Prosecution Insights
Last updated: May 29, 2026
Application No. 18/744,031

FORMATION OF N-PROTECTED 3,6-BIS-(4-AMINOBUTYL)-2,5-DIKETOPIPERAZINE THROUGH A CYCLIC ALPHA-N-PROTECTED AMINO ESTER INTERMEDIATE

Final Rejection §DOUBLEPATENT
Filed
Jun 14, 2024
Priority
Mar 15, 2013 — provisional 61/798,016 +7 more
Examiner
VAJDA, KRISTIN ANN
Art Unit
1622
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Mannkind Corporation
OA Round
4 (Final)
84%
Grant Probability
Favorable
5-6
OA Rounds
0m
Est. Remaining
95%
With Interview

Examiner Intelligence

Grants 84% — above average
84%
Career Allowance Rate
1342 granted / 1595 resolved
+24.1% vs TC avg
Moderate +11% lift
Without
With
+10.6%
Interview Lift
resolved cases with interview
Fast prosecutor
1y 9m
Avg Prosecution
41 currently pending
Career history
1633
Total Applications
across all art units

Statute-Specific Performance

§101
2.2%
-37.8% vs TC avg
§103
14.4%
-25.6% vs TC avg
§102
27.9%
-12.1% vs TC avg
§112
24.9%
-15.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1595 resolved cases

Office Action

§DOUBLEPATENT
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 . Claims 21-29 and 31-41 are pending in the instant application. Claims 35-40 are rejected. Claims 21-29, 31-34 and 41 are allowed. Response to Arguments/Remarks Applicant’s arguments/remarks filed on January 2, 2026 have been fully considered. With regards to the nonstatutory double patenting rejections as being unpatentable over U.S. Patent Nos. 10,870,628, 10,577,331, 9,944,609, 11,345,668, and 12,049,453, Applicant argues that “the Office has failed to meet their burden of properly rejecting the claims or of providing a sound motivation as to how an ordinary artisan would achieve the claims when starting from the claims of the reference patents…there is no doubt the rejections presented in the Office Action fail both of the requirements of MPEP §804(II)(B)(3). Unless and until proper factual findings are made regarding each of the differences between the examined claims and the claims of the prior patents and a proper articulated reasoning is presented for each of those differences, the rejections remain improper on their face and no prima facie case of obviousness has been established.” Upon further consideration and since the syntheses of the references do not involve mixing a cyclic amino compound with a first organic solvent to form a first mixture, this argument is found to be persuasive with regards to the nonstatutory double patenting rejections as being unpatentable over U.S. Patent Nos. 10,870,628, 10,577,331, 9,944,609, and 11,345,668 and the rejections have been withdrawn. However, with regards to the nonstatutory double patenting rejection as being unpatentable over U.S. Patent No. 12,049,453, the synthesis is so similar to that of the instant claims, with the only difference being that the method of the reference involves dropwise combining the mixture of a cyclic amino compound and a first organic solvent with the catalyst, which is later claimed to be benzamindoxine, in an organic solvent; and it is later claimed that the mixture is heated to a temperature of up to 60º C. Therefore, rejection is maintained and described below. Maintained 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 §§ 706.02(l)(1) - 706.02(l)(3) 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 USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The 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/process/file/efs/guidance/eTD-info-I.jsp. Claims 35-40 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 15-20 of U.S. Patent No. 12,049,453. Although the claims at issue are not identical, they are not patentably distinct from each other for the reasons given below. U.S. Patent No. 12,049,453 claims a very similar method for the synthesis of a diketopiperazine according to the same Formula II to the method for the synthesis of a diketopiperazine according to Formula II of the instant claims. The only difference in the syntheses is the method of the reference involves dropwise combining the mixture of a cyclic amino compound and a first organic solvent with the catalyst, which is later claimed to be benzamindoxine, in an organic solvent. It is also later claimed that the mixture is heated to a temperature of up to 60º C. However, it would have been obvious to one of ordinary skill in the art at the time of the invention through routine experimentation to arrive at the method of the instant claims in view of the reference with a reasonable expectation of success. The motivation would have been to find the optimal reaction conditions for the synthesis. Thus, a prima facie case of obviousness has been established. Allowable Subject Matter Claims 21-29, 31-34 and 41 are allowed. Conclusion THIS ACTION IS MADE FINAL. 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 KRISTIN ANN VAJDA whose telephone number is (571)270-5232. The examiner can normally be reached on Mon-Fri 6:00-4:00. 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, James Alstrum-Acevedo can be reached on 571-272-5548. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see https://ppair-my.uspto.gov/pair/PrivatePair. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /KRISTIN A VAJDA/Primary Examiner, Art Unit 1622
Read full office action

Prosecution Timeline

Show 2 earlier events
Dec 27, 2024
Non-Final Rejection mailed — §DOUBLEPATENT
Mar 27, 2025
Response Filed
Jun 13, 2025
Final Rejection mailed — §DOUBLEPATENT
Sep 15, 2025
Request for Continued Examination
Sep 18, 2025
Response after Non-Final Action
Oct 02, 2025
Non-Final Rejection mailed — §DOUBLEPATENT
Jan 02, 2026
Response Filed
Apr 15, 2026
Final Rejection mailed — §DOUBLEPATENT (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

5-6
Expected OA Rounds
84%
Grant Probability
95%
With Interview (+10.6%)
1y 9m (~0m remaining)
Median Time to Grant
High
PTA Risk
Based on 1595 resolved cases by this examiner. Grant probability derived from career allowance rate.

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