Prosecution Insights
Last updated: April 19, 2026
Application No. 17/997,384

SONOSENSITIVE LIPOSOME AND METHOD FOR PREPARING SAME

Non-Final OA §103§112§DP
Filed
Oct 28, 2022
Examiner
BROWE, DAVID
Art Unit
1617
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Imgt Co. Ltd.
OA Round
3 (Non-Final)
26%
Grant Probability
At Risk
3-4
OA Rounds
4y 2m
To Grant
54%
With Interview

Examiner Intelligence

Grants only 26% of cases
26%
Career Allow Rate
183 granted / 715 resolved
-34.4% vs TC avg
Strong +29% interview lift
Without
With
+28.8%
Interview Lift
resolved cases with interview
Typical timeline
4y 2m
Avg Prosecution
64 currently pending
Career history
779
Total Applications
across all art units

Statute-Specific Performance

§101
2.2%
-37.8% vs TC avg
§103
42.1%
+2.1% vs TC avg
§102
6.9%
-33.1% vs TC avg
§112
34.2%
-5.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 715 resolved cases

Office Action

§103 §112 §DP
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 . DETAILED ACTION Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on December 24, 2025, that includes a response to the Final Office Action mailed September 24, 2025, has been entered. Claims 1 and 23 have been amended; and claims 2-5, 8, 9, 11-16, 18, 21, and 24-28 have been canceled. Claims 6, 7, 10, 17, 19, 20, 22, 23, and 29 have been withdrawn. Claim 1 is under examination. Withdrawal of Prior Objection - Abstract The abstract of the disclosure has been satisfactorily amended. Therefore, the objection to the abstract presented in the Final Office Action mailed September 24, 2025 is hereby withdrawn. Withdrawal of Prior Claim Rejections - 35 USC § 103 Neither Zhigaltsev et al. (U.S. Patent No. 7,273,620) nor Houser (Chemistry and Physics of Lipids. 1987; 43: 283-299) explicitly disclose or reasonably suggest “a liposome comprising a membrane consisting of DSPC, DSPE-mPEG2000, DOPE, cholesterol, and lyso-PC, wherein the DSPC, the DSPE-mPEG2000, the DOPE, the cholesterol, and the lyso-PC are included at a mol% of 1 to 40:1 to 9:35 to 80:0.1 to 40:1 to 10”, as now stipulated in newly amended claim 1. Zhigaltsev, the cited primary reference, is directed to a liposome comprising a membrane. However, Zhigaltsev’s liposome membrane necessarily requires a charged lipid, e.g. an anionic lipid such as DOPG, or a cationic lipid such as DODAC, which are excluded by*** the presently claimed liposome. Therefore, the 35 USC 103 rejection presented in the Final Office Action mailed September 24, 2025 is hereby withdrawn. ***It is noted that Zhigaltsev, in column 6, lines 18-40, expressly provides that DOPE is one such cationic lipid, which of course is not excluded, but rather required, by the present claims. However, one of ordinary skill in the art generally would not recognize DOPE itself as being a cationic lipid; and in column 12, lines 1-23, Zhigaltsev does not mention DOPE itself as being among the cationic lipids. Obviousness-Type 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. Claim 1 is provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 26-28 of copending U.S. Application No. 18/264,628. Claim 1 is directed to a liposome comprising a membrane consisting of DSPC, DSPE-mPEG2000, DOPE, cholesterol, and lyso-PC in a mole% ratio of 1 to 40:1 to 9:35 to 80:0.1 to 40:1 to 10. Claims 26-28 of copending U.S. Application No. 18/264,628 disclose a composition comprising sonosensitive liposomes comprising DSPC, DSPE-mPEG2000, DOPE, cholesterol, and lyso-PC in a mole% ratio of 1 to 50:1 to 10:5 to 80:0.1 to 50:0.1 to 20; and wt% amounts of 0.1-50%, 3-50%, 1-80%, 0.05-40%, and 0.5-10%, respectively. Although the claims at issue are not identical, they are not patentably distinct from each other because the composition of the copending Application does not require any ingredient that is necessarily excluded by the liposome of the present claims, or any additional ingredients or properties that would clearly make the composition of the copending Application patentably distinct from the liposomes themselves. By way of analogy, lemonade comprising lemon juice, water, and sucrose could reasonably be said to be patentably distinct from sucrose, but a generic “composition comprising sucrose” is not necessarily patentably distinct from sucrose. This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented. Claim Rejections - 35 USC § 112(a) The following is a quotation of the first paragraph of 35 U.S.C. 112(a): (a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention. The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112: The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention. Claim 1 is rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. Claim 1, as now amended, stipulates that “the DSPC, the DSPE-mPEG2000, the DOPE, the cholesterol, and the lyso-PC are included at a mol% of 1 to 40:1 to 9:35 to 80:0.1 to 40:1 to 10”. Applicant points to original claims 1-5 for support. Original claim 2 (filed October 28, 2022) stipulates that the “the DSPC, the DSPE-mPEG2000, the DOPE, the cholesterol, and the lyso-PC are included at a molar ratio (mol%) of 1 to 50:1 to 10:5 to 80:0.1 to 50:01 to 20”. The expression “molar ratio (mol%)” in the original specification and claims is being interpreted as the molar ratio, based on or derived from the mol% values. However, “molar ratio” and “mol%” are not one and the very same thing. A molar ratio represents the proportion of moles of one substance to another, whereas mol% is a percentage expressing the fraction of a specific element relative to the total composition. Applicant has amended the limitation as previously presented, i.e. “the DSPC, the DSPE-mPEG2000, the DOPE, the cholesterol, and the lyso-PC are included at a molar ratio (mol%) of 1 to 40:1 to 9:35 to 80:0.1 to 40:1 to 10” to the limitation now presented, i.e. “the DSPC, the DSPE-mPEG2000, the DOPE, the cholesterol, and the lyso-PC are included at a mol% of 1 to 40:1 to 9:35 to 80:0.1 to 40:1 to 10”. However, because “molar ratio” is not one and the very same as “mol%”, the current limitation is not one and the same as the subject matter disclosed in the original specification and claims. This constitutes new matter. Claim Rejections - 35 USC § 112(b) 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 1 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 1, as now amended, is directed to a liposome with a membrane that consists of DSPC, DSPE-mPEG2000, DOPE, cholesterol, and lyso-PC, and stipulates in a wherein clause that the DSPC, the DSPE-mPEG2000, the DOPE, the cholesterol, and the lyso-PC are included at a mol% of 1 to 40:1 to 9:35 to 80:0.1 to 40:1 to 10”, which renders the claim indefinite for the following reasons: 1. One of ordinary skill in the art cannot definitively ascertain whether the “mol%” values recited are based on the total number of moles of the 5 recited compounds in the membrane, or the total number of moles of lipid in the liposome, or the total number of moles of all compounds the liposome as a whole, or what. 2. In light of the specification which discloses molar ratios based on mol% values, one of ordinary skill in the art cannot definitively ascertain whether or not the mol% values stipulated for DSPC, the DSPE-mPEG2000, the DOPE, the cholesterol, and the lyso-PC are the actual mol% values, or rather the molar ratio based on the mol% values. One of ordinary skill in the art cannot definitively ascertain the metes and bounds of the claimed subject matter. ***For examination at this time, the claim is being interpreted as had been done previously, in which the “mol%” values are the molar ratio based on the total moles of the lipids in the membrane, and can be any equivalent ratio, e.g. a ratio of 20:15:10:10:5 is equivalent to a ratio of 4:3:2:2:1. Response to Arguments Applicant's arguments filed December 24, 2025 have been fully considered but they are not persuasive. i) Applicant contends, regarding the ODP rejection, that “the inventions are patentably distinct from each other” since “the claims of ‘628 are open” and “relate to a composition for use in penetrating the blood-brain barrier” while “the claims of the present application relate to liposomes themselves which are sonosensitive”. The Examiner, however, would like to point out the following: 1. Claim 1 is directed to a sonosensitive liposome comprising a membrane consisting of DSPC, DSPE-mPEG2000, DOPE, cholesterol, and lyso-PC in a mole% ratio of 1 to 40:1 to 9:35 to 80:0.1 to 40:1 to 10. Claim 26 of ‘628 discloses a sonosensitive liposome comprising DSPC, DSPE-mPEG2000, DOPE, cholesterol, and lyso-PC in a mole% ratio of 8 to 12:3 to 6:50 to 66:10 to 32:5 to 11. 2. Anyone of ordinary skill in the art would understand in the context of the present subject matter that the recited lipids in the liposome of ‘628 are in the membrane of the liposome, just as is the case for the present claims. 3. Hence, in contrast to Applicant’s assertion, the sonosensitive lipsosome disclosed in claim 26 of ‘628 is not patentably distinct from the sonosensitive lipsosome of present claim 1. The liposome of ‘628 includes all the requisite elements in the requisite mole ratios as required by the present claims, and does not include any elements necessarily excluded by the present claims. For the foregoing reasons, the ODP rejection is hereby maintained. Potential Future Rejoinder of Claims Claims 6, 7, 10, 17, 19, 20, 22, 23, and 29 remain withdrawn at this time. However, if Applicant wishes to have these claims rejoined in the future upom allowance of claim 1, Applicant is advised to make sure these claims are also in condition for allowance to avoid further Office Actions. While not necessarily an exhaustive list, the following issues are recognized which would need to be addressed: 1. Claim 10, which depends from claim 1, makes reference to “drug encapsulation efficiency” being 50-100%. Claim 1, however, says nothing at all about any method of drug encapsulation, about any encapsulated drug, or even anything about any drug at all. 2. Claim 19 says nothing about cholesterol, and contains periods in the middle of the claim. 3. Claim 23 is directed to a method of treating cancer by administering the composition of claim 1 to a subject, and applying ultrasound. Claim 1 says nothing at all about any active agent. Even if claim 1 included an active agent, Applicant is not enabled for treating cancer with any and all active agents known to man. 4. Claim 29 is directed to a “method of delivering a drug” which comprises administering an “effective amount” of the liposome of claim 6 to a subject. One of ordinary skill in the art cannot definitively ascertain the metes and bounds of “delivering a drug”. Does delivering a drug mean delivering the drug compound to its site of action such that it functions to treat a disease? Or, rather does delivering a drug really entail delivering the liposome containing the drug to the GI tract of a subject, where the drug may not be released or exert any therapeutic activity. In the latter scenario, the method would not appear to have any real utility. Further, one of ordinary skill in the art would not understand the “effective amount” of the liposome, since the goal is simply to deliver it to some undefined destination on or in a subject. Conclusion No claims are allowed. Inquiries Any inquiry concerning this communication or earlier communications from the examiner should be directed to DAVID BROWE whose telephone number is (571)270-1320. The examiner can normally be reached Monday - Friday, 9:30 AM to 6 PM EST. 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, Sue Liu can be reached at 571-272-5539. 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 BROWE/Primary Examiner, Art Unit 1617
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Prosecution Timeline

Oct 28, 2022
Application Filed
May 31, 2025
Non-Final Rejection — §103, §112, §DP
Sep 04, 2025
Response Filed
Sep 20, 2025
Final Rejection — §103, §112, §DP
Dec 24, 2025
Request for Continued Examination
Dec 31, 2025
Response after Non-Final Action
Jan 24, 2026
Non-Final Rejection — §103, §112, §DP (current)

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

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Prosecution Projections

3-4
Expected OA Rounds
26%
Grant Probability
54%
With Interview (+28.8%)
4y 2m
Median Time to Grant
High
PTA Risk
Based on 715 resolved cases by this examiner. Grant probability derived from career allow rate.

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