Ex Parte Mehlhorn

Board of Patent Appeals and Interferences

May 25, 2011

10759222 (B.P.A.I. May. 25, 2011)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
10/759,222 01/20/2004 Rolf Joachim Mehlhorn 088799.00002 6448
44955 7590 05/25/2011
SQUIRE, SANDERS & DEMPSEY (US) LLP
275 BATTERY STREET, SUITE 2600
SAN FRANCISCO, CA 94111-3356
EXAMINER
WEDDINGTON, KEVIN E
ART UNIT PAPER NUMBER
1629
MAIL DATE DELIVERY MODE
05/25/2011 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte ROLF JOACHIM MEHLHORN
__________

Appeal 2010-010938
Application 10/759,222
Technology Center 1600
__________

Before DONALD E. ADAMS, DEMETRA J. MILLS, and STEPHEN
WALSH, Administrative Patent Judges.

WALSH, Administrative Patent Judge.

DECISION ON REQUEST FOR REHEARING
Rolf Joachim Mehlhorn (Appellant) requests reconsideration of the
Decision on Appeal entered January 18, 2011, which affirmed the rejection
of claims 1-12 on the ground of obviousness.
BACKGROUND
In its Decision, the Board agreed with the Examiner’s findings
concerning the scope and content of the prior art, and concluded that the
record evidence supported the Examiner’s conclusion of obviousness. The
Examiner had found that prior art patents of Nichols, Deamer, and Cramer,
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Application 10/759,222

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taught methods of loading liposomes using pH gradients. We agreed with
the Examiner that the prior art methods were similar to Appellant’s method,
and there were no nonobvious differences between the methods. We
concluded that certain features recited in Appellant’s claims served to
identify latent properties of the prior art methods or materials rather than to
define nonobvious methods or materials.
Appellant contends that non-obviousness of the claimed method is
predicated on the “surprising finding that . . . a drug may be maintained
within a vesicle for a substantial period of time after the pH gradient used to
load the vesicle has been destroyed” if a vesicle/buffer combination is used
in which the vesicle is impermeable to the buffer. (Req. Reh’g 1-2.)
Appellant disagrees that vesicle buffer impermeability was an inherent or
latent property of the prior art vesicles. (Id. at 2.) Appellant provides a
review of each reference (id. at 2-3) and summarizes: “there appears to be
no support for the position that maintenance of a concentration gradient in a
vesicle as required by the instant invention is an inherent or latent property
of vesicles – in fact quite the opposite is suggested by the cited references”
(id. at 3).
ANALYSIS
The claims define a method of loading lipid-like vesicles with a
chemical species and include the step “adjusting the exterior solution to a
physiologically benign pH; wherein: the chemical species is substantially
maintained in the vesicle for at least one quarter hour after the adjustment of
the exterior solution.” According to Appellant, both Nichols and Deamer
show that when a pH gradient is destroyed, the concentration gradient of the
chemical species across the vesicle collapses. Appellant thus argues that
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Application 10/759,222

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maintenance of the gradient “as required by the instant invention,” could not
be an inherent or latent property of the prior art vesicles. (Req. Reh’g 3.)
We agree that Nichols and Deamer demonstrate the collapse of a
gradient when the exterior solution is adjusted to pH 5. However, the
claimed method adjusts to “a physiologically benign pH.” Appellant does
not demonstrate that a person of ordinary skill in the art would have
interpreted the claim term to include pH 5. In our review of the
Specification we find this indication:
[i]n instances where it is desirable to inject the animal
immediately with the vesicle containing solution having the
adjusted pH, the pH is adjusted to a physiologically benign
value of between about 7 and about 7.8, preferably about 7.4.

(Spec. 13.) Given that the prior art gradient collapse occurs at pH 5, not in
the “between about 7 and about 7.8” pH range indicated as “physiologically
benign,” we find Appellant’s evidence insufficient to rebut the Examiner’s
original finding that because the claims use the same materials as the prior
art, the prior art liposomes would have had the claimed properties.
The Request redirects attention to the Nichols and Deamer
disclosures. We have reviewed those disclosures again as requested. We
note that Nichols prepared its liposomes with egg phospatidylcholine
(Nichols at 270), and Deamer prepared its liposomes from egg lecithin
(Deamer at 324). Appellant’s Specification indicates that phosphatidyl
choline may be used in the invention. (Spec. 18, Example 3.) We again find
no error in the Examiner’s finding that the claimed method uses the prior art
materials.

Appeal 2010-010938
Application 10/759,222

4
CONCLUSIONS
We have reconsidered all the evidence, but conclude that the totality
of the evidence of record is sufficient to show obviousness.

SUMMARY
We deny the requested relief.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

DENIED

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