The Journal of Bone and Joint Surgery (American) 86:1961-1972 (2004)
© 2004 The Journal of Bone and Joint Surgery, Inc.
Recombinant Human Bone Morphogenetic Protein-2 Delivered in an Injectable Calcium Phosphate Paste Accelerates Osteotomy-Site Healing in a Nonhuman Primate Model
Howard J. Seeherman, PhD, VMD1,
Mary Bouxsein, PhD1,
Hyun Kim, PhD1,
Rebecca Li, PhD1,
X. Jian Li, MD1,
Maria Aiolova, PhD2 and
John M. Wozney, PhD1
1 Women's Health and Bone, Wyeth Discovery Research, 200 Cambridge Park Drive,
Cambridge, MA 02140. E-mail address for H.J. Seeherman:
hseeherman{at}wyeth.com
2 ETEX, University Park at MIT, 350 Massachusetts Avenue, Cambridge, MA
02139
Investigation performed at Women's Health and Bone, Wyeth Discovery
Research, Cambridge, Massachusetts
The authors did not receive grants or outside funding in support of their
research or preparation of this manuscript. One or more of the authors
received payments or other benefits or a commitment or agreement to provide
such benefits from a commercial entity. (H.J. Seeherman, M. Bouxsein, H. Kim,
R. Li, X.J. Li, and J. M. Wozney are employees of Wyeth. M. Aiolova is an
employee of ETEX. The -BSM was provided by ETEX.) No commercial entity
paid or directed, or agreed to pay or direct, any benefits to any research
fund, foundation, educational institution, or other charitable or nonprofit
organization with which the authors are affiliated or associated.
Background: In recent clinical trials demonstrating the efficacy of
recombinant human bone morphogenetic protein-2 (rhBMP-2) for the acceleration
of bone-healing, investigators used carriers requiring open surgery for
administration. In this study, we used a nonhuman primate fibular osteotomy
model to evaluate injectable rhBMP-2/carrier formulations that can be
administered in closed fractures.
Methods: The fibular osteotomy model was first characterized by
evaluating surgically harvested fibular segments containing untreated
osteotomy sites (controls) from seventy adult male Cynomolgus monkeys at eight
weeks (twenty-four monkeys), ten weeks (thirty-four), twelve weeks (six), and
fourteen weeks (six). Fibular segments, from twenty-four animals, in which an
osteotomy had not been performed served as normal controls (intact). The
contralateral limb of twenty-four of the animals was then used to evaluate the
effect of rhBMP-2 administered, three hours after the osteotomy, in eight
carrier formulations (buffer, calcium phosphate paste, and hyaluronan gel,
hyaluronan paste, and gelatin foam formulated with and without tricalcium
phosphate granules). Each carrier was used in three monkeys. At ten weeks, the
fibulae with the treated osteotomy sites were harvested and were compared with
the contralateral, untreated osteotomized fibulae (paired control). The most
promising carrier, calcium phosphate paste (alpha bone substitute material, or
-BSM), was then evaluated in eleven additional animals. The outcomes
included the findings on radiographs made weekly until the time of fibular
harvest, the callus area, the biomechanical properties, and the histologic
findings.
Results: Radiographic and histologic studies confirmed complete
bridging of the control osteotomy sites in most animals by fourteen weeks. The
mean torsional stiffness and maximum torque of the control osteotomy sites
were 42.7% and 53.7%, 55.2% and 60.4%, 66.7% and 66.4% of the mean torsional
stiffness and maximum torque of the intact fibulae at eight, ten, and twelve
weeks, respectively, but they were not substantially different from the mean
torsional stiffness and maximum torque of the intact fibulae at fourteen weeks
(82.3% and 79.8%). In the carrier screening study, outcome measures of healing
were more consistently enhanced in the rhBMP-2/ -BSM-treated osteotomy
sites. In the confirmatory study, the mean callus area, torsional stiffness,
and maximum torque were 86%, 72%, and 68% greater in the
rhBMP-2/ -BSM-treated osteotomy sites than in the paired-control
osteotomy sites at ten weeks (p < 0.001). The torsional stiffness and
maximum torque in the rhBMP-2/ -BSM-treated osteotomy sites were equal
to those in the intact fibulae, whereas those parameters in the paired-control
osteotomy sites were only 55% and 58%, respectively, of the torsional
stiffness and maximum torque of the intact fibulae. Histologic analysis
confirmed complete osseous bridging of the rhBMP-2/ -BSM-treated
osteotomy sites but incomplete bridging of the paired-control osteotomy sites
at ten weeks.
Conclusions: A single percutaneous injection of rhBMP-2/ -BSM
accelerates the healing of fibular osteotomy sites in nonhuman primates by
approximately 40% compared with the healing of untreated osteotomy sites.
Clinical Relevance: These results provide a rationale for evaluating
rhBMP-2/ -BSM as a means with which to accelerate healing in humans with
closed fractures.

CiteULike Connotea Del.icio.us Technorati What's this?
This article has been cited by other articles:

|
 |

|
 |
 
H. J. Seeherman, K. Azari, S. Bidic, L. Rogers, X. J. Li, J. O. Hollinger, and J. M. Wozney
rhBMP-2 Delivered in a Calcium Phosphate Cement Accelerates Bridging of Critical-Sized Defects in Rabbit Radii
J. Bone Joint Surg. Am.,
July 1, 2006;
88(7):
1553 - 1565.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
H. Seeherman, R. Li, M. Bouxsein, H. Kim, X. J. Li, E. A. Smith-Adaline, M. Aiolova, and J. M. Wozney
rhBMP-2/Calcium Phosphate Matrix Accelerates Osteotomy-Site Healing in a Nonhuman Primate Model at Multiple Treatment Times and Concentrations
J. Bone Joint Surg. Am.,
January 1, 2006;
88(1):
144 - 160.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. A. Rodeo, C. Hidaka, and S. A. Maher
What's New in Orthopaedic Research
J. Bone Joint Surg. Am.,
October 1, 2005;
87(10):
2356 - 2365.
[Full Text]
[PDF]
|
 |
|
|