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 .
Priority
Receipt is acknowledged of some of the certified copies of papers required by 37 CFR 1.55.
Election/Restrictions
Applicant's election with traverse of Group I, Claims 1-3 drawn to a process of making a mesenchymal stem cell (MSC)-derived extracellular vesicle (EV) in the reply filed on 01/30/2026 is acknowledged. Applicant’s submission that a single step of tangential flow filtration is not sufficient to produce the EV is also acknowledged. The traversal is on the grounds that the process of making the MSC-derived EV and the produced MSC-EV are intertwined and form a single general inventive concept. This is not found persuasive because the product as claimed can be made by another materially different process such as supplementing the culture medium with human platelet lysate in place of fetal bovine serum in step (b) of Claim 1.
The requirement is still deemed proper and is therefore made final.
Status of the Application/Claims
Claims 1-20, filed 10/04/2023, are pending. Claims 4-20 are withdrawn from consideration. Claims 1-3 are the subject of the present Official action.
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 3 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.
The term “size” in claim 3 renders the claim indefinite. The term “size” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. The size of the MSC-derived EV can refer to the diameter, radius, inner diameter, outer diameter, circumference, etc. Therefore, it is indefinite which aspect of size to attribute the recited length to.
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 1-3 are rejected under 35 U.S.C. 103 as being unpatentable over Woo et al., 2020 (Journal of Extracellular Vesicles; hereinafter Woo), and further in view of Ding et al., 2013 (Journal of Biomedical Science; hereinafter Ding).
With regard to Claim 1, Woo teaches a method for preparing an MSC-derived EV comprising providing a human MSC, culturing and maintaining the MSC in Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with fetal bovine serum (FBS), collecting a cultured human MSC and removing cell debris using a centrifugation process, and filtering supernatant thus formed to obtain the MSC-derived EV. See page 2, left column, paragraph 2 of Woo.
Woo does not teach culturing and maintaining the MSC in keratinocyte serum-free medium (KSFM) supplemented with FBS, N-acetyl-L-cysteine (NAC), and L-ascorbic acid 2-phosphate.
Ding teaches culturing human adipose-derived MSCs in KSFM supplemented with FBS, N-acetyl cysteine (NAC), and L-ascorbic acid-2-phosphate. Ding teaches that culturing the MSCs in a medium of low calcium and low serum with hormone and antioxidant supplements such as the KSFM may overcome the donor-age effect of adipose-derived stem cells. After characterization of the growth and differentiation properties, senescence, and telomere length in KSFM-cultured adipose-derived stem cells, Ding showed a comparable growth and non-adipogenic differentiation capacities in the cells regardless of the donor’s age. See page 2, left column, paragraph 3 and page 2, right column, paragraph 2 of Ding.
It would have been prima facie obvious to one of ordinary skill in the art to modify the method of preparing the MSC-derived EVs of Woo with the cell culture medium of Ding, to prepare the MSC-derived EVs in a low calcium culture medium with antioxidant supplements. One of ordinary skill in the art would be motivated to make such a modification with a reasonable expectation of success to overcome the donor-age effect of the adipose-derived MSCs.
With regard to Claim 2, Woo teaches that the human mesenchymal stem cell is adipose-derived mesenchymal stem cell. See, for example, the abstract of Woo.
Note that the scope of Claim 3 is indefinite as stated above in the rejection under 35 U.S.C. 112(b). Size is being interpreted as the diameter of the MSC EVs in the rejection under 35 U.S.C. 103.
With regard to Claim 3, Woo teaches that the particle size distribution of the MSC EVs is within the range of 50 nm to 500 nm. See Figure 1b of Woo. Woo teaches that the isolated human adipose-derived MSC EVs have a round spherical shape with a double-layer membrane structure, and their mean diameter was 86.46 nm. See Figure 1(a-b) and page 5, left column, paragraph 3 of Woo.
Conclusion
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/H.P./Examiner, Art Unit 1631
/JAMES D SCHULTZ/Supervisory Patent Examiner, Art Unit 1631