Prosecution Insights
Last updated: April 19, 2026
Application No. 18/004,403

METHODS AND COMPOSITIONS FOR PRODUCING VIRAL FUSOSOMES

Final Rejection §103§112§DP
Filed
Jan 05, 2023
Examiner
BERKE-SCHLESSEL, DAVID W
Art Unit
1651
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Flagship Pioneering Innovations V Inc.
OA Round
2 (Final)
66%
Grant Probability
Favorable
3-4
OA Rounds
3y 0m
To Grant
99%
With Interview

Examiner Intelligence

Grants 66% — above average
66%
Career Allow Rate
484 granted / 731 resolved
+6.2% vs TC avg
Strong +32% interview lift
Without
With
+32.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 0m
Avg Prosecution
40 currently pending
Career history
771
Total Applications
across all art units

Statute-Specific Performance

§101
8.1%
-31.9% vs TC avg
§103
34.4%
-5.6% vs TC avg
§102
19.5%
-20.5% vs TC avg
§112
24.2%
-15.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 731 resolved cases

Office Action

§103 §112 §DP
DETAILED ACTION 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 . Response to Arguments The Applicant has provided a response dated 11/7/205; in the Response, the Applicant has provided amendments to the claims and arguments based upon the rejections. The amendments to the claims has provided for the withdrawal of the claim objections. The amendment to claim 5 has allowed for the withdrawal of the 35 USC 112(a) Written Description of the claims; The Applicant has provided a reasonable argument to assert that the claimed cell does not need to be deposited, and as such, these 35 USC 112(a) Written Description rejections are withdrawn. The claim amendments also provide for the 35 USC 112(b) rejections to be withdrawn. All of the prior 35 USC 112(a) and (b) rejections are withdrawn. On pages 17 of the Applicant’s Arguments, the Applicant states that von Maltzahn does not teach cathepsin. This was discussed in the rejections, and is why Pager, et al (Virology, 346, 251-257, 2006 [IDS Reference]) is used as a supporting reference. Similarly, on page 18 of the Applicant’s Arguments, the Applicant states that Pager does not teach all of the elements that are taught by von Maltzahn. Based upon this assessment, the Applicant is arguing the references individually; one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In the rejection is was noted that von Maltzahn provides for all of the claimed elements except for the inclusion of the cathepsin limitation. The rejection further notes that there is a clear nexus between the fusosomes of von Maltzahn and the cathepsin of Pager, wherein von Maltzahn teaches a virus that can be cleaved by the cathepsin of Pager. The Applicant has proved no reasons as to why the two references cannot be combined, nor is there an argument as to why the ordinary artisan would not find this combination obvious and predictable. As such, all of the 35 USC 103 rejections are maintained for all of the reasons provided in the previous rejection. On page 19 of the Applicant’s Arguments, the Applicant states that claim 4 has been canceled, and as such, the Non-Statutory Double Patenting rejection should be withdrawn. The rejection also applied to independent claim 5, and still continues to apply. As such, the Non-Statutory Double Patenting rejections will be modified to account for the fact that the rejection only applies to claim 5, and related dependent claims. New claims 30-36 have been added; these will be discussed in the rejections below. All of the claim objections have been withdrawn. All of the 35 USC 112(a) and (b) rejections are withdrawn. All of the 35 USC 103 rejections are maintained on the pending/non-canceled claims. All of the Non-Statutory Double Patenting rejections are maintained on the pending/non-canceled claims. No claims are allowed. Specification The lengthy specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claim 31 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 31 is indefinite because it is unclear how the claim limitation relates to the claim from which it depends. Claim 31 is dependent on claim 5, which states that at least 33% of the henipavirus F molecules are “active.” While the limitation of claim 5 is not necessarily indefinite, since the activation of various proteins would be clear to the ordinary artisan (for example, fibrinogen is activated into fibrin by the enzymatic cleavage of the inactive portion), it is unclear if the claimed truncation results in the claimed activation; furthermore, if at least 33% are active, it is unclear if the other 67% has the same truncation, or if there is no truncation resulting in inactive proteins. That is to say, if the limitation of claim 31 was performed on all of the claimed henipavirus proteins, would 100% of the proteins be active? Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing Ta background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1-3, 5-16, 18-22, 24-26, 28-30 and 32-36 are rejected under 35 U.S.C. 103 as being unpatentable over von Maltzahn, et al (PGPub 2020/0060980 [IDS Reference]) and Pager, et al (Virology, 346, 251-257, 2006 [IDS Reference]). von Maltzahn provides for methods of making fusosomes. See paragraph [0004]. The composition is made from a host/source cell. See paragraph [0005]. von Maltzahn states that the host cell can be modified to over express a protease, but does not explicitly state that it can be cathepsin. See paragraph [0737]. von Maltzahn includes henipavirus F and G, wherein they can be included together. See paragraph [0449]. von Maltzahn cultures the cells to produce a fusosome. See paragraph [0421]. Although von Maltzahn does not state the inclusion of cathepsin as the recommended protease, Pager indicates that cathepsin is particularly effective in cleaving henipavirus proteins. See page 251, entire. Since it is clear that cathepsin is a particularly effective protease for the cleavage of the proteins described in von Maltzahn, it would be obvious to substitute the general disclosure of “protease” with the specifically described cathepsin. With respect to claims 1-3, von Maltzahn generally describes the claimed method, and the cell used for making fusosomes. Although von Maltzahn does not explicitly state cathepsin, von Maltzahn does suggest proteases. Pager shows that cathepsin is particularly effective in cleaving the henipavirus proteins of von Maltzahn. With respect to claims 5 and 6, von Maltzahn appears to describe the same fusosome. With respect to claims 7, 8, 34 and 35, von Maltzahn describes methods of delivering exogenous cargo. See paragraph [0003]. With respect to claims 9 and 10, the retargeted henipavirus of von Maltzahn appears consistent with the claimed modification. See paragraph [0449]. With respect to claims 11, 12, 20-22, and 24-26, although Pager does not teach the sequence of the cathepsin molecules and von Maltzahn does not teach the sequences of the henipavirus proteins, these are well-known to the ordinary artisan. The Applicant has explicitly stated, in the most recent Applicant’s Arguments, that these sequences are known. With respect to claims 13-16, 18 and 19, since the rejection is based on the combination of references, the claimed limitation is not explicitly taught in the prior art. However, if the ordinary artisan were to combine von Maltzahn and Pager, there is a reasonable expectation that the claimed limitations would be met. With respect to claims 28, 30, and 32, von Maltzahn teaches that the cargo can be therapeutic nucleic acids. See paragraph [0004]. Lentiviral vectors are exceptionally well-known in the art. With respect to claim 29, von Maltzahn teaches human cells. See paragraph [0288]. With respect to claims 33 and 36, von Maltzahn teaches the presence of both henipavirus F and G proteins. Double Patenting The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969). A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b). The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13. The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer. Claims 5-8, 31, 34 and 35 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-40 of U.S. Patent No. 11,576,872. Although the claims at issue are not identical, they are not patentably distinct from each other because the patent describes fusosomes that include both henipavirus F and G proteins; this reads upon the claimed fusosomes that include these proteins. The patent is broader than the instant claim-set, since it describes fusosomes with other proteins. The fusosomes of the patent read upon, both, the fusosomes and the methods of delivery, of the instant claim-set. Furthermore, the patent provides for methods of administering the composition, and as such, anticipates the method provided in claims 7 and 8. 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 DAVID W BERKE-SCHLESSEL whose telephone number is (571)270-3643. The examiner can normally be reached M-F 8AM-5:30PM. 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, Melenie Gordon can be reached at 571-272-8037. 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. /DAVID W BERKE-SCHLESSEL/Primary Examiner, Art Unit 1651
Read full office action

Prosecution Timeline

Jan 05, 2023
Application Filed
Aug 05, 2025
Non-Final Rejection — §103, §112, §DP
Nov 07, 2025
Response Filed
Jan 14, 2026
Final Rejection — §103, §112, §DP (current)

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Prosecution Projections

3-4
Expected OA Rounds
66%
Grant Probability
99%
With Interview (+32.5%)
3y 0m
Median Time to Grant
Moderate
PTA Risk
Based on 731 resolved cases by this examiner. Grant probability derived from career allow rate.

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