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
Claim Status
Applicant’s amendment filed April 13, 2026 has been received and entered.
Claims 16-19, 25-26, 28-30, 32, and 34 have been amended.
Claim 22 has been canceled.
Claims 1-15 were previously canceled.
Claims 16-21 and 23-35 are pending and under consideration.
Claim Objections
In view of Applicant’s amendment, the previous objections to the claims have been withdrawn.
Claim Rejections - 35 USC § 112(a) - Written Description - Withdrawn
The previous rejection of claim 22 under 35 U.S.C. 112(a), first paragraph, for failing to comply with the written description requirement has been withdrawn, as claim 22 has been canceled making the rejection moot.
Claim Rejections - 35 USC § 112(a) - Enablement - Maintained/Updated
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.
Claims 30-31 are rejected under 35 U.S.C. 112(a), first paragraph, because the specification, while being enabling for:
A method of inducing specific lysis of CD25 positive cells without inhibiting IL-2 signaling in T-cells, comprising the step of administering to a subject a therapeutically effective amount of the isolated anti-human CD25 antibody or antigen-binding fragment thereof according to claim 16,
does not reasonably provide enablement for:
A method for treating a cancer or an infectious disease in a subject in need thereof, comprising administering to the subject the isolated anti-human CD25 antibody or an antigen-binding fragment thereof according to claim 16.
The claim(s) contains subject matter which was not described in the specification in such a way as to enable one skilled in the art to which it pertains, or with which it is most nearly connected, to make and/or use the invention.
As a general rule, enablement must be commensurate with the scope of claim language. MPEP § 2164.08 states, “The Federal Circuit has repeatedly held that “the specification must teach those skilled in the art how to make and use the full scope of the claimed invention without undue experimentation.” In re Wright, 999 F.2d 1557, 1561, 27 USPQ2d 1510, 1513 (Fed. Cir. 1993)” (emphasis added). The “make and use the full scope of the invention without undue experimentation” language was repeated in 2005 in Warner-Lambert Co. v. Teva Pharmaceuticals USA Inc., 75 USPQ2d 1865, and Scripps Research Institute v. Nemerson, 78 USPQ2d 1019 asserts: “A lack of enablement for the full scope of a claim, however, is a legitimate rejection.” The principle was explicitly affirmed in Auto. Tech. Int’l, Inc. v. BMW of N. Am., Inc., 501 F.3d 1274, 84 USPQ2d 1108 (Fed. Cir. 2007), Monsanto Co. v. Syngenta Seeds, Inc., 503 F.3d 1352, 84 U.S.P.Q.2d 1705 (Fed. Cir. 2007), and Sitrick v. Dreamworks, LLC, 516 F.3d 993, 85 USPQ2d 1826 (Fed. Cir. 2008). See also In re Cortright, 49 USPQ2d 1464, 1466 and Bristol-Myers Squibb Co. v. Rhone-Poulenc Rorer Inc., 49 USPQ2d 1370.
The factors to be considered in determining whether a disclosure meets the enablement requirement of 35 U.S.C. 112, first paragraph, have been described in In re Wands, 8 USPQ2d 1400 (Fed. Cir. 1988). Among these factors are: (1) the nature or the invention; (2) the state of the prior art; (3) the relative skill of those in the art; (4) the predictability or unpredictability of the art; (5) the breadth of the claims; (6) the amount of direction or guidance presented; (7) the presence or absence of working examples; and (8) the quantity of experimentation necessary. When the above factors are weighed, it is the examiner’s position that one skilled in the art could not practice the invention without undue experimentation. Some experimentation is not fatal; the issue is whether the amount of experimentation is “undue”; see In re Vaeck, 20 USPQ2d 1438, 1444.
(1) The nature of the invention and (5) The breadth of the claims:
Claim 31 is directed to a method of treating a cancer or infectious disease comprising administering to a subject an isolated antibody that specifically binds human CD25.
(2) The state of the prior art and (4) The predictability or unpredictability of the art:
The state of the art regarding anti-CD25 antibodies for the use in treating cancer is a complex process. For example, as taught by Vargas et al. (2017; cited IDS 7/28/2023), CD25 is constitutively expressed on Treg cells, which are regarded as one of the major obstacles to the successful clinical application of tumor immunotherapy. Therefore, most cancer therapies target Treg cells by depletion or modulation. However, most anti-CD25 antibodies have displayed limited activity against established tumors [Introduction]. Further, although the frequency of circulating or tumor-infiltrating Tregs has been associated with poor patient survival in many cancers including breast, melanoma and lung, high infiltrates of Tregs have been associated with a positive outcome of patients in some cancers including colorectal, bladder and esophageal [Abstract] (Ward-Hartstonge and Kemp, 2017; cited Office action 1/12/2026).
The state of the art regarding anti-CD25 antibodies for the use in treating infectious diseases is also complex and unpredictable, and can often lead to worse outcomes. For example, a study by Huo et al. (Oncotarget, 2016; 7(10):1-14) teaches depletion of Tregs in mice with chronic peritonitis that were treated with anti-CD25 antibodies results in significantly increased bacterial clearance and survival. However, mortality significantly increases upon subsequent sub-acute sepsis. These results demonstrate that using anti-CD25 antibodies to deplete Tregs for the treatment of sepsis can ameliorate immunosuppression through increasing T cells and NK cells responses which is beneficial for preventing chronic infection, but will likely have deleterious effects during later stages of infection [Abstract].
Given the lack of predictability of anti-CD25 non-blocking antibodies, one of skill in the art would have to engage in undue experimentation to identify what specific cancer or infectious disease would be effectively treated by the instantly claimed antibody.
6) the amount of direction or guidance provided by the inventor; 7) the existence of working examples;
Claim 30 broadly encompasses treating any cancer or infectious disease with the instantly claimed anti-CD25 antibodies. However, the instant specification only recites examples wherein the anti-CD25 antibodies of the present invention (H09, DO1, E04-2, B05, C01, GO1, G02-2, F03, D05, B07, B12) induced antibody dependent cell phagocytosis in a cell culture model and depleted Treg cells from anti-CD3+anti-CD28 activated human peripheral mononuclear cells in in vitro assays [pg. 144]. There are no examples wherein an instantly claimed anti-CD25 non-blocking antibody was used to treat any cancer or any infectious disease.
Thus, given the unpredictability of the art and the breadth of the claims, the instant specification must provide a sufficient an enabling disclosure commensurate in scope with the instant claims. The specification provides guidance for using non-blocking anti-CD25 antibodies for Treg depletion and antibody dependent cell phagocytosis, which may be useful in the treatment of some cancers. The specification does not provide any guidance or examples for using non-blocking anti-CD25 antibodies for the treatment of any cancer or infectious disease as broadly encompassed by the instant claims. Thus, given the unpredictability of the art and the lack of guidance provided by the instant specification, it would require undue experimentation to practice the method as broadly claimed.
Claim 31 is included in the rejection as it depends from and requires all the limitations of the rejected claim.
Response to Arguments
Applicant argues starting on page 14 of the reply received April 13, 2026, that the claimed anti- CD25 antibodies bind human CD25 and are non-blocking, in that they do not significantly impact IL-2-induced effector T cell proliferation. Further, the claimed antibodies induce cell lysis via antibody-dependent cellular phagocytosis (ADCP) and selectively deplete regulatory T cells. Therefore, the data in the present application support the therapeutic use of the claimed anti-CD25 antibodies in diseases where depletion of Tregs is beneficial.
Applicant’s arguments were fully considered and were not deemed persuasive.
Specifically, although the instant application supports the therapeutic rationale underlying the present invention, namely, the use of anti-CD25 antibodies to deplete Treg cells for the treatment of cancer, Applicant has provided no evidence to support that the instantly claimed anti-CD25 non-blocking antibodies are effective in the treatment of any cancer or any infectious disease.
The current state of the art regarding anti-CD25 non-blocking antibodies does not support enablement of the instantly claimed antibodies without working examples. For example, Gambardella et al. (Cancer Res Commun, 2025;5(3):422–432) teaches RG6292 (vopikitug) targets CD25 (IL-2Ra) and mediates regulatory T-cell depletion while not interfering with IL-2 signaling. Peripheral and intratumoral Treg depletion was shown in two phase I studies for the treatment of adult patients with advanced solid tumors. However, RG6292 alone or in combination with atezolizumab was insufficient to reverse and rescue from established resistance mechanisms in solid tumors. Therefore, although RG6292 induced a dose-dependent peripheral blood and measurable intratumoral Treg depletion in concordance with the proposed mode of action, clinical efficacy as a single agent or combined with atezolizumab was insufficient to warrant further exploration in this population [Abstract].
In regard to treatment of infectious disease, there have been some studies administration of a nondepleting anti-CD25 monoclonal antibody reduces disease severity in mice infected with Trypanosoma cruzi (Nihei et al., Eur J Microbiol Immunol, 2014 May 21;4(2):128–13), however, the instant specification of the state of the art do not provide enablement for the treatment of an infectious disease with a non-blocking anti-CD25 monoclonal antibody.
Accordingly, the prior art suggests unpredictability and the state of the art reveals complex results. Thus, the rejection of claims 30-31 is maintained for lack of enablement.
Conclusion
Accordingly, claims 16-21, 23-29, and 32-35 are allowed. Claims 30-31 are rejected.
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.
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/MAUREEN VARINA DRISCOLL/ Examiner, Art Unit 1642
/SAMIRA J JEAN-LOUIS/Supervisory Patent Examiner, Art Unit 1642
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