Prosecution Insights
Last updated: April 19, 2026
Application No. 18/555,388

Methods For Treating Drug and Vaccine Induced Immune Thrombocytopenia by Administering Specific Compounds

Non-Final OA §102§103§112
Filed
Oct 13, 2023
Examiner
ROZOF, TIMOTHY R
Art Unit
1625
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Principia Biopharma Inc.
OA Round
1 (Non-Final)
73%
Grant Probability
Favorable
1-2
OA Rounds
2y 2m
To Grant
97%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allow Rate
690 granted / 951 resolved
+12.6% vs TC avg
Strong +24% interview lift
Without
With
+24.0%
Interview Lift
resolved cases with interview
Fast prosecutor
2y 2m
Avg Prosecution
32 currently pending
Career history
983
Total Applications
across all art units

Statute-Specific Performance

§101
1.6%
-38.4% vs TC avg
§103
20.1%
-19.9% vs TC avg
§102
34.4%
-5.6% vs TC avg
§112
23.5%
-16.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 951 resolved cases

Office Action

§102 §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 is a response to Applicant’s communication filed on June 10, 2024. Application No. 18/555,388, filed October 13, 2023, is a 371 of PCT/US2022/024806, filed April 14, 2022, which claims the benefit of U.S. Provisional application No. 63/175,976, filed April 16, 2021. In a preliminary amendment filed June 10, 2024, Applicant cancelled claims 7-9, 19, and 23. Claims 1-6, 10-18, 20-22 and 24 are pending. Claim Rejections - 35 USC § 112(a) The following is a quotation of- the first paragraph of 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. Claims 1-6, 10-18, 20-22 and 24 are rejected under 35 U.S.C. 112(a) because the specification, while being enabling for a method of treating drug-induced thrombocytopenia (DITP) or vaccine-induced thrombosis and thrombocytopenia syndrome (VITT), the specification does not reasonably provide enablement for preventing these thrombocytopenia syndromes. The specification does not enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to practice the invention commensurate in scope with these claims. Factors to be considered when determining whether claims in an application for patent are enabling include (1) the breadth of the claims, (2) the nature of the invention, (3) the state of the prior art, (4) the level of one of ordinary skill, (5) the level of predictability in the art, (6) the amount of direction provided by the inventor, (7) the existence of working examples, and (8) the quantity of experimentation needed to make or use the invention based on the content of the disclosure. See MPEP § 2164.08, citing In re Wands, 858 F.2d 731, 737, 8 USPQ2d 1400, 1404 (Fed. Cir. 1988). The claims are drawn to a method of preventing both DITP and VITT via the administration of the BTK inhibitors, Compound (I) (rilzabrutinib) or Compound (II) (atuzabrutinib). The specification teaches that BTK inhibitors block platelet activation thereby preventing platelet aggregation in patients already presenting thrombosis and/or thrombocytopenia. (Specification, p. 20-31, Examples.) The specification provides no direction as to how BTK inhibitors can be employed to prevent platelet aggregation in patients who are not yet suffering from thrombosis and/or thrombocytopenia of DITP or VITT patients. In addition, the prior art fails to provide compensatory guidance. In this case, there is no correlation between platelet activation and preventing either DITP or VITT. It would require undue experimentation for the artisan to practice the invention as broadly claimed. Claim Rejections - 35 USC § 102(a)(1) The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. Claims 2-5, 10-18, and 20 are rejected under 35 U.S.C. 102(a)(1) as being clearly anticipated by von Hundelshausen et al., 121(11) Thromb. Haemost., 1395-1399 (2021) (Publ’d April 13, 2021) (cited in the June 10, 2024, IDS) Von Hundelshausen discloses a method for treating vaccine-induced thrombosis and thrombocytopenia syndrome (VITT) with the Bruton Tyrosine Kinase Inhibitor of Compound (I), rilzabrutinib. See von Hundelshausen et al., p. 1398, 1st col., last paragraph. Similarly, Claims 1 and 6 are rejected under 35 U.S.C. 102(a)(1) as being clearly anticipated by von Hundelshausen (above). Von Hundelshausen also discloses a method for treating drug-induced thrombocytopenia (DITP) (i.e., heparin induced thrombocytopenia (HIT)). Von Hundelshausen discloses that the mechanism of action of VITT is similar to that of HIT. See Id., Abstract. HIT is a DITP. (See the present invention, Claim 6, subsection (b).) Therefore, rilzabrutinib is also effective in treating DITP. 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. The factual inquiries for establishing a 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. Claims 1-6, 10-18, 20-22 and 24 are rejected under 35 U.S.C. 103 as being unpatentable over von Hundelshausen et al., 121(11) Thromb. Haemost., 1395-1399 (2021) (cited above), in view of Gourlay et al., US2018/0050027 A1. As stated in the 35 U.S.C. 102(a)(1), rejection above, von Hundelshausen discloses a method for treating both vaccine-induced thrombosis and thrombocytopenia syndrome (VITT) and drug-induced thrombocytopenia (DITP) with the Bruton Tyrosine Kinase (BTK) inhibitor of Compound (I), i.e., rilzabrutinib. The difference between the prior art and present invention is the use of Compound (II), atuzabrutinib. Gourlay teaches that Compound (II), atuzabrutinib is a BTK inhibitor similar to that of compound (I), rilzabrutinib. See Gourlay et al., p. 12, paras. [0272]–[0273]. Accordingly, all the elements of the present invention were known in the art at the time of the invention. It would have been obvious for to the ordinary artisan to use the BTK inhibitor atuzabrutinib as taught by Gourlay in the methods of the claimed invention as taught by Hundelshausen. In this case, the present invention combines prior art elements according to known methods to yield predictable results. Conclusion No claims are allowed. Contact Information Any inquiry concerning this communication or earlier communications from the examiner should be directed to TIMOTHY R ROZOF whose telephone number is (571)270-5992. The examiner can normally be reached Monday - Friday, 9:00 a.m. -5:00 p.m.. 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, Andrew Kosar can be reached at (571) 272-0913. 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. /TIMOTHY R ROZOF/Primary Examiner, Art Unit 1625
Read full office action

Prosecution Timeline

Oct 13, 2023
Application Filed
Jan 08, 2026
Non-Final Rejection — §102, §103, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12594259
TREATMENT REGIMEN FOR THE TREATMENT OF NEUROLOGICAL DISEASES OR CONDITIONS
2y 5m to grant Granted Apr 07, 2026
Patent 12595264
HETEROCYCLIC GLP-1 AGONISTS
2y 5m to grant Granted Apr 07, 2026
Patent 12595255
HETEROARYL-SUBSTITUTED IMIDAZOLE DERIVATIVES
2y 5m to grant Granted Apr 07, 2026
Patent 12577204
A SOLUTION OF TEMPO-DERIVATIVES FOR USE AS ELECTROLYTE IN REDOX-FLOW CELLS
2y 5m to grant Granted Mar 17, 2026
Patent 12577205
HYDROGENATION OF IMINES BY PALLADIUM BASED CATALYST
2y 5m to grant Granted Mar 17, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

1-2
Expected OA Rounds
73%
Grant Probability
97%
With Interview (+24.0%)
2y 2m
Median Time to Grant
Low
PTA Risk
Based on 951 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month