77DETAILED ACTION
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 1-10, 12-21 and 23-26 are pending in the present application.
The current status of all of the claims in the application, including any previously canceled or withdrawn claims, must be given. A claim being canceled must be indicated as “canceled;” the text of the claim must not be presented. MPEP 714(II)(C). Claims 11, 22 and 27-31 have been lined through but the claims do not contain the status identifier (Canceled). Also, the text of canceled claims should not be presented. For example, the claims should state, “11. (Canceled)” without the text being presented.
Withdrawn Objections/Rejections
The objection to claims 11 and 22 is moot in view of the claims being cancelled. The objection to claim 25 is withdrawn in view of the amendment to insert “of”.
The rejection of claims 1, 6 and 13 under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, is withdrawn in view of the amendments to the claims.
The rejection of claim 29 under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, is moot in view of the claim being cancelled.
The rejections of claims 11, 22 and 27-31 under 35 U.S.C. 103 are moot in view of the claims being cancelled.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-10 and 12-13 are rejected under 35 U.S.C. 103 as being obvious over Niklason et al. (US 6,537,567).
Regarding instant claim 1, Niklason et al. teach improved methods for the production of tissue-engineered constructs, including muscular tissue constructs such as vascular constructs. The methods include the use of improved substrates for cell growth, improved cell culture media for cell growth, and the use of distensible bodies to impart pulsatile stretching force to the lumens of constructs during growth (col. 2, ln. 8-14). Preferably, the substrate material comprises a biodegradable or bioerodable material (col. 10, ln. 53-54; col. 27, ln. 16 to col. 30, ln. 8). Niklason et al. further teach that progenitor cells, such as myoblasts or stem cells, may be advantageously employed to produce their corresponding differentiated cell types in a tissue-engineered construct (col. 16, ln. 5-8).
Niklason et al. teach that in one aspect, the invention provides a method for producing a muscular tissue-engineered construct in which a porous substrate, comprising a biocompatible material, and having an inner surface and an outer surface, is first provided. The inner surface of the porous substrate defines a lumen. Within the lumen, a distensible body is provided which is capable of distending within the lumen so as to contact the inner surface of the substrate. The porous substrate, either before or after inserting the distensible body, is contacted with a suspension comprising muscle cells which adhere to and infiltrate the porous substrate, thereby forming a primary cell-seeded construct. The primary cell-seeded construct is then maintained for a first growth period in an environment suitable for growth of the muscle cells to form a primary tissue-engineered construct. During the first growth period, cyclical increases in pressure within the distensible body are provided, thereby causing the distensible body to distend within the lumen of the construct and to apply pulsatile stretch to the construct. This pulsatile stretch mimics natural pulsatile stretching forces encountered in the body, and aids the growing construct in developing strength and/or an appropriate phenotype (col. 2, ln. 21-42). See also col. 2, ln. 43 to col. 3, ln. 33.
Niklason et al. teach that employing the methods of the present invention, muscular tubular constructs have been produced which are capable of withstanding >2,000 mm Hg for sustained periods, but constructs capable of withstanding at least 130-150 mm Hg, preferably at least 150-175 mm Hg, and more preferably at least 175-200 mm Hg of internal pressure without rupturing will have utility in many applications. It is believed that the application of pulsatile stretching forces during the growth of the construct, in combination with the hydrophilic substrates, large void volumes, higher seeding densities and/or enhanced growth medium, permits the production of the high strength muscular, tubular tissue constructs of the present invention (col. 26, ln. 14-27). Niklason et al. teach that the measured rupture strengths of the constructs are in the range of 600–2,800 mm Hg, and vary with the conditions under which the construct is cultured (col. 32, ln. 23-43).
Further, in preferred embodiments, the muscular, tubular construct is capable of retaining sutures of 4-0 size that are sewn 1 mm from the cut edge of the construct with a force of greater than 50 grams, more preferably with a force of greater than 75 grams, and most preferably with a force greater than 100 grams (col. 26, ln. 43-48). Niklason et al. measured suture retention strengths for tubular constructs of 30-150 grams, depending on the culture conditions used to grow the construct (col. 32, ln. 45-62).
Therefore, it would have been prima facie obvious to prepare tissue-engineered vascular construct according to Niklason et al. comprising a biodegradable substrate (i.e., biodegradable scaffold) seeded with a plurality of vascular smooth muscle cells derived from progenitor cells, such as myoblasts or stem cells, and cultured under mechanical and biochemical stimulation, wherein the tissue-engineered vascular construct is capable of withstanding a pressure of up to 2,800 mm Hg without rupturing, and has a suture retention strength of greater than 100 grams, including about 150 grams.
The examiner respectfully points out the following from MPEP 2144.05: “[W]here 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.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); see also Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382 (“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.”); In re Hoeschele, 406 F.2d 1403, 160 USPQ 809 (CCPA 1969); Merck & Co. Inc. v. Biocraft Laboratories Inc., 874 F.2d 804, 10 USPQ2d 1843 (Fed. Cir.), cert. denied, 493 U.S. 975 (1989); In re Kulling, 897 F.2d 1147, 14 USPQ2d 1056 (Fed.Cir. 1990); and In re Geisler, 116 F.3d 1465, 43 USPQ2d 1362 (Fed. Cir. 1997).
Regarding instant claim 2, Niklason et al. teach that the polymeric substrate material comprises a polymer selected from polyesters of hydroxy carboxylic acids, polyanhydrides of dicarboxylic acids, or copolymers of hydroxy carboxylic acids and dicarboxylic acids. In particularly preferred embodiments, the polymeric material is selected from the polymers or copolymers of glycolic acid, lactic acid, and sebacic acid (col. 4, ln. 27-34; col. 5, ln. 6-15).
Regarding instant claims 3, 6, 8-10 and 12-13, “[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). See MPEP 2113. In the absence of evidence to the contrary, the vascular smooth muscle cells according to Niklason et al. are the same as the instantly claimed stem cell-derived VSMCs.
Regarding instant claims 4 and 7, Niklason et al. teach that preferably, the cells are obtained from a live donor and cultured as a primary cell line. In particular, if the tissue engineered construct is intended to be implanted into a living host, the cells are preferably harvested from the intended host or a histocompatible donor, thereby minimizing or eliminating the possibility of tissue rejection. For example, the required cells may be obtained from a biopsy of the patient. Thus, in the case of a patient requiring a coronary by-pass procedure, a biopsy of an artery (e.g. subclavian, axillary, brachial, radial, iliac, ulnar, femoral, anterior or posterior tibial) or peripheral vein (e.g., cephalic, basilic, saphenous, femoral) may be used to obtain arterial smooth muscle, endothelial and fibroblast cells (col. 16, ln. 35-47).
Regarding instant claim 5, Niklason et al. teach that in preferred embodiments, the above-described muscular tissue-engineered constructs are vascular tissue constructs. Therefore, in these preferred embodiments, the porous substrate is a substantially tubular substrate, the first type of mammalian cells are smooth muscle cells, and the second type of mammalian cells are endothelial cells which are contacted with the inner surface of the lumen (col. 3, ln. 48-54). Niklason et al. further teach that after the first growth period, the resulting primary tissue-engineered construct may be seeded with a second suspension of cells including at least one cell type (e.g., endothelial cells applied to the outer and inner surfaces of the primary tissue-engineered construct), and this secondary cell-seeded construct may be maintained for a second growth period to produce a secondary tissue-engineered construct (col. 9, ln. 61 to col. 10, ln. 11).
Regarding instant claims 8-10, Niklason et al. teach that a pulsatile flow system was developed for use in producing muscular, tubular tissue-engineered constructs. The cell-seeded constructs with the distensible tube are maintained in culture medium (or “enhanced” medium) in a bioreactor. Pressure is applied to the lumen of the tubular constructs in a continuous or pulsatile fashion by causing the distensible tube to distend under pressure from within. Initially, pressures are chosen such that the lumen of the construct is distended only 4-6% in diameter. Over a period of weeks, as the cells replicate and the constructs become stronger, the pressures and flows applied to the vessels may be gradually increased to the appropriate physiologic range. Rates of flow and pressure increase are adjusted to maximize the transmural and shear forces applied to the vessel without causing gross structural damage to the tissue (col. 31, ln. 45 to col. 32, ln. 4).
Regarding instant claim 9, Niklason et al. teach a pulsatile flow system, wherein the rates of flow and pressure increase are adjusted to maximize the transmural and shear forces applied to the vessel without causing gross structural damage to the tissue (col. 32, ln. 2-4). In preferred embodiments for producing a vascular tissue construct, a distensible tube is distended in a cyclic manner which mimics a pulse of the organism from which the seeded cells are derived. The pulse rate may be chosen to mimic the pulse rate of the adult organism, or the higher pulse rate of the fetal organism. Thus, for example, a pulse rate of approximately 60-90/min, typically about 75/min, would mimic a resting pulse of a human adult. A pulse rate of approximately 140-160/min would mimic a human fetal pulse rate. In addition, higher pulse rates may be generally preferred as they may provide a greater stimulus for development of a contractile phenotype and mechanical strength in muscular tissue. In addition, for a vascular construct, the degree of pulsatile stretch induced in a cell-seeded construct or a tissue-engineered construct, as measured by the induced change in diameter of the construct, is preferably chosen so as to mimic that seen in a natural artery, but without applying excessive stretch which would disrupt the growing tissue (col. 20, ln. 48-65). Niklason et al. teach pulsatile pressures up to 300/200 mm Hg at a pulse rate of 60-165 beats per minute (col. 32, ln. 23-33).
Thus, it would have been prima facie obvious for a person of ordinary skill in the art prior to the effective filing date of the instant claims to determine through routine experimentation the optimum pulse rate for distending the tube such that the rate provides stimulus for development of a contractile phenotype and mechanical strength in muscular tissue, but without applying excessive stretch which would disrupt the growing tissue.
Regarding instant claim 10, Niklason et al. teach that the cell-seeded constructs with the distensible tube are maintained in culture medium (or “enhanced” medium) in a bioreactor (col. 31, ln. 59-61).
In the absence of evidence to the contrary, the processes according to claims 8-10 are product-by-process limitations that do not result in a product that is distinct and/or non-obvious over Niklason et al.
Response to Arguments
Applicant's arguments filed 27 May 2025 have been fully considered but they are not persuasive. Applicant argues that Niklason does not disclose, teach, or suggest a TEVG having the combination of features as set forth in the claims including a biodegradable synthetic polymer scaffold and a plurality of stem cell-derived vascular smooth muscle cells (VSMCs), let alone “wherein the TEVG comprises a rupture pressure of 1419.0 ± 174.4 mmHg and a suture retention strength of 157.5 ± 16.5 g.” Applicant asserts that nowhere does Niklason disclose, teach, or suggest “incremental” pulsatile radial stretching, let alone coupled with the novel TEVG medium of the present invention, to achieve the markedly improved the biomechanical properties of the present invention.
The examiner respectfully argues that Niklason et al. teach that the porous substrate comprises a synthetic polymeric material having a hydrophilic surface. Preferably, the substrate material comprises a biodegradable or bioerodable material, such as one which is slowly hydrolyzed under physiological conditions. Niklason et al. teach that in preferred embodiments, the muscular tissue-engineered constructs are vascular tissue constructs. Therefore, in these preferred embodiments, the porous substrate is a substantially tubular substrate, the first type of mammalian cells are smooth muscle cells.
It would have been prima facie obvious for a person of ordinary skill in the art to prepare stem cell-derived vascular smooth muscle cells for seeding onto the synthetic biodegradable substrate.
Also, Niklason et al. teach that it is believed that the application of pulsatile stretching forces during the growth of the construct, in combination with the hydrophilic substrates, large void volumes, higher seeding densities and/or enhanced growth medium, permits the production of the high strength muscular, tubular tissue constructs of the present invention. Niklason et al. teach that the measured rupture strengths of the constructs are in the range of 600–2,800 mm Hg, and vary with the conditions under which the construct is cultured. In preferred embodiments, the muscular, tubular construct is capable of retaining sutures of 4-0 size that are sewn 1 mm from the cut edge of the construct with a force of greater than 50 grams, more preferably with a force of greater than 75 grams, and most preferably with a force greater than 100 grams.
Therefore, it would have been prima facie obvious for a person of ordinary skill in the art to optimize the conditions under which the construct is cultured, such as the pulsatile stretching forces and culture medium, in order to attain the desired rupture strength and suture retention strength.
Claim 14 is rejected under 35 U.S.C. 103 as being obvious over Niklason et al. (US 6,537,567) as applied to claims 1-10 and 12-13 above, further in view of Gui et al. (Tissue Engineering, 2011).
The teachings of Niklason et al. are discussed above.
Regarding instant claim 14, Niklason et al. teach that the polymeric substrate material comprises a polymer selected from polyesters of hydroxy carboxylic acids, polyanhydrides of dicarboxylic acids, or copolymers of hydroxy carboxylic acids and dicarboxylic acids. In particularly preferred embodiments, the polymeric material is selected from the polymers or copolymers of glycolic acid, lactic acid, and sebacic acid (col. 4, ln. 27-34; col. 5, ln. 6-15). Niklason et al. do not explicitly disclose fast-degrading polymers comprising 87% glycolide, 7% trimethylene carbonate (TMC), and 6% polyethylene glycol.
Gui et al. teach that functional connective tissues have been developed using tissue engineering approach by seeding cells on biodegradable scaffolds such as polyglycolic acid (PGA). Polymer III (comprising 87% glycolide, 7% TMC, and 6% polyethylene glycol) had a more extensive degradation as compared to PGA, supported cell proliferation, and improved collagen production and engineered vessel mechanics as compared with PGA. These results suggest that polymers that degrade more quickly during tissue culture actually result in improved engineered tissue mechanics, by virtue of decreased disruption of collagenous extracellular matrix (Abstract).
Therefore, it would have been prima facie obvious for a person of ordinary skill in the art prior to the effective filing date of the instant claim to prepare the tissue-engineered vascular construct of Niklason et al. wherein the biodegradable polymer comprises 87% glycolide, 7% TMC, and 6% polyethylene glycol, as reasonably suggested by Gui et al. Such would have been obvious because Gui et al. teach the benefits of Polymer III include a more extensive degradation as compared to PGA, supported cell proliferation, and improved collagen production and engineered vessel mechanics as compared with PGA.
Response to Arguments
Applicant's arguments are the same as above. Therefore, the examiner’s response above is repeated herein.
Claims 15, 18 and 23-24 are rejected under 35 U.S.C. 103 as being obvious over Niklason et al. (US 6,537,567) as applied to claims 1-10 and 12-13 above, further in view of Serbo et al. (Stem Cell Research & Therapy, 2013).
The teachings of Niklason et al. are discussed above.
Regarding instant claims 15 and 23-24, Niklason et al. teach vascular smooth muscle cells and progenitor cells, such as stem cells. Niklason et al. also teach that cells may be employed which are derived from an established cell culture line, wherein fetal cell lines or progenitor cell lines may be more desirable because such cells are generally more robust. These cells may also be grown in vitro in a standard cell growth medium until a suitable number or density of cells are obtained (col. 17, ln. 6-16).
Niklason et al. teach that during the first growth period, cyclical increases in pressure within the distensible body are provided, thereby causing the distensible body to distend within the lumen of the construct and to apply pulsatile stretch to the construct. This pulsatile stretch mimics natural pulsatile stretching forces encountered in the body, and aids the growing construct in devel oping strength and/or an appropriate phenotype (col. 2, ln. 36-42; col. 2, ln. 63 to col. 3, ln. 4; col. 3, ln. 26-33; col. 8, ln. 22-27).
Niklason do not explicitly disclose obtaining a plurality of hiPSCs, and inducing the plurality of hiPSCs to differentiate into a population of hi-PSC-VSMCs.
Serbo et al. teach that cell sources for tissue engineering can be divided into three categories: somatic cells, adult progenitor and stem cells, and pluripotent stem cells (PSCs). In these categories, there are numerous cell types that are used for vascular tissue engineering. Briefly, some common cell sources used for vascular constructs are ECs, SMCs, endothelial progenitor cells (EPCs), mesenchymal stem cells, and PSCs. For mature vascular cells, ECs and SMCs can be derived autologously, directly from a patient (pg. 3, col. 1-2). Adult stem cells, such as mesenchymal stem cells, are an autologous multipotent cell source that have high proliferative capacity, can differentiate into SMCs, and have been suggested to be able to differentiate into ECs (pg. 3, col. 2). PSCs, including induced PSCs and embryonic stem cells, can differentiate into all three germ layers. They have an unlimited ability to self-renew, making them easy to expand for therapeutic use. Induced PSCs are generated by the reprogramming of somatic or adult progenitor and stem cells. Induced PSCs hold the potential to be a useful autologous cell source. Human PSCs have been successfully differentiated into mature and functional vascular ECs and SMCs (pg. 4, col. 1).
Therefore, it would have been prima facie obvious for a person of ordinary skill in the art prior to the effective filing date to obtain a plurality of human induced pluripotent stem cells according to Serbo et al. and differentiating them into hiPSC-VSMCs and hiPSC-ECs in the teachings of Niklason et al.
Regarding instant claim 18, Niklason et al. teach that the polymeric substrate material comprises a polymer selected from polyesters of hydroxy carboxylic acids, polyanhydrides of dicarboxylic acids, or copolymers of hydroxy carboxylic acids and dicarboxylic acids. In particularly preferred embodiments, the polymeric material is selected from the polymers or copolymers of glycolic acid, lactic acid, and sebacic acid (col. 4, ln. 27-34; col. 5, ln. 6-15).
Response to Arguments
Applicant argues that nowhere does Niklason disclose, teach, or suggest “incremental” pulsatile radial stretching, let alone coupled with the novel TEVG medium of the present invention, to achieve the markedly improved the biomechanical properties of the present invention.
The examiner respectfully argues that Niklason et al. teach that it is believed that the application of pulsatile stretching forces during the growth of the construct, in combination with the hydrophilic substrates, large void volumes, higher seeding densities and/or enhanced growth medium, permits the production of the high strength muscular, tubular tissue constructs of the present invention. Niklason et al. teach that the measured rupture strengths of the constructs are in the range of 600–2,800 mm Hg, and vary with the conditions under which the construct is cultured. In preferred embodiments, the muscular, tubular construct is capable of retaining sutures of 4-0 size that are sewn 1 mm from the cut edge of the construct with a force of greater than 50 grams, more preferably with a force of greater than 75 grams, and most preferably with a force greater than 100 grams.
A person of ordinary skill in the art would have been motivated to determine through routine experimentation the optimum culture conditions, such as the pulsatile pressure, to achieve the desired rupture strength and suture retention strength.
Regarding the TEVG medium, see the rejection of claim 21 below.
Claims 16-17 and 26 are rejected under 35 U.S.C. 103 as being obvious over Niklason et al. (US 6,537,567) in view of Serbo et al. (Stem Cell Research & Therapy, 2013) as applied to claims 1-10, 12-13, 15, 18 and 23-24 above, further in view of Gui et al. (Tissue Engineering, 2011).
The teachings of Niklason et al. and Serbo et al. are discussed above.
Regarding instant claims 16 and 17, Gui et al. teach that generally, the components used in vascular engineering are a biodegradable scaffold, cells from either an autologous or an allogeneic source, and growth factors necessary to create a stimulating microenvironment. The use of autologous cells can be ideal for vascular engineering because there is no immunogenic response or cell rejection upon implantation (pg. 3, col. 1-2). Allogeneic cells either from healthy donors or from animals can make cells available via an off-the-shelf route, as cells can be expanded beforehand in large quantities (pg. 4, col. 1).
Therefore, it would have been prima facie obvious for a person of ordinary skill in the art prior to the effective filing date to prepare tissue-engineered vascular constructs according to Niklason et al. wherein the pluripotent stem cells according to Serbo et al. are allogeneic or autogeneic, as reasonably taught by Gui et al. Such would have been obvious because Gui et al. teach that the use of autologous cells can be ideal for vascular engineering because there is no immunogenic response or cell rejection upon implantation. Allogeneic cells either from healthy donors or from animals can make cells available via an off-the-shelf route, as cells can be expanded beforehand in large quantities (pg. 4, col. 1).
Regarding instant claim 26, Niklason et al. teach that the polymeric substrate material comprises a polymer selected from polyesters of hydroxy carboxylic acids, polyanhydrides of dicarboxylic acids, or copolymers of hydroxy carboxylic acids and dicarboxylic acids. In particularly preferred embodiments, the polymeric material is selected from the polymers or copolymers of glycolic acid, lactic acid, and sebacic acid (col. 4, ln. 27-34; col. 5, ln. 6-15). Niklason et al. do not explicitly disclose fast-degrading polymers comprising 87% glycolide, 7% trimethylene carbonate (TMC), and 6% polyethylene glycol.
Gui et al. teach that functional connective tissues have been developed using tissue engineering approach by seeding cells on biodegradable scaffolds such as polyglycolic acid (PGA). Polymer III (comprising 87% glycolide, 7% TMC, and 6% polyethylene glycol) had a more extensive degradation as compared to PGA, supported cell proliferation, and improved collagen production and engineered vessel mechanics as compared with PGA. These results suggest that polymers that degrade more quickly during tissue culture actually result in improved engineered tissue mechanics, by virtue of decreased disruption of collagenous extracellular matrix (Abstract).
Therefore, it would have been prima facie obvious for a person of ordinary skill in the art prior to the effective filing date of the instant claim to prepare the tissue-engineered vascular construct of Niklason et al. wherein the biodegradable polymer comprises 87% glycolide, 7% TMC, and 6% polyethylene glycol, as reasonably suggested by Gui et al. Such would have been obvious because Gui et al. teach the benefits of Polymer III include a more extensive degradation as compared to PGA, supported cell proliferation, and improved collagen production and engineered vessel mechanics as compared with PGA.
Response to Arguments
Applicant's arguments are the same as above. Therefore, the examiner’s response above is repeated herein.
Claims 19-20 are rejected under 35 U.S.C. 103 as being obvious over Niklason et al. (US 6,537,567) in view of Serbo et al. (Stem Cell Research & Therapy, 2013) as applied to claims 1-10, 12-13, 15, 18 and 23-24 above, further in view of Poh et al. (Lancet, 2005).
Regarding instant claims 19-20, Niklason et al. teach a pulsatile flow system, wherein the rates of flow and pressure increase are adjusted to maximize the transmural and shear forces applied to the vessel without causing gross structural damage to the tissue (col. 32, ln. 2-4). In preferred embodiments for producing a vascular tissue construct, a distensible tube is distended in a cyclic manner which mimics a pulse of the organism from which the seeded cells are derived. The pulse rate may be chosen to mimic the pulse rate of the adult organism, or the higher pulse rate of the fetal organism. Thus, for example, a pulse rate of approximately 60-90/min, typically about 75/min, would mimic a resting pulse of a human adult. A pulse rate of approximately 140-160/min would mimic a human fetal pulse rate. In addition, higher pulse rates may be generally preferred as they may provide a greater stimulus for development of a contractile phenotype and mechanical strength in muscular tissue. In addition, for a vascular construct, the degree of pulsatile stretch induced in a cell-seeded construct or a tissue-engineered construct, as measured by the induced change in diameter of the construct, is preferably chosen so as to mimic that seen in a natural artery, but without applying excessive stretch which would disrupt the growing tissue (col. 20, ln. 48-65). Niklason et al. teach pulsatile pressures up to 300/200 mm Hg at a pulse rate of 60-165 beats per minute (col. 32, ln. 23-33).
Poh et al. teach that to culture blood vessels, they prepared bioreactors and pulsatile flow systems. Biodegradable polyglycolic acid scaffolds (7 cm length by 3 mm internal diameter) were threaded over compliant silicone tubing inside bioreactors and then seeded with control or hTERT smooth-muscle cells (passage 3–6). They filled every bioreactor with smooth-muscle cell medium and placed it in an incubator with 10% carbon dioxide at 37ºC. The pulsatile flow system was initiated 5 days after seeding (165 beats per minute, 1% radial distention) (pg. 2123).
Thus, it would have been prima facie obvious for a person of ordinary skill in the art prior to the effective filing date of the instant claims to determine through routine experimentation the optimum pulse rate for distending the tube such that the rate provides stimulus for development of a contractile phenotype and mechanical strength in muscular tissue, but without applying excessive stretch which would disrupt the growing tissue. Also, it would have been prima facie obvious to initiate the pulsatile flow system 5 days after seeding, as reasonably suggested by Poh et al.
Response to Arguments
Applicant argues that nowhere does Niklason disclose, teach, or suggest “incremental” pulsatile radial stretching, let alone coupled with the novel TEVG medium of the present invention, to achieve the markedly improved the biomechanical properties of the present invention.
The examiner respectfully argues that Niklason et al. teach that it is believed that the application of pulsatile stretching forces during the growth of the construct, in combination with the hydrophilic substrates, large void volumes, higher seeding densities and/or enhanced growth medium, permits the production of the high strength muscular, tubular tissue constructs of the present invention. Niklason et al. teach that the measured rupture strengths of the constructs are in the range of 600–2,800 mm Hg, and vary with the conditions under which the construct is cultured. In preferred embodiments, the muscular, tubular construct is capable of retaining sutures of 4-0 size that are sewn 1 mm from the cut edge of the construct with a force of greater than 50 grams, more preferably with a force of greater than 75 grams, and most preferably with a force greater than 100 grams. Also, Poh et al. teach that the pulsatile flow system was initiated 5 days after seeding.
A person of ordinary skill in the art would have been motivated to determine through routine experimentation the optimum culture conditions, such as delaying the pulsatile flow system and the pulsatile pressure.
Claim 21 is rejected under 35 U.S.C. 103 as being obvious over Niklason et al. (US 6,537,567) in view of Serbo et al. (Stem Cell Research & Therapy, 2013) and Poh et al. (Lancet, 2005) as applied to claims 1-10, 12-13, 15, 18-20 and 23-24 above, further in view of Dahl et al. (Science Translational Medicine, 2011).
Regarding instant claim 21, Niklason et al. teach that the cell-seeded constructs with the distensible tube are maintained in culture medium (or “enhanced” medium) in a bioreactor (col. 31, ln. 59-61).
Niklason et al. teach with respect to any particular type of cells, an environment suitable for growth may require the presence of particular nutrients required by that cell type, or the presence of particular growth factors necessary for the survival and reproduction of those cells (col. 8, ln. 28-38). Suitable growth conditions and media for cells in culture are well known in the art. Cell culture media typically comprise essential nutrients, but also optionally include additional elements (e.g., growth factors, salts and minerals) which may be customized for the growth and differentiation of particular cell types (col. 19, ln. 3-8). Growth factors, such as acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), platelet derived growth factor (PDGF), transforming growth factor β (TGF-β), or vascular endothelial cell derived growth factor (VEGF), may be employed at suitable concentrations (i.e., 1-10 ng/ml) to enhance cell growth or differentiation or the secretion of extracellular matrix proteins (col. 19, ln. 45-52).
Dahl et al. teach that the medium for growth of human TEVGs was high glucose Dulbecco’s modified Eagle’s medium (DMEM) with 20% serum, insulin (0.13 U/ml), basic fibroblast growth factor (bFGF) (10 ng/ml), epidermal growth factor (EGF) (0.5 ng/ml), penicillin G (10,000 U/ml), copper sulfate (3 ng/ml), L-proline (50 ng/ml), L-alanine (40 ng/ml), and glycine (50 ng/ml), and was changed thrice weekly. The medium for growth of canine TEVGs was low-glucose DMEM with 20% serum, platelet-derived growth factor–BB (PDGF-BB) (10 ng/ml), bFGF (10 ng/ml), penicillin G (500 U/ml), copper sulfate (3 ng/ml), L-proline (50 ng/ml), L-alanine (20 ng/ml), and glycine (50 ng/ml) and was changed once per week. L-ascorbic acid was added thrice weekly to both human and canine TEVG cultures (pg. 8, col. 2).
Therefore, it would have been prima facie obvious for a person of ordinary skill in the art prior to the effective filing date of the instant claims to prepare a culture medium comprising according to Dahl et al. wherein the components are optimized for the compositions according to Niklason et al.
Response to Arguments
Applicant's arguments are the same as above. Therefore, the examiner’s response above is repeated herein.
Claim 25 is rejected under 35 U.S.C. 103 as being obvious over Niklason et al. (US 6,537,567) in view of Serbo et al. (Stem Cell Research & Therapy, 2013) as applied to claims 1-10, 12-13, 15, 18 and 23-24 above, further in view of Xu et al. (Cell Stem Cell, 2011).
The teachings of Niklason et al. and Serbo et al. are discussed above.
Regarding instant claim 25, Niklason et al. do not explicitly disclose modulating the human leukocyte antigen (HLA) expression of the plurality of hiPSCs.
Xu et al. teach that they deleted HLA-A and HLA-B biallelically and retained a single haplotype of HLA-C to generate HLA-C-retained iPSCs (also preserving non-canonical HLA-E, -F, and -G), which greatly expand donor compatibility (pg. 567, col. 1).
Therefore, it would have been prima facie obvious for a person of ordinary skill in the art prior to the effective filing date of the instant claims to modulate the human leukocyte antigen (HLA) expression of the plurality of hiPSCs of Niklason et al. and Serbo et al. for the purpose of developing a broad application of methods of generating a TEVG using various hiPSCs, including immunocompatible hiPSCs.
Response to Arguments
Applicant's arguments are the same as above. Therefore, the examiner’s response above is repeated herein.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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.
Contact Information
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/N.W.S/Examiner, Art Unit 1616
/Mina Haghighatian/Primary Examiner, Art Unit 1616