Office Action Predictor
Last updated: April 15, 2026
Application No. 18/471,468

CELL RETENTION DEVICE

Final Rejection §103
Filed
Sep 21, 2023
Examiner
PATEL, PRANAV N
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Sunflower Therapeutics, Pbc
OA Round
4 (Final)
68%
Grant Probability
Favorable
5-6
OA Rounds
2y 11m
To Grant
90%
With Interview

Examiner Intelligence

Grants 68% — above average
68%
Career Allow Rate
433 granted / 637 resolved
+3.0% vs TC avg
Strong +22% interview lift
Without
With
+22.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
45 currently pending
Career history
682
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
50.8%
+10.8% vs TC avg
§102
17.0%
-23.0% vs TC avg
§112
26.6%
-13.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 637 resolved cases

Office Action

§103
Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1, 7-10, and 16-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 3390774 (hereinafter referred as “Neely”), US 5906737 (hereinafter referred as “Hoeppner”), and US 4476022 (hereinafter referred as “Doll”). Regarding claims 1 and 7-10, Neely teaches a filter comprising: an elongated element (40) having a plurality of axial ribs circumferentially distributed around an exterior portion thereof, the axial ribs having radial peaks (43) and recessions (37, 44) therebetween (refer fig. 1, 2), the elongated element (combination of 40 and 48) being nonporous (refer Column 3-Lines 23-26), a membrane filter medium (12) surrounding the exterior portion of the elongated element and in contact with the elongated element at only the radial peaks of the axial ribs (refer fig. 1, 2), thereby forming a plurality of axial voids between the radial recessions and the membrane filter medium; a central channel (42) extending axially through at least a portion of the elongated element and terminating in an outlet (26); and at least one radial channel (opening 46) fluidically coupling the axial voids to the central channel. The limitation “negative pressure at the outlet propagates through the axial voids to the membrane filter medium” recites a manner of operating the filter without imparting additional structure. "[A]pparatus claims cover what a device is, not what a device does." Hewlett-Packard Co. v. Bausch & Lomb Inc., 909 F.2d 1464, 1469, 15 USPQ2d 1525, 1528 (Fed. Cir. 1990) (emphasis in original). A claim containing a "recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus" if the prior art apparatus teaches all the structural limitations of the claim. Ex parte Masham, 2 USPQ2d 1647 (Bd. Pat. App. & Inter. 1987). Gohl discloses supplying liquid to be filtered Neely does not teach that the elongated element having a plurality of longitudinal segments, adjacent longitudinal segments are sealably fitted together in a stacked sequence. Hoeppner teaches filter core unit a plurality of segments having a plurality of holes and means to attach one segment to a second segment whereby the length of the filter core unit can be varied by adding and subtracting segments (abstract, fig. 3, fig. 4). It would have been obvious to one of ordinary skill in the art before the effective filing date of invention to modify the elongated element of Neely to include a plurality of longitudinal segments, adjacent longitudinal segments are sealably fitted together in a stacked sequence to enable varying of length of the elongate element by adding or subtracting segments as taught by Hoeppner. Neely does not disclose that the recesses are radial, the at least one radial channel has a first end opening into the central channel and a second end opening into an annular region radially recessed relative to the ribs, wherein the annular region is unribbed, wherein the annular region has a plurality of circumferentially distributed radial channels therethrough, and wherein the elongated element includes a plurality of unribbed annular regions each having a plurality of circumferentially distributed radial channel therethrough. Doll teaches a filter comprising an elongated element (10) having a plurality of ribs and recesses (refer ribs 12 and recesses 14), wherein radial channels (16) open into an annular region radially recessed and relative to the ribs (refer openings 16 provided in radially recessed portions 14). Selecting shape of the ribs and recesses would have been an obvious matter of design choice to one of ordinary skill in the art. Doll discloses that flow velocity through the module is controlled by the shape and spacing of the ribs (refer column 3 – lines 43-51). It would have been obvious to one of ordinary skill in the art to modify the elongated element of modified Zeiler such that the radial channel opens into an annular region radially recessed relative to the ribs to control flow velocity as taught by Doll. Doll further teaches that the annular region (14) is unribbed, the annular region (14) has a plurality of circumferentially distributed radial channels (16) therethrough, that the elongated element includes a plurality of unribbed annular regions (14) each having a plurality of circumferentially distributed radial channels (16) therethrough. Regarding the limitation “a membrane filter medium wrapped as planar sheet around the exterior portion of the elongated element”, Doll discloses a planar membrane wrapped around an elongated element (10) having a plurality of ribs and recesses (refer ribs 12 and recesses 14). Selection of whether to use corrugated membrane or planar membrane would have been an obvious matter of choice to one of ordinary skill in the in view of membrane types disclosed by Neely, Doll and Hoeppner. Regarding claim 16, Neely further teaches that the elongated element has a substantially circular cross-section (Refer fig. 1, 2). Regarding claim 17, fig. 2 of Neely suggest that the radial peaks and radial recessions have substantially same width and height/depth. Court has held that "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Selecting relative dimensions of the height and width would have been an obvious matter of design choice to one of ordinary skill in the art. Regarding claims 18-19, The central channel of Neely inherently has a diameter (first diameter), and the membrane surrounding the elongated member also inherently has a diameter (second diameter). Neely does not disclose that a ratio of the first diameter to the second diameter ranging from 0.1 to 0.95. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Selecting diameters of the membrane and the central channel would have been an obvious matter of design choice to one of ordinary skill in the art. Regarding claim 20, The elongated element of Neely inherently has a length, and the wrapped membrane around the elongated element inherently has a diameter. Neely does not disclose that a ratio of the element length to the diameter being approximately 3.0. Court has held that "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Selecting length and diameters of the elongated element and membrane would have been an obvious matter of design choice to one of ordinary skill in the art. Claim(s) 11-15 are rejected under 35 U.S.C. 103 as being unpatentable over Neely, in view of Hoeppner and Doll as applied to claim 1 above, and further in view of US 201802272286 (hereinafter referred as “Gronwald”). Regarding claims 11-15, modified Neely teaches limitations of claim 1 as set forth above. Neely does not teach that the filter medium is cellulose ester (cl. 11), or polyethersulfone (cl. 12), or Cellulose acetate (cl. 13), polyvinylidene fluoride (cl. 14), or polycarbonate (cl. 15). Gronwald teaches membranes are made of various materials including cellulose ester, polyethersulfone, Cellulose acetate, polyvinylidene fluoride, and polycarbonate (refer [0039], [0046], [0079]). It would have been an obvious matter of choice to one of ordinary skill in the art to select known membrane material based on its suitability for its intended function in the filter device of modified Neely because Gronwald establishes that cellulose ester, polyethersulfone, Cellulose acetate, polyvinylidene fluoride, and polycarbonate are known membrane materials. Response to Arguments Applicant's arguments filed 10/17/2025 have been fully considered but they are not persuasive. Regarding rejection of claim 1, applicant argued that PNG media_image1.png 220 634 media_image1.png Greyscale This is not found to be persuasive because Doll discloses a planar membrane wrapped around an elongated element (10) having a plurality of ribs and recesses (refer ribs 12 and recesses 14). Selection of whether to use corrugated membrane or planar membrane would have been an obvious matter of choice to one of ordinary skill in the in view of membrane types disclosed by Neely, Doll and Hoeppner. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to PRANAV PATEL whose telephone number is (571)272-5142. The examiner can normally be reached M-F 6AM-4PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Bobby Ramdhanie can be reached at (571) 270-3240. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. PRANAV PATEL Examiner Art Unit 1777 /PRANAV N PATEL/Primary Examiner, Art Unit 1777
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Prosecution Timeline

Sep 21, 2023
Application Filed
Sep 21, 2023
Response after Non-Final Action
May 29, 2024
Non-Final Rejection — §103
Aug 29, 2024
Response Filed
Nov 26, 2024
Final Rejection — §103
May 29, 2025
Request for Continued Examination
Jun 02, 2025
Response after Non-Final Action
Jun 13, 2025
Non-Final Rejection — §103
Oct 17, 2025
Response Filed
Dec 30, 2025
Final Rejection — §103
Apr 06, 2026
Request for Continued Examination
Apr 07, 2026
Response after Non-Final Action

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
68%
Grant Probability
90%
With Interview (+22.2%)
2y 11m
Median Time to Grant
High
PTA Risk
Based on 637 resolved cases by this examiner. Grant probability derived from career allow rate.

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