUSE Bone Graft could completely change the way surgeons perform spinal fusions for the treatment of low back pain,” says Thomas Zdeblick, chairman of the Department of Orthopedics and Rehabilitation at the Medical School.

“We’ll be able to eliminate the second surgery necessary to harvest the patient’s bone and still achieve equal, if not better, results compared to the current standard procedure,” says Zdeblick, one of the primary investigators for the clinical studies of INFUSE Bone Graft.

Low back pain affects an estimated 65 million Americans, and treatment options include pain medications, physical therapy and spine surgery. Spinal fusions, the most common type of spine surgery, essentially “weld” two or more vertebrae together to eliminate pain caused by movement of the problematic vertebrae.

Lumbar spinal fusion surgery currently requires two surgeries — one to remove small pieces of bone from the patient’s hip (autograft) and the second to implant it in the spine. Numerous studies have shown that patients experience considerably more pain from the hip surgery than they do from the fusion procedure itself.

INFUSE Bone Graft replaces the use of autograft bone because it contains a recombinant human bone morphogenetic protein or rhBMP-2, which causes the body to grow its own bone where needed.

When surgeons use INFUSE Bone Graft, rhBMP-2 powder is reconstituted with sterile water and then applied to a collagen sponge. The sponge is placed inside a thimble-like titanium device called an LT-CAGE and implanted between the vertebrae. The LT-CAGE keeps the INFUSE Bone Graft at the fusion site, maintains the proper height between the vertebrae and stabilizes the spine while it is fusing.

A large-scale, randomized, two-year study including patients from the UW was conducted to evaluate the safety and therapeutic benefits of INFUSE Bone Graft. Approximately half of the patients received autograft bone and the other half received INFUSE Bone Graft. Study results indicated that patients who underwent spine surgery using INFUSE Bone Graft showed a trend toward having higher fusion rates as compared to autograft patients at 24 months (94.5 percent fused versus 88.7 percent).

Zdeblick, who is also medical director for the UW Comprehensive Spine Center, says that INFUSE Bone Graft-which has rhBMP-2 as its active ingredient-is the only product statistically proven to produce results at least equivalent to transplanted bone.

The FDA panel conditions for approval include three additional post-approval studies in the areas of antibody response during pregnancy, dosing and the production of tumors.