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 .
Applicant’s December 31, 2025 claim amendments and reply are persuasive to overcome the rejections under 35 USC §§ 103 and 112(b). However, an updated search in the prior art identified pertinent prior art. Prosecution is reopened.
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, 2, 4, 6, 7, 9, 10, 13-23, and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Kirn et al. (WO 2013/022764, cited previously), Guo et al. (Molecular Therapy Methods & Clinical Development. 2017 Dec 15; 7: 112-122), and Thompson et al. (USPgPub 2012/0219588, cited previously).
Claims 1 and 24-32 and 34 of Kirn et al. are drawn a method of producing vaccinia by infecting HeLa cells (as required by instant claims 19 and 20) adhered to a surface at a multiplicity of infection (m.o.i.) ranging between 0.005 and 1.0 plaque forming units. Paragraph [0009] states that the preferred m.o.i. is between 0.01 and 0.05. The m.o.i. ranges of Kirn et al. overlap and lie inside the ranges recited in instant claim 1. The vaccinia-infected HeLa cells of Kirn et al. are cultured in a bioreactor that possesses a surface area of about, at least, or at most 1,700 to 50,000 cm2, see claims 1(b), 35, 36, and paragraph [0011] of Kirn et al., as recited in instant claim 1(i). Claims 1(c), 19, and 20 and paragraphs [0068 and 0087] of Kirn et al. teach harvesting vaccinia from the culture with one or more purification steps, such as hypo-osmotic lysis buffer and nuclease and protease treatments to remove HeLa cell nucleic acids and cell proteins, as required in claim 13.
However, Kirn et al. do not teach lysing the infected cells with a Tris buffer comprising a pH greater than 8.0, as recited in claims 1(iii) and 18, or the genetically engineered Serratia nuclease (Benzonase®), recited in instant claim 17, or the concentration of the enzyme ranging between 50 IU/mL to about 200 IU/mL, recited in claim 14, or incubating the cells for about 2 hours with the enzyme, as required in claim 15, at a temperature ranging between about 22 °C to about 28 °C, recited in claim 16.
Guo et al. teach adding Tris-HCl, pH 9.0, to vaccinia-infected cells, followed by homogenization, centrifugation, and sonication. To the lysate, 50 U/mL of Benzonase® nuclease in Tris-HCl, pH 9.0, is added and incubated for 2 hours at room temperature, i.e., between about 22 °C to about 28 °C, see the paragraph bridging the columns on page 120.
One of ordinary skill in the art prior to the effective filing date would have been motivated to have harvested the virus-infected host cells of Kirn et al. by incubating the cells with Tris-HCl, pH 9.0, followed by adding 50 U/mL of Benzonase® nuclease in Tris-HCl, pH 9.0, incubating for 2 hours at room temperature, as taught by Guo et al., to produce a clinical-grade oncolytic vaccinia virus composition, see the title and abstract of Guo et al., in large quantities, 1.1x109 PFU/mL, see Table 1 of Guo et al. One of ordinary skill in the art prior to the effective filing date would have had a reasonable expectation of success to have harvested the virus-infected host cells of Kirn et al. by incubating the cells with Tris-HCl, pH 9.0, followed by adding 50 U/mL of Benzonase® nuclease in Tris-HCl, pH 9.0, incubating for 2 hours at room temperature, as taught by Guo et al. because Kirn et al. teach increasing the pH alkalinity value between 7.5 to 10.5 after virus elution in paragraph [0070].
Claims 21-23 of Kirn et al. are drawn to purifying the lysate to produce a purified virus, as required in instant claim 1(iv). Paragraph [0061] of Kirn et al. teaches that at least 50% to 90% of the vaccinia is retained during purification, recited as the percentage of purified vaccinia in instant claim 1. Claim 4 and paragraph [0044] of Kirn et al. teach that the bioreactor comprises microcarriers, as required by instant claim 2. Paragraph [0085] and claims 7, 8, and 11 of Kirn et al. teach seeding virus-infected cells into vessels at least at 1 x 104 cells/cm2 and culturing the cells for 40-80 hours, as required by instant claims 6 and 7, and claims 9 and 10 of Kirn et al. require that the culture of the virus-infected cells is maintained between 36° C to 37° C at a pH between 7.2 and 7.3, as required by instant claims 9 and 10. Claim 21 and paragraphs [0068, 0069, and 0087] of Kirn et al. teach tangential filtration of the lysate to produce a filtered lysate, as required in instant claims 21 and 22.
In paragraph [0054], Kirn et al. teach nuclease and protease treatments are employed to reduce or eliminate contaminating HeLa cell DNA and protein. Paragraph [0057] of Kirn et al. defines contaminants as host cell DNA and protein and paragraphs [0066, 0068, and 0087] discuss techniques for removing host cell protein and DNA. The process of Guo et al., adding Tris-HCl, pH 9.0, to vaccinia-infected cells and incubating 50 U/mL of Benzonase® nuclease in Tris-HCl, pH 9.0, for 2 hours at room temperature generates high titers of clinical-grade vaccinia, see the paragraph bridging the columns on page 120 and Table 1. However, neither Kirn et al. nor Guo et al. teach that the purified recombinant oncolytic virus comprises less than 50 ug host cell protein and less than 250 ng host cell DNA per unit dose of purified recombinant virus, as required by instant claim 1.
Paragraphs [0015, 0124-0126, and 0130], Thompson et al. teach a purified virus composition comprising less than 200 ng of host cell DNA (HCD) and less than 50 ug host cell protein (HCP) per unit dose, meeting the HCD and HCP quantities instantly recited.
One of ordinary skill in the art prior to the instant effective filing date would have been motivated to have reduced the quantities of HCP and HCD, as taught by Thompson et al., in the virus product produced by the method of Kirn et al. and Guo et a., to reach clinically acceptable limits of HCD and HCP, see paragraphs [0124 and 0144] of Thompson et al. One of ordinary skill in the art prior to the instant effective filing date would have had a reasonable expectation of success for reducing the quantities of HCP and HCD, taught by Thompson et al., in the virus product produced by the method of Kirn et al. and Guo et al. because Thompson et al. and Kirn et al. apply Benzonase® nuclease and a final filtration step to remove residual HCD and HCP, see paragraphs [0068, 0069, and 0087] of Kirn et al. and paragraphs [0133, 0134-0137, 0141, 0144, and 0458] of Thompson et al.
The vaccinia-infected cells of Kirn et al. are cultured in fixed bed microcarriers within a bioreactor in claim 4 and paragraph [0044]. However, neither Kirn et al. nor Guo et al. teach the volume of the fixed bed to range between 0.01 L to 100 L, as recited in instant claims 4 and 25.
Thompson et al. teach volume of the culture flask paragraph [0101] ranging between 1-100 L.
It would have been prima facie obvious to one of ordinary skill in the art prior to the instant effective filing date to have used the cell culture flask volume of Thompson et al. as the flask volume to culture infected cells in the method of Kirn et al. and Guo e al. to optimize the area for cell growth. One of ordinary skill in the art prior to the instant effective filing date would have had a reasonable expectation of success for using the cell culture flask volume of Thompson et al. as the flask volume to culture infected cells in the method of Kirn et al. and Guo et al. because both Thompson et al. and Kirn et al teach propagating viruses in cells grown on microcarriers within bioreactors, see paragraphs [0057, 0077, and 0329] of Thompson et al. and claim 4 and paragraph [0044] of Kirn et al.
Regarding instant claim 23, specifying that a filtration of 1.2 µm following one or more tangential flow filtration steps, paragraph [0087] and claims 21-23 of Kirn et al. specify membrane adsorption chromatography (filtration) follows tangential flow filtration and paragraphs [0055 and 0062] of Kirn et al. specify that the membrane pore size is microporous, measuring between 1.0-2.0 µm. However, Kirn et al. do not further specify a 1.2 µm pore-size filtration.
Thompson et al. teach clarifying the viral harvest by tangential flow filtration with at least one membrane having a pore size of 1.2 µm in paragraphs [0158 and 0167].
It would have been prima facie obvious to one of ordinary skill in the art prior to the instant effective filing date to have incorporated the 1.2 µm pore size membrane of Thompson et al. as the membrane pore size of Kirn et al. to allow virus to pass through, but retain cell debris, see paragraph [0158] of Thompson et al. One of ordinary skill in the art prior to the instant effective filing date to have incorporated the 1.2 µm pore size membrane of Thompson et al. as the membrane pore size of Kirn et al. because the 1.2 µm pore size membrane of Thompson et al. is within the preferred 1.0-2.0 µm pore size range of Kirn et al. in paragraphs [0055 and 0062].
Claims 5 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Kirn et al., Guo et al., and Thompson et al. as applied to claims 1, 2, 4, 6, 7, 9, 10, 13-23, and 25 above, and further in view of Cappello et al. (US 10,851,350, cited previously).
See the teachings of Kirn et al., Guo et al., and Thompson et al. above. Thompson et al. and Kirn et al teach propagating viruses in cells grown on microcarriers within bioreactors, see paragraphs [0057, 0077, and 0329] of Thompson et al. and claim 4 and paragraph [0044] of Kirn et al. However, neither reference teaches a compaction density ranging between 80-144 g/L, as required by instant claim 5.
Capello et al. teach exemplary packing densities range between 80-144 g/L, as instantly required, see column 9, line 43 to column 10, line 15.
It would have been prima facie obvious to one of ordinary skill in the art prior to the instant effective filing date to have used the packing densities of Capello et al. as the bioreactor parameters of Kirn et al., and Thompson et al., to maintain cell entrapment in the matrix and increase scaled-up yields of virus, see column 9, line 43 to column 10, line 15 of Capello et al. One of ordinary skill in the art prior to the effective filing date would have had a reasonable expectation of success for using the packing densities and fixed bed volume of Capello et al. as the bioreactor parameters of Kirn et al. and Thompson et al., because Kirn et al., Thompson et al., and Capello et al. teach a method of producing vaccinia by infecting HeLa cells, cultured in a bioreactor comprising microcarriers, see claims 1, 24-32, 34-36, and paragraphs [0011 and 0044] of Kirn et al.; paragraphs [0035 and 0042] of Thompson et al.; and claims 1, 2, 8, 13-15, column 2, lines 29-35, and column 9, line 39 to column 10, line 15 of Capello et al.
None of Kirn et al., Guo et al. or Thompson et al. mention dissolved oxygen or percentage levels, as required in instant claim 8. While Thompson et al. mention dissolved oxygen content ranging between 5% and 100% in paragraphs [0091, 0103], Thompson et al. do not disclose a motivation for amount of oxygen dissolved, as required in instant claim 8.
In column 9, lines 2-5, Capello et al. teach maintaining dissolved oxygen levels in the bioreactor and column 11, lines Capello et al. teach dissolved oxygen levels are maintained between 50%-75%, encompassed by instant claim 8. While Capello et al. do not use the term “tension”, the maintenance of dissolved oxygen levels within a particular percentage range, requires tension.
One of ordinary skill in the art prior to the instant effective filing date would have been motivated to have maintained dissolved oxygen levels in the bioreactor between 50%-75% in the bioreactor comprising virus-infected cells of Kirn et al., Guo et al., and Thompson et al. because Capello et al. teach the range of dissolved oxygen in a bioreactor is suitable for optimal growth of mammalian cells. One of ordinary skill in the art prior to the instant effective filing date would have had a reasonable expectation of success to have maintained dissolved oxygen levels in the bioreactor of Kirn et al., Guo et al., and Thompson et al. between 50%-75% because Capello et al., Kirn et al., Guo et al., and Thompson et al. propagate virus-infected mammalian cells in a bioreactor.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Hughes et al. (Journal of Virological Methods. 2017 May 1; 243: 68-73) teach purification of orthopoxvirus from infected cells by resuspension in Tris-HCL (pH 9.0), followed by addition and incubation with Benzonase® combined with Tris-HCL (pH 9.0) in section 2.2.1.
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/Shanon A. Foley/ Primary Examiner, Art Unit 1671