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 .
Status of the Claims
Claims 1-38 are pending.
Applicant’s election without traverse of group I claims 1-34 in the reply filed on 2/3/2026 is acknowledged. Claims 35-38 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected group, there being no allowable generic or linking claim.
Claim Rejections - 35 USC § 112
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.
The following is a quotation of the first paragraph of pre-AIA 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 1-7, 10, 13, 17, 21, 25, 29, 33-34 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention
These claims do not list concentrations of induction agents in the medium of the claimed method, only that each component is present in the media. The prior art recognizes that concentrations of induction agents is crucial for differentiation of hPSC/progenitor cells into specific lineages such as CD31+ endothelial cells. Loh teaches that in some instances, the effective concentration of an induction agent will be below a critical concentration such that the induction produces the desired effect essentially without undesirable effects. As used herein, the term “critical concentration” refers to a concentration of induction agent above which undesirable effects are produced. Undesirable effects that may be the result of a concentration exceeding the critical concentration include but are not limited to, e.g., off- target effects (off-target activation of signaling, off-target inhibition of signaling), reduction or loss of function (e.g., loss of desired activator function, loss of desired inhibitor function) reduction of cell viability, increase in cell mortality, lineage restriction towards an undesired ceil type, differentiation into an undesired cell type, loss of expression of a particular desired marker, etc. Whether a particular induction agent will have a critical concentration and what the critical concentrations of those agents having a critical concentration are will depend on the agent and the specific conditions in which the agent is used.
That is, the specification does not provide an adequate written description to support a method that uses just any concentration of each of the claimed components in the differentiation media to produce CD31+ EC cells from human early mesoderm progenitor cells. Instead, applicant discloses specific ranges for these components in said media that will produce the desired cell.
Claims 8 and 9 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claims 8 and 9 recite ranges for the concentration of CHIR99021 in the claimed method in terms of 3-9 mM, and 6 mM. However, this is not supported in the specification. This appears to be a typo, as the specification does support a value of 3-9 μM, and 6 μM. (Spec. [0017]).
For purposes of examination, claims 8 and 9 were examined as if they were claiming the 3-9 μM, and 6 μM concentrations.
Claim Objections
Claims 11-12, 14-16, 18-20, 22-24, 26-28, and 30-32 are objected to for being dependent on a rejected claim, but are otherwise free of the art, particularly if the claimed method comprised a media with each of these concentrations or concentration ranges recited in the claim.
The closest prior art is Loh (WO2021207251A1) as evidenced by Promocell EGM2 product data sheet (attached).
Regarding claim 1, Loh teaches methods for the efficient differentiation of human pluripotent stem cells ( hPSCs) into HSC-like cells and endothelial cells in defined, monolayer conditions solely using extracellular signals to guide differentiation. (Loh, Abstract).
Regarding the generation of CD31+ endothelial cells, among other differentiation pathways, Lo teaches a differentiation protocol for generating an artery progenitor cells from hematopoietic stem cells that uses the claimed extracellular signals with the exception of heparin. Lo teaches that the resulting artery progenitor/ endothelial cells generated by their method express CD31 (Fig. 2D [0018] [0005] [0053]], Fig 1, Fig 2, Fig 8).).
Regarding VEGFR agonist (VEGF), Lo’s artery progenitor differentiation protocol teaches the use of VEGF (10-100ng/mL) from day 1-2. (Fig 1, [0017]).
Regarding FGFR agonist (FGF2), Lo teaches the use of FGF activator (aka FGFR agonist) (Day 0-1). Lo teaches that the FGF activator may include FGF2 (Loh [0067, 0068]).
Regarding the RA pathway agonist, Loh teaches that to generate artery progenitor cells, the population of dorsal lateral mesoderm cells is cultured in media comprising a VEGF agonist and WNT inhibitor; optionally in the presence of a retinoic acid (RA) agonist for a period of about 1 day to produce a population of artery progenitor cells. (Loh [0052, 0074]).
Regarding a SHH antagonist, Loh also teaches that in some instances, an inducing agent useful in a particular induction composition may include an activator or inhibitor of the Hedgehog pathway. Lo teaches that SANT-1 specifically may be the used as an inhibitor (antagonist) of hedgehog pathway, [0074]
Regarding a Wnt pathway antagonist (XAV939), Loh teaches the use of a WNT inhibitor (XAV939) (Day 1-2). (Fig 1, [0017]).
Regarding a GSK-3β inhibitor, Loh teaches the use of WNT agonist (CHIR99021, 1-6uM) on day 0-1. (Fig 1, [0017]).
Loh fails to teach the inclusion of heparin or a heparin mimetic in their artery progenitor differentiation protocol.
Loh teaches that the artery progenitor cells may be maintained in an arterial state by continued exposure to endothelial cell growth medium 2. This commercially available medium contains heparin (see Promocell EGM2 product data sheet)
Thus, Loh teaches a method of generating human CD31+ ECs comprising culturing human early mesoderm progenitor cells in a culture media comprising VEGFR agonist, FGFR agonist, RA pathway agonist, SHH agonist, heparin, and a Wnt pathway agonist to generate human CD31+ ECs.
However, Loh’s method is stepwise, with the cells undergoing “brief” washes in between the steps, swapping out different medias as the days progressed. (Loh 0222-0227, Fig 1). Specifically, Loh teaches the following relevant components for generating arterial cells (i.e. the CD31+ endothelial cells):
Day 1 : hESC are cultured in GSK-3β inhibitor (CHIR99021, 6 μM), and FGFR agonist (FGF2 (20 ng/mL). (Loh [0222])
Day 2: Resulting mid primitive streak cells are washed and suspended in CDM2 media comprising VEGFR agonist (VEGF, 100 ng/mL), Wnt pathway antagonist (XAV939, 1 µM), and RA agonist (TTNPB (0.5 nM)) (Loh [0223, 0226])
Day 3: Resulting dorsal lateral mesoderm cells were washed and suspended in CDM2 media comprising (VEGF, 100 ng/mL), Wnt pathway antagonist (XAV939, 1 µM), and RA agonist (TTNPB (0.5 nM)) (Loh [0224] [0227])
Day 4+ Resulting arterial cells were maintained in a media comprising heparin (EGM2 media) (Loh [0225] Promocell EGM2 product data sheet)
Loh teaches the inclusion of SHH antagonist but does not specify at which step in their method it is to be added. (Loh 0074-0075])
The claimed method requires “a” media, i.e. a single media at any point of the cell differentiation method comprises the claimed components. Loh teaches away from this composition by changing media for new media without the claimed components, especially considering that the heparin component is only added in at day 4+ as a maintaince media.
Regarding claim 4, Loh teaches the following relevant components for generating arterial cells (i.e. the CD31+ endothelial cells), but does not teach or suggest the claimed method using the claimed composition, particularly one comprising each component recited in step (b). Loh’s method includes the following steps:
Day 1 : hESC are cultured in GSK-3β inhibitor (CHIR99021, 6 μM), and FGFR agonist (FGF2 (20 ng/mL). (Loh [0222])
Day 2: Resulting mid primitive streak cells are washed and suspended in CDM2 media comprising VEGFR agonist (VEGF, 100 ng/mL), Wnt pathway antagonist (XAV939, 1 µM), and RA agonist (TTNPB (0.5 nM)) (Loh [0223, 0226])
Day 3: Resulting dorsal lateral mesoderm cells were washed and suspended in CDM2 media comprising (VEGF, 100 ng/mL), Wnt pathway antagonist (XAV939, 1 µM), and RA agonist (TTNPB (0.5 nM)) (Loh [0224] [0227])
Day 4+ Resulting arterial cells were maintained in EGM2 media only (no VEGF) a media comprising heparin (EGM2 media) (Loh [0225], Promocell EGM2 product data sheet)
Loh teaches the inclusion of SHH antagonist but does not specify at which step in their method it is to be added. (Loh 0074-0075])
Regarding step (a) Loh teaches culturing a hPSC in CHIR99021 for 24 hours (Day 1), and then washing and replacing with fresh media for 24 hours (with at least some residual CHIR99021 remaining in the day 2 media). The resulting cell after two days of culture is a dorsal lateral mesoderm cell, i.e. an early mesoderm progenitor cell.
Regarding step (b), Loh’s Day 3 media comprises (VEGF, 100 ng/mL), Wnt pathway antagonist (XAV939, 1 µM), and RA agonist (TTNPB (0.5 nM)). ) (Loh [0225]). Regarding SHH agonist, Loh teaches the inclusion of SHH antagonist, which may be SANT-1. (Loh 0074-0075]).
However, the claimed addition of heparin does not come until much later, at Day 4 in the maintaince medium. Loh does not teach or suggest using heparin as part of their induction media, and once EGM2 is added, other claimed components of the media are omitted, most notably VEGF.
Thus, the claimed method is free of the art.
Conclusion
Claims 1-10, 13, 17, 21, 25, 29, 33-34 are rejected.
Claims 11-12, 14-16, 18-20, 22-24, 26-28, and 30-32 are objected to.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to THOMAS RUSSE AMICK whose telephone number is (571)272-5474. The examiner can normally be reached 7:30-5 M-F.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Tracy Vivlemore can be reached at (571) 272-2914. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/THOMAS R. AMICK/Examiner, Art Unit 1638
/Tracy Vivlemore/Supervisory Primary Examiner, Art Unit 1638
Prosecution Insights