Appeal No. 2006-2213 Page 5
Application No. 09/771,151
2. Anticipation by Abra
The examiner rejected claims 1, 3-9, and 16, all of the pending claims, under
35 U.S.C. § 102(b) on the basis that the claimed method is anticipated by Abra.2 The
examiner stated that Abra “discloses a method of preparation of liposomes containing
supersaturated solution of an active compound. The Iiposomes further contain a
hydrophilic polymer (PEG) (note the abstract, page 2 line 15 through page 3, line 24,
page 6, lines 14-26, page 12, lines 4-21, Example 3 and claims).” Answer, page 4.
In response, Appellants argue that “Abra et al. fail to teach selection of liposome
size in order to maintain the compound in the form of a supersaturated solution.
Specifically, Abra et al. fail to teach each of steps (ii), (iii) and (iv) as set forth in
independent claims 1 and 16.” Brief, page 8. Appellants urge that Abra’s process
comprises only the two steps of (a) heating a cisplatin solution to increase the drug’s
solubility, and (b) producing liposomes from the heated drug solution, and that
“[n]owhere does Abra et al. teach steps of ‘preparing liposomes at selected size
intervals’, ‘analyzing the liposomes as a function of size for the presence of precipitated
compound’, or ‘based on the analyzing selecting a liposome size that corresponds to
liposomes having no precipitated compound’ as presently claimed.” Id.
Appellants emphasize Abra’s explicit statement, at page 4, lines 34-35, that the
cisplatin is entrapped within the liposomes “in dissolved form or in precipitated form.”
Id., at pages 8 and 9. Thus, Appellants urge, “[b]ecause the liposomes of Abra et al.
could include the cisplatin drug in precipitated form, it cannot be said that Abra et al.
inherently anticipates the claimed process of preparing liposomes with drug solely in the
2 Abra, WO 98/07409, published February 26, 1998
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