Prosecution Insights
Last updated: April 19, 2026
Application No. 18/564,796

USE OF MITOXANTRONE HYDROCHLORIDE LIPOSOME IN PREPARATION OF DRUGS FOR TREATING ADVANCED SOLID TUMORS

Final Rejection §103
Filed
Nov 28, 2023
Examiner
PURDY, KYLE A
Art Unit
1611
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Cspc Zhongqi Pharmaceutical Technology (Shijiazhuang) Co. Ltd.
OA Round
2 (Final)
41%
Grant Probability
Moderate
3-4
OA Rounds
4y 0m
To Grant
78%
With Interview

Examiner Intelligence

Grants 41% of resolved cases
41%
Career Allow Rate
395 granted / 968 resolved
-19.2% vs TC avg
Strong +37% interview lift
Without
With
+36.9%
Interview Lift
resolved cases with interview
Typical timeline
4y 0m
Avg Prosecution
79 currently pending
Career history
1047
Total Applications
across all art units

Statute-Specific Performance

§101
1.2%
-38.8% vs TC avg
§103
60.6%
+20.6% vs TC avg
§102
14.8%
-25.2% vs TC avg
§112
14.0%
-26.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 968 resolved cases

Office Action

§103
DETAILED ACTION Status of Application The Examiner acknowledges receipt of the amendments filed on 12/19/2025 wherein claims 7, 11-13, 15 and 17-19 have been amended and claim 22 has been added. Claims 7, 11-19 and 22 are presented for examination on the merits. The following rejections are made. Response to Applicants’ Arguments Applicant’s amendments filed 12/19/2025 overcome the rejection of claims 12, 13, 17 and 21 made by the Examiner under 35 USC 112(b). This rejection has been withdrawn. Applicant’s amendments filed 12/19/2025 overcome the rejection of claims 7, 8, 11, 14, 17 and 18 made by the Examiner under 35 USC 102(a)(1) over Li et al. (US 2016/0235671). This rejection is withdrawn as Li fails to disclose treating ovarian or fallopian tube cancers. Applicant’s amendments filed 12/19/2025 overcome the rejection of claims 7, 11-14 and 16 made by the Examiner under 35 USC 102(a)(1) over Ahmad et al. (US 2003/0219476). This rejection is withdrawn as Ahmad fails to disclose a phospholipid bilayer. Applicant’s amendments filed 12/19/2025 overcome the rejection of claims 12, 13, 15 and 16 made by the Examiner under 35 USC 103 over Li et al. (US 2016/0235671) further in view of Ahmad et al. (US 2003/0219476). This rejection is withdrawn as the primary rejection over Li has been withdrawn. Applicant’s amendments filed 12/19/2025 overcome the rejection of claims 20 and 21 made by the Examiner under 35 USC 103 over Li et al. (US 2016/0235671) further in view of Alberts et al. (Cancer Research, 45, 1985, 1879-1884). This rejection is withdrawn as the primary rejection over Li has been withdrawn. Rejections 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 7, 11-19 and 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (US 2016/0235671). Li provides a method for treating tumors (e.g. solid tumors, see Table 6) of the prostate, liver, bladder (see [0034]) by administering a liposomal composition comprising mitoxantrone hydrochloride (see [0049] and Example 21) (see instant claim 7). The liposome particles are to have a mean size of between 30-80 nm (see claims 20 and 17) (see instant claim 17 and 18). The liposome, in addition to the mitoxantrone, possess a phospholipid bilayer with a phase transition temperature higher than body temperature (see abstract and claim 20) wherein the phospholipid is selected from hydrogenated soybean lecithin (see [0012] and claim 21) (see instant claim 7). The administration of the liposome is done intravenously (see [0072]) (see instant claim 14). In regards to instant claim 11, ‘advanced’ is understood by the Examiner to relate to any tumor to have advanced to a treatable stage. Li’s mitoxantrone liposome are to comprise hydrogenated soybean phosphatidylcholine, (i.e. lecithin), cholesterol and PEG-2000 modified distearoyl phosphatidyl ethanolamine (DSPE-PEG2000) at a weight ratio of 3:1:1 wherein the liposomal composition comprises sulfate (see Example 2, [0051]) (see instant claim 18). Li teaches that their mitoxantrone liposome is made by combining the empty liposomes at a liposome/mitoxantrone ratio of 16:1 (see Example 2). Although the ratio described by instant claim 19 is not explicitly described by Li, such a ratio would have been well within the skill of an ordinary person to identify as differences in concentration does not support patentability of subject matter encompassed by the prior art unless there is evidence indicating such concertation is critical. See MPEP 2144.05(II)(A). Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. Such a rationale is appropriate in the current case. Li fails to teach the method as treating ovarian or fallopian tube cancers wherein the method comprises the liposome in a concentration of between 0.5-5 mg/mL. Ahmad, like Li, is directed to mitoxantrone liposomes and their use in treating diseases such as ovarian cancer (e.g. solid tumors; see Example 19) (see abstract, [0031] and claim 1) (see instant claim 1). The liposome is to be present in a concentration of between 0.5- mg/mL (see [0008, 0046] and claim 10) (see instant claim 12 and 22) such that between 0.5-100 mg/m2 mitoxantrone is administered (see [0033]) (see instant claims 13). The mitoxantrone is to be provided as a hydrochloride salt (see [0002]) (see instant claim 7) and is to be administered alone in the treatment of disease. Intravenous administration is described as a preferred means of treatment (see [0032]) (see instant claim 14) wherein the mitoxantrone is administered via short intravenous infusions every 21 days (i.e. 3 weeks) (see [0003]) (see instant claim 16) wherein the infusion process is to administer the liposomal composition over a period of 45 minutes (see [0024]) (see instant claim 15). Regarding the time for infusion treatment, it would have been obvious to modify/optimize the infusion time to identify the best treatment. If such a manipulation was that infusion was to be not less than 60 minutes, then such would have been the product of an obvious modification of the prior art, not one of innovation. Moreover, it would have been obvious to modify Li’s method to utilize the concentration of liposomes and concentration of mitoxantrone described by Li as such concentrations were known to be useful in treatment of cancer. See MPEP 2143(I)(A). Therefore, the invention as a whole is prima facie obvious to one of ordinary skill in the art at the time the invention was filed, as evidenced by the references, especially in absence of evidence to the contrary. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to KYLE A PURDY whose telephone number is (571)270-3504. The examiner can normally be reached from 9AM to 5PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Bethany Barham, can be reached on 571-272-6175. 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 http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). /KYLE A PURDY/Primary Examiner, Art Unit 1611
Read full office action

Prosecution Timeline

Nov 28, 2023
Application Filed
Sep 28, 2025
Non-Final Rejection — §103
Dec 19, 2025
Response Filed
Mar 20, 2026
Final Rejection — §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
41%
Grant Probability
78%
With Interview (+36.9%)
4y 0m
Median Time to Grant
Moderate
PTA Risk
Based on 968 resolved cases by this examiner. Grant probability derived from career allow rate.

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