Prosecution Insights
Last updated: April 19, 2026
Application No. 18/554,006

TREATMENT OF VIRUS INFECTIONS

Non-Final OA §103§112
Filed
Oct 05, 2023
Examiner
OLSON, ANDREA STEFFEL
Art Unit
1693
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Tx Medic AB
OA Round
1 (Non-Final)
62%
Grant Probability
Moderate
1-2
OA Rounds
3y 4m
To Grant
50%
With Interview

Examiner Intelligence

Grants 62% of resolved cases
62%
Career Allow Rate
868 granted / 1397 resolved
+2.1% vs TC avg
Minimal -12% lift
Without
With
+-12.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
64 currently pending
Career history
1461
Total Applications
across all art units

Statute-Specific Performance

§101
2.0%
-38.0% vs TC avg
§103
37.3%
-2.7% vs TC avg
§102
18.6%
-21.4% vs TC avg
§112
21.2%
-18.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1397 resolved cases

Office Action

§103 §112
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 This application is a national stage application of PCT/SE2022/050577, filed June 10, 2022, which claims benefit of foreign applications PCT/SE2021050344, filed April 14, 2021, SE2151258-7, filed October 14, 2021, and SE2151582-0, filed December 21, 2021. Claims 19-44 are pending in this application and examined on the merits herein. Applicant’s preliminary amendment submitted October 5, 2023 is acknowledged wherein claims 1-18 are canceled and new claims 19-44 are introduced. 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 19 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. This claim is directed to a method of treating a condition described as a “flavivirus infection or infectious disease.” Based on the syntax of this phrase, it is unclear whether “flavivirus” is intended to modify “infectious disease,” or whether it is only applied to “infection.” Therefore it is unclear whether or not the scope of the claim includes methods of treating or preventing infectious diseases not caused by flavivirus, rendering the claim indefinite. Claim Rejections - 35 USC § 103 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. Claims 19-22, 24-34, and 43-44 are rejected under 35 U.S.C. 103 as being unpatentable over Comper et al. (PCT international publication 2005/004882, Reference included with PTO-1449) Independent claim 19 claims a method for treating a disease including a flavivirus infection, comprising administering to a subject a dextran sulfate having an average molecular weight below 1000 Da and an average sulfur content at least 15%. Dependent claims 20-26 specify particular flaviviruses as the infectious agent. Dependent claims 27, 28, and 43 furthermore specify systemic administration of the dextran sulfate. Dependent claims 29-34 further describe the molecular weight, sulfur percent, and degree of sulfation of the dextran sulfate. Comper et al. discloses the use of sulfated polysaccharides for treating microbial infections including viral infections. (p. 3 paragraph 8) Comper et al. further discloses dextran sulfates having a molecular weight between 1000 and 1000000 for oral or parenteral administration (p. 4 paragraph 9) and a percent sulfation of 13-25%. (p. 4 paragraph 10) Specific viral infections that can be treated include flaviviruses. (p. 21 paragraph 74) Specific viruses which can be treated in this manner include the particular flaviviruses Dengue virus, Hepatitis C virus, Japanese encephalitis virus, West Nile virus, and Yellow fever virus, for example, which are all flaviviruses according to present claims 20-26. Regarding claims 27 and 28, Comper et al. discloses routes of parenteral administration including subcutaneous and intravenous administration. (p. 13 paragraph 113) The disclosure of Comper et al. differs from the present claims in that the ranges described by Comper et al. for molecular weight and sulfur percent are not exactly the same as those recited in the present claims. However, the ranges (e.g. 1000-1 million for mw or 13-25% for sulfur percentage) substantially overlap with those recited in the present claims. Furthermore both of these ranges are described as significant by the disclosure of Comper et al., indicating that these are result-effective variables. Therefore it would have been obvious to one of ordinary skill in the art at the time of the invention to arrive at the claimed values of mw and sulfur percent through routine experimentation. Therefore the invention taken as a whole is prima facie obvious. Claims 23 and 39-42 are rejected under 35 U.S.C. 103 as being unpatentable over Comper et al. as applied to claims 19-22, 24-34, and 43-44 above, and further in view of Tan et al. (Reference included with PTO-892) The disclosure of Comper et al. is discussed above. Comper et al. does not specifically disclose a method of treating Zika virus, although the reference does describe treating flaviviruses in general. Tan et al. discloses a study of inhibition of Zika virus infectivity by sulfated polysaccharides. (p. 187 left column second paragraph) While Tan et al. primarily focuses on glycosaminoglycans and suramin as the specific agents, dextran sulfate was also tested. (p. 187 section 2.2) Dextran sulfate was indeed found to inhibit ZIKV. (p. 194 section 3.1) Furthermore the inhibitory effect was found to increase with the degree of sulfation. (p. 190 section 4) It would have been obvious to one of ordinary skill in the art at the time of the invention to administer the dextran sulfate described by Comper et al. to a subject suffering from infection with Zika virus. One of ordinary skill in the art would have been motivated to do so because Tan et al. specifically suggests that DS inhibits Zika virus infectivity, and would have reasonably expected success because Comper et al. suggests that DS is useful against a wide range of viruses and particularly mentions flaviviruses. Therefore the invention taken as a whole is prima facie obvious. Claims 33-42 are rejected under 35 U.S.C. 103 as being unpatentable over Comper et al. as applied to claims 19-22, 24-34, and 43-44 above, and further in view of Bruce et al. (PCT international publication 2016/076780, Reference included with 10/5/2023 PTO-1449) The disclosure of Comper et al. is discussed above. Comper et al. does not specifically disclose a dextran sulfate having the particular Mn or degree of sulfation recited in claims 33-42. However, Bruce et al. discloses a dextran sulfate having improved biological effects while not being toxic at pharmaceutically relevant dosages. (p. 1 paragraphs 27-28) In particular, Bruce et al. discloses DS having a specific number average molecular weight between 1850-3500 or 1850-2000, and an average number of sulfate groups between 2.5-3.0, or 2.6-2.7. (p. 5 lines 29 – p. 7 line 2) Additionally, Bruce et al. discloses a number of different batches of dextran sulfate, including batch number 3, which has an average sulfate number of 2.7 and a Mn of 1929. (p. 22 paragraph 5) This batch was administered to experimental animals and its toxicity compared to other reference dextran sulfates. (p. 31 line 20 – p. 33 line 3, tables 8 and 9) The toxic effects of batch 3 were found to be lower than the reference dextran sulfates. It would have been obvious to one of ordinary skill in the art at the time of the invention to use the dextran sulfate described by Bruce et al. as the active agent in the method described by Comper et al. One of ordinary skill in the art would have found it to be obvious to use this particular dextran sulfate in the expectation that it would have reduced side effects. While the “improved biological effects” described by Bruce et al. do not specifically mention antiviral activity, one of ordinary skill in the art would have considered the reduced toxicity to be relevant as an improvement of Comper’s method. Therefore the invention taken as a whole is prima facie obvious. Conclusion No claims are allowed in this action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANDREA OLSON whose telephone number is (571)272-9051. The examiner can normally be reached M-F 6am-3:00pm. 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, Scarlett Y Goon can be reached at 571-270-5241. 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. /ANDREA OLSON/Primary Examiner, Art Unit 1693 1/21/2026
Read full office action

Prosecution Timeline

Oct 05, 2023
Application Filed
Jan 21, 2026
Non-Final Rejection — §103, §112 (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

1-2
Expected OA Rounds
62%
Grant Probability
50%
With Interview (-12.1%)
3y 4m
Median Time to Grant
Low
PTA Risk
Based on 1397 resolved cases by this examiner. Grant probability derived from career allow rate.

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