Appeal No. 2006-0704 Page 4
Application No. 10/060,697
and separation of bone powder occurs to an excessive extent where a
particular application is concerned, a thickener such as a . . . cellulosic
ester such as hydroxypropyl methylcellulose . . . can be combined with the
carrier in an amount sufficient to significantly improve the suspension-
keeping characteristics of the composition.
Id., pages 4-5 (emphasis added).
The examiner concludes that O’Leary therefore “provides the motivation to
produce a bone graft substitute composition comprising a mixing solution [i.e.,
biocompatible liquid synthetic organic material such as glycerol], a plasticizing
substance [i.e., hydroxypropyl methylcellulose] . . . and demineralized bone matrix.”
Id., page 5.
The examiner acknowledges that O’Leary does not teach a composition
comprising calcium sulfate, but cites Yim for this limitation. See the Examiner’s Answer,
page 6. The examiner notes that Yim teaches compositions for promoting the growth of
bone comprising bone morphogenic proteins and a calcium sulfate hemihydrate-
containing substance (CSHS). Id. The examiner notes that Yim’s compositions can
also contain hydroxypropyl methylcellulose, among other things, as a “protein-
sequestering agent.” Id., page 7. Thus, the examiner finds that Yim discloses
a bone graft substitute composition, similar to O’Leary et al., which
contains calcium sulfate, a mixing solution [i.e., “water or saline or other
buffers”; Examiner’s Answer, page 9, line 16], and a plasticizing substance
[i.e., hydroxypropyl methylcellulose] and which has improved moldability
and consistency.
Id., page 9.
The examiner concludes that “it would have been obvious to one of ordinary skill
in the art at the time the invention was made to modify the composition of O’Leary et al.,
with components of the composition of Yim et al.” Id., page 10. Specifically, “[o]ne of
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